nova/nova/wsgi.py
Spencer Yu 70730c09ab [2/3]Replace six.iteritems() with .items()
1.As mentioned in [1], we should avoid using
six.iteritems to achieve iterators. We can
use dict.items instead, as it will return
iterators in PY3 as well. And dict.items/keys
will more readable. 2.In py2, the performance
about list should be negligible, see the link [2].
[1] https://wiki.openstack.org/wiki/Python3
[2] http://lists.openstack.org/pipermail/openstack-dev/2015-June/066391.html

The patch list:
    1. cells.
    2. compute api.
    3. image.
    4. network.
    5. objects.
    6. scheduler.
    7. virt.
    8. other resources.

Partial-Implements: blueprint replace-iteritems-with-items

Change-Id: Ic6e469eb80ee1774de1374bb36f38b5134b6b311
2017-01-09 09:11:00 +00:00

501 lines
17 KiB
Python

# 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."""
from __future__ import print_function
import os.path
import socket
import ssl
import sys
import eventlet
import eventlet.wsgi
import greenlet
from oslo_log import log as logging
from oslo_service import service
from oslo_utils import excutils
from paste import deploy
import routes.middleware
import six
import webob.dec
import webob.exc
import nova.conf
from nova import exception
from nova.i18n import _, _LE, _LI
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(_LE("Could not bind to %(host)s:%(port)s"),
{'host': host, 'port': port})
raise
(self.host, self.port) = self._socket.getsockname()[0:2]
LOG.info(_LI("%(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(_LE("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(_LI("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(_LI("WSGI server has stopped."))
class Request(webob.Request):
def __init__(self, environ, *args, **kwargs):
if CONF.wsgi.secure_proxy_ssl_header:
scheme = environ.get(CONF.wsgi.secure_proxy_ssl_header)
if scheme:
environ['wsgi.url_scheme'] = scheme
super(Request, self).__init__(environ, *args, **kwargs)
class Application(object):
"""Base WSGI application wrapper. Subclasses need to implement __call__."""
@classmethod
def factory(cls, global_config, **local_config):
"""Used for paste app factories in paste.deploy config files.
Any local configuration (that is, values under the [app:APPNAME]
section of the paste config) will be passed into the `__init__` method
as kwargs.
A hypothetical configuration would look like:
[app:wadl]
latest_version = 1.3
paste.app_factory = nova.api.fancy_api:Wadl.factory
which would result in a call to the `Wadl` class as
import nova.api.fancy_api
fancy_api.Wadl(latest_version='1.3')
You could of course re-implement the `factory` method in subclasses,
but using the kwarg passing it shouldn't be necessary.
"""
return cls(**local_config)
def __call__(self, environ, start_response):
r"""Subclasses will probably want to implement __call__ like this:
@webob.dec.wsgify(RequestClass=Request)
def __call__(self, req):
# Any of the following objects work as responses:
# Option 1: simple string
res = 'message\n'
# Option 2: a nicely formatted HTTP exception page
res = exc.HTTPForbidden(explanation='Nice try')
# Option 3: a webob Response object (in case you need to play with
# headers, or you want to be treated like an iterable, or ...)
res = Response()
res.app_iter = open('somefile')
# Option 4: any wsgi app to be run next
res = self.application
# Option 5: you can get a Response object for a wsgi app, too, to
# play with headers etc
res = req.get_response(self.application)
# You can then just return your response...
return res
# ... or set req.response and return None.
req.response = res
See the end of http://pythonpaste.org/webob/modules/dec.html
for more info.
"""
raise NotImplementedError(_('You must implement __call__'))
class Middleware(Application):
"""Base WSGI middleware.
These classes require an application to be
initialized that will be called next. By default the middleware will
simply call its wrapped app, or you can override __call__ to customize its
behavior.
"""
@classmethod
def factory(cls, global_config, **local_config):
"""Used for paste app factories in paste.deploy config files.
Any local configuration (that is, values under the [filter:APPNAME]
section of the paste config) will be passed into the `__init__` method
as kwargs.
A hypothetical configuration would look like:
[filter:analytics]
redis_host = 127.0.0.1
paste.filter_factory = nova.api.analytics:Analytics.factory
which would result in a call to the `Analytics` class as
import nova.api.analytics
analytics.Analytics(app_from_paste, redis_host='127.0.0.1')
You could of course re-implement the `factory` method in subclasses,
but using the kwarg passing it shouldn't be necessary.
"""
def _factory(app):
return cls(app, **local_config)
return _factory
def __init__(self, application):
self.application = application
def process_request(self, req):
"""Called on each request.
If this returns None, the next application down the stack will be
executed. If it returns a response then that response will be returned
and execution will stop here.
"""
return None
def process_response(self, response):
"""Do whatever you'd like to the response."""
return response
@webob.dec.wsgify(RequestClass=Request)
def __call__(self, req):
response = self.process_request(req)
if response:
return response
response = req.get_response(self.application)
return self.process_response(response)
class Debug(Middleware):
"""Helper class for debugging a WSGI application.
Can be inserted into any WSGI application chain to get information
about the request and response.
"""
@webob.dec.wsgify(RequestClass=Request)
def __call__(self, req):
print(('*' * 40) + ' REQUEST ENVIRON')
for key, value in req.environ.items():
print(key, '=', value)
print()
resp = req.get_response(self.application)
print(('*' * 40) + ' RESPONSE HEADERS')
for (key, value) in resp.headers.items():
print(key, '=', value)
print()
resp.app_iter = self.print_generator(resp.app_iter)
return resp
@staticmethod
def print_generator(app_iter):
"""Iterator that prints the contents of a wrapper string."""
print(('*' * 40) + ' BODY')
for part in app_iter:
sys.stdout.write(six.text_type(part))
sys.stdout.flush()
yield part
print()
class Router(object):
"""WSGI middleware that maps incoming requests to WSGI apps."""
def __init__(self, mapper):
"""Create a router for the given routes.Mapper.
Each route in `mapper` must specify a 'controller', which is a
WSGI app to call. You'll probably want to specify an 'action' as
well and have your controller be an object that can route
the request to the action-specific method.
Examples:
mapper = routes.Mapper()
sc = ServerController()
# Explicit mapping of one route to a controller+action
mapper.connect(None, '/svrlist', controller=sc, action='list')
# Actions are all implicitly defined
mapper.resource('server', 'servers', controller=sc)
# Pointing to an arbitrary WSGI app. You can specify the
# {path_info:.*} parameter so the target app can be handed just that
# section of the URL.
mapper.connect(None, '/v1.0/{path_info:.*}', controller=BlogApp())
"""
self.map = mapper
self._router = routes.middleware.RoutesMiddleware(self._dispatch,
self.map)
@webob.dec.wsgify(RequestClass=Request)
def __call__(self, req):
"""Route the incoming request to a controller based on self.map.
If no match, return a 404.
"""
return self._router
@staticmethod
@webob.dec.wsgify(RequestClass=Request)
def _dispatch(req):
"""Dispatch the request to the appropriate controller.
Called by self._router after matching the incoming request to a route
and putting the information into req.environ. Either returns 404
or the routed WSGI app's response.
"""
match = req.environ['wsgiorg.routing_args'][1]
if not match:
return webob.exc.HTTPNotFound()
app = match['controller']
return app
class Loader(object):
"""Used to load WSGI applications from paste configurations."""
def __init__(self, config_path=None):
"""Initialize the loader, and attempt to find the config.
:param config_path: Full or relative path to the paste config.
:returns: None
"""
self.config_path = None
config_path = config_path or CONF.wsgi.api_paste_config
if not os.path.isabs(config_path):
self.config_path = CONF.find_file(config_path)
elif os.path.exists(config_path):
self.config_path = config_path
if not self.config_path:
raise exception.ConfigNotFound(path=config_path)
def load_app(self, name):
"""Return the paste URLMap wrapped WSGI application.
:param name: Name of the application to load.
:returns: Paste URLMap object wrapping the requested application.
:raises: `nova.exception.PasteAppNotFound`
"""
try:
LOG.debug("Loading app %(name)s from %(path)s",
{'name': name, 'path': self.config_path})
return deploy.loadapp("config:%s" % self.config_path, name=name)
except LookupError:
LOG.exception(_LE("Couldn't lookup app: %s"), name)
raise exception.PasteAppNotFound(name=name, path=self.config_path)