platypush/platypush/app/_app.py

380 lines
12 KiB
Python

from contextlib import contextmanager
import logging
import os
import signal
import subprocess
import sys
from typing import Optional, Sequence
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')
class Application:
"""Main class for the Platypush application."""
# Default Redis port
_default_redis_port = 6379
# backend_name => backend_obj map
backends = None
# number of executions retries before a request fails
n_tries = 2
def __init__(
self,
config_file: Optional[str] = None,
workdir: Optional[str] = None,
logsdir: Optional[str] = None,
device_id: Optional[str] = None,
pidfile: Optional[str] = None,
requests_to_process: Optional[int] = None,
no_capture_stdout: bool = False,
no_capture_stderr: bool = False,
redis_queue: Optional[str] = None,
verbose: bool = False,
start_redis: bool = False,
redis_host: Optional[str] = None,
redis_port: Optional[int] = None,
ctrl_sock: Optional[str] = None,
):
"""
:param config_file: Configuration file override (default: None).
:param workdir: Overrides the ``workdir`` setting in the configuration
file (default: None).
:param logsdir: Set logging directory. If not specified, the
``filename`` setting under the ``logging`` section of the
configuration file is used. If not set, logging will be sent to
stdout and stderr.
:param device_id: Override the device ID used to identify this
instance. If not passed here, it is inferred from the configuration
(device_id field). If not present there either, it is inferred from
the hostname.
:param pidfile: File where platypush will store its PID upon launch,
useful if you're planning to integrate the application within a
service or a launcher script (default: None).
:param requests_to_process: Exit after processing the specified
number of requests (default: None, loop forever).
:param no_capture_stdout: Set to true if you want to disable the
stdout capture by the logging system (default: False).
:param no_capture_stderr: Set to true if you want to disable the
stderr capture by the logging system (default: False).
:param redis_queue: Name of the (Redis) queue used for dispatching
messages (default: platypush/bus).
:param verbose: Enable debug/verbose logging, overriding the stored
configuration (default: False).
:param start_redis: If set, it starts a managed Redis instance upon
boot (it requires the ``redis-server`` executable installed on the
server). This is particularly useful when running the application
inside of Docker containers, without relying on ``docker-compose``
to start multiple containers, and in tests (default: False).
:param redis_host: Host of the Redis server to be used. It overrides
the settings in the ``redis`` section of the configuration file.
:param redis_port: Port of the local Redis server. It overrides the
settings in the ``redis`` section of the configuration file.
:param ctrl_sock: If set, it identifies a path to a UNIX domain socket
that the application can use to send control messages (e.g. STOP
and RESTART) to its parent.
"""
self.pidfile = pidfile
self.bus: Optional[Bus] = None
self.redis_queue = redis_queue or RedisBus.DEFAULT_REDIS_QUEUE
self.config_file = config_file
self._verbose = verbose
self._logsdir = (
os.path.abspath(os.path.expanduser(logsdir)) if logsdir else None
)
Config.init(
self.config_file,
device_id=device_id,
workdir=os.path.abspath(os.path.expanduser(workdir)) if workdir else None,
ctrl_sock=os.path.abspath(os.path.expanduser(ctrl_sock))
if ctrl_sock
else None,
)
self.no_capture_stdout = no_capture_stdout
self.no_capture_stderr = no_capture_stderr
self.event_processor = EventProcessor()
self.entities_engine: Optional[EntitiesEngine] = None
self.requests_to_process = requests_to_process
self.processed_requests = 0
self.cron_scheduler = None
self.start_redis = start_redis
self.redis_host = redis_host
self.redis_port = redis_port
self.redis_conf = {}
self._redis_proc: Optional[subprocess.Popen] = None
self.cmd_stream = CommandStream(ctrl_sock)
self._init_bus()
self._init_logging()
def _init_bus(self):
self._redis_conf = get_redis_conf()
self._redis_conf['port'] = self.redis_port or self._redis_conf.get(
'port', self._default_redis_port
)
if self.redis_host:
self._redis_conf['host'] = self.redis_host
Config.set('redis', self._redis_conf)
self.bus = RedisBus(
redis_queue=self.redis_queue,
on_message=self.on_message(),
**self._redis_conf,
)
def _init_logging(self):
logging_conf = Config.get('logging') or {}
if self._verbose:
logging_conf['level'] = logging.DEBUG
if self._logsdir:
logging_conf['filename'] = os.path.join(self._logsdir, 'platypush.log')
logging_conf.pop('stream', None)
Config.set('logging', logging_conf)
logging.basicConfig(**logging_conf)
def _start_redis(self):
if self._redis_proc and self._redis_proc.poll() is None:
log.warning(
'A local Redis instance is already running, refusing to start it again'
)
return
port = self._redis_conf['port']
log.info('Starting local Redis instance on %s', port)
redis_cmd_args = [
'redis-server',
'--bind',
'localhost',
'--port',
str(port),
]
try:
self._redis_proc = subprocess.Popen( # pylint: disable=consider-using-with
redis_cmd_args,
stdout=subprocess.PIPE,
)
except Exception as e:
log.error(
'Failed to start local Redis instance: "%s": %s',
' '.join(redis_cmd_args),
e,
)
sys.exit(1)
log.info('Waiting for Redis to start')
for line in self._redis_proc.stdout: # type: ignore
if b'Ready to accept connections' in line:
break
def _stop_redis(self):
if self._redis_proc and self._redis_proc.poll() is None:
log.info('Stopping local Redis instance')
self._redis_proc.kill()
self._redis_proc = None
@classmethod
def from_cmdline(cls, args: Sequence[str]) -> "Application":
"""
Build the app from command line arguments.
"""
opts = parse_cmdline(args)
return cls(
config_file=opts.config,
workdir=opts.workdir,
logsdir=opts.logsdir,
device_id=opts.device_id,
pidfile=opts.pidfile,
no_capture_stdout=opts.no_capture_stdout,
no_capture_stderr=opts.no_capture_stderr,
redis_queue=opts.redis_queue,
verbose=opts.verbose,
start_redis=opts.start_redis,
redis_host=opts.redis_host,
redis_port=opts.redis_port,
ctrl_sock=opts.ctrl_sock,
)
def on_message(self):
"""
Default message handler.
"""
def _f(msg):
"""
on_message closure
Params:
msg -- platypush.message.Message instance
"""
if isinstance(msg, Request):
try:
msg.execute(n_tries=self.n_tries)
except PermissionError:
log.info('Dropped unauthorized request: %s', msg)
self.processed_requests += 1
if (
self.requests_to_process
and self.processed_requests >= self.requests_to_process
):
self.stop()
elif isinstance(msg, Response):
msg.log()
elif isinstance(msg, Event):
msg.log()
self.event_processor.process_event(msg)
return _f
def stop(self):
"""Stops the backends and the bus."""
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)
]
for backend in backends:
backend.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.start_redis:
self._stop_redis()
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)
if not self.no_capture_stderr:
sys.stderr = Logger(log.warning)
log.info('---- Starting platypush v.%s', __version__)
# Start the local Redis service if required
if self.start_redis:
self._start_redis()
# Initialize the backends and link them to the bus
self.backends = register_backends(bus=self.bus, global_scope=True)
# Start the backend threads
for backend in self.backends.values():
backend.start()
# Initialize the plugins
register_plugins(bus=self.bus)
# Initialize the entities engine
self.entities_engine = init_entities_engine()
# Start the cron scheduler
if Config.get_cronjobs():
self.cron_scheduler = CronScheduler(jobs=Config.get_cronjobs())
self.cron_scheduler.start()
assert self.bus, 'The bus is not running'
self.bus.post(ApplicationStartedEvent())
# Poll for messages on the bus
try:
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):
"""
Application entry point.
"""
app = Application.from_cmdline(args)
try:
app.run()
except KeyboardInterrupt:
pass
return 0
# vim:sw=4:ts=4:et: