Initial skeleton project

1 files changed, 346 insertions, 0 deletions

diff --git a/openstack/common/wsgi.py b/openstack/common/wsgi.py
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+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2011 OpenStack LLC.
+# 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 json
+import logging
+import sys
+import datetime
+
+import eventlet
+import eventlet.wsgi
+eventlet.patcher.monkey_patch(all=False, socket=True)
+import routes
+import routes.middleware
+import webob.dec
+import webob.exc
+
+from openstack.common import exception
+
+
+class WritableLogger(object):
+    """A thin wrapper that responds to `write` and logs."""
+
+    def __init__(self, logger, level=logging.DEBUG):
+        self.logger = logger
+        self.level = level
+
+    def write(self, msg):
+        self.logger.log(self.level, msg.strip("\n"))
+
+
+def run_server(application, port):
+    """Run a WSGI server with the given application."""
+    sock = eventlet.listen(('0.0.0.0', port))
+    eventlet.wsgi.server(sock, application)
+
+
+class Server(object):
+    """Server class to manage multiple WSGI sockets and applications."""
+
+    def __init__(self, threads=1000):
+        self.pool = eventlet.GreenPool(threads)
+
+    def start(self, application, port, host='0.0.0.0', backlog=128):
+        """Run a WSGI server with the given application."""
+        socket = eventlet.listen((host, port), backlog=backlog)
+        self.pool.spawn_n(self._run, application, socket)
+
+    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."""
+        logger = logging.getLogger('eventlet.wsgi.server')
+        eventlet.wsgi.server(socket, application, custom_pool=self.pool,
+                             log=WritableLogger(logger))
+
+
+class Middleware(object):
+    """
+    Base WSGI middleware wrapper. 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.
+    """
+
+    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
+    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 that can be inserted into any WSGI application chain
+    to get information about the request and response.
+    """
+
+    @webob.dec.wsgify
+    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.iteritems():
+            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 iterator
+        when iterated.
+        """
+        print ("*" * 40) + " BODY"
+        for part in app_iter:
+            sys.stdout.write(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 a wsgi.Controller, who will route
+        the request to the action 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
+    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
+    def _dispatch(req):
+        """
+        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 Request(webob.Request):
+
+    """Add some Openstack API-specific logic to the base webob.Request."""
+
+    def best_match_content_type(self):
+        """Determine the requested response content-type."""
+        supported = ('application/json',)
+        bm = self.accept.best_match(supported)
+        return bm or 'application/json'
+
+    def get_content_type(self, allowed_content_types):
+        """Determine content type of the request body."""
+        if not "Content-Type" in self.headers:
+            raise exception.InvalidContentType(content_type=None)
+
+        content_type = self.content_type
+
+        if content_type not in allowed_content_types:
+            raise exception.InvalidContentType(content_type=content_type)
+        else:
+            return content_type
+
+
+class JSONRequestDeserializer(object):
+    def has_body(self, request):
+        """
+        Returns whether a Webob.Request object will possess an entity body.
+
+        :param request:  Webob.Request object
+        """
+        if 'transfer-encoding' in request.headers:
+            return True
+        elif request.content_length > 0:
+            return True
+
+        return False
+
+    def from_json(self, datastring):
+        return json.loads(datastring)
+
+    def default(self, request):
+        if self.has_body(request):
+            return {'body': self.from_json(request.body)}
+        else:
+            return {}
+
+
+class JSONResponseSerializer(object):
+
+    def to_json(self, data):
+        def sanitizer(obj):
+            if isinstance(obj, datetime.datetime):
+                return obj.isoformat()
+            return obj
+
+        return json.dumps(data, default=sanitizer)
+
+    def default(self, response, result):
+        response.headers.add('Content-Type', 'application/json')
+        response.body = self.to_json(result)
+
+
+class Resource(object):
+    """
+    WSGI app that handles (de)serialization and controller dispatch.
+
+    Reads routing information supplied by RoutesMiddleware and calls
+    the requested action method upon its deserializer, controller,
+    and serializer. Those three objects may implement any of the basic
+    controller action methods (create, update, show, index, delete)
+    along with any that may be specified in the api router. A 'default'
+    method may also be implemented to be used in place of any
+    non-implemented actions. Deserializer methods must accept a request
+    argument and return a dictionary. Controller methods must accept a
+    request argument. Additionally, they must also accept keyword
+    arguments that represent the keys returned by the Deserializer. They
+    may raise a webob.exc exception or return a dict, which will be
+    serialized by requested content type.
+    """
+    def __init__(self, controller, deserializer, serializer):
+        """
+        :param controller: object that implement methods created by routes lib
+        :param deserializer: object that supports webob request deserialization
+                             through controller-like actions
+        :param serializer: object that supports webob response serialization
+                           through controller-like actions
+        """
+        self.controller = controller
+        self.serializer = serializer
+        self.deserializer = deserializer
+
+    @webob.dec.wsgify(RequestClass=Request)
+    def __call__(self, request):
+        """WSGI method that controls (de)serialization and method dispatch."""
+        action_args = self.get_action_args(request.environ)
+        action = action_args.pop('action', None)
+
+        deserialized_request = self.dispatch(self.deserializer,
+                                             action, request)
+        action_args.update(deserialized_request)
+
+        action_result = self.dispatch(self.controller, action,
+                                      request, **action_args)
+        try:
+            response = webob.Response()
+            self.dispatch(self.serializer, action, response, action_result)
+            return response
+
+        # return unserializable result (typically a webob exc)
+        except Exception:
+            return action_result
+
+    def dispatch(self, obj, action, *args, **kwargs):
+        """Find action-specific method on self and call it."""
+        try:
+            method = getattr(obj, action)
+        except AttributeError:
+            method = getattr(obj, 'default')
+
+        return method(*args, **kwargs)
+
+    def get_action_args(self, request_environment):
+        """Parse dictionary created by routes library."""
+        try:
+            args = request_environment['wsgiorg.routing_args'][1].copy()
+        except Exception:
+            return {}
+
+        try:
+            del args['controller']
+        except KeyError:
+            pass
+
+        try:
+            del args['format']
+        except KeyError:
+            pass
+
+        return args