1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
|
#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2022 The Matrix.org Foundation C.I.C.
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import argparse
import importlib
import itertools
import multiprocessing
import os
import signal
import sys
from types import FrameType
from typing import Any, Callable
from twisted.internet.main import installReactor
from synapse.app.complement_fork_proxied_reactor import ProxiedReactor
# a list of the original signal handlers, before we installed our custom ones.
# We restore these in our child processes.
_original_signal_handlers: dict[int, Any] = {}
def _worker_entrypoint(
func: Callable[[], None], proxy_reactor: ProxiedReactor, args: list[str]
) -> None:
"""
Entrypoint for a forked worker process.
We just need to set up the command-line arguments, create our real reactor
and then kick off the worker's main() function.
"""
from synapse.util.stringutils import strtobool
sys.argv = args
# reset the custom signal handlers that we installed, so that the children start
# from a clean slate.
for sig, handler in _original_signal_handlers.items():
signal.signal(sig, handler)
# Install the asyncio reactor if the
# SYNAPSE_COMPLEMENT_FORKING_LAUNCHER_ASYNC_IO_REACTOR is set to 1. The
# SYNAPSE_ASYNC_IO_REACTOR variable would be used, but then causes
# synapse/__init__.py to also try to install an asyncio reactor.
if strtobool(
os.environ.get("SYNAPSE_COMPLEMENT_FORKING_LAUNCHER_ASYNC_IO_REACTOR", "0")
):
import asyncio
from twisted.internet.asyncioreactor import AsyncioSelectorReactor
reactor = AsyncioSelectorReactor(asyncio.get_event_loop())
proxy_reactor._install_real_reactor(reactor)
else:
from twisted.internet.epollreactor import EPollReactor
proxy_reactor._install_real_reactor(EPollReactor())
func()
def main() -> None:
"""
Entrypoint for the forking launcher.
"""
parser = argparse.ArgumentParser()
parser.add_argument("db_config", help="Path to database config file")
parser.add_argument(
"args",
nargs="...",
help="Argument groups separated by `--`. "
"The first argument of each group is a Synapse app name. "
"Subsequent arguments are passed through.",
)
ns = parser.parse_args()
# Split up the subsequent arguments into each workers' arguments;
# `--` is our delimiter of choice.
args_by_worker: list[list[str]] = [
list(args)
for cond, args in itertools.groupby(ns.args, lambda ele: ele != "--")
if cond and args
]
# Prevent Twisted from installing a shared reactor that all the workers will
# inherit when we fork(), by installing our own beforehand.
proxy_reactor = ProxiedReactor()
installReactor(proxy_reactor)
# Import the entrypoints for all the workers.
worker_functions = []
for worker_args in args_by_worker:
worker_module = importlib.import_module(worker_args[0])
worker_functions.append(worker_module.main)
# We need to prepare the database first as otherwise all the workers will
# try to create a schema version table and some will crash out.
from synapse._scripts import update_synapse_database
update_proc = multiprocessing.Process(
target=_worker_entrypoint,
args=(
update_synapse_database.main,
proxy_reactor,
[
"update_synapse_database",
"--database-config",
ns.db_config,
"--run-background-updates",
],
),
)
print("===== PREPARING DATABASE =====", file=sys.stderr)
update_proc.start()
update_proc.join()
print("===== PREPARED DATABASE =====", file=sys.stderr)
processes: list[multiprocessing.Process] = []
# Install signal handlers to propagate signals to all our children, so that they
# shut down cleanly. This also inhibits our own exit, but that's good: we want to
# wait until the children have exited.
def handle_signal(signum: int, frame: FrameType | None) -> None:
print(
f"complement_fork_starter: Caught signal {signum}. Stopping children.",
file=sys.stderr,
)
for p in processes:
if p.pid:
os.kill(p.pid, signum)
for sig in (signal.SIGINT, signal.SIGTERM):
_original_signal_handlers[sig] = signal.signal(sig, handle_signal)
# At this point, we've imported all the main entrypoints for all the workers.
# Now we basically just fork() out to create the workers we need.
# Because we're using fork(), all the workers get a clone of this launcher's
# memory space and don't need to repeat the work of loading the code!
# Instead of using fork() directly, we use the multiprocessing library,
# which uses fork() on Unix platforms.
for func, worker_args in zip(worker_functions, args_by_worker):
process = multiprocessing.Process(
target=_worker_entrypoint, args=(func, proxy_reactor, worker_args)
)
process.start()
processes.append(process)
# Be a good parent and wait for our children to die before exiting.
for process in processes:
process.join()
if __name__ == "__main__":
main()
|
