diff options
Diffstat (limited to 'synapse/app/_base.py')
| -rw-r--r-- | synapse/app/_base.py | 149 |
1 files changed, 93 insertions, 56 deletions
diff --git a/synapse/app/_base.py b/synapse/app/_base.py index 895b38ae76..9840a9d55b 100644 --- a/synapse/app/_base.py +++ b/synapse/app/_base.py @@ -1,5 +1,6 @@ # -*- coding: utf-8 -*- # Copyright 2017 New Vector Ltd +# Copyright 2019-2021 The Matrix.org Foundation C.I.C # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. @@ -15,11 +16,12 @@ import gc import logging import os +import platform import signal import socket import sys import traceback -from typing import Iterable +from typing import Awaitable, Callable, Iterable from typing_extensions import NoReturn @@ -143,6 +145,45 @@ def quit_with_error(error_string: str) -> NoReturn: sys.exit(1) +def register_start(cb: Callable[..., Awaitable], *args, **kwargs) -> None: + """Register a callback with the reactor, to be called once it is running + + This can be used to initialise parts of the system which require an asynchronous + setup. + + Any exception raised by the callback will be printed and logged, and the process + will exit. + """ + + async def wrapper(): + try: + await cb(*args, **kwargs) + except Exception: + # previously, we used Failure().printTraceback() here, in the hope that + # would give better tracebacks than traceback.print_exc(). However, that + # doesn't handle chained exceptions (with a __cause__ or __context__) well, + # and I *think* the need for Failure() is reduced now that we mostly use + # async/await. + + # Write the exception to both the logs *and* the unredirected stderr, + # because people tend to get confused if it only goes to one or the other. + # + # One problem with this is that if people are using a logging config that + # logs to the console (as is common eg under docker), they will get two + # copies of the exception. We could maybe try to detect that, but it's + # probably a cost we can bear. + logger.fatal("Error during startup", exc_info=True) + print("Error during startup:", file=sys.__stderr__) + traceback.print_exc(file=sys.__stderr__) + + # it's no use calling sys.exit here, since that just raises a SystemExit + # exception which is then caught by the reactor, and everything carries + # on as normal. + os._exit(1) + + reactor.callWhenRunning(lambda: defer.ensureDeferred(wrapper())) + + def listen_metrics(bind_addresses, port): """ Start Prometheus metrics server. @@ -227,7 +268,7 @@ def refresh_certificate(hs): logger.info("Context factories updated.") -def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]): +async def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]): """ Start a Synapse server or worker. @@ -241,71 +282,67 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]): hs: homeserver instance listeners: Listener configuration ('listeners' in homeserver.yaml) """ - try: - # Set up the SIGHUP machinery. - if hasattr(signal, "SIGHUP"): + # Set up the SIGHUP machinery. + if hasattr(signal, "SIGHUP"): + reactor = hs.get_reactor() - @wrap_as_background_process("sighup") - def handle_sighup(*args, **kwargs): - # Tell systemd our state, if we're using it. This will silently fail if - # we're not using systemd. - sdnotify(b"RELOADING=1") + @wrap_as_background_process("sighup") + def handle_sighup(*args, **kwargs): + # Tell systemd our state, if we're using it. This will silently fail if + # we're not using systemd. + sdnotify(b"RELOADING=1") - for i, args, kwargs in _sighup_callbacks: - i(*args, **kwargs) + for i, args, kwargs in _sighup_callbacks: + i(*args, **kwargs) - sdnotify(b"READY=1") + sdnotify(b"READY=1") - # We defer running the sighup handlers until next reactor tick. This - # is so that we're in a sane state, e.g. flushing the logs may fail - # if the sighup happens in the middle of writing a log entry. - def run_sighup(*args, **kwargs): - hs.get_clock().call_later(0, handle_sighup, *args, **kwargs) + # We defer running the sighup handlers until next reactor tick. This + # is so that we're in a sane state, e.g. flushing the logs may fail + # if the sighup happens in the middle of writing a log entry. + def run_sighup(*args, **kwargs): + # `callFromThread` should be "signal safe" as well as thread + # safe. + reactor.callFromThread(handle_sighup, *args, **kwargs) - signal.signal(signal.SIGHUP, run_sighup) + signal.signal(signal.SIGHUP, run_sighup) - register_sighup(refresh_certificate, hs) + register_sighup(refresh_certificate, hs) - # Load the certificate from disk. - refresh_certificate(hs) + # Load the certificate from disk. + refresh_certificate(hs) - # Start the tracer - synapse.logging.opentracing.init_tracer( # type: ignore[attr-defined] # noqa - hs - ) + # Start the tracer + synapse.logging.opentracing.init_tracer( # type: ignore[attr-defined] # noqa + hs + ) - # It is now safe to start your Synapse. - hs.start_listening(listeners) - hs.get_datastore().db_pool.start_profiling() - hs.get_pusherpool().start() + # It is now safe to start your Synapse. + hs.start_listening(listeners) + hs.get_datastore().db_pool.start_profiling() + hs.get_pusherpool().start() - # Log when we start the shut down process. - hs.get_reactor().addSystemEventTrigger( - "before", "shutdown", logger.info, "Shutting down..." - ) + # Log when we start the shut down process. + hs.get_reactor().addSystemEventTrigger( + "before", "shutdown", logger.info, "Shutting down..." + ) - setup_sentry(hs) - setup_sdnotify(hs) - - # If background tasks are running on the main process, start collecting the - # phone home stats. - if hs.config.run_background_tasks: - start_phone_stats_home(hs) - - # We now freeze all allocated objects in the hopes that (almost) - # everything currently allocated are things that will be used for the - # rest of time. Doing so means less work each GC (hopefully). - # - # This only works on Python 3.7 - if sys.version_info >= (3, 7): - gc.collect() - gc.freeze() - except Exception: - traceback.print_exc(file=sys.stderr) - reactor = hs.get_reactor() - if reactor.running: - reactor.stop() - sys.exit(1) + setup_sentry(hs) + setup_sdnotify(hs) + + # If background tasks are running on the main process, start collecting the + # phone home stats. + if hs.config.run_background_tasks: + start_phone_stats_home(hs) + + # We now freeze all allocated objects in the hopes that (almost) + # everything currently allocated are things that will be used for the + # rest of time. Doing so means less work each GC (hopefully). + # + # This only works on Python 3.7 + if platform.python_implementation() == "CPython" and sys.version_info >= (3, 7): + gc.collect() + gc.freeze() def setup_sentry(hs): |