Large refactor + stability fixes for the external process control logic.

platypush/__main__.py

@@ -1,10 +1,5 @@
 import sys
 
-from platypush.app import main
+from platypush.runner import main
 
-
-if __name__ == '__main__':
-    main(*sys.argv[1:])
-
-
-# vim:sw=4:ts=4:et:
+main(*sys.argv[1:])

platypush/app/__init__.py

@@ -0,0 +1,4 @@
+from ._app import Application, main
+
+
+__all__ = ["Application", "main"]

platypush/app/__main__.py

@@ -0,0 +1,7 @@
+import sys
+
+from ._app import main
+
+
+if __name__ == '__main__':
+    sys.exit(main(*sys.argv[1:]))

platypush/app/_app.py

@@ -1,24 +1,26 @@
+from contextlib import contextmanager
 import logging
 import os
+import signal
 import subprocess
 import sys
 from typing import Optional, Sequence
 
-from .bus import Bus
-from .bus.redis import RedisBus
-from .cli import parse_cmdline
-from .commands import CommandStream
-from .config import Config
-from .context import register_backends, register_plugins
-from .cron.scheduler import CronScheduler
-from .entities import init_entities_engine, EntitiesEngine
-from .event.processor import EventProcessor
-from .logger import Logger
-from .message.event import Event
-from .message.event.application import ApplicationStartedEvent
-from .message.request import Request
-from .message.response import Response
-from .utils import get_enabled_plugins, get_redis_conf
+from platypush.bus import Bus
+from platypush.bus.redis import RedisBus
+from platypush.cli import parse_cmdline
+from platypush.commands import CommandStream
+from platypush.config import Config
+from platypush.context import register_backends, register_plugins
+from platypush.cron.scheduler import CronScheduler
+from platypush.entities import init_entities_engine, EntitiesEngine
+from platypush.event.processor import EventProcessor
+from platypush.logger import Logger
+from platypush.message.event import Event
+from platypush.message.event.application import ApplicationStartedEvent
+from platypush.message.request import Request
+from platypush.message.response import Response
+from platypush.utils import get_enabled_plugins, get_redis_conf
 
 log = logging.getLogger('platypush')
 
@@ -87,10 +89,6 @@ class Application:
         """
 
         self.pidfile = pidfile
-        if pidfile:
-            with open(pidfile, 'w') as f:
-                f.write(str(os.getpid()))
-
         self.bus: Optional[Bus] = None
         self.redis_queue = redis_queue or RedisBus.DEFAULT_REDIS_QUEUE
         self.config_file = config_file
@@ -98,7 +96,9 @@ class Application:
         self._logsdir = (
             os.path.abspath(os.path.expanduser(logsdir)) if logsdir else None
         )
+
         Config.init(self.config_file)
+        Config.set('ctrl_sock', ctrl_sock)
 
         if workdir:
             Config.set('workdir', os.path.abspath(os.path.expanduser(workdir)))
@@ -244,36 +244,66 @@ class Application:
 
     def stop(self):
         """Stops the backends and the bus."""
-        from .plugins import RunnablePlugin
+        from platypush.plugins import RunnablePlugin
 
         log.info('Stopping the application')
+        backends = (self.backends or {}).copy().values()
+        runnable_plugins = [
+            plugin
+            for plugin in get_enabled_plugins().values()
+            if isinstance(plugin, RunnablePlugin)
+        ]
 
-        if self.backends:
-            for backend in self.backends.values():
-                backend.stop()
+        for backend in backends:
+            backend.stop()
 
-        for plugin in get_enabled_plugins().values():
-            if isinstance(plugin, RunnablePlugin):
-                plugin.stop()
+        for plugin in runnable_plugins:
+            plugin.stop()
+
+        for backend in backends:
+            backend.wait_stop()
+
+        for plugin in runnable_plugins:
+            plugin.wait_stop()
+
+        if self.entities_engine:
+            self.entities_engine.stop()
+            self.entities_engine.wait_stop()
+            self.entities_engine = None
+
+        if self.cron_scheduler:
+            self.cron_scheduler.stop()
+            self.cron_scheduler.wait_stop()
+            self.cron_scheduler = None
 
         if self.bus:
             self.bus.stop()
             self.bus = None
 
-        if self.cron_scheduler:
-            self.cron_scheduler.stop()
-            self.cron_scheduler = None
-
-        if self.entities_engine:
-            self.entities_engine.stop()
-            self.entities_engine = None
-
         if self.start_redis:
             self._stop_redis()
 
-    def run(self):
-        """Start the daemon."""
-        from . import __version__
+        log.info('Exiting application')
+
+    @contextmanager
+    def _open_pidfile(self):
+        if self.pidfile:
+            try:
+                with open(self.pidfile, 'w') as f:
+                    f.write(str(os.getpid()))
+            except OSError as e:
+                log.warning('Failed to create PID file %s: %s', self.pidfile, e)
+
+        yield
+
+        if self.pidfile:
+            try:
+                os.remove(self.pidfile)
+            except OSError as e:
+                log.warning('Failed to remove PID file %s: %s', self.pidfile, e)
+
+    def _run(self):
+        from platypush import __version__
 
         if not self.no_capture_stdout:
             sys.stdout = Logger(log.info)
@@ -312,9 +342,17 @@ class Application:
             self.bus.poll()
         except KeyboardInterrupt:
             log.info('SIGINT received, terminating application')
+            # Ignore other SIGINT signals
+            signal.signal(signal.SIGINT, signal.SIG_IGN)
         finally:
             self.stop()
 
+    def run(self):
+        """Run the application."""
+
+        with self._open_pidfile():
+            self._run()
+
 
 def main(*args: str):
     """
@@ -327,12 +365,7 @@ def main(*args: str):
     except KeyboardInterrupt:
         pass
 
-    log.info('Application stopped')
     return 0
 
 
-if __name__ == '__main__':
-    sys.exit(main(*sys.argv[1:]))
-
-
 # vim:sw=4:ts=4:et:

platypush/commands/_stream.py

@@ -31,7 +31,7 @@ class CommandStream(ControllableProcess):
     """Close the client socket after this amount of seconds."""
 
     def __init__(self, path: Optional[str] = None):
-        super().__init__(name='platypush-cmd-stream')
+        super().__init__(name='platypush:cmd:stream')
         self.path = os.path.abspath(os.path.expanduser(path or self._default_sock_path))
         self._sock: Optional[socket.socket] = None
         self._cmd_queue: Queue["Command"] = Queue()
@@ -64,6 +64,7 @@ class CommandStream(ControllableProcess):
         sock.bind(self.path)
         os.chmod(self.path, 0o600)
         sock.listen(1)
+        self.start()
         return self
 
     def __exit__(self, *_, **__):

platypush/plugins/system/manifest.yaml

@@ -3,6 +3,5 @@ manifest:
   install:
     pip:
     - py-cpuinfo
-    - psutil
   package: platypush.plugins.system
   type: plugin

platypush/process/__init__.py

@@ -1,5 +1,5 @@
 from abc import ABC, abstractmethod
-from logging import getLogger
+import logging
 from multiprocessing import Event, Process, RLock
 from os import getpid
 from typing import Optional
@@ -17,8 +17,9 @@ class ControllableProcess(Process, ABC):
     def __init__(self, *args, timeout: Optional[float] = None, **kwargs):
         kwargs['name'] = kwargs.get('name', self.__class__.__name__)
         super().__init__(*args, **kwargs)
+
         self.timeout = timeout
-        self.logger = getLogger(self.name)
+        self.logger = logging.getLogger(self.name)
         self._should_stop = Event()
         self._stop_lock = RLock()
         self._should_restart = False
@@ -60,23 +61,22 @@ class ControllableProcess(Process, ABC):
 
         :param timeout: The maximum time to wait for the process to stop.
         """
-        timeout = timeout if timeout is not None else self.timeout
+        timeout = timeout if timeout is not None else self._kill_timeout
         with self._stop_lock:
             self._should_stop.set()
             self.on_stop()
 
-            if self.pid == getpid():
-                return  # Prevent termination deadlock
-
             try:
-                self.wait_stop(timeout=timeout)
+                if self.pid != getpid():
+                    self.wait_stop(timeout=timeout)
             except TimeoutError:
                 pass
             finally:
                 self.terminate()
 
             try:
-                self.wait_stop(timeout=self._kill_timeout)
+                if self.pid != getpid():
+                    self.wait_stop(timeout=self._kill_timeout)
             except TimeoutError:
                 self.logger.warning(
                     'The process %s is still alive after %f seconds, killing it',

platypush/runner/__init__.py

@@ -0,0 +1,17 @@
+from ._runner import ApplicationRunner
+
+
+def main(*args: str):
+    """
+    Main application entry point.
+
+    This is usually the entry point that you want to use to start your
+    application, rather than :meth:`platypush.app.main`, as this entry point
+    wraps the main application in a controllable process.
+    """
+
+    app_runner = ApplicationRunner()
+    app_runner.run(*args)
+
+
+__all__ = ["ApplicationRunner", "main"]

platypush/runner/__main__.py

@@ -0,0 +1,5 @@
+import sys
+
+from . import main
+
+main(sys.argv[1:])

platypush/runner/_app.py

@@ -0,0 +1,59 @@
+import logging
+import os
+import signal
+import subprocess
+import sys
+from typing_extensions import override
+
+from platypush.process import ControllableProcess
+
+
+class ApplicationProcess(ControllableProcess):
+    """
+    Controllable process wrapper interface for the main application.
+    """
+
+    def __init__(self, *args: str, pidfile: str, **kwargs):
+        super().__init__(name='platypush', **kwargs)
+
+        self.logger = logging.getLogger('platypush')
+        self.args = args
+        self.pidfile = pidfile
+
+    def __enter__(self) -> "ApplicationProcess":
+        self.start()
+        return self
+
+    def __exit__(self, *_, **__):
+        self.stop()
+
+    @override
+    def main(self):
+        self.logger.info('Starting application...')
+
+        with subprocess.Popen(
+            ['python', '-m', 'platypush.app', *self.args],
+            stdin=sys.stdin,
+            stdout=sys.stdout,
+            stderr=sys.stderr,
+        ) as app:
+            try:
+                app.wait()
+            except KeyboardInterrupt:
+                pass
+
+    @override
+    def on_stop(self):
+        try:
+            with open(self.pidfile, 'r') as f:
+                pid = int(f.read().strip())
+        except (OSError, ValueError):
+            pid = None
+
+        if not pid:
+            return
+
+        try:
+            os.kill(pid, signal.SIGINT)
+        except OSError:
+            pass

platypush/runner/_runner.py

@@ -0,0 +1,91 @@
+import logging
+import sys
+from threading import Thread
+from typing import Optional
+
+from platypush.cli import parse_cmdline
+from platypush.commands import CommandStream
+
+from ._app import ApplicationProcess
+
+
+class ApplicationRunner:
+    """
+    Runner for the main application.
+
+    It wraps the main application and provides an interface to control it
+    externally.
+    """
+
+    _default_timeout = 0.5
+
+    def __init__(self):
+        logging.basicConfig(level=logging.INFO, stream=sys.stdout)
+        self.logger = logging.getLogger('platypush:runner')
+        self._proc: Optional[ApplicationProcess] = None
+
+    def _listen(self, stream: CommandStream):
+        """
+        Listens for external application commands and executes them.
+        """
+        while self.is_running:
+            cmd = stream.read(timeout=self._default_timeout)
+            if not cmd:
+                continue
+
+            self.logger.info(cmd)
+            Thread(target=cmd, args=(self,)).start()
+
+    def _print_version(self):
+        from platypush import __version__
+
+        print(__version__)
+        sys.exit(0)
+
+    def _run(self, *args: str) -> None:
+        parsed_args = parse_cmdline(args)
+
+        if parsed_args.version:
+            self._print_version()
+
+        while True:
+            with (
+                CommandStream(parsed_args.ctrl_sock) as stream,
+                ApplicationProcess(
+                    *args, pidfile=parsed_args.pidfile, timeout=self._default_timeout
+                ) as self._proc,
+            ):
+                try:
+                    self._listen(stream)
+                except KeyboardInterrupt:
+                    pass
+
+                if self.should_restart:
+                    self.logger.info('Restarting application...')
+                    continue
+
+                break
+
+    def run(self, *args: str) -> None:
+        try:
+            self._run(*args)
+        finally:
+            self._proc = None
+
+    def stop(self):
+        if self._proc is not None:
+            self._proc.stop()
+
+    def restart(self):
+        if self._proc is not None:
+            self._proc.mark_for_restart()
+
+        self.stop()
+
+    @property
+    def is_running(self) -> bool:
+        return bool(self._proc and self._proc.is_alive())
+
+    @property
+    def should_restart(self) -> bool:
+        return self._proc.should_restart if self._proc is not None else False

requirements.txt

@@ -11,6 +11,7 @@ frozendict
 marshmallow
 marshmallow_dataclass
 paho-mqtt
+psutil
 python-dateutil
 python-magic
 pyyaml

setup.py

@@ -68,6 +68,7 @@ setup(
         'frozendict',
         'marshmallow',
         'marshmallow_dataclass',
+        'psutil',
         'python-dateutil',
         'python-magic',
         'pyyaml',
@@ -224,7 +225,7 @@ setup(
         # Support for Graphite integration
         'graphite': ['graphyte'],
         # Support for CPU and memory monitoring and info
-        'sys': ['py-cpuinfo', 'psutil'],
+        'sys': ['py-cpuinfo'],
         # Support for nmap integration
         'nmap': ['python-nmap'],
         # Support for zigbee2mqtt