diff options
| -rw-r--r-- | changelog.d/8011.misc | 1 | ||||
| -rw-r--r-- | synapse/app/_base.py | 16 | ||||
| -rw-r--r-- | synapse/python_dependencies.py | 1 | ||||
| -rw-r--r-- | synapse/util/daemonize.py | 131 |
4 files changed, 135 insertions, 14 deletions
diff --git a/changelog.d/8011.misc b/changelog.d/8011.misc new file mode 100644 index 0000000000..dfeb4bdaf1 --- /dev/null +++ b/changelog.d/8011.misc @@ -0,0 +1 @@ +Replace daemonize library with a local implementation. diff --git a/synapse/app/_base.py b/synapse/app/_base.py index 373a80a4a7..fa40c68f53 100644 --- a/synapse/app/_base.py +++ b/synapse/app/_base.py @@ -12,7 +12,6 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. - import gc import logging import os @@ -22,7 +21,6 @@ import sys import traceback from typing import Iterable -from daemonize import Daemonize from typing_extensions import NoReturn from twisted.internet import defer, error, reactor @@ -34,6 +32,7 @@ from synapse.config.server import ListenerConfig from synapse.crypto import context_factory from synapse.logging.context import PreserveLoggingContext from synapse.util.async_helpers import Linearizer +from synapse.util.daemonize import daemonize_process from synapse.util.rlimit import change_resource_limit from synapse.util.versionstring import get_version_string @@ -129,17 +128,8 @@ def start_reactor( if print_pidfile: print(pid_file) - daemon = Daemonize( - app=appname, - pid=pid_file, - action=run, - auto_close_fds=False, - verbose=True, - logger=logger, - ) - daemon.start() - else: - run() + daemonize_process(pid_file, logger) + run() def quit_with_error(error_string: str) -> NoReturn: diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py index abea2be4ef..e5f22fb858 100644 --- a/synapse/python_dependencies.py +++ b/synapse/python_dependencies.py @@ -59,7 +59,6 @@ REQUIREMENTS = [ "pyyaml>=3.11", "pyasn1>=0.1.9", "pyasn1-modules>=0.0.7", - "daemonize>=2.3.1", "bcrypt>=3.1.0", "pillow>=4.3.0", "sortedcontainers>=1.4.4", diff --git a/synapse/util/daemonize.py b/synapse/util/daemonize.py new file mode 100644 index 0000000000..a7913fa1af --- /dev/null +++ b/synapse/util/daemonize.py @@ -0,0 +1,131 @@ +# -*- coding: utf-8 -*- +# Copyright (c) 2012, 2013, 2014 Ilya Otyutskiy <ilya.otyutskiy@icloud.com> +# Copyright 2020 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. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +import atexit +import fcntl +import logging +import os +import signal +import sys + + +def daemonize_process(pid_file: str, logger: logging.Logger, chdir: str = "/") -> None: + """daemonize the current process + + This calls fork(), and has the main process exit. When it returns we will be + running in the child process. + """ + + # If pidfile already exists, we should read pid from there; to overwrite it, if + # locking will fail, because locking attempt somehow purges the file contents. + if os.path.isfile(pid_file): + with open(pid_file, "r") as pid_fh: + old_pid = pid_fh.read() + + # Create a lockfile so that only one instance of this daemon is running at any time. + try: + lock_fh = open(pid_file, "w") + except IOError: + print("Unable to create the pidfile.") + sys.exit(1) + + try: + # Try to get an exclusive lock on the file. This will fail if another process + # has the file locked. + fcntl.flock(lock_fh, fcntl.LOCK_EX | fcntl.LOCK_NB) + except IOError: + print("Unable to lock on the pidfile.") + # We need to overwrite the pidfile if we got here. + # + # XXX better to avoid overwriting it, surely. this looks racey as the pid file + # could be created between us trying to read it and us trying to lock it. + with open(pid_file, "w") as pid_fh: + pid_fh.write(old_pid) + sys.exit(1) + + # Fork, creating a new process for the child. + process_id = os.fork() + + if process_id != 0: + # parent process + sys.exit(0) + + # This is the child process. Continue. + + # Stop listening for signals that the parent process receives. + # This is done by getting a new process id. + # setpgrp() is an alternative to setsid(). + # setsid puts the process in a new parent group and detaches its controlling + # terminal. + + os.setsid() + + # point stdin, stdout, stderr at /dev/null + devnull = "/dev/null" + if hasattr(os, "devnull"): + # Python has set os.devnull on this system, use it instead as it might be + # different than /dev/null. + devnull = os.devnull + + devnull_fd = os.open(devnull, os.O_RDWR) + os.dup2(devnull_fd, 0) + os.dup2(devnull_fd, 1) + os.dup2(devnull_fd, 2) + os.close(devnull_fd) + + # now that we have redirected stderr to /dev/null, any uncaught exceptions will + # get sent to /dev/null, so make sure we log them. + # + # (we don't normally expect reactor.run to raise any exceptions, but this will + # also catch any other uncaught exceptions before we get that far.) + + def excepthook(type_, value, traceback): + logger.critical("Unhanded exception", exc_info=(type_, value, traceback)) + + sys.excepthook = excepthook + + # Set umask to default to safe file permissions when running as a root daemon. 027 + # is an octal number which we are typing as 0o27 for Python3 compatibility. + os.umask(0o27) + + # Change to a known directory. If this isn't done, starting a daemon in a + # subdirectory that needs to be deleted results in "directory busy" errors. + os.chdir(chdir) + + try: + lock_fh.write("%s" % (os.getpid())) + lock_fh.flush() + except IOError: + logger.error("Unable to write pid to the pidfile.") + print("Unable to write pid to the pidfile.") + sys.exit(1) + + # write a log line on SIGTERM. + def sigterm(signum, frame): + logger.warning("Caught signal %s. Stopping daemon." % signum) + sys.exit(0) + + signal.signal(signal.SIGTERM, sigterm) + + # Cleanup pid file at exit. + def exit(): + logger.warning("Stopping daemon.") + os.remove(pid_file) + sys.exit(0) + + atexit.register(exit) + + logger.warning("Starting daemon.") |