def run_child(self):
def child_hup(*args):
"""Shuts down child processes, existing requests are handled."""
signal.signal(signal.SIGHUP, signal.SIG_IGN)
eventlet.wsgi.is_accepting = False
self.sock.close()
pid = os.fork()
if pid == 0:
signal.signal(signal.SIGHUP, child_hup)
signal.signal(signal.SIGTERM, signal.SIG_DFL)
# ignore the interrupt signal to avoid a race whereby
# a child worker receives the signal before the parent
# and is respawned unnecessarily as a result
signal.signal(signal.SIGINT, signal.SIG_IGN)
# The child has no need to stash the unwrapped
# socket, and the reference prevents a clean
# exit on sighup
self._sock = None
self.run_server()
LOG.info(_LI('Child %d exiting normally'), os.getpid())
# self.pool.waitall() is now called in wsgi's server so
# it's safe to exit here
sys.exit(0)
else:
LOG.info(_LI('Started child %s'), pid)
self.children.add(pid)
def run_child(self):
def child_hup(*args):
"""Shuts down child processes, existing requests are handled."""
signal.signal(signal.SIGHUP, signal.SIG_IGN)
eventlet.wsgi.is_accepting = False
self.sock.close()
pid = os.fork()
if pid == 0:
signal.signal(signal.SIGHUP, child_hup)
signal.signal(signal.SIGTERM, signal.SIG_DFL)
# ignore the interrupt signal to avoid a race whereby
# a child worker receives the signal before the parent
# and is respawned unnecessarily as a result
signal.signal(signal.SIGINT, signal.SIG_IGN)
# The child has no need to stash the unwrapped
# socket, and the reference prevents a clean
# exit on sighup
self._sock = None
self.run_server()
LOG.info(_LI('Child %d exiting normally'), os.getpid())
# self.pool.waitall() is now called in wsgi's server so
# it's safe to exit here
sys.exit(0)
else:
LOG.info(_LI('Started child %s'), pid)
self.children.add(pid)
def _remove_children(self, pid):
if pid in self.children:
self.children.remove(pid)
LOG.info(_LI('Removed dead child %s'), pid)
elif pid in self.stale_children:
self.stale_children.remove(pid)
LOG.info(_LI('Removed stale child %s'), pid)
else:
LOG.warn(_LW('Unrecognised child %s'), pid)
def _remove_children(self, pid):
if pid in self.children:
self.children.remove(pid)
LOG.info(_LI('Removed dead child %s'), pid)
elif pid in self.stale_children:
self.stale_children.remove(pid)
LOG.info(_LI('Removed stale child %s'), pid)
else:
LOG.warn(_LW('Unrecognised child %s'), pid)
def _single_run(self, application, sock):
"""Start a WSGI server in a new green thread."""
LOG.info(_LI("Starting single process server"))
eventlet.wsgi.server(sock, application,
custom_pool=self.pool,
url_length_limit=URL_LENGTH_LIMIT,
log=self._wsgi_logger,
debug=cfg.CONF.debug)
def _single_run(self, application, sock):
"""Start a WSGI server in a new green thread."""
LOG.info(_LI("Starting single process server"))
eventlet.wsgi.server(sock,
application,
custom_pool=self.pool,
url_length_limit=URL_LENGTH_LIMIT,
log=self._wsgi_logger,
debug=cfg.CONF.debug)
def _verify_and_respawn_children(self, pid, status):
if len(self.stale_children) == 0:
LOG.debug('No stale children')
if os.WIFEXITED(status) and os.WEXITSTATUS(status) != 0:
LOG.error(_LE('Not respawning child %d, cannot '
'recover from termination'), pid)
if not self.children and not self.stale_children:
LOG.info(
_LI('All workers have terminated. Exiting'))
self.running = False
else:
if len(self.children) < self.conf.workers:
self.run_child()
def start_wsgi(self):
if self.conf.workers == 0:
# Useful for profiling, test, debug etc.
self.pool = eventlet.GreenPool(size=self.threads)
self.pool.spawn_n(self._single_run, self.application, self.sock)
return
LOG.info(_LI("Starting %d workers"), self.conf.workers)
signal.signal(signal.SIGTERM, self.kill_children)
signal.signal(signal.SIGINT, self.kill_children)
signal.signal(signal.SIGHUP, self.hup)
while len(self.children) < self.conf.workers:
self.run_child()
def _verify_and_respawn_children(self, pid, status):
if len(self.stale_children) == 0:
LOG.debug('No stale children')
if os.WIFEXITED(status) and os.WEXITSTATUS(status) != 0:
LOG.error(
_LE('Not respawning child %d, cannot '
'recover from termination'), pid)
if not self.children and not self.stale_children:
LOG.info(_LI('All workers have terminated. Exiting'))
self.running = False
else:
if len(self.children) < self.conf.workers:
self.run_child()
def start_wsgi(self):
if self.conf.workers == 0:
# Useful for profiling, test, debug etc.
self.pool = eventlet.GreenPool(size=self.threads)
self.pool.spawn_n(self._single_run, self.application, self.sock)
return
LOG.info(_LI("Starting %d workers"), self.conf.workers)
signal.signal(signal.SIGTERM, self.kill_children)
signal.signal(signal.SIGINT, self.kill_children)
signal.signal(signal.SIGHUP, self.hup)
while len(self.children) < self.conf.workers:
self.run_child()
def wait_on_children(self):
while self.running:
try:
pid, status = os.wait()
if os.WIFEXITED(status) or os.WIFSIGNALED(status):
self._remove_children(pid)
self._verify_and_respawn_children(pid, status)
except OSError as err:
if err.errno not in (errno.EINTR, errno.ECHILD):
raise
except KeyboardInterrupt:
LOG.info(_LI('Caught keyboard interrupt. Exiting.'))
os.killpg(0, signal.SIGTERM)
break
except exception.SIGHUPInterrupt:
self.reload()
continue
eventlet.greenio.shutdown_safe(self.sock)
self.sock.close()
LOG.debug('Exited')
def wait_on_children(self):
while self.running:
try:
pid, status = os.wait()
if os.WIFEXITED(status) or os.WIFSIGNALED(status):
self._remove_children(pid)
self._verify_and_respawn_children(pid, status)
except OSError as err:
if err.errno not in (errno.EINTR, errno.ECHILD):
raise
except KeyboardInterrupt:
LOG.info(_LI('Caught keyboard interrupt. Exiting.'))
os.killpg(0, signal.SIGTERM)
break
except exception.SIGHUPInterrupt:
self.reload()
continue
eventlet.greenio.shutdown_safe(self.sock)
self.sock.close()
LOG.debug('Exited')
def main():
try:
logging.register_options(cfg.CONF)
cfg.CONF(project='abbot',
prog='abbot-api',
version=version.version_info.version_string())
logging.setup(cfg.CONF, 'abbot-api')
messaging.setup()
app = config.load_paste_app()
port = cfg.CONF.abbot_api.bind_port
host = cfg.CONF.abbot_api.bind_host
LOG.info(_LI('Starting abbot REST API on %(host)s:%(port)s'), {
'host': host,
'port': port
})
server = wsgi.Server('abbot-api', cfg.CONF.abbot_api)
server.start(app, default_port=port)
systemd.notify_once()
server.wait()
except RuntimeError as e:
msg = six.text_type(e)
sys.exit("ERROR: %s" % msg)
