Basic Easy API functionality

1 files changed, 163 insertions, 0 deletions

diff --git a/nova/api/easy.py b/nova/api/easy.py
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index 000000000..a284e9685
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+++ b/nova/api/easy.py
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+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# 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.
+
+"""Public HTTP interface that allows services to self-register.
+
+The general flow of a request is:
+    - Request is parsed into WSGI bits.
+    - Some middleware checks authentication.
+    - Routing takes place based on the URL to find a controller.
+      (/controller/method)
+    - Parameters are parsed from the request and passed to a method on the
+      controller as keyword arguments.
+      - Optionally json_body is decoded to provide all the parameters.
+    - Actual work is done and a result is returned.
+    - That result is turned into json and returned.
+
+"""
+
+import json
+import urllib
+
+import routes
+import webob
+
+from nova import context
+from nova import flags
+from nova import wsgi
+
+# prxy compute_api in amazon tests
+
+
+EASY_ROUTES = {}
+
+
+def register_service(path, handle):
+    EASY_ROUTES[path] = handle
+
+
+class DelegatedAuthMiddleware(wsgi.Middleware):
+    def process_request(self, request):
+        os_user = request.headers['X-OpenStack-User']
+        os_project = request.headers['X-OpenStack-Project']
+        context_ref = context.RequestContext(user=os_user, project=os_project)
+        request.environ['openstack.context'] = context_ref
+
+
+class JsonParamsMiddleware(wsgi.Middleware):
+    def process_request(self, request):
+        if 'json' not in request.params:
+            return
+
+        params_json = request.params['json']
+        params_parsed = json.loads(params_json)
+        params = {}
+        for k, v in params_parsed.iteritems():
+            if k in ('self', 'context'):
+                continue
+            if k.startswith('_'):
+                continue
+            params[k] = v
+
+        request.environ['openstack.params'] = params
+
+
+class ReqParamsMiddleware(wsgi.Middleware):
+    def process_request(self, request):
+        params_parsed = request.params
+        params = {}
+        for k, v in params_parsed.iteritems():
+            if k in ('self', 'context'):
+                continue
+            if k.startswith('_'):
+                continue
+            params[k] = v
+
+        request.environ['openstack.params'] = params
+
+
+class SundayMorning(wsgi.Router):
+    def __init__(self, mapper=None):
+        if mapper is None:
+            mapper = routes.Mapper()
+        
+        self._load_registered_routes(mapper)
+        super(SundayMorning, self).__init__(mapper=mapper)
+
+    def _load_registered_routes(self, mapper):
+        for route in EASY_ROUTES:
+            mapper.connect('/%s/{action}' % route,
+                           controller=ServiceWrapper(EASY_ROUTES[route]))
+
+
+class ServiceWrapper(wsgi.Controller):
+    def __init__(self, service_handle):
+        self.service_handle = service_handle
+    
+    @webob.dec.wsgify
+    def __call__(self, req):
+        arg_dict = req.environ['wsgiorg.routing_args'][1]
+        action = arg_dict['action']
+        del arg_dict['action']
+
+        context = req.environ['openstack.context']
+        # allow middleware up the stack to override the params
+        params = {}
+        if 'openstack.params' in req.environ:
+            params = req.environ['openstack.params']
+        
+        # TODO(termie): do some basic normalization on methods
+        method = getattr(self.service_handle, action)
+        
+        result = method(context, **params)
+        if type(result) is dict:
+            return self._serialize(result, req)
+        else:
+            return result
+
+
+class Proxy(object):
+    """Pretend an Easy API endpoint is an object."""
+    def __init__(self, app, prefix=None):
+        self.app = app
+        self.prefix = prefix
+    
+    def __do_request(self, path, context, **kwargs):
+        req = webob.Request.blank(path)
+        req.method = 'POST'
+        req.body = urllib.urlencode({'json': json.dumps(kwargs)})
+        req.environ['openstack.context'] = context
+        resp = req.get_response(self.app)
+        try:
+            return json.loads(resp.body)
+        except Exception:
+            return resp.body
+
+    def __getattr__(self, key):
+        if self.prefix is None:
+            return self.__class__(self.app, key)
+        
+        def _wrapper(context, **kwargs):
+            return self.__do_request('/%s/%s' % (self.prefix, key),
+                                     context,
+                                     **kwargs)
+        _wrapper.func_name = key
+        return _wrapper
+
+
+