docstrings and full test coverage for server module; small adjustments

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = asyncio-taskpool
-version = 0.3.0
+version = 0.3.1
 author = Daniil Fajnberg
 author_email = mail@daniil.fajnberg.de
 description = Dynamically manage pools of asyncio tasks

src/asyncio_taskpool/server.py

@@ -31,74 +31,121 @@ from typing import Optional, Union
 from .client import ControlClient, UnixControlClient
 from .pool import TaskPool, SimpleTaskPool
 from .session import ControlSession
+from .types import ConnectedCallbackT
 
 
 log = logging.getLogger(__name__)
 
 
 class ControlServer(ABC):  # TODO: Implement interface for normal TaskPool instances, not just SimpleTaskPool
+    """
+    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: Union[TaskPool, SimpleTaskPool], **server_kwargs) -> None:
+        """
+        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
 
-    def __str__(self) -> str:
-        return f"{self.__class__.__name__} for {self._pool}"
-
     @property
     def pool(self) -> Union[TaskPool, SimpleTaskPool]:
+        """Read-only property for accessing the task pool instance controlled by the server."""
         return self._pool
 
     def is_serving(self) -> bool:
+        """Wrapper around the `asyncio.Server.is_serving` method."""
         return self._server.is_serving()
 
     async def _client_connected_cb(self, reader: StreamReader, writer: StreamWriter) -> None:
+        """
+        The universal client callback that will be passed into the `_get_server_instance` method.
+        Instantiates a control session, performs the client handshake, and enters the session's `listen` loop.
+        """
         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):
+    """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))

src/asyncio_taskpool/types.py

@@ -34,4 +34,5 @@ CoroutineFunc = Callable[[...], Awaitable[Any]]
 EndCallbackT = Callable
 CancelCallbackT = Callable
 
+ConnectedCallbackT = Callable[[StreamReader, StreamWriter], Awaitable[None]]
 ClientConnT = Union[Tuple[StreamReader, StreamWriter], Tuple[None, None]]

tests/test_server.py

@@ -0,0 +1,143 @@
+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()