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PyLink/launcher.py
Ian Carpenter 28166ed4ee Only write the pid file when --no-pid isn't passed (#633)
Prevents --no-pid from breaking

(cherry picked from commit 30387c9ed5)
2019-03-31 01:25:23 -07:00

204 lines
8.6 KiB
Python

#!/usr/bin/env python3
"""
PyLink IRC Services launcher.
"""
import os
import sys
import signal
import time
from pylinkirc import world, conf, __version__, real_version
try:
import psutil
except ImportError:
psutil = None
args = {}
def _main():
conf.load_conf(args.config)
from pylinkirc.log import log
from pylinkirc import classes, utils, coremods, selectdriver
# Write and check for an existing PID file unless specifically told not to.
if not args.no_pid:
pidfile = '%s.pid' % conf.confname
pid_exists = False
pid = None
if os.path.exists(pidfile):
try:
with open(pidfile) as f:
pid = int(f.read())
except OSError:
log.exception("Could not read PID file %s:", pidfile)
else:
pid_exists = True
if psutil is not None and os.name == 'posix':
# FIXME: Haven't tested this on other platforms, so not turning it on by default.
try:
proc = psutil.Process(pid)
except psutil.NoSuchProcess: # Process doesn't exist!
pid_exists = False
log.info("Ignoring stale PID %s from PID file %r: no such process exists.", pid, pidfile)
else:
# This PID got reused for something that isn't us?
if not any('pylink' in arg.lower() for arg in proc.cmdline()):
log.info("Ignoring stale PID %s from PID file %r: process command line %r is not us", pid, pidfile, proc.cmdline())
pid_exists = False
if pid and pid_exists:
if args.rehash:
os.kill(pid, signal.SIGUSR1)
log.info('OK, rehashed PyLink instance %s (config %r)', pid, args.config)
sys.exit()
elif args.stop or args.restart: # Handle --stop and --restart options
os.kill(pid, signal.SIGTERM)
log.info("Waiting for PyLink instance %s (config %r) to stop...", pid, args.config)
while os.path.exists(pidfile):
# XXX: this is ugly, but os.waitpid() only works on non-child processes on Windows
time.sleep(0.2)
log.info("Successfully killed PID %s for config %r.", pid, args.config)
if args.stop:
sys.exit()
else:
log.error("PID file %r exists; aborting!", pidfile)
if psutil is None:
log.error("If PyLink didn't shut down cleanly last time it ran, or you're upgrading "
"from PyLink < 1.1-dev, delete %r and start the server again.", pidfile)
if os.name == 'posix':
log.error("Alternatively, you can install psutil for Python 3 (pip3 install psutil), "
"which will allow this launcher to detect stale PID files and ignore them.")
sys.exit(1)
elif args.stop or args.restart or args.rehash: # XXX: also repetitive
# --stop and --restart should take care of stale PIDs.
if pid:
world._should_remove_pid = True
log.error('Cannot stop/rehash PyLink: no process with PID %s exists.', pid)
else:
log.error('Cannot stop/rehash PyLink: PID file %r does not exist or cannot be read.', pidfile)
sys.exit(1)
world._should_remove_pid = True
log.info('PyLink %s starting...', __version__)
world.daemon = args.daemonize
if args.daemonize:
if args.no_pid:
print('ERROR: Combining --no-pid and --daemonize is not supported.')
sys.exit(1)
elif os.name != 'posix':
print('ERROR: Daemonization is not supported outside POSIX systems.')
sys.exit(1)
else:
log.info('Forking into the background.')
log.removeHandler(world.console_handler)
# Adapted from https://stackoverflow.com/questions/5975124/
if os.fork():
# Fork and exit the parent process.
os._exit(0)
os.setsid() # Decouple from our lovely terminal
if os.fork():
# Fork again to prevent starting zombie apocalypses.
os._exit(0)
else:
# For foreground sessions, set the terminal window title.
# See https://bbs.archlinux.org/viewtopic.php?id=85567 &
# https://stackoverflow.com/questions/7387276/
if os.name == 'nt':
import ctypes
ctypes.windll.kernel32.SetConsoleTitleW("PyLink %s" % __version__)
elif os.name == 'posix':
sys.stdout.write("\x1b]2;PyLink %s\x07" % __version__)
if not args.no_pid:
# Write the PID file only after forking.
with open(pidfile, 'w') as f:
f.write(str(os.getpid()))
# Load configured plugins
to_load = conf.conf['plugins']
utils._reset_module_dirs()
for plugin in to_load:
try:
world.plugins[plugin] = pl = utils._load_plugin(plugin)
except Exception as e:
log.exception('Failed to load plugin %r: %s: %s', plugin, type(e).__name__, str(e))
else:
if hasattr(pl, 'main'):
log.debug('Calling main() function of plugin %r', pl)
pl.main()
# Initialize all the networks one by one
for network, sdata in conf.conf['servers'].items():
try:
protoname = sdata['protocol']
except (KeyError, TypeError):
log.error("(%s) Configuration error: No protocol module specified, aborting.", network)
else:
# Fetch the correct protocol module.
try:
proto = utils._get_protocol_module(protoname)
# Create and connect the network.
world.networkobjects[network] = irc = proto.Class(network)
log.debug('Connecting to network %r', network)
irc.connect()
except:
log.exception('(%s) Failed to connect to network %r, skipping it...',
network, network)
continue
world.started.set()
log.info("Loaded plugins: %s", ', '.join(sorted(world.plugins.keys())))
selectdriver.start()
def main():
import argparse
global args
parser = argparse.ArgumentParser(description='Starts an instance of PyLink IRC Services.')
parser.add_argument('config', help='specifies the path to the config file (defaults to pylink.yml)', nargs='?', default='pylink.yml')
parser.add_argument("-v", "--version", help="displays the program version and exits", action='store_true')
parser.add_argument("-c", "--check-pid", help="no-op; kept for compatibility with PyLink <= 1.2.x", action='store_true')
parser.add_argument("-n", "--no-pid", help="skips generating and checking PID files", action='store_true')
parser.add_argument("-r", "--restart", help="restarts the PyLink instance with the given config file", action='store_true')
parser.add_argument("-s", "--stop", help="stops the PyLink instance with the given config file", action='store_true')
parser.add_argument("-R", "--rehash", help="rehashes the PyLink instance with the given config file", action='store_true')
parser.add_argument("-d", "--daemonize", help="[experimental] daemonizes the PyLink instance on POSIX systems", action='store_true')
parser.add_argument("-t", "--trace", help="traces through running Python code; useful for debugging", action='store_true')
parser.add_argument('--trace-ignore-mods', help='comma-separated list of extra modules to ignore when tracing', action='store', default='')
parser.add_argument('--trace-ignore-dirs', help='comma-separated list of extra directories to ignore when tracing', action='store', default='')
args = parser.parse_args()
if args.version: # Display version and exit
print('PyLink %s (in VCS: %s)' % (__version__, real_version))
sys.exit()
# XXX: repetitive
elif args.no_pid and (args.restart or args.stop or args.rehash):
print('ERROR: --no-pid cannot be combined with --restart or --stop')
sys.exit(1)
elif args.rehash and os.name != 'posix':
print('ERROR: Rehashing via the command line is not supported outside Unix.')
sys.exit(1)
if args.trace:
import trace
tracer = trace.Trace(ignoremods=args.trace_ignore_mods.split(','),
ignoredirs=args.trace_ignore_dirs.split(','))
tracer.runctx('_main()', globals=globals(), locals=locals())
else:
_main()