Move synctl into `synapse._scripts` and expose as an entrypoint (#12140)

1 files changed, 360 insertions, 0 deletions

diff --git a/synapse/_scripts/synctl.py b/synapse/_scripts/synctl.py
new file mode 100755
index 0000000000..1ab36949c7
--- /dev/null
+++ b/synapse/_scripts/synctl.py
@@ -0,0 +1,360 @@
+#!/usr/bin/env python
+# Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
+#
+# 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 argparse
+import collections
+import errno
+import glob
+import os
+import os.path
+import signal
+import subprocess
+import sys
+import time
+from typing import Iterable, Optional
+
+import yaml
+
+from synapse.config import find_config_files
+
+MAIN_PROCESS = "synapse.app.homeserver"
+
+GREEN = "\x1b[1;32m"
+YELLOW = "\x1b[1;33m"
+RED = "\x1b[1;31m"
+NORMAL = "\x1b[m"
+
+SYNCTL_CACHE_FACTOR_WARNING = """\
+Setting 'synctl_cache_factor' in the config is deprecated. Instead, please do
+one of the following:
+ - Either set the environment variable 'SYNAPSE_CACHE_FACTOR'
+ - or set 'caches.global_factor' in the homeserver config.
+--------------------------------------------------------------------------------"""
+
+
+def pid_running(pid):
+    try:
+        os.kill(pid, 0)
+    except OSError as err:
+        if err.errno == errno.EPERM:
+            pass  # process exists
+        else:
+            return False
+
+    # When running in a container, orphan processes may not get reaped and their
+    # PIDs may remain valid. Try to work around the issue.
+    try:
+        with open(f"/proc/{pid}/status") as status_file:
+            if "zombie" in status_file.read():
+                return False
+    except Exception:
+        # This isn't Linux or `/proc/` is unavailable.
+        # Assume that the process is still running.
+        pass
+
+    return True
+
+
+def write(message, colour=NORMAL, stream=sys.stdout):
+    # Lets check if we're writing to a TTY before colouring
+    should_colour = False
+    try:
+        should_colour = stream.isatty()
+    except AttributeError:
+        # Just in case `isatty` isn't defined on everything. The python
+        # docs are incredibly vague.
+        pass
+
+    if not should_colour:
+        stream.write(message + "\n")
+    else:
+        stream.write(colour + message + NORMAL + "\n")
+
+
+def abort(message, colour=RED, stream=sys.stderr):
+    write(message, colour, stream)
+    sys.exit(1)
+
+
+def start(pidfile: str, app: str, config_files: Iterable[str], daemonize: bool) -> bool:
+    """Attempts to start a synapse main or worker process.
+    Args:
+        pidfile: the pidfile we expect the process to create
+        app: the python module to run
+        config_files: config files to pass to synapse
+        daemonize: if True, will include a --daemonize argument to synapse
+
+    Returns:
+        True if the process started successfully or was already running
+        False if there was an error starting the process
+    """
+
+    if os.path.exists(pidfile) and pid_running(int(open(pidfile).read())):
+        print(app + " already running")
+        return True
+
+    args = [sys.executable, "-m", app]
+    for c in config_files:
+        args += ["-c", c]
+    if daemonize:
+        args.append("--daemonize")
+
+    try:
+        subprocess.check_call(args)
+        write("started %s(%s)" % (app, ",".join(config_files)), colour=GREEN)
+        return True
+    except subprocess.CalledProcessError as e:
+        err = "%s(%s) failed to start (exit code: %d). Check the Synapse logfile" % (
+            app,
+            ",".join(config_files),
+            e.returncode,
+        )
+        if daemonize:
+            err += ", or run synctl with --no-daemonize"
+        err += "."
+        write(err, colour=RED, stream=sys.stderr)
+        return False
+
+
+def stop(pidfile: str, app: str) -> Optional[int]:
+    """Attempts to kill a synapse worker from the pidfile.
+    Args:
+        pidfile: path to file containing worker's pid
+        app: name of the worker's appservice
+
+    Returns:
+        process id, or None if the process was not running
+    """
+
+    if os.path.exists(pidfile):
+        pid = int(open(pidfile).read())
+        try:
+            os.kill(pid, signal.SIGTERM)
+            write("stopped %s" % (app,), colour=GREEN)
+            return pid
+        except OSError as err:
+            if err.errno == errno.ESRCH:
+                write("%s not running" % (app,), colour=YELLOW)
+            elif err.errno == errno.EPERM:
+                abort("Cannot stop %s: Operation not permitted" % (app,))
+            else:
+                abort("Cannot stop %s: Unknown error" % (app,))
+    else:
+        write(
+            "No running worker of %s found (from %s)\nThe process might be managed by another controller (e.g. systemd)"
+            % (app, pidfile),
+            colour=YELLOW,
+        )
+    return None
+
+
+Worker = collections.namedtuple(
+    "Worker", ["app", "configfile", "pidfile", "cache_factor", "cache_factors"]
+)
+
+
+def main():
+
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument(
+        "action",
+        choices=["start", "stop", "restart"],
+        help="whether to start, stop or restart the synapse",
+    )
+    parser.add_argument(
+        "configfile",
+        nargs="?",
+        default="homeserver.yaml",
+        help="the homeserver config file. Defaults to homeserver.yaml. May also be"
+        " a directory with *.yaml files",
+    )
+    parser.add_argument(
+        "-w", "--worker", metavar="WORKERCONFIG", help="start or stop a single worker"
+    )
+    parser.add_argument(
+        "-a",
+        "--all-processes",
+        metavar="WORKERCONFIGDIR",
+        help="start or stop all the workers in the given directory"
+        " and the main synapse process",
+    )
+    parser.add_argument(
+        "--no-daemonize",
+        action="store_false",
+        dest="daemonize",
+        help="Run synapse in the foreground for debugging. "
+        "Will work only if the daemonize option is not set in the config.",
+    )
+
+    options = parser.parse_args()
+
+    if options.worker and options.all_processes:
+        write('Cannot use "--worker" with "--all-processes"', stream=sys.stderr)
+        sys.exit(1)
+    if not options.daemonize and options.all_processes:
+        write('Cannot use "--no-daemonize" with "--all-processes"', stream=sys.stderr)
+        sys.exit(1)
+
+    configfile = options.configfile
+
+    if not os.path.exists(configfile):
+        write(
+            f"Config file {configfile} does not exist.\n"
+            f"To generate a config file, run:\n"
+            f"    {sys.executable} -m {MAIN_PROCESS}"
+            f" -c {configfile} --generate-config"
+            f" --server-name=<server name> --report-stats=<yes/no>\n",
+            stream=sys.stderr,
+        )
+        sys.exit(1)
+
+    config_files = find_config_files([configfile])
+    config = {}
+    for config_file in config_files:
+        with open(config_file) as file_stream:
+            yaml_config = yaml.safe_load(file_stream)
+        if yaml_config is not None:
+            config.update(yaml_config)
+
+    pidfile = config["pid_file"]
+    cache_factor = config.get("synctl_cache_factor")
+    start_stop_synapse = True
+
+    if cache_factor:
+        write(SYNCTL_CACHE_FACTOR_WARNING)
+        os.environ["SYNAPSE_CACHE_FACTOR"] = str(cache_factor)
+
+    cache_factors = config.get("synctl_cache_factors", {})
+    for cache_name, factor in cache_factors.items():
+        os.environ["SYNAPSE_CACHE_FACTOR_" + cache_name.upper()] = str(factor)
+
+    worker_configfiles = []
+    if options.worker:
+        start_stop_synapse = False
+        worker_configfile = options.worker
+        if not os.path.exists(worker_configfile):
+            write(
+                "No worker config found at %r" % (worker_configfile,), stream=sys.stderr
+            )
+            sys.exit(1)
+        worker_configfiles.append(worker_configfile)
+
+    if options.all_processes:
+        # To start the main synapse with -a you need to add a worker file
+        # with worker_app == "synapse.app.homeserver"
+        start_stop_synapse = False
+        worker_configdir = options.all_processes
+        if not os.path.isdir(worker_configdir):
+            write(
+                "No worker config directory found at %r" % (worker_configdir,),
+                stream=sys.stderr,
+            )
+            sys.exit(1)
+        worker_configfiles.extend(
+            sorted(glob.glob(os.path.join(worker_configdir, "*.yaml")))
+        )
+
+    workers = []
+    for worker_configfile in worker_configfiles:
+        with open(worker_configfile) as stream:
+            worker_config = yaml.safe_load(stream)
+        worker_app = worker_config["worker_app"]
+        if worker_app == "synapse.app.homeserver":
+            # We need to special case all of this to pick up options that may
+            # be set in the main config file or in this worker config file.
+            worker_pidfile = worker_config.get("pid_file") or pidfile
+            worker_cache_factor = (
+                worker_config.get("synctl_cache_factor") or cache_factor
+            )
+            worker_cache_factors = (
+                worker_config.get("synctl_cache_factors") or cache_factors
+            )
+            # The master process doesn't support using worker_* config.
+            for key in worker_config:
+                if key == "worker_app":  # But we allow worker_app
+                    continue
+                assert not key.startswith(
+                    "worker_"
+                ), "Main process cannot use worker_* config"
+        else:
+            worker_pidfile = worker_config["worker_pid_file"]
+            worker_cache_factor = worker_config.get("synctl_cache_factor")
+            worker_cache_factors = worker_config.get("synctl_cache_factors", {})
+        workers.append(
+            Worker(
+                worker_app,
+                worker_configfile,
+                worker_pidfile,
+                worker_cache_factor,
+                worker_cache_factors,
+            )
+        )
+
+    action = options.action
+
+    if action == "stop" or action == "restart":
+        running_pids = []
+        for worker in workers:
+            pid = stop(worker.pidfile, worker.app)
+            if pid is not None:
+                running_pids.append(pid)
+
+        if start_stop_synapse:
+            pid = stop(pidfile, MAIN_PROCESS)
+            if pid is not None:
+                running_pids.append(pid)
+
+        if len(running_pids) > 0:
+            write("Waiting for processes to exit...")
+            for running_pid in running_pids:
+                while pid_running(running_pid):
+                    time.sleep(0.2)
+            write("All processes exited")
+
+    if action == "start" or action == "restart":
+        error = False
+        if start_stop_synapse:
+            if not start(pidfile, MAIN_PROCESS, (configfile,), options.daemonize):
+                error = True
+
+        for worker in workers:
+            env = os.environ.copy()
+
+            if worker.cache_factor:
+                os.environ["SYNAPSE_CACHE_FACTOR"] = str(worker.cache_factor)
+
+            for cache_name, factor in worker.cache_factors.items():
+                os.environ["SYNAPSE_CACHE_FACTOR_" + cache_name.upper()] = str(factor)
+
+            if not start(
+                worker.pidfile,
+                worker.app,
+                (configfile, worker.configfile),
+                options.daemonize,
+            ):
+                error = True
+
+            # Reset env back to the original
+            os.environ.clear()
+            os.environ.update(env)
+
+        if error:
+            exit(1)
+
+
+if __name__ == "__main__":
+    main()