libervia-backend/libervia/backend/core/launcher.py
Goffi f7a42771e8 core: implement isolation mode:
Normally the backend is made to have a singleton instance, and handle all profiles.
However, it may be useful to run instances independently (e.g., for development, to run
components in independent processes, for testing, etc).

This was previously possible by using a specific configuration files at backend's root.
This patch introduce a cleaner way by using an isolation mode.

Isolation mode is activated by settings the `LIBERVIA_ISOLATION` environment variable to
the name of the isolated instance. `LIBERVIA_ISOLATION_MODE` can be used to specify one of
the following mode:
- normal (default): config and shared files are in XDG in a `isolated/<name>` subdirectory
  (usually `~/.local/share/libervia/isolated/<name>` and
  `~/.config/libervia/isolated/<name>`). Runtime files and other instance specific data
  (such as D-Bus name) are also isolated. Config uses cascade as usual.
- full: same as above, but config isn't cascading, it's using only its own isolated config
  file.
- tmp: same as normal but the local directory is put in a temporary directory, and deleted
  on backend startup. It stays on termination, so data can be checked if necessary (this mode is
  usually used for development).

This feature will notably be useful to test severless mode on a single machine.

rel 479
2026-07-17 16:45:29 +02:00

387 lines
14 KiB
Python

#!/usr/bin/env python3
# Libervia: an XMPP client
# Copyright (C) 2009-2026 Jérôme Poisson (goffi@goffi.org)
# 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.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
"""Script launching Libervia backend"""
import sys
import os
import argparse
import shutil
import tempfile
from argparse import _SubParsersAction
from pathlib import Path
# We want to install asyncreactor before any import from twisted or Libervia to be sure
# that the right reactor is used.
import asyncio
from twisted.internet import asyncioreactor
# FIXME: In Python 3.14+, asyncio.get_event_loop() raises a RuntimeError and no longer
# implicitly creates a new loop. This behavior was making the backend launch fail. So to
# work around this, we create a new loop here, before installing asyncioreactor. A fix
# is present in a non-released version of Twisted (commit ef6160a). Once the new version
# is realeased and used in Libervia, we can remove this workaround.
try:
asyncio.get_event_loop()
except RuntimeError:
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
asyncioreactor.install()
from libervia.backend.core.constants import Const as C
from libervia.backend.tools.config import parse_main_conf
from twisted.application import app
from twisted.python import usage
class LiberviaLogger(app.AppLogger):
def start(self, application):
# logging is initialised by libervia.baceknd.core.log_config via the Twisted
# plugin, nothing to do here
self._initialLog()
def stop(self):
pass
class Launcher:
APP_NAME = C.APP_NAME
APP_NAME_FILE = C.APP_NAME_FILE
@property
def NOT_RUNNING_MSG(self):
return f"{self.APP_NAME} is *NOT* running"
def __init__(self):
try:
self.config = parse_main_conf(log_filenames=True)
except Exception as e:
print(rf"/!\ Can't read main config! {e}")
sys.exit(1)
if C.isolation_mode == "tmp":
self.clean_tmp_dir()
if C.isolation_mode is not None:
print(
f"Isolation mode '{C.isolation_mode}' active "
f"(instance: {C.isolation_name}, "
f"config: {C.ISOLATED_CONFIG_DIR})"
)
def clean_tmp_dir(self) -> None:
"""Remove temporary isolation directory on startup."""
tmp_path = C.ISOLATED_LOCAL_DIR
if tmp_path is None:
return
# We want to be sure that we delete a temporary directory, and not accidentally
# another local directory.
if str(tmp_path).startswith(tempfile.gettempdir()):
shutil.rmtree(tmp_path, ignore_errors=True)
print(f"Cleaned temp isolation directory: {tmp_path}")
def cmd_no_subparser(self, args):
"""Command launched by default"""
args.extra_args = []
self.cmd_background(args)
def cmd_background(self, args):
self.run_twistd(args)
def cmd_foreground(self, args):
self.run_twistd(args, twistd_opts=["--nodaemon"])
def cmd_debug(self, args):
self.run_twistd(args, twistd_opts=["--debug"])
def cmd_stop(self, args):
import signal
import time
pid_file = self.get_pid_file()
if not pid_file.is_file():
print(self.NOT_RUNNING_MSG)
sys.exit(0)
try:
pid = int(pid_file.read_text())
except Exception as e:
print(f"Can't read PID file at {pid_file}: {e}")
# we use the same exit code as DATA_ERROR in CLI frontend
sys.exit(17)
print(f"Terminating {self.APP_NAME}…")
os.kill(pid, signal.SIGTERM)
kill_started = time.time()
state = "init"
import errno
while True:
try:
os.kill(pid, 0)
except OSError as e:
if e.errno == errno.ESRCH:
break
elif e.errno == errno.EPERM:
print(
f"Can't kill {self.APP_NAME}, the process is owned by an other user",
file=sys.stderr,
)
sys.exit(18)
else:
raise e
time.sleep(0.2)
now = time.time()
if state == "init" and now - kill_started > 5:
if state == "init":
state = "waiting"
print(f"Still waiting for {self.APP_NAME} to be terminated…")
elif state == "waiting" and now - kill_started > 10:
state == "killing"
print("Waiting for too long, we kill the process")
os.kill(pid, signal.SIGKILL)
sys.exit(1)
sys.exit(0)
def cmd_status(self, args):
pid_file = self.get_pid_file()
if pid_file.is_file():
import errno
try:
pid = int(pid_file.read_text())
except Exception as e:
print(f"Can't read PID file at {pid_file}: {e}")
# we use the same exit code as DATA_ERROR in CLI frontend
sys.exit(17)
# we check if there is a process
# inspired by https://stackoverflow.com/a/568285 and https://stackoverflow.com/a/6940314
try:
os.kill(pid, 0)
except OSError as e:
if e.errno == errno.ESRCH:
running = False
elif e.errno == errno.EPERM:
print("Process {pid} is run by an other user")
running = True
else:
running = True
if running:
print(f"{self.APP_NAME} is running (pid: {pid})")
sys.exit(0)
else:
print(
f"{self.NOT_RUNNING_MSG}, but a pid file is present (bad exit ?): {pid_file}"
)
sys.exit(2)
else:
print(self.NOT_RUNNING_MSG)
sys.exit(1)
def parse_args(self) -> argparse.Namespace:
"""Parse command-line arguments and return the resulting namespace.
Subclasses can override to add custom subparsers before calling
``parser.parse_args()``.
@return: The configured argument parser.
"""
parser = argparse.ArgumentParser(description=f"Launch {self.APP_NAME} backend")
parser.set_defaults(cmd=self.cmd_no_subparser)
subparsers: _SubParsersAction = parser.add_subparsers()
self.add_subparsers(subparsers)
return parser.parse_args()
def add_subparsers(self, subparsers: _SubParsersAction) -> None:
"""Add subparsers (bg, fg, debug, stop, status).
@param subparsers: The subparsers object from the argument parser.
"""
extra_help = f"arguments to pass to {self.APP_NAME} service"
bg_parser = subparsers.add_parser(
"background",
aliases=["bg"],
help=f"run {self.APP_NAME} backend in background (as a daemon)",
)
bg_parser.add_argument("extra_args", nargs=argparse.REMAINDER, help=extra_help)
bg_parser.set_defaults(cmd=self.cmd_background)
fg_parser = subparsers.add_parser(
"foreground",
aliases=["fg"],
help=f"run {self.APP_NAME} backend in foreground",
)
fg_parser.add_argument("extra_args", nargs=argparse.REMAINDER, help=extra_help)
fg_parser.set_defaults(cmd=self.cmd_foreground)
dbg_parser = subparsers.add_parser(
"debug", aliases=["dbg"], help=f"run {self.APP_NAME} backend in debug mode"
)
dbg_parser.add_argument("extra_args", nargs=argparse.REMAINDER, help=extra_help)
dbg_parser.set_defaults(cmd=self.cmd_debug)
stop_parser = subparsers.add_parser(
"stop", help=f"stop running {self.APP_NAME} backend"
)
stop_parser.set_defaults(cmd=self.cmd_stop)
status_parser = subparsers.add_parser(
"status", help=f"indicate if {self.APP_NAME} backend is running"
)
status_parser.set_defaults(cmd=self.cmd_status)
def get_pid_file(self) -> Path:
return self.config.common.pid_dir / f"{self.APP_NAME_FILE}.pid"
def wait_for_service(
self, service_host: str, service_port: int, timeout: int, service_name: str
) -> None:
"""Waits for a network service to become available.
@param service_host: The hostname or IP address of the service.
@param service_port: The port number of the service.
@param timeout: The maximum number of seconds to wait for the service.
@param service_name: The name of the service.
@raise TimeoutError: If the service is not available within the specified timeout.
"""
import socket
import time
start_time = time.time()
wait_interval = 5
while True:
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
sock.settimeout(1)
try:
sock.connect((service_host, service_port))
return
except socket.error:
elapsed_time = time.time() - start_time
if elapsed_time % wait_interval < 1:
print(f"Waiting for {service_name}…")
if elapsed_time > timeout:
raise TimeoutError(
f"{service_name} on {service_host}:{service_port} not "
f"available after {timeout} seconds."
)
time.sleep(1)
def run_twistd(self, args, twistd_opts=None):
"""Run twistd settings options with args"""
from twisted.python.runtime import platformType
if platformType == "win32":
from twisted.scripts._twistw import (
ServerOptions,
WindowsApplicationRunner as app_runner,
)
else:
from twisted.scripts._twistd_unix import (
ServerOptions,
UnixApplicationRunner as app_runner,
)
app_runner.loggerFactory = LiberviaLogger
server_options = ServerOptions()
# wait for a service (e.g. XMPP server)
wait_for_service_value = self.config.common.init_wait_for_service
if wait_for_service_value is not None:
try:
# Syntax: [ipv6_address]:port[:timeout][:service_name]
# or hostname:port[:timeout][:service_name]
parts = wait_for_service_value.split(":")
if parts[0] and parts[0][0] == "[" and parts[0][-1] == "]":
# IPv6 address
host = parts[0][1:-1]
else:
# Hostname or IPv4
host = parts[0]
port = int(parts[1])
# Defaults
timeout = 60
service_name = "service"
if len(parts) > 2:
timeout_part = parts[2]
# Check if timeout is skipped (double colon for service_name)
if timeout_part:
timeout = int(timeout_part)
if len(parts) > 3:
service_name = parts[3]
except (ValueError, IndexError):
raise ValueError(
f'Invalid "init_wait_for_service" value: {wait_for_service_value!r}'
)
else:
self.wait_for_service(host, port, timeout, service_name)
pid_file = self.get_pid_file()
log_dir = self.config.common.log_dir
log_file = log_dir / f"{self.APP_NAME_FILE}.log"
server_opts = [
"--no_save",
"--pidfile",
str(pid_file),
"--logfile",
str(log_file),
]
if twistd_opts is not None:
server_opts.extend(twistd_opts)
server_opts.append(self.APP_NAME_FILE)
if args.extra_args:
try:
args.extra_args.remove("--")
except ValueError:
pass
server_opts.extend(args.extra_args)
try:
server_options.parseOptions(server_opts)
except usage.error as ue:
print(server_options)
print("%s: %s" % (sys.argv[0], ue))
sys.exit(1)
else:
runner = app_runner(server_options)
runner.run()
if runner._exitSignal is not None:
app._exitWithSignal(runner._exitSignal)
# FIXME: The loop is not closing correctly as soon as
# libervia.backend.tools.utils.aio decoractor is used. Asyncio loop doesn't
# seem to have any task left, and reactor is stopped, but there is still
# something preventing proper exit. `os._exit` is not great, but currently
# the way to actually close the backend in this case. This needs further
# investigation.
try:
os._exit(app._exit_code)
except AttributeError:
os._exit(C.EXIT_ERROR)
@classmethod
def run(cls):
args = cls().parse_args()
args.cmd(args)
if __name__ == "__main__":
Launcher.run()