Improve startup times in Complement test runs against workers, particularly in CPU-constrained environments. (#13127)

Co-authored-by: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
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reivilibre 2022-06-30 12:58:12 +01:00 committed by GitHub
parent 09f6e43025
commit 9667bad55d
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9 changed files with 243 additions and 51 deletions

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@ -328,51 +328,8 @@ jobs:
- arrangement: monolith
database: Postgres
steps:
# The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
# See https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#adding-a-system-path
- name: "Set Go Version"
run: |
# Add Go 1.17 to the PATH: see https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-Readme.md#environment-variables-2
echo "$GOROOT_1_17_X64/bin" >> $GITHUB_PATH
# Add the Go path to the PATH: We need this so we can call gotestfmt
echo "~/go/bin" >> $GITHUB_PATH
- name: "Install Complement Dependencies"
run: |
sudo apt-get update && sudo apt-get install -y libolm3 libolm-dev
go get -v github.com/haveyoudebuggedit/gotestfmt/v2/cmd/gotestfmt@latest
- name: Run actions/checkout@v2 for synapse
uses: actions/checkout@v2
with:
path: synapse
- name: "Install custom gotestfmt template"
run: |
mkdir .gotestfmt/github -p
cp synapse/.ci/complement_package.gotpl .gotestfmt/github/package.gotpl
# Attempt to check out the same branch of Complement as the PR. If it
# doesn't exist, fallback to HEAD.
- name: Checkout complement
run: synapse/.ci/scripts/checkout_complement.sh
- run: |
set -o pipefail
POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
shell: bash
name: Run Complement Tests
# We only run the workers tests on `develop` for now, because they're too slow to wait for on PRs.
# Sadly, you can't have an `if` condition on the value of a matrix, so this is a temporary, separate job for now.
# GitHub Actions doesn't support YAML anchors, so it's full-on duplication for now.
complement-developonly:
if: "${{ !failure() && !cancelled() && (github.ref == 'refs/heads/develop') }}"
needs: linting-done
runs-on: ubuntu-latest
name: "Complement Workers (develop only)"
- arrangement: workers
database: Postgres
steps:
# The path is set via a file given by $GITHUB_PATH. We need both Go 1.17 and GOPATH on the path to run Complement.
@ -406,7 +363,7 @@ jobs:
- run: |
set -o pipefail
WORKERS=1 COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
POSTGRES=${{ (matrix.database == 'Postgres') && 1 || '' }} WORKERS=${{ (matrix.arrangement == 'workers') && 1 || '' }} COMPLEMENT_DIR=`pwd`/complement synapse/scripts-dev/complement.sh -json 2>&1 | gotestfmt
shell: bash
name: Run Complement Tests

1
changelog.d/13127.misc Normal file
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@ -0,0 +1 @@
Improve startup times in Complement test runs against workers, particularly in CPU-constrained environments.

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@ -59,6 +59,9 @@ if [[ -n "$SYNAPSE_COMPLEMENT_USE_WORKERS" ]]; then
synchrotron, \
appservice, \
pusher"
# Improve startup times by using a launcher based on fork()
export SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER=1
else
# Empty string here means 'main process only'
export SYNAPSE_WORKER_TYPES=""

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@ -1,3 +1,24 @@
{% if use_forking_launcher %}
[program:synapse_fork]
command=/usr/local/bin/python -m synapse.app.complement_fork_starter
{{ main_config_path }}
synapse.app.homeserver
--config-path="{{ main_config_path }}"
--config-path=/conf/workers/shared.yaml
{%- for worker in workers %}
-- {{ worker.app }}
--config-path="{{ main_config_path }}"
--config-path=/conf/workers/shared.yaml
--config-path=/conf/workers/{{ worker.name }}.yaml
{%- endfor %}
stdout_logfile=/dev/stdout
stdout_logfile_maxbytes=0
stderr_logfile=/dev/stderr
stderr_logfile_maxbytes=0
autorestart=unexpected
exitcodes=0
{% else %}
[program:synapse_main]
command=/usr/local/bin/prefix-log /usr/local/bin/python -m synapse.app.homeserver
--config-path="{{ main_config_path }}"
@ -13,7 +34,7 @@ autorestart=unexpected
exitcodes=0
{% for worker in workers %}
{% for worker in workers %}
[program:synapse_{{ worker.name }}]
command=/usr/local/bin/prefix-log /usr/local/bin/python -m {{ worker.app }}
--config-path="{{ main_config_path }}"
@ -27,4 +48,5 @@ stdout_logfile_maxbytes=0
stderr_logfile=/dev/stderr
stderr_logfile_maxbytes=0
{% endfor %}
{% endfor %}
{% endif %}

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@ -2,7 +2,11 @@ version: 1
formatters:
precise:
{% if include_worker_name_in_log_line %}
format: '{{ worker_name }} | %(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
{% else %}
format: '%(asctime)s - %(name)s - %(lineno)d - %(levelname)s - %(request)s - %(message)s'
{% endif %}
handlers:
{% if LOG_FILE_PATH %}

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@ -26,6 +26,9 @@
# * SYNAPSE_TLS_CERT: Path to a TLS certificate in PEM format.
# * SYNAPSE_TLS_KEY: Path to a TLS key. If this and SYNAPSE_TLS_CERT are specified,
# Nginx will be configured to serve TLS on port 8448.
# * SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER: Whether to use the forking launcher,
# only intended for usage in Complement at the moment.
# No stability guarantees are provided.
#
# NOTE: According to Complement's ENTRYPOINT expectations for a homeserver image (as defined
# in the project's README), this script may be run multiple times, and functionality should
@ -525,6 +528,7 @@ def generate_worker_files(
"/etc/supervisor/conf.d/synapse.conf",
workers=worker_descriptors,
main_config_path=config_path,
use_forking_launcher=environ.get("SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER"),
)
# healthcheck config
@ -560,6 +564,9 @@ def generate_worker_log_config(
log_config_filepath,
worker_name=worker_name,
**extra_log_template_args,
include_worker_name_in_log_line=environ.get(
"SYNAPSE_USE_EXPERIMENTAL_FORKING_LAUNCHER"
),
)
return log_config_filepath

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@ -110,7 +110,11 @@ def generate_config_from_template(
log_config_file = environ["SYNAPSE_LOG_CONFIG"]
log("Generating log config file " + log_config_file)
convert("/conf/log.config", log_config_file, environ)
convert(
"/conf/log.config",
log_config_file,
{**environ, "include_worker_name_in_log_line": False},
)
# Hopefully we already have a signing key, but generate one if not.
args = [

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@ -106,7 +106,9 @@ def register_sighup(func: Callable[P, None], *args: P.args, **kwargs: P.kwargs)
def start_worker_reactor(
appname: str,
config: HomeServerConfig,
run_command: Callable[[], None] = reactor.run,
# Use a lambda to avoid binding to a given reactor at import time.
# (needed when synapse.app.complement_fork_starter is being used)
run_command: Callable[[], None] = lambda: reactor.run(),
) -> None:
"""Run the reactor in the main process
@ -141,7 +143,9 @@ def start_reactor(
daemonize: bool,
print_pidfile: bool,
logger: logging.Logger,
run_command: Callable[[], None] = reactor.run,
# Use a lambda to avoid binding to a given reactor at import time.
# (needed when synapse.app.complement_fork_starter is being used)
run_command: Callable[[], None] = lambda: reactor.run(),
) -> None:
"""Run the reactor in the main process

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@ -0,0 +1,190 @@
# Copyright 2022 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.
#
# ## What this script does
#
# This script spawns multiple workers, whilst only going through the code loading
# process once. The net effect is that start-up time for a swarm of workers is
# reduced, particularly in CPU-constrained environments.
#
# Before the workers are spawned, the database is prepared in order to avoid the
# workers racing.
#
# ## Stability
#
# This script is only intended for use within the Synapse images for the
# Complement test suite.
# There are currently no stability guarantees whatsoever; especially not about:
# - whether it will continue to exist in future versions;
# - the format of its command-line arguments; or
# - any details about its behaviour or principles of operation.
#
# ## Usage
#
# The first argument should be the path to the database configuration, used to
# set up the database. The rest of the arguments are used as follows:
# Each worker is specified as an argument group (each argument group is
# separated by '--').
# The first argument in each argument group is the Python module name of the application
# to start. Further arguments are then passed to that module as-is.
#
# ## Example
#
# python -m synapse.app.complement_fork_starter path_to_db_config.yaml \
# synapse.app.homeserver [args..] -- \
# synapse.app.generic_worker [args..] -- \
# ...
# synapse.app.generic_worker [args..]
#
import argparse
import importlib
import itertools
import multiprocessing
import sys
from typing import Any, Callable, List
from twisted.internet.main import installReactor
class ProxiedReactor:
"""
Twisted tracks the 'installed' reactor as a global variable.
(Actually, it does some module trickery, but the effect is similar.)
The default EpollReactor is buggy if it's created before a process is
forked, then used in the child.
See https://twistedmatrix.com/trac/ticket/4759#comment:17.
However, importing certain Twisted modules will automatically create and
install a reactor if one hasn't already been installed.
It's not normally possible to re-install a reactor.
Given the goal of launching workers with fork() to only import the code once,
this presents a conflict.
Our work around is to 'install' this ProxiedReactor which prevents Twisted
from creating and installing one, but which lets us replace the actual reactor
in use later on.
"""
def __init__(self) -> None:
self.___reactor_target: Any = None
def _install_real_reactor(self, new_reactor: Any) -> None:
"""
Install a real reactor for this ProxiedReactor to forward lookups onto.
This method is specific to our ProxiedReactor and should not clash with
any names used on an actual Twisted reactor.
"""
self.___reactor_target = new_reactor
def __getattr__(self, attr_name: str) -> Any:
return getattr(self.___reactor_target, attr_name)
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.
"""
sys.argv = args
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)
# 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.
processes = []
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()