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# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2010 OpenStack Foundation
# 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.
"""Utility methods for working with WSGI servers."""
import os.path
import socket
import ssl
import eventlet
import eventlet.wsgi
import greenlet
from oslo_log import log as logging
from oslo_service import service
from oslo_utils import excutils
import nova.conf
from nova import exception
from nova.i18n import _
from nova import utils
CONF = nova.conf.CONF
LOG = logging.getLogger(__name__)
class Server(service.ServiceBase):
"""Server class to manage a WSGI server, serving a WSGI application."""
default_pool_size = CONF.wsgi.default_pool_size
def __init__(self, name, app, host='0.0.0.0', port=0, pool_size=None,
protocol=eventlet.wsgi.HttpProtocol, backlog=128,
use_ssl=False, max_url_len=None):
"""Initialize, but do not start, a WSGI server.
:param name: Pretty name for logging.
:param app: The WSGI application to serve.
:param host: IP address to serve the application.
:param port: Port number to server the application.
:param pool_size: Maximum number of eventlets to spawn concurrently.
:param backlog: Maximum number of queued connections.
:param max_url_len: Maximum length of permitted URLs.
:returns: None
:raises: nova.exception.InvalidInput
"""
# Allow operators to customize http requests max header line size.
eventlet.wsgi.MAX_HEADER_LINE = CONF.wsgi.max_header_line
self.name = name
self.app = app
self._server = None
self._protocol = protocol
self.pool_size = pool_size or self.default_pool_size
self._pool = eventlet.GreenPool(self.pool_size)
self._logger = logging.getLogger("nova.%s.wsgi.server" % self.name)
self._use_ssl = use_ssl
self._max_url_len = max_url_len
self.client_socket_timeout = CONF.wsgi.client_socket_timeout or None
if backlog < 1:
raise exception.InvalidInput(
reason=_('The backlog must be more than 0'))
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:
family = socket.AF_INET
try:
self._socket = eventlet.listen(bind_addr, family, backlog=backlog)
except EnvironmentError:
LOG.error("Could not bind to %(host)s:%(port)s",
{'host': host, 'port': port})
raise
(self.host, self.port) = self._socket.getsockname()[0:2]
LOG.info("%(name)s listening on %(host)s:%(port)s",
{'name': self.name, 'host': self.host, 'port': self.port})
def start(self):
"""Start serving a WSGI application.
:returns: None
"""
# The server socket object will be closed after server exits,
# but the underlying file descriptor will remain open, and will
# give bad file descriptor error. So duplicating the socket object,
# to keep file descriptor usable.
dup_socket = self._socket.dup()
dup_socket.setsockopt(socket.SOL_SOCKET,
socket.SO_REUSEADDR, 1)
# sockets can hang around forever without keepalive
dup_socket.setsockopt(socket.SOL_SOCKET,
socket.SO_KEEPALIVE, 1)
# This option isn't available in the OS X version of eventlet
if hasattr(socket, 'TCP_KEEPIDLE'):
dup_socket.setsockopt(socket.IPPROTO_TCP,
socket.TCP_KEEPIDLE,
CONF.wsgi.tcp_keepidle)
if self._use_ssl:
try:
ca_file = CONF.wsgi.ssl_ca_file
cert_file = CONF.wsgi.ssl_cert_file
key_file = CONF.wsgi.ssl_key_file
if cert_file and not os.path.exists(cert_file):
raise RuntimeError(
_("Unable to find cert_file : %s") % cert_file)
if ca_file and not os.path.exists(ca_file):
raise RuntimeError(
_("Unable to find ca_file : %s") % ca_file)
if key_file and not os.path.exists(key_file):
raise RuntimeError(
_("Unable to find key_file : %s") % key_file)
if self._use_ssl and (not cert_file or not key_file):
raise RuntimeError(
_("When running server in SSL mode, you must "
"specify both a cert_file and key_file "
"option value in your configuration file"))
ssl_kwargs = {
'server_side': True,
'certfile': cert_file,
'keyfile': key_file,
'cert_reqs': ssl.CERT_NONE,
}
if CONF.wsgi.ssl_ca_file:
ssl_kwargs['ca_certs'] = ca_file
ssl_kwargs['cert_reqs'] = ssl.CERT_REQUIRED
dup_socket = eventlet.wrap_ssl(dup_socket,
**ssl_kwargs)
except Exception:
with excutils.save_and_reraise_exception():
LOG.error(
"Failed to start %(name)s on %(host)s:%(port)s with "
"SSL support",
{'name': self.name, 'host': self.host,
'port': self.port})
wsgi_kwargs = {
'func': eventlet.wsgi.server,
'sock': dup_socket,
'site': self.app,
'protocol': self._protocol,
'custom_pool': self._pool,
'log': self._logger,
'log_format': CONF.wsgi.wsgi_log_format,
'debug': False,
'keepalive': CONF.wsgi.keep_alive,
'socket_timeout': self.client_socket_timeout
}
if self._max_url_len:
wsgi_kwargs['url_length_limit'] = self._max_url_len
self._server = utils.spawn(**wsgi_kwargs)
def reset(self):
"""Reset server greenpool size to default.
:returns: None
"""
self._pool.resize(self.pool_size)
def stop(self):
"""Stop this server.
This is not a very nice action, as currently the method by which a
server is stopped is by killing its eventlet.
:returns: None
"""
LOG.info("Stopping WSGI server.")
if self._server is not None:
# Resize pool to stop new requests from being processed
self._pool.resize(0)
self._server.kill()
def wait(self):
"""Block, until the server has stopped.
Waits on the server's eventlet to finish, then returns.
:returns: None
"""
try:
if self._server is not None:
self._pool.waitall()
self._server.wait()
except greenlet.GreenletExit:
LOG.info("WSGI server has stopped.")
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