Various improvements.

- Better synchronization logic on stop for `AsyncRunnablePlugin`.
- Fixed several thread names by dropping `prctl.set_name` in favour of
  specifying the name directly on thread creation.
- Several LINT fixes.

platypush/backend/http/__init__.py

@@ -6,14 +6,14 @@ from multiprocessing import Process
 
 try:
     from websockets.exceptions import ConnectionClosed
-    from websockets import serve as websocket_serve
+    from websockets import serve as websocket_serve  # type: ignore
 except ImportError:
-    from websockets import ConnectionClosed, serve as websocket_serve
+    from websockets import ConnectionClosed, serve as websocket_serve  # type: ignore
 
 from platypush.backend import Backend
 from platypush.backend.http.app import application
 from platypush.context import get_or_create_event_loop
-from platypush.utils import get_ssl_server_context, set_thread_name
+from platypush.utils import get_ssl_server_context
 
 
 class HttpBackend(Backend):
@@ -186,7 +186,7 @@ class HttpBackend(Backend):
         maps=None,
         run_externally=False,
         uwsgi_args=None,
-        **kwargs
+        **kwargs,
     ):
         """
         :param port: Listen port for the web server (default: 8008)
@@ -283,15 +283,13 @@ class HttpBackend(Backend):
                 '--enable-threads',
             ]
 
-        self.local_base_url = '{proto}://localhost:{port}'.format(
+        protocol = 'https' if ssl_cert else 'http'
-            proto=('https' if ssl_cert else 'http'), port=self.port
+        self.local_base_url = f'{protocol}://localhost:{self.port}'
-        )
-
         self._websocket_lock_timeout = 10
         self._websocket_lock = threading.RLock()
         self._websocket_locks = {}
 
-    def send_message(self, msg, **kwargs):
+    def send_message(self, msg, *_, **__):
         self.logger.warning('Use cURL or any HTTP client to query the HTTP backend')
 
     def on_stop(self):
@@ -351,9 +349,7 @@ class HttpBackend(Backend):
             timeout=self._websocket_lock_timeout
         )
         if not acquire_ok:
-            raise TimeoutError(
+            raise TimeoutError(f'Websocket on address {addr} not ready to receive data')
-                'Websocket on address {} not ready to receive data'.format(addr)
-            )
 
     def _release_websocket_lock(self, ws):
         try:
@@ -368,7 +364,7 @@ class HttpBackend(Backend):
                 self._websocket_locks[addr].release()
         except Exception as e:
             self.logger.warning(
-                'Unhandled exception while releasing websocket lock: {}'.format(str(e))
+                'Unhandled exception while releasing websocket lock: %s', e
             )
         finally:
             self._websocket_lock.release()
@@ -381,7 +377,7 @@ class HttpBackend(Backend):
                 self._acquire_websocket_lock(ws)
                 await ws.send(str(event))
             except Exception as e:
-                self.logger.warning('Error on websocket send_event: {}'.format(e))
+                self.logger.warning('Error on websocket send_event: %s', e)
             finally:
                 self._release_websocket_lock(ws)
 
@@ -393,7 +389,7 @@ class HttpBackend(Backend):
                 loop.run_until_complete(send_event(_ws))
             except ConnectionClosed:
                 self.logger.warning(
-                    'Websocket client {} connection lost'.format(_ws.remote_address)
+                    'Websocket client %s connection lost', _ws.remote_address
                 )
                 self.active_websockets.remove(_ws)
                 if _ws.remote_address in self._websocket_locks:
@@ -401,7 +397,6 @@ class HttpBackend(Backend):
 
     def websocket(self):
         """Websocket main server"""
-        set_thread_name('WebsocketServer')
 
         async def register_websocket(websocket, path):
             address = (
@@ -411,16 +406,14 @@ class HttpBackend(Backend):
             )
 
             self.logger.info(
-                'New websocket connection from {} on path {}'.format(address, path)
+                'New websocket connection from %s on path %s', address, path
             )
             self.active_websockets.add(websocket)
 
             try:
                 await websocket.recv()
             except ConnectionClosed:
-                self.logger.info(
+                self.logger.info('Websocket client %s closed connection', address)
-                    'Websocket client {} closed connection'.format(address)
-                )
                 self.active_websockets.remove(websocket)
                 if address in self._websocket_locks:
                     del self._websocket_locks[address]
@@ -435,14 +428,14 @@ class HttpBackend(Backend):
                 register_websocket,
                 self.bind_address,
                 self.websocket_port,
-                **websocket_args
+                **websocket_args,
             )
         )
         self._websocket_loop.run_forever()
 
     def _start_web_server(self):
         def proc():
-            self.logger.info('Starting local web server on port {}'.format(self.port))
+            self.logger.info('Starting local web server on port %s', self.port)
             kwargs = {
                 'host': self.bind_address,
                 'port': self.port,
@@ -470,7 +463,10 @@ class HttpBackend(Backend):
 
         if not self.disable_websocket:
             self.logger.info('Initializing websocket interface')
-            self.websocket_thread = threading.Thread(target=self.websocket)
+            self.websocket_thread = threading.Thread(
+                target=self.websocket,
+                name='WebsocketServer',
+            )
             self.websocket_thread.start()
 
         if not self.run_externally:
@@ -481,13 +477,13 @@ class HttpBackend(Backend):
             self.server_proc.join()
         elif self.uwsgi_args:
             uwsgi_cmd = ['uwsgi'] + self.uwsgi_args
-            self.logger.info('Starting uWSGI with arguments {}'.format(uwsgi_cmd))
+            self.logger.info('Starting uWSGI with arguments %s', uwsgi_cmd)
             self.server_proc = subprocess.Popen(uwsgi_cmd)
         else:
             self.logger.info(
                 'The web server is configured to be launched externally but '
-                + 'no uwsgi_args were provided. Make sure that you run another external service'
+                'no uwsgi_args were provided. Make sure that you run another external service'
-                + 'for the webserver (e.g. nginx)'
+                'for the web server (e.g. nginx)'
             )
 
         self._service_registry_thread = threading.Thread(target=self._register_service)

platypush/backend/mqtt/__init__.py

@@ -13,7 +13,6 @@ from platypush.message import Message
 from platypush.message.event.mqtt import MQTTMessageEvent
 from platypush.message.request import Request
 from platypush.plugins.mqtt import MqttPlugin as MQTTPlugin
-from platypush.utils import set_thread_name
 
 
 class MqttClient(mqtt.Client, threading.Thread):
@@ -39,6 +38,7 @@ class MqttClient(mqtt.Client, threading.Thread):
         mqtt.Client.__init__(self, *args, client_id=client_id, **kwargs)
         threading.Thread.__init__(self)
 
+        self.name = f'MQTTClient:{client_id}'
         self.host = host
         self.port = port
         self.topics = set(topics or [])
@@ -393,7 +393,6 @@ class MqttBackend(Backend):
         def handler(_, __, msg):
             # noinspection PyShadowingNames
             def response_thread(msg):
-                set_thread_name('MQTTProcessor')
                 response = self.get_message_response(msg)
                 if not response:
                     return
@@ -428,7 +427,9 @@ class MqttBackend(Backend):
 
             if isinstance(msg, Request):
                 threading.Thread(
-                    target=response_thread, name='MQTTProcessor', args=(msg,)
+                    target=response_thread,
+                    name='MQTTProcessorResponseThread',
+                    args=(msg,),
                 ).start()
 
         return handler

platypush/plugins/__init__.py

@@ -1,7 +1,6 @@
 import asyncio
 import logging
 import threading
-import time
 
 from abc import ABC, abstractmethod
 from functools import wraps
@@ -11,7 +10,7 @@ from platypush.bus import Bus
 from platypush.common import ExtensionWithManifest
 from platypush.event import EventGenerator
 from platypush.message.response import Response
-from platypush.utils import get_decorators, get_plugin_name_by_class, set_thread_name
+from platypush.utils import get_decorators, get_plugin_name_by_class
 
 PLUGIN_STOP_TIMEOUT = 5  # Plugin stop timeout in seconds
 
@@ -107,25 +106,22 @@ class RunnablePlugin(Plugin):
         return self._should_stop.wait(timeout=timeout)
 
     def start(self):
-        set_thread_name(self.__class__.__name__)
+        self._thread = threading.Thread(
-        self._thread = threading.Thread(target=self._runner)
+            target=self._runner, name=self.__class__.__name__
+        )
         self._thread.start()
 
     def stop(self):
         self._should_stop.set()
         if self._thread and self._thread.is_alive():
-            self.logger.info('Waiting for %s to stop', self.__class__.__name__)
+            self.logger.info('Waiting for the plugin to stop')
             try:
                 if self._thread:
                     self._thread.join(timeout=self._stop_timeout)
                     if self._thread and self._thread.is_alive():
                         self.logger.warning(
-                            'Timeout (seconds={%s}) on exit for the plugin %s',
+                            'Timeout (seconds=%s) on exit for the plugin',
                             self._stop_timeout,
-                            (
-                                get_plugin_name_by_class(self.__class__)
-                                or self.__class__.__name__
-                            ),
                         )
             except Exception as e:
                 self.logger.warning('Could not join thread on stop: %s', e)
@@ -142,7 +138,7 @@ class RunnablePlugin(Plugin):
                 self.logger.exception(e)
 
             if self.poll_interval:
-                time.sleep(self.poll_interval)
+                self.wait_stop(self.poll_interval)
 
         self._thread = None
 
@@ -156,18 +152,27 @@ class AsyncRunnablePlugin(RunnablePlugin, ABC):
         super().__init__(*args, **kwargs)
 
         self._loop: Optional[asyncio.AbstractEventLoop] = None
-        self._loop_runner: Optional[threading.Thread] = None
         self._task: Optional[asyncio.Task] = None
 
     @property
     def _should_start_runner(self):
+        """
+        This property is used to determine if the runner and the event loop
+        should be started for this plugin.
+        """
         return True
 
     @abstractmethod
     async def listen(self):
-        pass
+        """
+        Main body of the async plugin. When it's called, the event loop should
+        already be running and available over `self._loop`.
+        """
 
     async def _listen(self):
+        """
+        Wrapper for :meth:`.listen` that catches any exceptions and logs them.
+        """
         try:
             await self.listen()
         except KeyboardInterrupt:
@@ -179,41 +184,37 @@ class AsyncRunnablePlugin(RunnablePlugin, ABC):
             ):
                 raise e
 
-    def _start_listener(self):
+    def _run_listener(self):
-        set_thread_name(self.__class__.__name__ + ':listener')
         self._loop = asyncio.new_event_loop()
         asyncio.set_event_loop(self._loop)
 
         self._task = self._loop.create_task(self._listen())
         if hasattr(self._task, 'set_name'):
             self._task.set_name(self.__class__.__name__ + '.listen')
-        self._loop.run_forever()
+        try:
+            self._loop.run_until_complete(self._task)
+        except Exception as e:
+            self.logger.info('The loop has terminated with an error: %s', e)
+
+        self._task.cancel()
 
     def main(self):
-        if self.should_stop() or (self._loop_runner and self._loop_runner.is_alive()):
+        if self.should_stop():
-            self.logger.info('The main loop is already being run/stopped')
+            self.logger.info('The plugin is already scheduled to stop')
             return
 
+        self._loop = asyncio.new_event_loop()
+
         if self._should_start_runner:
-            self._loop_runner = threading.Thread(target=self._start_listener)
+            self._run_listener()
-            self._loop_runner.start()
 
         self.wait_stop()
 
     def stop(self):
-        if self._task and self._loop and not self._task.done():
-            self._loop.call_soon_threadsafe(self._task.cancel)
-
         if self._loop and self._loop.is_running():
             self._loop.call_soon_threadsafe(self._loop.stop)
             self._loop = None
 
-        if self._loop_runner and self._loop_runner.is_alive():
-            try:
-                self._loop_runner.join(timeout=self._stop_timeout)
-            finally:
-                self._loop_runner = None
-
         super().stop()
 
 

platypush/plugins/ntfy/__init__.py

@@ -1,7 +1,7 @@
 import asyncio
 import json
 import os
-from typing import Optional, Collection, Mapping
+from typing import Any, Callable, Dict, Optional, Collection, Mapping
 
 import requests
 import websockets
@@ -53,12 +53,12 @@ class NtfyPlugin(AsyncRunnablePlugin):
         reconnect_wait_secs_max = 60
 
         while not self.should_stop():
-            self.logger.debug(f'Connecting to {url}')
+            self.logger.debug('Connecting to %s', url)
 
             try:
-                async with websockets.connect(url) as ws:  # type: ignore
+                async with websockets.connect(url) as ws:  # pylint: disable=no-member
                     reconnect_wait_secs = 1
-                    self.logger.info(f'Connected to {url}')
+                    self.logger.info('Connected to %s', url)
                     async for msg in ws:
                         try:
                             msg = json.loads(msg)
@@ -122,7 +122,7 @@ class NtfyPlugin(AsyncRunnablePlugin):
         tags: Optional[Collection[str]] = None,
         schedule: Optional[str] = None,
     ):
-        """
+        r"""
         Send a message/notification to a topic.
 
         :param topic: Topic where the message will be delivered.
@@ -148,7 +148,7 @@ class NtfyPlugin(AsyncRunnablePlugin):
                 - ``broadcast``: Send an `Android broadcast <https://developer.android.com/guide/components/broadcasts>`
                       intent upon action selection (only available on Android).
 
-            Example:
+        Actions example:
 
         .. code-block:: json
 
@@ -196,9 +196,9 @@ class NtfyPlugin(AsyncRunnablePlugin):
                   ``tomorrow, 3pm``)
 
         """
-        method = requests.post
+        method: Callable[..., requests.Response] = requests.post
         url = server_url or self._server_url
-        args = {}
+        args: Dict[str, Any] = {}
         if username and password:
             args['auth'] = (username, password)
 
@@ -247,8 +247,8 @@ class NtfyPlugin(AsyncRunnablePlugin):
             }
 
         rs = method(url, **args)
-        assert rs.ok, 'Could not send message to {}: {}'.format(
+        assert rs.ok, f'Could not send message to {topic}: ' + rs.json().get(
-            topic, rs.json().get('error', f'HTTP error: {rs.status_code}')
+            'error', f'HTTP error: {rs.status_code}'
         )
 
         return rs.json()