# 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)