full unit test coverage and docstrings for session module

minor rephrasing
simplified method
2022-02-14 17:59:11 +01:00 · 2022-02-13 21:12:35 +01:00 · 2022-02-13 20:58:36 +01:00 · 2022-02-13 19:55:27 +01:00 · 2022-02-13 19:45:53 +01:00 · 2022-02-13 19:39:21 +01:00
22 changed files with 2699 additions and 207 deletions
--- a/.coveragerc
+++ b/.coveragerc
@@ -8,5 +8,8 @@ omit =
 fail_under = 100
 show_missing = True
 skip_covered = False
 exclude_lines =
    if TYPE_CHECKING:
    if __name__ == ['"]__main__['"]:
 omit =
    tests/*
--- a/674
+++ b/674
@@ -0,0 +1,674 @@
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    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.
 The hypothetical commands `show w' and `show c' should show the appropriate
 parts of the General Public License.  Of course, your program's commands
 might be different; for a GUI interface, you would use an "about box".
  You should also get your employer (if you work as a programmer) or school,
 if any, to sign a "copyright disclaimer" for the program, if necessary.
 For more information on this, and how to apply and follow the GNU GPL, see
 <https://www.gnu.org/licenses/>.
  The GNU General Public License does not permit incorporating your program
 into proprietary programs.  If your program is a subroutine library, you
 may consider it more useful to permit linking proprietary applications with
 the library.  If this is what you want to do, use the GNU Lesser General
 Public License instead of this License.  But first, please read
 <https://www.gnu.org/licenses/why-not-lgpl.html>.
--- a/COPYING.LESSER
+++ b/COPYING.LESSER
@@ -0,0 +1,165 @@
                   GNU LESSER GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007
 Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.
  This version of the GNU Lesser General Public License incorporates
 the terms and conditions of version 3 of the GNU General Public
 License, supplemented by the additional permissions listed below.
  0. Additional Definitions.
  As used herein, "this License" refers to version 3 of the GNU Lesser
 General Public License, and the "GNU GPL" refers to version 3 of the GNU
 General Public License.
  "The Library" refers to a covered work governed by this License,
 other than an Application or a Combined Work as defined below.
  An "Application" is any work that makes use of an interface provided
 by the Library, but which is not otherwise based on the Library.
 Defining a subclass of a class defined by the Library is deemed a mode
 of using an interface provided by the Library.
  A "Combined Work" is a work produced by combining or linking an
 Application with the Library.  The particular version of the Library
 with which the Combined Work was made is also called the "Linked
 Version".
  The "Minimal Corresponding Source" for a Combined Work means the
 Corresponding Source for the Combined Work, excluding any source code
 for portions of the Combined Work that, considered in isolation, are
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  The "Corresponding Application Code" for a Combined Work means the
 object code and/or source code for the Application, including any data
 and utility programs needed for reproducing the Combined Work from the
 Application, but excluding the System Libraries of the Combined Work.
  1. Exception to Section 3 of the GNU GPL.
  You may convey a covered work under sections 3 and 4 of this License
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  2. Conveying Modified Versions.
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   on the Library, uncombined with any other library facilities,
   conveyed under the terms of this License.
   b) Give prominent notice with the combined library that part of it
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  6. Revised Versions of the GNU Lesser General Public License.
  The Free Software Foundation may publish revised and/or new versions
 of the GNU Lesser General Public License from time to time. Such new
 versions will be similar in spirit to the present version, but may
 differ in detail to address new problems or concerns.
  Each version is given a distinguishing version number. If the
 Library as you received it specifies that a certain numbered version
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 conditions either of that published version or of any later version
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 Library.
--- a/README.md
+++ b/README.md
@@ -1,19 +1,61 @@
 # asyncio-taskpool
-Dynamically manage pools of asyncio tasks
+**Dynamically manage pools of asyncio tasks**
 ## Summary
 A task pool is an object with a simple interface for aggregating and dynamically managing asynchronous tasks.
 With an interface that is intentionally similar to the [`multiprocessing.Pool`](https://docs.python.org/3/library/multiprocessing.html#module-multiprocessing.pool) class from the standard library, the `TaskPool` provides you such methods as `apply`, `map`, and `starmap` to execute coroutines concurrently as [`asyncio.Task`](https://docs.python.org/3/library/asyncio-task.html#task-object) objects. There is no limitation imposed on what kind of tasks can be run or in what combination, when new ones can be added, or when they can be cancelled.
 For a more streamlined use-case, the `SimpleTaskPool` provides an even more intuitive and simple interface at the cost of flexibility.
 If you need control over a task pool at runtime, you can launch an asynchronous `ControlServer` to be able to interface with the pool from an outside process or via a network, and stop/start tasks within the pool as you wish.
 ## Usage
-See [USAGE.md](usage/USAGE.md)
+Generally speaking, a task is added to a pool by providing it with a coroutine function reference as well as the arguments for that function. Here is what that could look like in the most simplified form:
 ```python
 from asyncio_taskpool import SimpleTaskPool
 ...
 async def work(foo, bar): ...
 ...
 async def main():
    pool = SimpleTaskPool(work, args=('xyz', 420))
    await pool.start(5)
    ...
    pool.stop(3)
    ...
    pool.lock()
    await pool.gather()
    ...
 ```
 Since one of the main goals of `asyncio-taskpool` is to be able to start/stop tasks dynamically or "on-the-fly", _most_ of the associated methods are non-blocking _most_ of the time. A notable exception is the `gather` method for awaiting the return of all tasks in the pool. (It is essentially a glorified wrapper around the [`asyncio.gather`](https://docs.python.org/3/library/asyncio-task.html#asyncio.gather) function.)
 For working and fully documented demo scripts see [USAGE.md](usage/USAGE.md).
 ## Installation
-`pip install asyncio-taskpool`
+```shell
 pip install asyncio-taskpool
 ```
 ## Dependencies
 Python Version 3.8+, tested on Linux
-## Building from source
+## Testing
-Run `python -m build`
+Install `asyncio-taskpool[dev]` dependencies or just manually install `coverage` with `pip`. 
 Execute the [`./coverage.sh`](coverage.sh) shell script to run all unit tests and receive the coverage report.
 ## License
 `asyncio-taskpool` is licensed under the **GNU LGPL version 3.0** specifically.
 The full license texts for the [GNU GPLv3.0](COPYING) and the [GNU LGPLv3.0](COPYING.LESSER) are included in this repository. If not, see https://www.gnu.org/licenses/.
 ## Copyright
 © 2022 Daniil Fajnberg
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,17 +1,25 @@
 [metadata]
 name = asyncio-taskpool
-version = 0.1.5
+version = 0.3.3
 author = Daniil Fajnberg
 author_email = mail@daniil.fajnberg.de
 description = Dynamically manage pools of asyncio tasks
 long_description = file: README.md
 long_description_content_type = text/markdown
 keywords = asyncio, concurrency, tasks, coroutines, asynchronous, server
 url = https://git.fajnberg.de/daniil/asyncio-taskpool
 project_urls =
    Bug Tracker = https://git.fajnberg.de/daniil/asyncio-taskpool/issues
 classifiers =
    Development Status :: 3 - Alpha
    Programming Language :: Python :: 3
    Operating System :: OS Independent
    License :: OSI Approved :: GNU Lesser General Public License v3 (LGPLv3)
    Intended Audience :: Developers
    Intended Audience :: System Administrators
    Framework :: AsyncIO
    Topic :: Software Development :: Libraries
    Topic :: Software Development :: Libraries :: Python Modules
 [options]
 package_dir =
--- a/src/asyncio_taskpool/init.py
+++ b/src/asyncio_taskpool/init.py
@@ -1,2 +1,23 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Brings the main classes up to package level for import convenience.
 """
 from .pool import TaskPool, SimpleTaskPool
 from .server import UnixControlServer
--- a/src/asyncio_taskpool/main.py
+++ b/src/asyncio_taskpool/main.py
@@ -1,3 +1,24 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 CLI client entry point.
 """
 import sys
 from argparse import ArgumentParser
 from asyncio import run
--- a/src/asyncio_taskpool/client.py
+++ b/src/asyncio_taskpool/client.py
@@ -1,10 +1,33 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Classes of control clients for a simply interface to a task pool control server.
 """
 import json
 import shutil
 import sys
 from abc import ABC, abstractmethod
 from asyncio.streams import StreamReader, StreamWriter, open_unix_connection
 from pathlib import Path
-from asyncio_taskpool import constants
+from .constants import CLIENT_EXIT, CLIENT_INFO, SESSION_MSG_BYTES
-from asyncio_taskpool.types import ClientConnT
+from .types import ClientConnT
 class ControlClient(ABC):
@@ -13,19 +36,29 @@ class ControlClient(ABC):
    async def open_connection(self, **kwargs) -> ClientConnT:
        raise NotImplementedError
    @staticmethod
    def client_info() -> dict:
        return {CLIENT_INFO.TERMINAL_WIDTH: shutil.get_terminal_size().columns}
    def __init__(self, **conn_kwargs) -> None:
        self._conn_kwargs = conn_kwargs
        self._connected: bool = False
    async def _server_handshake(self, reader: StreamReader, writer: StreamWriter) -> None:
        self._connected = True
        writer.write(json.dumps(self.client_info()).encode())
        await writer.drain()
        print("Connected to", (await reader.read(SESSION_MSG_BYTES)).decode())
    async def _interact(self, reader: StreamReader, writer: StreamWriter) -> None:
        try:
            msg = input("> ").strip().lower()
        except EOFError:
-            msg = constants.CLIENT_EXIT
+            msg = CLIENT_EXIT
        except KeyboardInterrupt:
            print()
            return
-        if msg == constants.CLIENT_EXIT:
+        if msg == CLIENT_EXIT:
            writer.close()
            self._connected = False
            return
@@ -36,15 +69,14 @@ class ControlClient(ABC):
            self._connected = False
            print(e, file=sys.stderr)
            return
-        print((await reader.read(constants.MSG_BYTES)).decode())
+        print((await reader.read(SESSION_MSG_BYTES)).decode())
    async def start(self):
        reader, writer = await self.open_connection(**self._conn_kwargs)
        if reader is None:
            print("Failed to connect.", file=sys.stderr)
            return
-        self._connected = True
+        await self._server_handshake(reader, writer)
        print("Connected to", (await reader.read(constants.MSG_BYTES)).decode())
        while self._connected:
            await self._interact(reader, writer)
        print("Disconnected from control server.")
--- a/src/asyncio_taskpool/constants.py
+++ b/src/asyncio_taskpool/constants.py
@@ -1,8 +1,44 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Constants used by more than one module in the package.
 """
 PACKAGE_NAME = 'asyncio_taskpool'
-MSG_BYTES = 1024
+
 CMD_START = 'start'
 CMD_STOP = 'stop'
 CMD_STOP_ALL = 'stop_all'
 CMD_SIZE = 'size'
 CMD_FUNC = 'func'
 CLIENT_EXIT = 'exit'
 SESSION_MSG_BYTES = 1024 * 100
 SESSION_PARSER_WRITER = 'session_writer'
 class CLIENT_INFO:
    __slots__ = ()
    TERMINAL_WIDTH = 'terminal_width'
 class CMD:
    __slots__ = ()
    CMD = 'command'
    NAME = 'name'
    POOL_SIZE = 'pool-size'
    NUM_RUNNING = 'num-running'
    START = 'start'
    STOP = 'stop'
    STOP_ALL = 'stop-all'
    FUNC_NAME = 'func-name'
--- a/src/asyncio_taskpool/exceptions.py
+++ b/src/asyncio_taskpool/exceptions.py
@@ -1,8 +1,29 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Custom exception classes used in various modules.
 """
 class PoolException(Exception):
    pass
-class PoolIsClosed(PoolException):
+class PoolIsLocked(PoolException):
    pass
@@ -22,9 +43,25 @@ class InvalidTaskID(PoolException):
    pass
-class PoolStillOpen(PoolException):
+class PoolStillUnlocked(PoolException):
    pass
 class NotCoroutine(PoolException):
    pass
 class ServerException(Exception):
    pass
 class UnknownTaskPoolClass(ServerException):
    pass
 class NotATaskPool(ServerException):
    pass
 class HelpRequested(ServerException):
    pass
--- a/src/asyncio_taskpool/helpers.py
+++ b/src/asyncio_taskpool/helpers.py
@@ -1,6 +1,28 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Miscellaneous helper functions.
 """
 from asyncio.coroutines import iscoroutinefunction
 from asyncio.queues import Queue
-from typing import Any, Optional
+from inspect import getdoc
 from typing import Any, Optional, Union
 from .types import T, AnyCallableT, ArgsT, KwArgsT
@@ -27,3 +49,21 @@ def star_function(function: AnyCallableT, arg: Any, arg_stars: int = 0) -> T:
 async def join_queue(q: Queue) -> None:
    await q.join()
 def tasks_str(num: int) -> str:
    return "tasks" if num != 1 else "task"
 def get_first_doc_line(obj: object) -> str:
    return getdoc(obj).strip().split("\n", 1)[0].strip()
 async def return_or_exception(_function_to_execute: AnyCallableT, *args, **kwargs) -> Union[T, Exception]:
    try:
        if iscoroutinefunction(_function_to_execute):
            return await _function_to_execute(*args, **kwargs)
        else:
            return _function_to_execute(*args, **kwargs)
    except Exception as e:
        return e
--- a/src/asyncio_taskpool/pool.py
+++ b/src/asyncio_taskpool/pool.py
@@ -1,3 +1,36 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 This module contains the definitions of the task pool classes.
 A task pool is an object with a simple interface for aggregating and dynamically managing asynchronous tasks.
 Generally speaking, a task is added to a pool by providing it with a coroutine function reference as well as the 
 arguments for that function.
 The `BaseTaskPool` class is a parent class and not intended for direct use.
 The `TaskPool` and `SimpleTaskPool` are subclasses intended for direct use.
 While the former allows for heterogeneous collections of tasks that can be entirely unrelated to one another, the 
 latter requires a preemptive decision about the function **and** its arguments upon initialization and only allows
 to dynamically control the **number** of tasks running at any point in time.
 For further details about the classes check their respective docstrings.
 """
 import logging
 from asyncio import gather
 from asyncio.coroutines import iscoroutine, iscoroutinefunction
@@ -31,7 +64,7 @@ class BaseTaskPool:
        """Initializes the necessary internal attributes and adds the new pool to the general pools list."""
        self._enough_room: Semaphore = Semaphore()
        self.pool_size = pool_size
-        self._open: bool = True
+        self._locked: bool = False
        self._counter: int = 0
        self._running: Dict[int, Task] = {}
        self._cancelled: Dict[int, Task] = {}
@@ -45,6 +78,7 @@ class BaseTaskPool:
        log.debug("%s initialized", str(self))
    def __str__(self) -> str:
        """Returns the name of the task pool."""
        return f'{self.__class__.__name__}-{self._name or self._idx}'
    @property
@@ -71,9 +105,21 @@ class BaseTaskPool:
        self._pool_size = value
    @property
-    def is_open(self) -> bool:
+    def is_locked(self) -> bool:
-        """Returns `True` if more the pool has not been closed yet."""
+        """Returns `True` if more the pool has been locked (see below)."""
-        return self._open
+        return self._locked
    def lock(self) -> None:
        """Disallows any more tasks to be started in the pool."""
        if not self._locked:
            self._locked = True
            log.info("%s is locked!", str(self))
    def unlock(self) -> None:
        """Allows new tasks to be started in the pool."""
        if self._locked:
            self._locked = False
            log.info("%s was unlocked.", str(self))
    @property
    def num_running(self) -> int:
@@ -187,7 +233,7 @@ class BaseTaskPool:
        finally:
            await self._task_ending(task_id, custom_callback=end_callback)
-    async def _start_task(self, awaitable: Awaitable, ignore_closed: bool = False, end_callback: EndCallbackT = None,
+    async def _start_task(self, awaitable: Awaitable, ignore_lock: bool = False, end_callback: EndCallbackT = None,
                          cancel_callback: CancelCallbackT = None) -> int:
        """
        Starts a coroutine as a new task in the pool.
@@ -197,8 +243,8 @@ class BaseTaskPool:
        Args:
            awaitable:
                The actual coroutine to be run within the task pool.
-            ignore_closed (optional):
+            ignore_lock (optional):
-                If `True`, even if the pool is closed, the task will still be started.
+                If `True`, even if the pool is locked, the task will still be started.
            end_callback (optional):
                A callback to execute after the task has ended.
                It is run with the task's ID as its only positional argument.
@@ -208,12 +254,12 @@ class BaseTaskPool:
        Raises:
            `asyncio_taskpool.exceptions.NotCoroutine` if `awaitable` is not a coroutine.
-            `asyncio_taskpool.exceptions.PoolIsClosed` if the pool has been closed and `ignore_closed` is `False`.
+            `asyncio_taskpool.exceptions.PoolIsLocked` if the pool has been locked and `ignore_lock` is `False`.
        """
        if not iscoroutine(awaitable):
            raise exceptions.NotCoroutine(f"Not awaitable: {awaitable}")
-        if not (self.is_open or ignore_closed):
+        if self._locked and not ignore_lock:
-            raise exceptions.PoolIsClosed("Cannot start new tasks")
+            raise exceptions.PoolIsLocked("Cannot start new tasks")
        await self._enough_room.acquire()
        task_id = self._counter
        self._counter += 1
@@ -303,16 +349,11 @@ class BaseTaskPool:
            self._interrupt_flag.clear()
        return results
    def close(self) -> None:
        """Disallows any more tasks to be started in the pool."""
        self._open = False
        log.info("%s is closed!", str(self))
    async def gather(self, return_exceptions: bool = False):
        """
        Calls `asyncio.gather` on **all** tasks from the pool, returns their results, and forgets the tasks.
-        The `close()` method must have been called prior to this.
+        The `lock()` method must have been called prior to this.
        Note that there may be an unknown number of coroutine functions "queued" to be run as tasks.
        This can happen, if for example the `TaskPool.map` method was called with `num_tasks` set to a number smaller
@@ -327,10 +368,10 @@ class BaseTaskPool:
            return_exceptions (optional): Passed directly into `gather`.
        Raises:
-            `asyncio_taskpool.exceptions.PoolStillOpen` if the pool has not been closed yet.
+            `asyncio_taskpool.exceptions.PoolStillUnlocked` if the pool has not been locked yet.
        """
-        if self._open:
+        if not self._locked:
-            raise exceptions.PoolStillOpen("Pool must be closed, before tasks can be gathered")
+            raise exceptions.PoolStillUnlocked("Pool must be locked, before tasks can be gathered")
        await gather(*self._before_gathering)
        results = await gather(*self._ended.values(), *self._cancelled.values(), *self._running.values(),
                               return_exceptions=return_exceptions)
@@ -415,7 +456,7 @@ class TaskPool(BaseTaskPool):
        Raises:
            `NotCoroutine` if `func` is not a coroutine function.
-            `PoolIsClosed` if the pool has been closed already.
+            `PoolIsLocked` if the pool has been locked already.
        """
        ids = await gather(*(self._apply_one(func, args, kwargs, end_callback, cancel_callback) for _ in range(num)))
        # TODO: for some reason PyCharm wrongly claims that `gather` returns a tuple of exceptions
@@ -438,7 +479,7 @@ class TaskPool(BaseTaskPool):
                break
            await q.put(arg)  # This blocks as long as the queue is full.
-    async def _queue_consumer(self, q: Queue, func: CoroutineFunc, arg_stars: int = 0,
+    async def _queue_consumer(self, q: Queue, first_batch_started: Event, func: CoroutineFunc, arg_stars: int = 0,
                              end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
        """
        Wrapper around the `_start_task()` taking the next element from the arguments queue set up in `_map()`.
@@ -447,6 +488,9 @@ class TaskPool(BaseTaskPool):
        Args:
            q:
                The queue of function arguments to consume for starting the next task.
            first_batch_started:
                The event flag to wait for, before launching the next consumer.
                It can only set by the `_map()` method, which happens after the first batch of task has been started.
            func:
                The coroutine function to use for spawning the tasks within the task pool.
            arg_stars (optional):
@@ -465,16 +509,18 @@ class TaskPool(BaseTaskPool):
        try:
            await self._start_task(
                star_function(func, arg, arg_stars=arg_stars),
-                ignore_closed=True,
+                ignore_lock=True,
-                end_callback=partial(TaskPool._queue_callback, self, q=q, func=func, arg_stars=arg_stars,
+                end_callback=partial(TaskPool._queue_callback, self, q=q, first_batch_started=first_batch_started,
-                                     end_callback=end_callback, cancel_callback=cancel_callback),
+                                     func=func, arg_stars=arg_stars, end_callback=end_callback,
                                     cancel_callback=cancel_callback),
                cancel_callback=cancel_callback
            )
        finally:
            q.task_done()
-    async def _queue_callback(self, task_id: int, q: Queue, func: CoroutineFunc, arg_stars: int = 0,
+    async def _queue_callback(self, task_id: int, q: Queue, first_batch_started: Event, func: CoroutineFunc,
-                              end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
+                              arg_stars: int = 0, end_callback: EndCallbackT = None,
                              cancel_callback: CancelCallbackT = None) -> None:
        """
        Wrapper around an end callback function passed into the `_map()` method.
        Triggers the next `_queue_consumer` with the same arguments.
@@ -484,6 +530,9 @@ class TaskPool(BaseTaskPool):
                The ID of the ending task.
            q:
                The queue of function arguments to consume for starting the next task.
            first_batch_started:
                The event flag to wait for, before launching the next consumer.
                It can only set by the `_map()` method, which happens after the first batch of task has been started.
            func:
                The coroutine function to use for spawning the tasks within the task pool.
            arg_stars (optional):
@@ -495,7 +544,9 @@ class TaskPool(BaseTaskPool):
                The callback that was specified to execute after cancellation of the task (and the next one).
                It is run with the `task_id` as its only positional argument.
        """
-        await self._queue_consumer(q, func, arg_stars, end_callback=end_callback, cancel_callback=cancel_callback)
+        await first_batch_started.wait()
        await self._queue_consumer(q, first_batch_started, func, arg_stars,
                                   end_callback=end_callback, cancel_callback=cancel_callback)
        await execute_optional(end_callback, args=(task_id,))
    def _set_up_args_queue(self, args_iter: ArgsT, num_tasks: int) -> Queue:
@@ -569,15 +620,23 @@ class TaskPool(BaseTaskPool):
                It is run with the task's ID as its only positional argument.
        Raises:
-            `asyncio_taskpool.exceptions.PoolIsClosed` if the pool has been closed.
+            `asyncio_taskpool.exceptions.PoolIsLocked` if the pool has been locked.
        """
-        if not self.is_open:
+        if not self._locked:
-            raise exceptions.PoolIsClosed("Cannot start new tasks")
+            raise exceptions.PoolIsLocked("Cannot start new tasks")
        args_queue = self._set_up_args_queue(args_iter, num_tasks)
        # We need a flag to ensure that starting all tasks from the first batch here will not be blocked by the
        # `_queue_callback` triggered by one or more of them.
        # This could happen, e.g. if the pool has just enough room for one more task, but the queue here contains more
        # than one element, and the pool remains full until after the first task of the first batch ends. Then the
        # callback might trigger the next `_queue_consumer` before this method can, which will keep it blocked.
        first_batch_started = Event()
        for _ in range(args_queue.qsize()):
            # This is where blocking can occur, if the pool is full.
-            await self._queue_consumer(args_queue, func,
+            await self._queue_consumer(args_queue, first_batch_started, func,
                                       arg_stars=arg_stars, end_callback=end_callback, cancel_callback=cancel_callback)
        # Now the callbacks can immediately trigger more tasks.
        first_batch_started.set()
    async def map(self, func: CoroutineFunc, arg_iter: ArgsT, num_tasks: int = 1,
                  end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None) -> None:
@@ -610,7 +669,7 @@ class TaskPool(BaseTaskPool):
                It is run with the task's ID as its only positional argument.
        Raises:
-            `PoolIsClosed` if the pool has been closed.
+            `PoolIsLocked` if the pool has been locked.
            `NotCoroutine` if `func` is not a coroutine function.
        """
        await self._map(func, arg_iter, arg_stars=0, num_tasks=num_tasks,
@@ -638,9 +697,45 @@ class TaskPool(BaseTaskPool):
 class SimpleTaskPool(BaseTaskPool):
    """
    Simplified task pool class.
    A `SimpleTaskPool` instance can manage an arbitrary number of concurrent tasks,
    but they **must** come from a single coroutine function, called with the same arguments.
    The coroutine function and its arguments are defined upon initialization.
    As long as there is room in the pool, more tasks can be added. (By default, there is no pool size limit.)
    Each task started in the pool receives a unique ID, which can be used to cancel specific tasks at any moment.
    However, since all tasks come from the same function-arguments-combination, the specificity of the `cancel()` method
    is probably unnecessary. Instead, a simpler `stop()` method is introduced.
    Adding tasks blocks **only if** the pool is full at that moment.
    """
    def __init__(self, func: CoroutineFunc, args: ArgsT = (), kwargs: KwArgsT = None,
                 end_callback: EndCallbackT = None, cancel_callback: CancelCallbackT = None,
-                 name: str = None) -> None:
+                 pool_size: int = inf, name: str = None) -> None:
        """
        Args:
            func:
                The function to use for spawning new tasks within the pool.
            args (optional):
                The positional arguments to pass into each function call.
            kwargs (optional):
                The keyword-arguments to pass into each function call.
            end_callback (optional):
                A callback to execute after a task has ended.
                It is run with the task's ID as its only positional argument.
            cancel_callback (optional):
                A callback to execute after cancellation of a task.
                It is run with the task's ID as its only positional argument.
            pool_size (optional):
                The maximum number of tasks allowed to run concurrently in the pool
            name (optional):
                An optional name for the pool.
        """
        if not iscoroutinefunction(func):
            raise exceptions.NotCoroutine(f"Not a coroutine function: {func}")
        self._func: CoroutineFunc = func
@@ -648,32 +743,39 @@ class SimpleTaskPool(BaseTaskPool):
        self._kwargs: KwArgsT = kwargs if kwargs is not None else {}
        self._end_callback: EndCallbackT = end_callback
        self._cancel_callback: CancelCallbackT = cancel_callback
-        super().__init__(name=name)
+        super().__init__(pool_size=pool_size, name=name)
    @property
    def func_name(self) -> str:
        """Returns the name of the coroutine function used in the pool."""
        return self._func.__name__
    @property
    def size(self) -> int:
        return self.num_running
    async def _start_one(self) -> int:
        """Starts a single new task within the pool and returns its ID."""
        return await self._start_task(self._func(*self._args, **self._kwargs),
                                      end_callback=self._end_callback, cancel_callback=self._cancel_callback)
    async def start(self, num: int = 1) -> List[int]:
-        return [await self._start_one() for _ in range(num)]
+        """Starts `num` new tasks within the pool and returns their IDs as a list."""
        ids = await gather(*(self._start_one() for _ in range(num)))
        assert isinstance(ids, list)  # for PyCharm (see above to-do-item)
        return ids
    def stop(self, num: int = 1) -> List[int]:
-        num = min(num, self.size)
+        """
        Cancels `num` running tasks within the pool and returns their IDs as a list.
        The tasks are canceled in LIFO order, meaning tasks started later will be stopped before those started earlier.
        If `num` is greater than or equal to the number of currently running tasks, naturally all tasks are cancelled.
        """
        ids = []
        for i, task_id in enumerate(reversed(self._running)):
            if i >= num:
-                break
+                break  # We got the desired number of task IDs, there may well be more tasks left to keep running
            ids.append(task_id)
        self.cancel(*ids)
        return ids
    def stop_all(self) -> List[int]:
-        return self.stop(self.size)
+        """Cancels all running tasks and returns their IDs as a list."""
        return self.stop(self.num_running)
--- a/src/asyncio_taskpool/server.py
+++ b/src/asyncio_taskpool/server.py
@@ -1,3 +1,24 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 This module contains the task pool control server class definitions.
 """
 import logging
 from abc import ABC, abstractmethod
 from asyncio import AbstractServer
@@ -5,126 +26,126 @@ from asyncio.exceptions import CancelledError
 from asyncio.streams import StreamReader, StreamWriter, start_unix_server
 from asyncio.tasks import Task, create_task
 from pathlib import Path
-from typing import Tuple, Union, Optional
+from typing import Optional, Union
 from . import constants
 from .pool import SimpleTaskPool
 from .client import ControlClient, UnixControlClient
 from .pool import TaskPool, SimpleTaskPool
 from .session import ControlSession
 from .types import ConnectedCallbackT
 log = logging.getLogger(__name__)
 def tasks_str(num: int) -> str:
    return "tasks" if num != 1 else "task"
 def get_cmd_arg(msg: str) -> Union[Tuple[str, Optional[int]], Tuple[None, None]]:
    cmd = msg.strip().split(' ', 1)
    if len(cmd) > 1:
        try:
            return cmd[0], int(cmd[1])
        except ValueError:
            return None, None
    return cmd[0], None
 class ControlServer(ABC):  # TODO: Implement interface for normal TaskPool instances, not just SimpleTaskPool
-    client_class = ControlClient
+    """
    Abstract base class for a task pool control server.
    This class acts as a wrapper around an async server instance and initializes a `ControlSession` upon a client
    connecting to it. The entire interface is defined within that session class.
    """
    _client_class = ControlClient
    @classmethod
    @property
    def client_class_name(cls) -> str:
        """Returns the name of the control client class matching the server class."""
        return cls._client_class.__name__
    @abstractmethod
-    async def get_server_instance(self, client_connected_cb, **kwargs) -> AbstractServer:
+    async def _get_server_instance(self, client_connected_cb: ConnectedCallbackT, **kwargs) -> AbstractServer:
        """
        Initializes, starts, and returns an async server instance (Unix or TCP type).
        Args:
            client_connected_cb:
                The callback for when a client connects to the server (as per `asyncio.start_server` or
                `asyncio.start_unix_server`); will always be the internal `_client_connected_cb` method.
            **kwargs (optional):
                Keyword arguments to pass into the function that starts the server.
        Returns:
            The running server object (a type of `asyncio.Server`).
        """
        raise NotImplementedError
    @abstractmethod
-    def final_callback(self) -> None:
+    def _final_callback(self) -> None:
        """The method to run after the server's `serve_forever` methods ends for whatever reason."""
        raise NotImplementedError
-    def __init__(self, pool: SimpleTaskPool, **server_kwargs) -> None:
+    def __init__(self, pool: Union[TaskPool, SimpleTaskPool], **server_kwargs) -> None:
-        self._pool: SimpleTaskPool = pool
+        """
        Initializes by merely saving the internal attributes, but without starting the server yet.
        The task pool must be passed here and can not be set/changed afterwards. This means a control server is always
        tied to one specific task pool.
        Args:
            pool:
                An instance of a `BaseTaskPool` subclass to tie the server to.
            **server_kwargs (optional):
                Keyword arguments that will be passed into the function that starts the server.
        """
        self._pool: Union[TaskPool, SimpleTaskPool] = pool
        self._server_kwargs = server_kwargs
        self._server: Optional[AbstractServer] = None
-    async def _start_tasks(self, writer: StreamWriter, num: int = None) -> None:
+    @property
-        if num is None:
+    def pool(self) -> Union[TaskPool, SimpleTaskPool]:
-            num = 1
+        """Read-only property for accessing the task pool instance controlled by the server."""
-        log.debug("%s requests starting %s %s", self.client_class.__name__, num, tasks_str(num))
+        return self._pool
        writer.write(str(await self._pool.start(num)).encode())
-    def _stop_tasks(self, writer: StreamWriter, num: int = None) -> None:
+    def is_serving(self) -> bool:
-        if num is None:
+        """Wrapper around the `asyncio.Server.is_serving` method."""
-            num = 1
+        return self._server.is_serving()
        log.debug("%s requests stopping %s %s", self.client_class.__name__, num, tasks_str(num))
        # the requested number may be greater than the total number of running tasks
        writer.write(str(self._pool.stop(num)).encode())
    def _stop_all_tasks(self, writer: StreamWriter) -> None:
        log.debug("%s requests stopping all tasks", self.client_class.__name__)
        writer.write(str(self._pool.stop_all()).encode())
    def _pool_size(self, writer: StreamWriter) -> None:
        log.debug("%s requests pool size", self.client_class.__name__)
        writer.write(str(self._pool.size).encode())
    def _pool_func(self, writer: StreamWriter) -> None:
        log.debug("%s requests pool function", self.client_class.__name__)
        writer.write(self._pool.func_name.encode())
    async def _listen(self, reader: StreamReader, writer: StreamWriter) -> None:
        while self._server.is_serving():
            msg = (await reader.read(constants.MSG_BYTES)).decode().strip()
            if not msg:
                log.debug("%s disconnected", self.client_class.__name__)
                break
            cmd, arg = get_cmd_arg(msg)
            if cmd == constants.CMD_START:
                await self._start_tasks(writer, arg)
            elif cmd == constants.CMD_STOP:
                self._stop_tasks(writer, arg)
            elif cmd == constants.CMD_STOP_ALL:
                self._stop_all_tasks(writer)
            elif cmd == constants.CMD_SIZE:
                self._pool_size(writer)
            elif cmd == constants.CMD_FUNC:
                self._pool_func(writer)
            else:
                log.debug("%s sent invalid command: %s", self.client_class.__name__, msg)
                writer.write(b"Invalid command!")
            await writer.drain()
    async def _client_connected_cb(self, reader: StreamReader, writer: StreamWriter) -> None:
-        log.debug("%s connected", self.client_class.__name__)
+        """
-        writer.write(str(self._pool).encode())
+        The universal client callback that will be passed into the `_get_server_instance` method.
-        await writer.drain()
+        Instantiates a control session, performs the client handshake, and enters the session's `listen` loop.
-        await self._listen(reader, writer)
+        """
        session = ControlSession(self, reader, writer)
        await session.client_handshake()
        await session.listen()
    async def _serve_forever(self) -> None:
        """
        To be run as an `asyncio.Task` by the following method.
        Serves as a wrapper around the the `asyncio.Server.serve_forever` method that ensures that the `_final_callback`
        method is called, when the former method ends for whatever reason.
        """
        try:
            async with self._server:
                await self._server.serve_forever()
        except CancelledError:
            log.debug("%s stopped", self.__class__.__name__)
        finally:
-            self.final_callback()
+            self._final_callback()
    async def serve_forever(self) -> Task:
        """
        This method actually starts the server and begins listening to client connections on the specified interface.
        It should never block because the serving will be performed in a separate task.
        """
        log.debug("Starting %s...", self.__class__.__name__)
-        self._server = await self.get_server_instance(self._client_connected_cb, **self._server_kwargs)
+        self._server = await self._get_server_instance(self._client_connected_cb, **self._server_kwargs)
        return create_task(self._serve_forever())
 class UnixControlServer(ControlServer):
-    client_class = UnixControlClient
+    """Task pool control server class that exposes a unix socket for control clients to connect to."""
    _client_class = UnixControlClient
    def __init__(self, pool: SimpleTaskPool, **server_kwargs) -> None:
        self._socket_path = Path(server_kwargs.pop('path'))
        super().__init__(pool, **server_kwargs)
-    async def get_server_instance(self, client_connected_cb, **kwargs) -> AbstractServer:
+    async def _get_server_instance(self, client_connected_cb: ConnectedCallbackT, **kwargs) -> AbstractServer:
-        srv = await start_unix_server(client_connected_cb, self._socket_path, **kwargs)
+        server = await start_unix_server(client_connected_cb, self._socket_path, **kwargs)
        log.debug("Opened socket '%s'", str(self._socket_path))
-        return srv
+        return server
-    def final_callback(self) -> None:
+    def _final_callback(self) -> None:
        """Removes the unix socket on which the server was listening."""
        self._socket_path.unlink()
        log.debug("Removed socket '%s'", str(self._socket_path))
--- a/src/asyncio_taskpool/session.py
+++ b/src/asyncio_taskpool/session.py
@@ -0,0 +1,304 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 This module contains the the definition of the control session class used by the control server.
 """
 import logging
 import json
 from argparse import ArgumentError, HelpFormatter
 from asyncio.streams import StreamReader, StreamWriter
 from typing import Callable, Optional, Union, TYPE_CHECKING
 from .constants import CMD, SESSION_PARSER_WRITER, SESSION_MSG_BYTES, CLIENT_INFO
 from .exceptions import HelpRequested, NotATaskPool, UnknownTaskPoolClass
 from .helpers import get_first_doc_line, return_or_exception, tasks_str
 from .pool import BaseTaskPool, TaskPool, SimpleTaskPool
 from .session_parser import CommandParser, NUM
 if TYPE_CHECKING:
    from .server import ControlServer
 log = logging.getLogger(__name__)
 class ControlSession:
    """
    This class defines the API for controlling a task pool instance from the outside.
    The commands received from a connected client are translated into method calls on the task pool instance.
    A subclass of the standard `argparse.ArgumentParser` is used to handle the input read from the stream.
    """
    def __init__(self, server: 'ControlServer', reader: StreamReader, writer: StreamWriter) -> None:
        """
        Instantiation should happen once a client connection to the control server has already been established.
        For more convenient/efficient access, some of the server's properties are saved in separate attributes.
        The argument parser is _not_ instantiated in the constructor. It requires a bit of client information during
        initialization, which is obtained in the `client_handshake` method; only there is the parser fully configured.
        Args:
            server:
                The instance of a `ControlServer` subclass starting the session.
            reader:
                The `asyncio.StreamReader` created when a client connected to the server.
            writer:
                The `asyncio.StreamWriter` created when a client connected to the server.
        """
        self._control_server: 'ControlServer' = server
        self._pool: Union[TaskPool, SimpleTaskPool] = server.pool
        self._client_class_name = server.client_class_name
        self._reader: StreamReader = reader
        self._writer: StreamWriter = writer
        self._parser: Optional[CommandParser] = None
        self._subparsers = None
    def _add_command(self, name: str, prog: str = None, short_help: str = None, long_help: str = None,
                     **kwargs) -> CommandParser:
        """
        Convenience method for adding a subparser (i.e. another command) to the main `CommandParser` instance.
        Will always pass the session's main `CommandParser` instance as the `parent` keyword-argument.
        Args:
            name:
                The command name; passed directly into the `add_parser` method.
            prog (optional):
                Also passed into the `add_parser` method as the corresponding keyword-argument. By default, is set
                equal to the `name` argument.
            short_help (optional):
                Passed into the `add_parser` method as the `help` keyword-argument, unless it is left empty and the
                `long_help` argument is present; in that case the `long_help` argument is passed as `help`.
            long_help (optional):
                Passed into the `add_parser` method as the `description` keyword-argument, unless it is left empty and
                the `short_help` argument is present; in that case the `short_help` argument is passed as `description`.
            **kwargs (optional):
                Any keyword-arguments to directly pass into the `add_parser` method.
        Returns:
            An instance of the `CommandParser` class representing the newly added control command.
        """
        if prog is None:
            prog = name
        kwargs.setdefault('help', short_help or long_help)
        kwargs.setdefault('description', long_help or short_help)
        return self._subparsers.add_parser(name, prog=prog, parent=self._parser, **kwargs)
    def _add_base_commands(self) -> None:
        """
        Adds the commands that are supported regardless of the specific subclass of `BaseTaskPool` controlled.
        These include commands mapping to the following pool methods:
            - __str__
            - pool_size (get/set property)
            - num_running
        """
        self._add_command(CMD.NAME, short_help=get_first_doc_line(self._pool.__class__.__str__))
        self._add_command(
            CMD.POOL_SIZE, 
            short_help="Get/set the maximum number of tasks in the pool.", 
            formatter_class=HelpFormatter
        ).add_optional_num_argument(
            default=None,
            help=f"If passed a number: {get_first_doc_line(self._pool.__class__.pool_size.fset)} "
                 f"If omitted: {get_first_doc_line(self._pool.__class__.pool_size.fget)}"
        )
        self._add_command(CMD.NUM_RUNNING, short_help=get_first_doc_line(self._pool.__class__.num_running.fget))
    def _add_simple_commands(self) -> None:
        """
        Adds the commands that are only supported, if a `SimpleTaskPool` object is controlled.
        These include commands mapping to the following pool methods:
            - start
            - stop
            - stop_all
            - func_name
        """
        self._add_command(
            CMD.START, short_help=get_first_doc_line(self._pool.__class__.start)
        ).add_optional_num_argument(
            help="Number of tasks to start."
        )
        self._add_command(
            CMD.STOP, short_help=get_first_doc_line(self._pool.__class__.stop)
        ).add_optional_num_argument(
            help="Number of tasks to stop."
        )
        self._add_command(CMD.STOP_ALL, short_help=get_first_doc_line(self._pool.__class__.stop_all))
        self._add_command(CMD.FUNC_NAME, short_help=get_first_doc_line(self._pool.__class__.func_name.fget))
    def _add_advanced_commands(self) -> None:
        """
        Adds the commands that are only supported, if a `TaskPool` object is controlled.
        These include commands mapping to the following pool methods:
            - ...
        """
        raise NotImplementedError
    def _init_parser(self, client_terminal_width: int) -> None:
        """
        Initializes and fully configures the `CommandParser` responsible for handling the input.
        Depending on what specific task pool class is controlled by the server, different commands are added.
        Args:
            client_terminal_width:
                The number of columns of the client's terminal to be able to nicely format messages from the parser.
        """
        parser_kwargs = {
            'prog': '',
            SESSION_PARSER_WRITER: self._writer,
            CLIENT_INFO.TERMINAL_WIDTH: client_terminal_width,
        }
        self._parser = CommandParser(**parser_kwargs)
        self._subparsers = self._parser.add_subparsers(title="Commands", dest=CMD.CMD)
        self._add_base_commands()
        if isinstance(self._pool, TaskPool):
            self._add_advanced_commands()
        elif isinstance(self._pool, SimpleTaskPool):
            self._add_simple_commands()
        elif isinstance(self._pool, BaseTaskPool):
            raise UnknownTaskPoolClass(f"No interface defined for {self._pool.__class__.__name__}")
        else:
            raise NotATaskPool(f"Not a task pool instance: {self._pool}")
    async def client_handshake(self) -> None:
        """
        This method must be invoked before starting any other client interaction.
        Client info is retrieved, server info is sent back, and the `CommandParser` is initialized and configured.
        """
        client_info = json.loads((await self._reader.read(SESSION_MSG_BYTES)).decode().strip())
        log.debug("%s connected", self._client_class_name)
        self._init_parser(client_info[CLIENT_INFO.TERMINAL_WIDTH])
        self._writer.write(str(self._pool).encode())
        await self._writer.drain()
    async def _write_function_output(self, func: Callable, *args, **kwargs) -> None:
        """
        Acts as a wrapper around a call to a specific task pool method.
        The method is called and any exception is caught and saved. If there is no output and no exception caught, a
        generic confirmation message is sent back to the client. Otherwise the output or a string representation of
        the exception caught is sent back.
        Args:
            func:
                Reference to the task pool method.
            *args (optional):
                Any positional arguments to call the method with.
            *+kwargs (optional):
                Any keyword-arguments to call the method with.
        """
        output = await return_or_exception(func, *args, **kwargs)
        self._writer.write(b"ok" if output is None else str(output).encode())
    async def _cmd_name(self, **_kwargs) -> None:
        """Maps to the `__str__` method of any task pool class."""
        log.debug("%s requests task pool name", self._client_class_name)
        await self._write_function_output(self._pool.__class__.__str__, self._pool)
    async def _cmd_pool_size(self, **kwargs) -> None:
        """Maps to the `pool_size` property of any task pool class."""
        num = kwargs.get(NUM)
        if num is None:
            log.debug("%s requests pool size", self._client_class_name)
            await self._write_function_output(self._pool.__class__.pool_size.fget, self._pool)
        else:
            log.debug("%s requests setting pool size to %s", self._client_class_name, num)
            await self._write_function_output(self._pool.__class__.pool_size.fset, self._pool, num)
    async def _cmd_num_running(self, **_kwargs) -> None:
        """Maps to the `num_running` property of any task pool class."""
        log.debug("%s requests number of running tasks", self._client_class_name)
        await self._write_function_output(self._pool.__class__.num_running.fget, self._pool)
    async def _cmd_start(self, **kwargs) -> None:
        """Maps to the `start` method of the `SimpleTaskPool` class."""
        num = kwargs[NUM]
        log.debug("%s requests starting %s %s", self._client_class_name, num, tasks_str(num))
        await self._write_function_output(self._pool.start, num)
    async def _cmd_stop(self, **kwargs) -> None:
        """Maps to the `stop` method of the `SimpleTaskPool` class."""
        num = kwargs[NUM]
        log.debug("%s requests stopping %s %s", self._client_class_name, num, tasks_str(num))
        await self._write_function_output(self._pool.stop, num)
    async def _cmd_stop_all(self, **_kwargs) -> None:
        """Maps to the `stop_all` method of the `SimpleTaskPool` class."""
        log.debug("%s requests stopping all tasks", self._client_class_name)
        await self._write_function_output(self._pool.stop_all)
    async def _cmd_func_name(self, **_kwargs) -> None:
        """Maps to the `func_name` method of the `SimpleTaskPool` class."""
        log.debug("%s requests pool function name", self._client_class_name)
        await self._write_function_output(self._pool.__class__.func_name.fget, self._pool)
    async def _execute_command(self, **kwargs) -> None:
        """
        Dynamically gets the correct `_cmd_...` method depending on the name of the command passed and executes it.
        Args:
            **kwargs:
                Must include the `CMD.CMD` key mapping the the command name. The rest of the keyword-arguments is
                simply passed into the method determined from the command name.
        """
        method = getattr(self, f'_cmd_{kwargs.pop(CMD.CMD).replace("-", "_")}')
        await method(**kwargs)
    async def _parse_command(self, msg: str) -> None:
        """
        Takes a message from the client and attempts to parse it.
        If a parsing error occurs, it is returned to the client. If the `HelpRequested` exception was raised by the
        `CommandParser`, nothing else happens. Otherwise, the `_execute_command` method is called with the entire
        dictionary of keyword-arguments returned by the `CommandParser` passed into it.
        Args:
            msg:
                The non-empty string read from the client stream.
        """
        try:
            kwargs = vars(self._parser.parse_args(msg.split(' ')))
        except ArgumentError as e:
            self._writer.write(str(e).encode())
            return
        except HelpRequested:
            return
        await self._execute_command(**kwargs)
    async def listen(self) -> None:
        """
        Enters the main control loop that only ends if either the server or the client disconnect.
        Messages from the client are read and passed into the `_parse_command` method, which handles the rest.
        This method should be called, when the client connection was established and the handshake was successful.
        It will obviously block indefinitely.
        """
        while self._control_server.is_serving():
            msg = (await self._reader.read(SESSION_MSG_BYTES)).decode().strip()
            if not msg:
                log.debug("%s disconnected", self._client_class_name)
                break
            await self._parse_command(msg)
            await self._writer.drain()
--- a/src/asyncio_taskpool/session_parser.py
+++ b/src/asyncio_taskpool/session_parser.py
@@ -0,0 +1,60 @@
 from argparse import Action, ArgumentParser, ArgumentDefaultsHelpFormatter, HelpFormatter
 from asyncio.streams import StreamWriter
 from typing import Type, TypeVar
 from .constants import SESSION_PARSER_WRITER, CLIENT_INFO
 from .exceptions import HelpRequested
 FmtCls = TypeVar('FmtCls', bound=Type[HelpFormatter])
 FORMATTER_CLASS = 'formatter_class'
 NUM = 'num'
 class CommandParser(ArgumentParser):
    @staticmethod
    def help_formatter_factory(terminal_width: int, base_cls: FmtCls = None) -> FmtCls:
        if base_cls is None:
            base_cls = ArgumentDefaultsHelpFormatter
        class ClientHelpFormatter(base_cls):
            def __init__(self, *args, **kwargs) -> None:
                kwargs['width'] = terminal_width
                super().__init__(*args, **kwargs)
        return ClientHelpFormatter
    def __init__(self, *args, **kwargs) -> None:
        parent: CommandParser = kwargs.pop('parent', None)
        self._stream_writer: StreamWriter = parent.stream_writer if parent else kwargs.pop(SESSION_PARSER_WRITER)
        self._terminal_width: int = parent.terminal_width if parent else kwargs.pop(CLIENT_INFO.TERMINAL_WIDTH)
        kwargs[FORMATTER_CLASS] = self.help_formatter_factory(self._terminal_width, kwargs.get(FORMATTER_CLASS))
        kwargs.setdefault('exit_on_error', False)
        super().__init__(*args, **kwargs)
    @property
    def stream_writer(self) -> StreamWriter:
        return self._stream_writer
    @property
    def terminal_width(self) -> int:
        return self._terminal_width
    def _print_message(self, message: str, *args, **kwargs) -> None:
        if message:
            self.stream_writer.write(message.encode())
    def exit(self, status: int = 0, message: str = None) -> None:
        if message:
            self._print_message(message)
    def print_help(self, file=None) -> None:
        super().print_help(file)
        raise HelpRequested
    def add_optional_num_argument(self, *name_or_flags: str, **kwargs) -> Action:
        if not name_or_flags:
            name_or_flags = (NUM, )
        kwargs.setdefault('nargs', '?')
        kwargs.setdefault('default', 1)
        kwargs.setdefault('type', int)
        return self.add_argument(*name_or_flags, **kwargs)
--- a/src/asyncio_taskpool/types.py
+++ b/src/asyncio_taskpool/types.py
@@ -1,3 +1,24 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Custom type definitions used in various modules.
 """
 from asyncio.streams import StreamReader, StreamWriter
 from typing import Any, Awaitable, Callable, Iterable, Mapping, Tuple, TypeVar, Union
@@ -7,10 +28,11 @@ T = TypeVar('T')
 ArgsT = Iterable[Any]
 KwArgsT = Mapping[str, Any]
-AnyCallableT = Callable[[...], Union[Awaitable[T], T]]
+AnyCallableT = Callable[[...], Union[T, Awaitable[T]]]
 CoroutineFunc = Callable[[...], Awaitable[Any]]
 EndCallbackT = Callable
 CancelCallbackT = Callable
 ConnectedCallbackT = Callable[[StreamReader, StreamWriter], Awaitable[None]]
 ClientConnT = Union[Tuple[StreamReader, StreamWriter], Tuple[None, None]]
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -0,0 +1,128 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Unittests for the `asyncio_taskpool.helpers` module.
 """
 from unittest import IsolatedAsyncioTestCase
 from unittest.mock import MagicMock, AsyncMock, NonCallableMagicMock
 from asyncio_taskpool import helpers
 class HelpersTestCase(IsolatedAsyncioTestCase):
    async def test_execute_optional(self):
        f, args, kwargs = NonCallableMagicMock(), [1, 2], None
        a = [f, args, kwargs]  # to avoid IDE nagging
        self.assertIsNone(await helpers.execute_optional(*a))
        expected_output = 'foo'
        f = MagicMock(return_value=expected_output)
        output = await helpers.execute_optional(f, args, kwargs)
        self.assertEqual(expected_output, output)
        f.assert_called_once_with(*args)
        f.reset_mock()
        kwargs = {'a': 100, 'b': 200}
        output = await helpers.execute_optional(f, args, kwargs)
        self.assertEqual(expected_output, output)
        f.assert_called_once_with(*args, **kwargs)
        f = AsyncMock(return_value=expected_output)
        output = await helpers.execute_optional(f, args, kwargs)
        self.assertEqual(expected_output, output)
        f.assert_awaited_once_with(*args, **kwargs)
    def test_star_function(self):
        expected_output = 'bar'
        f = MagicMock(return_value=expected_output)
        a = (1, 2, 3)
        stars = 0
        output = helpers.star_function(f, a, stars)
        self.assertEqual(expected_output, output)
        f.assert_called_once_with(a)
        f.reset_mock()
        stars = 1
        output = helpers.star_function(f, a, stars)
        self.assertEqual(expected_output, output)
        f.assert_called_once_with(*a)
        f.reset_mock()
        a = {'a': 1, 'b': 2}
        stars = 2
        output = helpers.star_function(f, a, stars)
        self.assertEqual(expected_output, output)
        f.assert_called_once_with(**a)
        with self.assertRaises(ValueError):
            helpers.star_function(f, a, 3)
        with self.assertRaises(ValueError):
            helpers.star_function(f, a, -1)
        with self.assertRaises(ValueError):
            helpers.star_function(f, a, 123456789)
    async def test_join_queue(self):
        mock_join = AsyncMock()
        mock_queue = MagicMock(join=mock_join)
        self.assertIsNone(await helpers.join_queue(mock_queue))
        mock_join.assert_awaited_once_with()
    def test_task_str(self):
        self.assertEqual("task", helpers.tasks_str(1))
        self.assertEqual("tasks", helpers.tasks_str(0))
        self.assertEqual("tasks", helpers.tasks_str(-1))
        self.assertEqual("tasks", helpers.tasks_str(2))
        self.assertEqual("tasks", helpers.tasks_str(-10))
        self.assertEqual("tasks", helpers.tasks_str(42))
    def test_get_first_doc_line(self):
        expected_output = 'foo bar baz'
        mock_obj = MagicMock(__doc__=f"""{expected_output} 
        something else
        even more
        """)
        output = helpers.get_first_doc_line(mock_obj)
        self.assertEqual(expected_output, output)
    async def test_return_or_exception(self):
        expected_output = '420'
        mock_func = AsyncMock(return_value=expected_output)
        args = (1, 3, 5)
        kwargs = {'a': 1, 'b': 2, 'c': 'foo'}
        output = await helpers.return_or_exception(mock_func, *args, **kwargs)
        self.assertEqual(expected_output, output)
        mock_func.assert_awaited_once_with(*args, **kwargs)
        mock_func = MagicMock(return_value=expected_output)
        output = await helpers.return_or_exception(mock_func, *args, **kwargs)
        self.assertEqual(expected_output, output)
        mock_func.assert_called_once_with(*args, **kwargs)
        class TestException(Exception):
            pass
        test_exception = TestException()
        mock_func = MagicMock(side_effect=test_exception)
        output = await helpers.return_or_exception(mock_func, *args, **kwargs)
        self.assertEqual(test_exception, output)
        mock_func.assert_called_once_with(*args, **kwargs)
--- a/tests/test_pool.py
+++ b/tests/test_pool.py
@@ -1,3 +1,24 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Unittests for the `asyncio_taskpool.pool` module.
 """
 import asyncio
 from asyncio.exceptions import CancelledError
 from asyncio.queues import Queue
@@ -68,7 +89,7 @@ class BaseTaskPoolTestCase(CommonTestCase):
    def test_init(self):
        self.assertIsInstance(self.task_pool._enough_room, asyncio.locks.Semaphore)
-        self.assertTrue(self.task_pool._open)
+        self.assertFalse(self.task_pool._locked)
        self.assertEqual(0, self.task_pool._counter)
        self.assertDictEqual(EMPTY_DICT, self.task_pool._running)
        self.assertDictEqual(EMPTY_DICT, self.task_pool._cancelled)
@@ -103,9 +124,23 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.task_pool.pool_size = new_size = 69
        self.assertEqual(new_size, self.task_pool._pool_size)
-    def test_is_open(self):
+    def test_is_locked(self):
-        self.task_pool._open = FOO
+        self.task_pool._locked = FOO
-        self.assertEqual(FOO, self.task_pool.is_open)
+        self.assertEqual(FOO, self.task_pool.is_locked)
    def test_lock(self):
        assert not self.task_pool._locked
        self.task_pool.lock()
        self.assertTrue(self.task_pool._locked)
        self.task_pool.lock()
        self.assertTrue(self.task_pool._locked)
    def test_unlock(self):
        self.task_pool._locked = True
        self.task_pool.unlock()
        self.assertFalse(self.task_pool._locked)
        self.task_pool.unlock()
        self.assertFalse(self.task_pool._locked)
    def test_num_running(self):
        self.task_pool._running = ['foo', 'bar', 'baz']
@@ -211,11 +246,9 @@ class BaseTaskPoolTestCase(CommonTestCase):
    @patch.object(pool, 'create_task')
    @patch.object(pool.BaseTaskPool, '_task_wrapper', new_callable=MagicMock)
    @patch.object(pool.BaseTaskPool, '_task_name', return_value=FOO)
-    @patch.object(pool.BaseTaskPool, 'is_open', new_callable=PropertyMock)
+    async def test__start_task(self, mock__task_name: MagicMock, mock__task_wrapper: AsyncMock,
-    async def test__start_task(self, mock_is_open: MagicMock, mock__task_name: MagicMock,
+                               mock_create_task: MagicMock):
                               mock__task_wrapper: AsyncMock, mock_create_task: MagicMock):
        def reset_mocks() -> None:
            mock_is_open.reset_mock()
            mock__task_name.reset_mock()
            mock__task_wrapper.reset_mock()
            mock_create_task.reset_mock()
@@ -226,31 +259,27 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.task_pool._counter = count = 123
        self.task_pool._enough_room._value = room = 123
        def check_nothing_changed() -> None:
            self.assertEqual(count, self.task_pool._counter)
            self.assertNotIn(count, self.task_pool._running)
            self.assertEqual(room, self.task_pool._enough_room._value)
            mock__task_name.assert_not_called()
            mock__task_wrapper.assert_not_called()
            mock_create_task.assert_not_called()
            reset_mocks()
        with self.assertRaises(exceptions.NotCoroutine):
            await self.task_pool._start_task(MagicMock(), end_callback=mock_end_cb, cancel_callback=mock_cancel_cb)
-        self.assertEqual(count, self.task_pool._counter)
+        check_nothing_changed()
        self.assertNotIn(count, self.task_pool._running)
        self.assertEqual(room, self.task_pool._enough_room._value)
        mock_is_open.assert_not_called()
        mock__task_name.assert_not_called()
        mock__task_wrapper.assert_not_called()
        mock_create_task.assert_not_called()
        reset_mocks()
-        mock_is_open.return_value = ignore_closed = False
+        self.task_pool._locked = True
        ignore_closed = False
        mock_awaitable = mock_coroutine()
-        with self.assertRaises(exceptions.PoolIsClosed):
+        with self.assertRaises(exceptions.PoolIsLocked):
            await self.task_pool._start_task(mock_awaitable, ignore_closed,
                                             end_callback=mock_end_cb, cancel_callback=mock_cancel_cb)
        await mock_awaitable
-        self.assertEqual(count, self.task_pool._counter)
+        check_nothing_changed()
        self.assertNotIn(count, self.task_pool._running)
        self.assertEqual(room, self.task_pool._enough_room._value)
        mock_is_open.assert_called_once_with()
        mock__task_name.assert_not_called()
        mock__task_wrapper.assert_not_called()
        mock_create_task.assert_not_called()
        reset_mocks()
        ignore_closed = True
        mock_awaitable = mock_coroutine()
@@ -261,7 +290,6 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.assertEqual(count + 1, self.task_pool._counter)
        self.assertEqual(mock_task, self.task_pool._running[count])
        self.assertEqual(room - 1, self.task_pool._enough_room._value)
        mock_is_open.assert_called_once_with()
        mock__task_name.assert_called_once_with(count)
        mock__task_wrapper.assert_called_once_with(mock_awaitable, count, mock_end_cb, mock_cancel_cb)
        mock_create_task.assert_called_once_with(mock_wrapped, name=FOO)
@@ -280,7 +308,6 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.assertEqual(count + 1, self.task_pool._counter)
        self.assertNotIn(count, self.task_pool._running)
        self.assertEqual(room, self.task_pool._enough_room._value)
        mock_is_open.assert_called_once_with()
        mock__task_name.assert_called_once_with(count)
        mock__task_wrapper.assert_called_once_with(mock_awaitable, count, mock_end_cb, mock_cancel_cb)
        mock_create_task.assert_called_once_with(mock_wrapped, name=FOO)
@@ -345,11 +372,6 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.assertDictEqual(self.task_pool._ended, EMPTY_DICT)
        self.assertDictEqual(self.task_pool._cancelled, EMPTY_DICT)
    def test_close(self):
        assert self.task_pool._open
        self.task_pool.close()
        self.assertFalse(self.task_pool._open)
    async def test_gather(self):
        test_exception = TestException()
        mock_ended_func, mock_cancelled_func = AsyncMock(return_value=FOO), AsyncMock(side_effect=test_exception)
@@ -361,8 +383,8 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.task_pool._running = running = {789: mock_running_func()}
        self.task_pool._interrupt_flag.set()
-        assert self.task_pool._open
+        assert not self.task_pool._locked
-        with self.assertRaises(exceptions.PoolStillOpen):
+        with self.assertRaises(exceptions.PoolStillUnlocked):
            await self.task_pool.gather()
        self.assertDictEqual(self.task_pool._ended, ended)
        self.assertDictEqual(self.task_pool._cancelled, cancelled)
@@ -370,7 +392,7 @@ class BaseTaskPoolTestCase(CommonTestCase):
        self.assertListEqual(self.task_pool._before_gathering, before_gather)
        self.assertTrue(self.task_pool._interrupt_flag.is_set())
-        self.task_pool._open = False
+        self.task_pool._locked = True
        def check_assertions(output) -> None:
            self.assertListEqual([FOO, test_exception, BAR], output)
@@ -446,20 +468,20 @@ class TaskPoolTestCase(CommonTestCase):
        q, arg = Queue(), 420.69
        q.put_nowait(arg)
        mock_func, stars = MagicMock(), 3
-        end_cb, cancel_cb = MagicMock(), MagicMock()
+        mock_flag, end_cb, cancel_cb = MagicMock(), MagicMock(), MagicMock()
-        self.assertIsNone(await self.task_pool._queue_consumer(q, mock_func, stars, end_cb, cancel_cb))
+        self.assertIsNone(await self.task_pool._queue_consumer(q, mock_flag, mock_func, stars, end_cb, cancel_cb))
        self.assertTrue(q.empty())
-        mock__start_task.assert_awaited_once_with(awaitable, ignore_closed=True,
+        mock__start_task.assert_awaited_once_with(awaitable, ignore_lock=True,
                                                  end_callback=queue_callback, cancel_callback=cancel_cb)
        mock_star_function.assert_called_once_with(mock_func, arg, arg_stars=stars)
        mock_partial.assert_called_once_with(pool.TaskPool._queue_callback, self.task_pool,
-                                             q=q, func=mock_func, arg_stars=stars,
+                                             q=q, first_batch_started=mock_flag, func=mock_func, arg_stars=stars,
                                             end_callback=end_cb, cancel_callback=cancel_cb)
        mock__start_task.reset_mock()
        mock_star_function.reset_mock()
        mock_partial.reset_mock()
-        self.assertIsNone(await self.task_pool._queue_consumer(q, mock_func, stars, end_cb, cancel_cb))
+        self.assertIsNone(await self.task_pool._queue_consumer(q, mock_flag, mock_func, stars, end_cb, cancel_cb))
        self.assertTrue(q.empty())
        mock__start_task.assert_not_awaited()
        mock_star_function.assert_not_called()
@@ -470,9 +492,13 @@ class TaskPoolTestCase(CommonTestCase):
    async def test__queue_callback(self, mock__queue_consumer: AsyncMock, mock_execute_optional: AsyncMock):
        task_id, mock_q = 420, MagicMock()
        mock_func, stars = MagicMock(), 3
        mock_wait = AsyncMock()
        mock_flag = MagicMock(wait=mock_wait)
        end_cb, cancel_cb = MagicMock(), MagicMock()
-        self.assertIsNone(await self.task_pool._queue_callback(task_id, mock_q, mock_func, stars, end_cb, cancel_cb))
+        self.assertIsNone(await self.task_pool._queue_callback(task_id, mock_q, mock_flag, mock_func, stars,
-        mock__queue_consumer.assert_awaited_once_with(mock_q, mock_func, stars,
+                                                               end_callback=end_cb, cancel_callback=cancel_cb))
        mock_wait.assert_awaited_once_with()
        mock__queue_consumer.assert_awaited_once_with(mock_q, mock_flag, mock_func, stars,
                                                      end_callback=end_cb, cancel_callback=cancel_cb)
        mock_execute_optional.assert_awaited_once_with(end_cb, args=(task_id,))
@@ -521,32 +547,33 @@ class TaskPoolTestCase(CommonTestCase):
        mock__queue_producer.assert_not_called()
        mock_create_task.assert_not_called()
    @patch.object(pool, 'Event')
    @patch.object(pool.TaskPool, '_queue_consumer')
    @patch.object(pool.TaskPool, '_set_up_args_queue')
-    @patch.object(pool.TaskPool, 'is_open', new_callable=PropertyMock)
+    async def test__map(self, mock__set_up_args_queue: MagicMock, mock__queue_consumer: AsyncMock,
-    async def test__map(self, mock_is_open: MagicMock, mock__set_up_args_queue: MagicMock,
+                        mock_event_cls: MagicMock):
                        mock__queue_consumer: AsyncMock):
        qsize = 4
        mock__set_up_args_queue.return_value = mock_q = MagicMock(qsize=MagicMock(return_value=qsize))
        mock_flag_set = MagicMock()
        mock_event_cls.return_value = mock_flag = MagicMock(set=mock_flag_set)
        mock_func, stars = MagicMock(), 3
        args_iter, num_tasks = (FOO, BAR, 1, 2, 3), 2
        end_cb, cancel_cb = MagicMock(), MagicMock()
-        mock_is_open.return_value = False
+        self.task_pool._locked = False
-        with self.assertRaises(exceptions.PoolIsClosed):
+        with self.assertRaises(exceptions.PoolIsLocked):
            await self.task_pool._map(mock_func, args_iter, stars, num_tasks, end_cb, cancel_cb)
        mock_is_open.assert_called_once_with()
        mock__set_up_args_queue.assert_not_called()
        mock__queue_consumer.assert_not_awaited()
        mock_flag_set.assert_not_called()
-        mock_is_open.reset_mock()
+        self.task_pool._locked = True
        mock_is_open.return_value = True
        self.assertIsNone(await self.task_pool._map(mock_func, args_iter, stars, num_tasks, end_cb, cancel_cb))
        mock__set_up_args_queue.assert_called_once_with(args_iter, num_tasks)
-        mock__queue_consumer.assert_has_awaits(qsize * [call(mock_q, mock_func, arg_stars=stars,
+        mock__queue_consumer.assert_has_awaits(qsize * [call(mock_q, mock_flag, mock_func, arg_stars=stars,
                                                             end_callback=end_cb, cancel_callback=cancel_cb)])
        mock_flag_set.assert_called_once_with()
    @patch.object(pool.TaskPool, '_map')
    async def test_map(self, mock__map: AsyncMock):
@@ -574,3 +601,91 @@ class TaskPoolTestCase(CommonTestCase):
        self.assertIsNone(await self.task_pool.doublestarmap(mock_func, kwargs_iter, num_tasks, end_cb, cancel_cb))
        mock__map.assert_awaited_once_with(mock_func, kwargs_iter, arg_stars=2, num_tasks=num_tasks,
                                           end_callback=end_cb, cancel_callback=cancel_cb)
 class SimpleTaskPoolTestCase(CommonTestCase):
    TEST_CLASS = pool.SimpleTaskPool
    task_pool: pool.SimpleTaskPool
    TEST_POOL_FUNC = AsyncMock(__name__=FOO)
    TEST_POOL_ARGS = (FOO, BAR)
    TEST_POOL_KWARGS = {'a': 1, 'b': 2}
    TEST_POOL_END_CB = MagicMock()
    TEST_POOL_CANCEL_CB = MagicMock()
    def get_task_pool_init_params(self) -> dict:
        return super().get_task_pool_init_params() | {
            'func': self.TEST_POOL_FUNC,
            'args': self.TEST_POOL_ARGS,
            'kwargs': self.TEST_POOL_KWARGS,
            'end_callback': self.TEST_POOL_END_CB,
            'cancel_callback': self.TEST_POOL_CANCEL_CB,
        }
    def setUp(self) -> None:
        self.base_class_init_patcher = patch.object(pool.BaseTaskPool, '__init__')
        self.base_class_init = self.base_class_init_patcher.start()
        super().setUp()
    def tearDown(self) -> None:
        self.base_class_init_patcher.stop()
    def test_init(self):
        self.assertEqual(self.TEST_POOL_FUNC, self.task_pool._func)
        self.assertEqual(self.TEST_POOL_ARGS, self.task_pool._args)
        self.assertEqual(self.TEST_POOL_KWARGS, self.task_pool._kwargs)
        self.assertEqual(self.TEST_POOL_END_CB, self.task_pool._end_callback)
        self.assertEqual(self.TEST_POOL_CANCEL_CB, self.task_pool._cancel_callback)
        self.base_class_init.assert_called_once_with(pool_size=self.TEST_POOL_SIZE, name=self.TEST_POOL_NAME)
        with self.assertRaises(exceptions.NotCoroutine):
            pool.SimpleTaskPool(MagicMock())
    def test_func_name(self):
        self.assertEqual(self.TEST_POOL_FUNC.__name__, self.task_pool.func_name)
    @patch.object(pool.SimpleTaskPool, '_start_task')
    async def test__start_one(self, mock__start_task: AsyncMock):
        mock__start_task.return_value = expected_output = 99
        self.task_pool._func = MagicMock(return_value=BAR)
        output = await self.task_pool._start_one()
        self.assertEqual(expected_output, output)
        self.task_pool._func.assert_called_once_with(*self.task_pool._args, **self.task_pool._kwargs)
        mock__start_task.assert_awaited_once_with(BAR, end_callback=self.task_pool._end_callback,
                                                  cancel_callback=self.task_pool._cancel_callback)
    @patch.object(pool.SimpleTaskPool, '_start_one')
    async def test_start(self, mock__start_one: AsyncMock):
        mock__start_one.return_value = FOO
        num = 5
        output = await self.task_pool.start(num)
        expected_output = num * [FOO]
        self.assertListEqual(expected_output, output)
        mock__start_one.assert_has_awaits(num * [call()])
    @patch.object(pool.SimpleTaskPool, 'cancel')
    def test_stop(self, mock_cancel: MagicMock):
        num = 2
        id1, id2, id3 = 5, 6, 7
        self.task_pool._running = {id1: FOO, id2: BAR, id3: FOO + BAR}
        output = self.task_pool.stop(num)
        expected_output = [id3, id2]
        self.assertEqual(expected_output, output)
        mock_cancel.assert_called_once_with(*expected_output)
        mock_cancel.reset_mock()
        num = 50
        output = self.task_pool.stop(num)
        expected_output = [id3, id2, id1]
        self.assertEqual(expected_output, output)
        mock_cancel.assert_called_once_with(*expected_output)
    @patch.object(pool.SimpleTaskPool, 'num_running', new_callable=PropertyMock)
    @patch.object(pool.SimpleTaskPool, 'stop')
    def test_stop_all(self, mock_stop: MagicMock, mock_num_running: MagicMock):
        mock_num_running.return_value = num = 9876
        mock_stop.return_value = expected_output = 'something'
        output = self.task_pool.stop_all()
        self.assertEqual(expected_output, output)
        mock_num_running.assert_called_once_with()
        mock_stop.assert_called_once_with(num)
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -0,0 +1,164 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Unittests for the `asyncio_taskpool.server` module.
 """
 import asyncio
 import logging
 from pathlib import Path
 from unittest import IsolatedAsyncioTestCase
 from unittest.mock import AsyncMock, MagicMock, patch
 from asyncio_taskpool import server
 from asyncio_taskpool.client import ControlClient, UnixControlClient
 FOO, BAR = 'foo', 'bar'
 class ControlServerTestCase(IsolatedAsyncioTestCase):
    log_lvl: int
    @classmethod
    def setUpClass(cls) -> None:
        cls.log_lvl = server.log.level
        server.log.setLevel(999)
    @classmethod
    def tearDownClass(cls) -> None:
        server.log.setLevel(cls.log_lvl)
    def setUp(self) -> None:
        self.abstract_patcher = patch('asyncio_taskpool.server.ControlServer.__abstractmethods__', set())
        self.mock_abstract_methods = self.abstract_patcher.start()
        self.mock_pool = MagicMock()
        self.kwargs = {FOO: 123, BAR: 456}
        self.server = server.ControlServer(pool=self.mock_pool, **self.kwargs)
    def tearDown(self) -> None:
        self.abstract_patcher.stop()
    def test_client_class_name(self):
        self.assertEqual(ControlClient.__name__, server.ControlServer.client_class_name)
    async def test_abstract(self):
        with self.assertRaises(NotImplementedError):
            args = [AsyncMock()]
            await self.server._get_server_instance(*args)
        with self.assertRaises(NotImplementedError):
            self.server._final_callback()
    def test_init(self):
        self.assertEqual(self.mock_pool, self.server._pool)
        self.assertEqual(self.kwargs, self.server._server_kwargs)
        self.assertIsNone(self.server._server)
    def test_pool(self):
        self.assertEqual(self.mock_pool, self.server.pool)
    def test_is_serving(self):
        self.server._server = MagicMock(is_serving=MagicMock(return_value=FOO + BAR))
        self.assertEqual(FOO + BAR, self.server.is_serving())
    @patch.object(server, 'ControlSession')
    async def test__client_connected_cb(self, mock_client_session_cls: MagicMock):
        mock_client_handshake, mock_listen = AsyncMock(), AsyncMock()
        mock_client_session_cls.return_value = MagicMock(client_handshake=mock_client_handshake, listen=mock_listen)
        mock_reader, mock_writer = MagicMock(), MagicMock()
        self.assertIsNone(await self.server._client_connected_cb(mock_reader, mock_writer))
        mock_client_session_cls.assert_called_once_with(self.server, mock_reader, mock_writer)
        mock_client_handshake.assert_awaited_once_with()
        mock_listen.assert_awaited_once_with()
    @patch.object(server.ControlServer, '_final_callback')
    async def test__serve_forever(self, mock__final_callback: MagicMock):
        mock_aenter, mock_serve_forever = AsyncMock(), AsyncMock(side_effect=asyncio.CancelledError)
        self.server._server = MagicMock(__aenter__=mock_aenter, serve_forever=mock_serve_forever)
        with self.assertLogs(server.log, logging.DEBUG):
            self.assertIsNone(await self.server._serve_forever())
        mock_aenter.assert_awaited_once_with()
        mock_serve_forever.assert_awaited_once_with()
        mock__final_callback.assert_called_once_with()
        mock_aenter.reset_mock()
        mock_serve_forever.reset_mock(side_effect=True)
        mock__final_callback.reset_mock()
        self.assertIsNone(await self.server._serve_forever())
        mock_aenter.assert_awaited_once_with()
        mock_serve_forever.assert_awaited_once_with()
        mock__final_callback.assert_called_once_with()
    @patch.object(server, 'create_task')
    @patch.object(server.ControlServer, '_serve_forever', new_callable=MagicMock())
    @patch.object(server.ControlServer, '_get_server_instance')
    async def test_serve_forever(self, mock__get_server_instance: AsyncMock, mock__serve_forever: MagicMock,
                                 mock_create_task: MagicMock):
        mock__serve_forever.return_value = mock_awaitable = 'some_coroutine'
        mock_create_task.return_value = expected_output = 12345
        output = await self.server.serve_forever()
        self.assertEqual(expected_output, output)
        mock__get_server_instance.assert_awaited_once_with(self.server._client_connected_cb, **self.kwargs)
        mock__serve_forever.assert_called_once_with()
        mock_create_task.assert_called_once_with(mock_awaitable)
 class UnixControlServerTestCase(IsolatedAsyncioTestCase):
    log_lvl: int
    @classmethod
    def setUpClass(cls) -> None:
        cls.log_lvl = server.log.level
        server.log.setLevel(999)
    @classmethod
    def tearDownClass(cls) -> None:
        server.log.setLevel(cls.log_lvl)
    def setUp(self) -> None:
        self.base_init_patcher = patch.object(server.ControlServer, '__init__')
        self.mock_base_init = self.base_init_patcher.start()
        self.mock_pool = MagicMock()
        self.path = '/tmp/asyncio_taskpool'
        self.kwargs = {FOO: 123, BAR: 456}
        self.server = server.UnixControlServer(pool=self.mock_pool, path=self.path, **self.kwargs)
    def tearDown(self) -> None:
        self.base_init_patcher.stop()
    def test__client_class(self):
        self.assertEqual(UnixControlClient, self.server._client_class)
    def test_init(self):
        self.assertEqual(Path(self.path), self.server._socket_path)
        self.mock_base_init.assert_called_once_with(self.mock_pool, **self.kwargs)
    @patch.object(server, 'start_unix_server')
    async def test__get_server_instance(self, mock_start_unix_server: AsyncMock):
        mock_start_unix_server.return_value = expected_output = 'totally_a_server'
        mock_callback, mock_kwargs = MagicMock(), {'a': 1, 'b': 2}
        args = [mock_callback]
        output = await self.server._get_server_instance(*args, **mock_kwargs)
        self.assertEqual(expected_output, output)
        mock_start_unix_server.assert_called_once_with(mock_callback, Path(self.path), **mock_kwargs)
    def test__final_callback(self):
        self.server._socket_path = MagicMock()
        self.assertIsNone(self.server._final_callback())
        self.server._socket_path.unlink.assert_called_once_with()
--- a/tests/test_session.py
+++ b/tests/test_session.py
@@ -0,0 +1,324 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Unittests for the `asyncio_taskpool.session` module.
 """
 import json
 from argparse import ArgumentError, Namespace
 from unittest import IsolatedAsyncioTestCase
 from unittest.mock import AsyncMock, MagicMock, patch, call
 from asyncio_taskpool import session
 from asyncio_taskpool.constants import CLIENT_INFO, CMD, SESSION_MSG_BYTES, SESSION_PARSER_WRITER
 from asyncio_taskpool.exceptions import HelpRequested, NotATaskPool, UnknownTaskPoolClass
 from asyncio_taskpool.pool import BaseTaskPool, TaskPool, SimpleTaskPool
 FOO, BAR = 'foo', 'bar'
 class ControlServerTestCase(IsolatedAsyncioTestCase):
    log_lvl: int
    @classmethod
    def setUpClass(cls) -> None:
        cls.log_lvl = session.log.level
        session.log.setLevel(999)
    @classmethod
    def tearDownClass(cls) -> None:
        session.log.setLevel(cls.log_lvl)
    def setUp(self) -> None:
        self.mock_pool = MagicMock(spec=SimpleTaskPool(AsyncMock()))
        self.mock_client_class_name = FOO + BAR
        self.mock_server = MagicMock(pool=self.mock_pool,
                                     client_class_name=self.mock_client_class_name)
        self.mock_reader = MagicMock()
        self.mock_writer = MagicMock()
        self.session = session.ControlSession(self.mock_server, self.mock_reader, self.mock_writer)
    def test_init(self):
        self.assertEqual(self.mock_server, self.session._control_server)
        self.assertEqual(self.mock_pool, self.session._pool)
        self.assertEqual(self.mock_client_class_name, self.session._client_class_name)
        self.assertEqual(self.mock_reader, self.session._reader)
        self.assertEqual(self.mock_writer, self.session._writer)
        self.assertIsNone(self.session._parser)
        self.assertIsNone(self.session._subparsers)
    def test__add_command(self):
        expected_output = 123456
        mock_add_parser = MagicMock(return_value=expected_output)
        self.session._subparsers = MagicMock(add_parser=mock_add_parser)
        self.session._parser = MagicMock()
        name, prog, short_help, long_help = 'abc', None, 'short123', None
        kwargs = {'x': 1, 'y': 2}
        output = self.session._add_command(name, prog, short_help, long_help, **kwargs)
        self.assertEqual(expected_output, output)
        mock_add_parser.assert_called_once_with(name, prog=name, help=short_help, description=short_help,
                                                parent=self.session._parser, **kwargs)
        mock_add_parser.reset_mock()
        prog, long_help = 'ffffff', 'so long, wow'
        output = self.session._add_command(name, prog, short_help, long_help, **kwargs)
        self.assertEqual(expected_output, output)
        mock_add_parser.assert_called_once_with(name, prog=prog, help=short_help, description=long_help,
                                                parent=self.session._parser, **kwargs)
        mock_add_parser.reset_mock()
        short_help = None
        output = self.session._add_command(name, prog, short_help, long_help, **kwargs)
        self.assertEqual(expected_output, output)
        mock_add_parser.assert_called_once_with(name, prog=prog, help=long_help, description=long_help,
                                                parent=self.session._parser, **kwargs)
    @patch.object(session, 'get_first_doc_line')
    @patch.object(session.ControlSession, '_add_command')
    def test__adding_commands(self, mock__add_command: MagicMock, mock_get_first_doc_line: MagicMock):
        self.assertIsNone(self.session._add_base_commands())
        mock__add_command.assert_called()
        mock_get_first_doc_line.assert_called()
        mock__add_command.reset_mock()
        mock_get_first_doc_line.reset_mock()
        self.assertIsNone(self.session._add_simple_commands())
        mock__add_command.assert_called()
        mock_get_first_doc_line.assert_called()
        with self.assertRaises(NotImplementedError):
            self.session._add_advanced_commands()
    @patch.object(session.ControlSession, '_add_simple_commands')
    @patch.object(session.ControlSession, '_add_advanced_commands')
    @patch.object(session.ControlSession, '_add_base_commands')
    @patch.object(session, 'CommandParser')
    def test__init_parser(self, mock_command_parser_cls: MagicMock, mock__add_base_commands: MagicMock,
                          mock__add_advanced_commands: MagicMock, mock__add_simple_commands: MagicMock):
        mock_command_parser_cls.return_value = mock_parser = MagicMock()
        self.session._pool = TaskPool()
        width = 1234
        expected_parser_kwargs = {
            'prog': '',
            SESSION_PARSER_WRITER: self.mock_writer,
            CLIENT_INFO.TERMINAL_WIDTH: width,
        }
        self.assertIsNone(self.session._init_parser(width))
        mock_command_parser_cls.assert_called_once_with(**expected_parser_kwargs)
        mock_parser.add_subparsers.assert_called_once_with(title="Commands", dest=CMD.CMD)
        mock__add_base_commands.assert_called_once_with()
        mock__add_advanced_commands.assert_called_once_with()
        mock__add_simple_commands.assert_not_called()
        mock_command_parser_cls.reset_mock()
        mock_parser.add_subparsers.reset_mock()
        mock__add_base_commands.reset_mock()
        mock__add_advanced_commands.reset_mock()
        mock__add_simple_commands.reset_mock()
        async def fake_coroutine(): pass
        self.session._pool = SimpleTaskPool(fake_coroutine)
        self.assertIsNone(self.session._init_parser(width))
        mock_command_parser_cls.assert_called_once_with(**expected_parser_kwargs)
        mock_parser.add_subparsers.assert_called_once_with(title="Commands", dest=CMD.CMD)
        mock__add_base_commands.assert_called_once_with()
        mock__add_advanced_commands.assert_not_called()
        mock__add_simple_commands.assert_called_once_with()
        mock_command_parser_cls.reset_mock()
        mock_parser.add_subparsers.reset_mock()
        mock__add_base_commands.reset_mock()
        mock__add_advanced_commands.reset_mock()
        mock__add_simple_commands.reset_mock()
        class FakeTaskPool(BaseTaskPool):
            pass
        self.session._pool = FakeTaskPool()
        with self.assertRaises(UnknownTaskPoolClass):
            self.session._init_parser(width)
        mock_command_parser_cls.assert_called_once_with(**expected_parser_kwargs)
        mock_parser.add_subparsers.assert_called_once_with(title="Commands", dest=CMD.CMD)
        mock__add_base_commands.assert_called_once_with()
        mock__add_advanced_commands.assert_not_called()
        mock__add_simple_commands.assert_not_called()
        mock_command_parser_cls.reset_mock()
        mock_parser.add_subparsers.reset_mock()
        mock__add_base_commands.reset_mock()
        mock__add_advanced_commands.reset_mock()
        mock__add_simple_commands.reset_mock()
        self.session._pool = MagicMock()
        with self.assertRaises(NotATaskPool):
            self.session._init_parser(width)
        mock_command_parser_cls.assert_called_once_with(**expected_parser_kwargs)
        mock_parser.add_subparsers.assert_called_once_with(title="Commands", dest=CMD.CMD)
        mock__add_base_commands.assert_called_once_with()
        mock__add_advanced_commands.assert_not_called()
        mock__add_simple_commands.assert_not_called()
    @patch.object(session.ControlSession, '_init_parser')
    async def test_client_handshake(self, mock__init_parser: MagicMock):
        width = 5678
        msg = ' ' + json.dumps({CLIENT_INFO.TERMINAL_WIDTH: width, FOO: BAR}) + '  '
        mock_read = AsyncMock(return_value=msg.encode())
        self.mock_reader.read = mock_read
        self.mock_writer.drain = AsyncMock()
        self.assertIsNone(await self.session.client_handshake())
        mock_read.assert_awaited_once_with(SESSION_MSG_BYTES)
        mock__init_parser.assert_called_once_with(width)
        self.mock_writer.write.assert_called_once_with(str(self.mock_pool).encode())
        self.mock_writer.drain.assert_awaited_once_with()
    @patch.object(session, 'return_or_exception')
    async def test__write_function_output(self, mock_return_or_exception: MagicMock):
        self.mock_writer.write = MagicMock()
        mock_return_or_exception.return_value = None
        func, args, kwargs = MagicMock(), (1, 2, 3), {'a': 'A', 'b': 'B'}
        self.assertIsNone(await self.session._write_function_output(func, *args, **kwargs))
        mock_return_or_exception.assert_called_once_with(func, *args, **kwargs)
        self.mock_writer.write.assert_called_once_with(b"ok")
        mock_return_or_exception.reset_mock()
        self.mock_writer.write.reset_mock()
        mock_return_or_exception.return_value = output = MagicMock()
        self.assertIsNone(await self.session._write_function_output(func, *args, **kwargs))
        mock_return_or_exception.assert_called_once_with(func, *args, **kwargs)
        self.mock_writer.write.assert_called_once_with(str(output).encode())
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_name(self, mock__write_function_output: AsyncMock):
        self.assertIsNone(await self.session._cmd_name())
        mock__write_function_output.assert_awaited_once_with(self.mock_pool.__class__.__str__, self.session._pool)
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_pool_size(self, mock__write_function_output: AsyncMock):
        num = 12345
        kwargs = {session.NUM: num, FOO: BAR}
        self.assertIsNone(await self.session._cmd_pool_size(**kwargs))
        mock__write_function_output.assert_awaited_once_with(
            self.mock_pool.__class__.pool_size.fset, self.session._pool, num
        )
        mock__write_function_output.reset_mock()
        kwargs.pop(session.NUM)
        self.assertIsNone(await self.session._cmd_pool_size(**kwargs))
        mock__write_function_output.assert_awaited_once_with(
            self.mock_pool.__class__.pool_size.fget, self.session._pool
        )
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_num_running(self, mock__write_function_output: AsyncMock):
        self.assertIsNone(await self.session._cmd_num_running())
        mock__write_function_output.assert_awaited_once_with(
            self.mock_pool.__class__.num_running.fget, self.session._pool
        )
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_start(self, mock__write_function_output: AsyncMock):
        num = 12345
        kwargs = {session.NUM: num, FOO: BAR}
        self.assertIsNone(await self.session._cmd_start(**kwargs))
        mock__write_function_output.assert_awaited_once_with(self.mock_pool.start, num)
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_stop(self, mock__write_function_output: AsyncMock):
        num = 12345
        kwargs = {session.NUM: num, FOO: BAR}
        self.assertIsNone(await self.session._cmd_stop(**kwargs))
        mock__write_function_output.assert_awaited_once_with(self.mock_pool.stop, num)
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_stop_all(self, mock__write_function_output: AsyncMock):
        self.assertIsNone(await self.session._cmd_stop_all())
        mock__write_function_output.assert_awaited_once_with(self.mock_pool.stop_all)
    @patch.object(session.ControlSession, '_write_function_output')
    async def test__cmd_func_name(self, mock__write_function_output: AsyncMock):
        self.assertIsNone(await self.session._cmd_func_name())
        mock__write_function_output.assert_awaited_once_with(
            self.mock_pool.__class__.func_name.fget, self.session._pool
        )
    async def test__execute_command(self):
        mock_method = AsyncMock()
        cmd = 'this-is-a-test'
        setattr(self.session, '_cmd_' + cmd.replace('-', '_'), mock_method)
        kwargs = {FOO: BAR, 'hello': 'python'}
        self.assertIsNone(await self.session._execute_command(**{CMD.CMD: cmd}, **kwargs))
        mock_method.assert_awaited_once_with(**kwargs)
    @patch.object(session.ControlSession, '_execute_command')
    async def test__parse_command(self, mock__execute_command: AsyncMock):
        msg = 'asdf asd as a'
        kwargs = {FOO: BAR, 'hello': 'python'}
        mock_parse_args = MagicMock(return_value=Namespace(**kwargs))
        self.session._parser = MagicMock(parse_args=mock_parse_args)
        self.mock_writer.write = MagicMock()
        self.assertIsNone(await self.session._parse_command(msg))
        mock_parse_args.assert_called_once_with(msg.split(' '))
        self.mock_writer.write.assert_not_called()
        mock__execute_command.assert_awaited_once_with(**kwargs)
        mock__execute_command.reset_mock()
        mock_parse_args.reset_mock()
        mock_parse_args.side_effect = exc = ArgumentError(MagicMock(), "oops")
        self.assertIsNone(await self.session._parse_command(msg))
        mock_parse_args.assert_called_once_with(msg.split(' '))
        self.mock_writer.write.assert_called_once_with(str(exc).encode())
        mock__execute_command.assert_not_awaited()
        self.mock_writer.write.reset_mock()
        mock_parse_args.reset_mock()
        mock_parse_args.side_effect = HelpRequested()
        self.assertIsNone(await self.session._parse_command(msg))
        mock_parse_args.assert_called_once_with(msg.split(' '))
        self.mock_writer.write.assert_not_called()
        mock__execute_command.assert_not_awaited()
    @patch.object(session.ControlSession, '_parse_command')
    async def test_listen(self, mock__parse_command: AsyncMock):
        def make_reader_return_empty():
            self.mock_reader.read.return_value = b''
        self.mock_writer.drain = AsyncMock(side_effect=make_reader_return_empty)
        msg = "fascinating"
        self.mock_reader.read = AsyncMock(return_value=f' {msg} '.encode())
        self.assertIsNone(await self.session.listen())
        self.mock_reader.read.assert_has_awaits([call(SESSION_MSG_BYTES), call(SESSION_MSG_BYTES)])
        mock__parse_command.assert_awaited_once_with(msg)
        self.mock_writer.drain.assert_awaited_once_with()
        self.mock_reader.read.reset_mock()
        mock__parse_command.reset_mock()
        self.mock_writer.drain.reset_mock()
        self.mock_server.is_serving = MagicMock(return_value=False)
        self.assertIsNone(await self.session.listen())
        self.mock_reader.read.assert_not_awaited()
        mock__parse_command.assert_not_awaited()
        self.mock_writer.drain.assert_not_awaited()
--- a/usage/USAGE.md
+++ b/usage/USAGE.md
@@ -2,17 +2,17 @@
 ## Minimal example for `SimpleTaskPool`
-The minimum required setup is a "worker" coroutine function that can do something asynchronously, a main coroutine function that sets up the `SimpleTaskPool` and starts/stops the tasks as desired, eventually awaiting them all. 
+The minimum required setup is a "worker" coroutine function that can do something asynchronously, and a main coroutine function that sets up the `SimpleTaskPool`, starts/stops the tasks as desired, and eventually awaits them all. 
 The following demo code enables full log output first for additional clarity. It is complete and should work as is.
 ### Code
 ```python
 import logging
 import asyncio
-from asyncio_taskpool.pool import SimpleTaskPool
+from asyncio_taskpool import SimpleTaskPool
 logging.getLogger().setLevel(logging.NOTSET)
 logging.getLogger('asyncio_taskpool').addHandler(logging.StreamHandler())
@@ -23,8 +23,8 @@ async def work(n: int) -> None:
    Pseudo-worker function. 
    Counts up to an integer with a second of sleep before each iteration.
    In a real-world use case, a worker function should probably have access 
-    to some synchronisation primitive or shared resource to distribute work 
+    to some synchronisation primitive (such as a queue) or shared resource
-    between an arbitrary number of workers.
+    to distribute work between an arbitrary number of workers.
    """
    for i in range(n):
        await asyncio.sleep(1)
@@ -38,7 +38,7 @@ async def main() -> None:
    await pool.start()  # launches work task 3
    await asyncio.sleep(1.5)  # lets the tasks work for a bit
    pool.stop(2)  # cancels tasks 3 and 2
-    pool.close()  # required for the last line
+    pool.lock()  # required for the last line
    await pool.gather()  # awaits all tasks, then flushes the pool
@@ -60,7 +60,7 @@ did 1
 did 1
 did 1
 did 0
-SimpleTaskPool-0 is closed!
+SimpleTaskPool-0 is locked!
 Cancelling SimpleTaskPool-0_Task-3 ...
 Cancelled SimpleTaskPool-0_Task-3
 Ended SimpleTaskPool-0_Task-3
@@ -77,6 +77,157 @@ did 4
 did 4
 ```
-## Advanced example
+## Advanced example for `TaskPool`
-...
+This time, we want to start tasks from _different_ coroutine functions **and** with _different_ arguments. For this we need an instance of the more generalized `TaskPool` class.
 As with the simple example, we need "worker" coroutine functions that can do something asynchronously, as well as a main coroutine function that sets up the pool, starts the tasks, and eventually awaits them.
 The following demo code enables full log output first for additional clarity. It is complete and should work as is.
 ### Code
 ```python
 import logging
 import asyncio
 from asyncio_taskpool import TaskPool
 logging.getLogger().setLevel(logging.NOTSET)
 logging.getLogger('asyncio_taskpool').addHandler(logging.StreamHandler())
 async def work(start: int, stop: int, step: int = 1) -> None:
    """Pseudo-worker function counting through a range with a second of sleep in between each iteration."""
    for i in range(start, stop, step):
        await asyncio.sleep(1)
        print("work with", i)
 async def other_work(a: int, b: int) -> None:
    """Different pseudo-worker counting through a range with half a second of sleep in between each iteration."""
    for i in range(a, b):
        await asyncio.sleep(0.5)
        print("other_work with", i)
 async def main() -> None:
    # Initialize a new task pool instance and limit its size to 3 tasks.
    pool = TaskPool(3)
    # Queue up two tasks (IDs 0 and 1) to run concurrently (with the same positional arguments).
    print("Called `apply`")
    await pool.apply(work, kwargs={'start': 100, 'stop': 200, 'step': 10}, num=2)
    # Let the tasks work for a bit.
    await asyncio.sleep(1.5)
    # Now, let us enqueue four more tasks (which will receive IDs 2, 3, 4, and 5), each created with different 
    # positional arguments by using `starmap`, but have **no more than two of those** run concurrently.
    # Since we set our pool size to 3, and already have two tasks working within the pool,
    # only the first one of these will start immediately (and receive ID 2).
    # The second one will start (with ID 3), only once there is room in the pool,
    # which -- in this example -- will be the case after ID 2 ends;
    # until then the `starmap` method call **will block**!
    # Once there is room in the pool again, the third and fourth will each start (with IDs 4 and 5)
    # **only** once there is room in the pool **and** no more than one of these last four tasks is running.
    args_list = [(0, 10), (10, 20), (20, 30), (30, 40)]
    print("Calling `starmap`...")
    await pool.starmap(other_work, args_list, num_tasks=2)
    print("`starmap` returned")
    # Now we lock the pool, so that we can safely await all our tasks.
    pool.lock()
    # Finally, we block, until all tasks have ended.
    print("Called `gather`")
    await pool.gather()
    print("Done.")
 if __name__ == '__main__':
    asyncio.run(main())
 ```
 ### Output 
 Additional comments for the output are provided with `<---` next to the output lines.
 (Keep in mind that the logger and `print` asynchronously write to `stdout`.)
 ```
 TaskPool-0 initialized
 Started TaskPool-0_Task-0
 Started TaskPool-0_Task-1
 Called `apply`
 work with 100
 work with 100
 Calling `starmap`...    <--- notice that this blocks as expected
 Started TaskPool-0_Task-2
 work with 110
 work with 110
 other_work with 0
 other_work with 1
 work with 120
 work with 120
 other_work with 2
 other_work with 3
 work with 130
 work with 130
 other_work with 4
 other_work with 5
 work with 140
 work with 140
 other_work with 6
 other_work with 7
 work with 150
 work with 150
 other_work with 8
 Ended TaskPool-0_Task-2    <--- here Task-2 makes room in the pool and unblocks `main()`
 TaskPool-0 is locked!
 Started TaskPool-0_Task-3
 other_work with 9
 `starmap` returned
 Called `gather`    <--- now this will block `main()` until all tasks have ended
 work with 160
 work with 160
 other_work with 10
 other_work with 11
 work with 170
 work with 170
 other_work with 12
 other_work with 13
 work with 180
 work with 180
 other_work with 14
 other_work with 15
 Ended TaskPool-0_Task-0
 Ended TaskPool-0_Task-1    <--- even though there is room in the pool now, Task-5 will not start
 Started TaskPool-0_Task-4
 work with 190
 work with 190
 other_work with 16
 other_work with 20
 other_work with 17
 other_work with 21
 other_work with 18
 other_work with 22
 other_work with 19
 Ended TaskPool-0_Task-3    <--- now that only Task-4 is left, Task-5 will start
 Started TaskPool-0_Task-5
 other_work with 23
 other_work with 30
 other_work with 24
 other_work with 31
 other_work with 25
 other_work with 32
 other_work with 26
 other_work with 33
 other_work with 27
 other_work with 34
 other_work with 28
 other_work with 35
 Ended TaskPool-0_Task-4
 other_work with 29
 other_work with 36
 other_work with 37
 other_work with 38
 other_work with 39
 Done.
 Ended TaskPool-0_Task-5
 ```
 © 2022 Daniil Fajnberg
--- a/usage/example_server.py
+++ b/usage/example_server.py
@@ -1,3 +1,25 @@
 __author__ = "Daniil Fajnberg"
 __copyright__ = "Copyright © 2022 Daniil Fajnberg"
 __license__ = """GNU LGPLv3.0
 This file is part of asyncio-taskpool.
 asyncio-taskpool is free software: you can redistribute it and/or modify it under the terms of
 version 3.0 of the GNU Lesser General Public License as published by the Free Software Foundation.
 asyncio-taskpool is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; 
 without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 See the GNU Lesser General Public License for more details.
 You should have received a copy of the GNU Lesser General Public License along with asyncio-taskpool. 
 If not, see <https://www.gnu.org/licenses/>."""
 __doc__ = """
 Working example of a UnixControlServer in combination with the SimpleTaskPool.
 Use the main CLI client to interface at the socket.
 """
 import asyncio
 import logging
@@ -48,12 +70,12 @@ async def main() -> None:
    control_server_task = await UnixControlServer(pool, path='/tmp/py_asyncio_taskpool.sock').serve_forever()
    # We block until `.task_done()` has been called once by our workers for every item placed into the queue.
    await q.join()
-    # Since we don't need any "work" done anymore, we can close our control server by cancelling the task.
+    # Since we don't need any "work" done anymore, we can lock our control server by cancelling the task.
    control_server_task.cancel()
    # Since our workers should now be stuck waiting for more items to pick from the queue, but no items are left,
    # we can now safely cancel their tasks.
    pool.stop_all()
-    pool.close()
+    pool.lock()
    # Finally we allow for all tasks to do do their cleanup, if they need to do any, upon being cancelled.
    # We block until they all return or raise an exception, but since we are not interested in any of their exceptions,
    # we just silently collect their exceptions along with their return values.
Author	SHA1	Message	Date
Daniil Fajnberg	96d01e7259	full unit test coverage and docstrings for `session` module	2022-02-14 17:59:11 +01:00
Daniil Fajnberg	3f3eb7ce38	minor rephrasing	2022-02-13 21:12:35 +01:00
Daniil Fajnberg	05d51eface	simplified method	2022-02-13 20:58:36 +01:00
Daniil Fajnberg	b6aed727e9	additional unit tests	2022-02-13 19:55:27 +01:00
Daniil Fajnberg	c9a8d9ecd1	better placeholders	2022-02-13 19:45:53 +01:00
Daniil Fajnberg	538b9cc91c	major refactoring of the control session/parser classes; restructured constants	2022-02-13 19:39:21 +01:00
Daniil Fajnberg	3fb451a00e	docstrings and full test coverage for `server` module; small adjustments	2022-02-13 16:17:50 +01:00
Daniil Fajnberg	be03097bf4	massive overhaul of the control server interface; making use of `ArgumentParser` for client commands; new `ControlSession` object instantiated upon connection	2022-02-12 22:51:52 +01:00
Daniil Fajnberg	024e5db0d4	license & copyright notices; docstrings for each module; extended readme	2022-02-09 23:14:42 +01:00
Daniil Fajnberg	bc9d2f243e	renamed "closing" a pool to "locking" it	2022-02-08 23:09:33 +01:00
Daniil Fajnberg	012c8ac639	testing notes in readme	2022-02-08 16:43:44 +01:00
Daniil Fajnberg	8fd40839ee	full unittest coverage for the `helpers` module	2022-02-08 16:40:13 +01:00
Daniil Fajnberg	36d026f433	more precise comments	2022-02-08 16:24:37 +01:00
Daniil Fajnberg	410e73e68b	bugfix for `TaskPool._map`; usage example for `TaskPool`	2022-02-08 16:15:55 +01:00
Daniil Fajnberg	727f0b7c8b	added full test coverage and docstrings for `TaskPool` as well as minor improvements	2022-02-08 14:30:42 +01:00