congress/src/server/wsgi.py

122 lines
4.2 KiB
Python

# Copyright (c) 2013 VMware, Inc. All rights reserved.
#
# 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 errno
import socket
import sys
import time
import eventlet.wsgi
eventlet.patcher.monkey_patch(all=False, socket=True)
import webob.dec
import ovs.vlog
vlog = ovs.vlog.Vlog(__name__)
# Number of seconds to keep retrying to listen
RETRY_UNTIL_WINDOW = 30
# Sets the value of TCP_KEEPIDLE in seconds for each server socket.
TCP_KEEPIDLE = 600
# Number of backlog requests to configure the socket with
BACKLOG = 4096
class Server(object):
"""Server class to manage multiple WSGI sockets and applications."""
def __init__(self, name, threads=1000):
self.pool = eventlet.GreenPool(threads)
self.name = name
def _get_socket(self, host, port, backlog):
bind_addr = (host, port)
# TODO(dims): eventlet's green dns/socket module does not actually
# support IPv6 in getaddrinfo(). We need to get around this in the
# future or monitor upstream for a fix
try:
info = socket.getaddrinfo(bind_addr[0],
bind_addr[1],
socket.AF_UNSPEC,
socket.SOCK_STREAM)[0]
family = info[0]
bind_addr = info[-1]
except Exception:
vlog.exception(("Unable to listen on %(host)s:%(port)s") %
{'host': host, 'port': port})
sys.exit(1)
sock = None
retry_until = time.time() + RETRY_UNTIL_WINDOW
while not sock and time.time() < retry_until:
try:
sock = eventlet.listen(bind_addr,
backlog=backlog,
family=family)
except socket.error as err:
if err.errno != errno.EADDRINUSE:
raise
eventlet.sleep(0.1)
if not sock:
raise RuntimeError(("Could not bind to %(host)s:%(port)s "
"after trying for %(time)d seconds") %
{'host': host,
'port': port,
'time': RETRY_UNTIL_WINDOW})
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
# sockets can hang around forever without keepalive
sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
if hasattr(socket, 'TCP_KEEPIDLE'):
sock.setsockopt(socket.IPPROTO_TCP,
socket.TCP_KEEPIDLE,
TCP_KEEPIDLE)
return sock
def start(self, application, port, host='0.0.0.0'):
"""Run a WSGI server with the given application."""
self._host = host
self._port = port
backlog = BACKLOG
self._socket = self._get_socket(self._host,
self._port,
backlog=backlog)
self._server = self.pool.spawn(self._run, application, self._socket)
@property
def host(self):
return self._socket.getsockname()[0] if self._socket else self._host
@property
def port(self):
return self._socket.getsockname()[1] if self._socket else self._port
def stop(self):
self._server.kill()
def wait(self):
"""Wait until all servers have completed running."""
try:
self.pool.waitall()
except KeyboardInterrupt:
pass
def _run(self, application, socket):
"""Start a WSGI server in a new green thread."""
eventlet.wsgi.server(socket, application, custom_pool=self.pool)