Ensure that errors during startup are written to the logs and the console. (#10191)

* Defer stdio redirection until we are about to start the reactor

* Catch and handle exceptions during startup
This commit is contained in:
Richard van der Hoff 2021-06-21 11:41:25 +01:00 committed by GitHub
parent 7c536d0fef
commit 107c06081f
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5 changed files with 55 additions and 16 deletions

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@ -0,0 +1 @@
Ensure that errors during startup are written to the logs and the console.

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@ -26,7 +26,9 @@ from typing import Awaitable, Callable, Iterable
from cryptography.utils import CryptographyDeprecationWarning
from typing_extensions import NoReturn
import twisted
from twisted.internet import defer, error, reactor
from twisted.logger import LoggingFile, LogLevel
from twisted.protocols.tls import TLSMemoryBIOFactory
import synapse
@ -139,7 +141,7 @@ def start_reactor(
def quit_with_error(error_string: str) -> NoReturn:
message_lines = error_string.split("\n")
line_length = max(len(line) for line in message_lines if len(line) < 80) + 2
line_length = min(max(len(line) for line in message_lines), 80) + 2
sys.stderr.write("*" * line_length + "\n")
for line in message_lines:
sys.stderr.write(" %s\n" % (line.rstrip(),))
@ -147,6 +149,30 @@ def quit_with_error(error_string: str) -> NoReturn:
sys.exit(1)
def handle_startup_exception(e: Exception) -> NoReturn:
# Exceptions that occur between setting up the logging and forking or starting
# the reactor are written to the logs, followed by a summary to stderr.
logger.exception("Exception during startup")
quit_with_error(
f"Error during initialisation:\n {e}\nThere may be more information in the logs."
)
def redirect_stdio_to_logs() -> None:
streams = [("stdout", LogLevel.info), ("stderr", LogLevel.error)]
for (stream, level) in streams:
oldStream = getattr(sys, stream)
loggingFile = LoggingFile(
logger=twisted.logger.Logger(namespace=stream),
level=level,
encoding=getattr(oldStream, "encoding", None),
)
setattr(sys, stream, loggingFile)
print("Redirected stdout/stderr to logs")
def register_start(cb: Callable[..., Awaitable], *args, **kwargs) -> None:
"""Register a callback with the reactor, to be called once it is running

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@ -32,7 +32,12 @@ from synapse.api.urls import (
SERVER_KEY_V2_PREFIX,
)
from synapse.app import _base
from synapse.app._base import max_request_body_size, register_start
from synapse.app._base import (
handle_startup_exception,
max_request_body_size,
redirect_stdio_to_logs,
register_start,
)
from synapse.config._base import ConfigError
from synapse.config.homeserver import HomeServerConfig
from synapse.config.logger import setup_logging
@ -469,14 +474,21 @@ def start(config_options):
setup_logging(hs, config, use_worker_options=True)
try:
hs.setup()
# Ensure the replication streamer is always started in case we write to any
# streams. Will no-op if no streams can be written to by this worker.
hs.get_replication_streamer()
except Exception as e:
handle_startup_exception(e)
register_start(_base.start, hs)
# redirect stdio to the logs, if configured.
if not hs.config.no_redirect_stdio:
redirect_stdio_to_logs()
_base.start_worker_reactor("synapse-generic-worker", config)

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@ -37,10 +37,11 @@ from synapse.api.urls import (
)
from synapse.app import _base
from synapse.app._base import (
handle_startup_exception,
listen_ssl,
listen_tcp,
max_request_body_size,
quit_with_error,
redirect_stdio_to_logs,
register_start,
)
from synapse.config._base import ConfigError
@ -69,8 +70,6 @@ from synapse.rest.synapse.client import build_synapse_client_resource_tree
from synapse.rest.well_known import WellKnownResource
from synapse.server import HomeServer
from synapse.storage import DataStore
from synapse.storage.engines import IncorrectDatabaseSetup
from synapse.storage.prepare_database import UpgradeDatabaseException
from synapse.util.httpresourcetree import create_resource_tree
from synapse.util.module_loader import load_module
from synapse.util.versionstring import get_version_string
@ -362,10 +361,8 @@ def setup(config_options):
try:
hs.setup()
except IncorrectDatabaseSetup as e:
quit_with_error(str(e))
except UpgradeDatabaseException as e:
quit_with_error("Failed to upgrade database: %s" % (e,))
except Exception as e:
handle_startup_exception(e)
async def start():
# Load the OIDC provider metadatas, if OIDC is enabled.
@ -456,6 +453,11 @@ def main():
# check base requirements
check_requirements()
hs = setup(sys.argv[1:])
# redirect stdio to the logs, if configured.
if not hs.config.no_redirect_stdio:
redirect_stdio_to_logs()
run(hs)

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@ -259,9 +259,7 @@ def _setup_stdlib_logging(config, log_config_path, logBeginner: LogBeginner) ->
finally:
threadlocal.active = False
logBeginner.beginLoggingTo([_log], redirectStandardIO=not config.no_redirect_stdio)
if not config.no_redirect_stdio:
print("Redirected stdout/stderr to logs")
logBeginner.beginLoggingTo([_log], redirectStandardIO=False)
def _load_logging_config(log_config_path: str) -> None: