Clean up Deckhand 405/404 error handling

If a method is not allowed, Deckhand currently uses convoluted logic
to throw a 405. Instead, Deckhand should rely on falcon's native
logic which already does that.

This PS relies on falcon logic to throw a 404/405 when an endpoint
is invalid or if a HTTP verb is not support for an endpoint
(respectively).

This PS also adds a VersionsResource to Deckhand to allow information
about the API versions to be returned. This implementation is modeled
after Shipyard [0].

[0] c84e91bad1/shipyard_airflow/control/api.py (L32)

Change-Id: I805801892dbe1a6bca4d0ba5d445fee554c256f8

deckhand/control/api.py

@@ -20,10 +20,10 @@ from oslo_log import log as logging
 
 from deckhand.control import base
 from deckhand.control import buckets
-from deckhand.control import middleware
 from deckhand.control import revision_documents
 from deckhand.control import revision_tags
 from deckhand.control import revisions
+from deckhand.control import versions
 from deckhand.db.sqlalchemy import api as db_api
 
 CONF = cfg.CONF
@@ -40,28 +40,6 @@ def _get_config_files(env=None):
     return [os.path.join(dirname, config_file) for config_file in CONFIG_FILES]
 
 
-def _get_routing_map():
-    ROUTING_MAP = {
-        '/api/v1.0/bucket/[A-za-z0-9\-]+/documents': ['PUT'],
-        '/api/v1.0/revisions': ['GET', 'DELETE'],
-        '/api/v1.0/revisions/[A-za-z0-9\-]+': ['GET'],
-        '/api/v1.0/revisions/[A-za-z0-9\-]+/tags': ['GET', 'DELETE'],
-        '/api/v1.0/revisions/[A-za-z0-9\-]+/tags/[A-za-z0-9\-]+': [
-            'GET', 'POST', 'DELETE'],
-        '/api/v1.0/revisions/[A-za-z0-9\-]+/documents': ['GET']
-    }
-
-    for route in ROUTING_MAP.keys():
-        # Denote the start of the regex with "^".
-        route_re = '^.*' + route
-        # Debite the end of the regex with "$". Allow for an optional "/" at
-        # the end of each request uri.
-        route_re = route_re + '[/]{0,1}$'
-        ROUTING_MAP[route_re] = ROUTING_MAP.pop(route)
-
-    return ROUTING_MAP
-
-
 def start_api(state_manager=None):
     """Main entry point for initializing the Deckhand API service.
 
@@ -77,9 +55,7 @@ def start_api(state_manager=None):
     db_api.drop_db()
     db_api.setup_db()
 
-    control_api = falcon.API(
-        request_type=base.DeckhandRequest,
-        middleware=[middleware.ContextMiddleware(_get_routing_map())])
+    control_api = falcon.API(request_type=base.DeckhandRequest)
 
     v1_0_routes = [
         ('bucket/{bucket_name}/documents', buckets.BucketsResource()),
@@ -95,4 +71,6 @@ def start_api(state_manager=None):
     for path, res in v1_0_routes:
         control_api.add_route(os.path.join('/api/v1.0', path), res)
 
+    control_api.add_route('/versions', versions.VersionsResource())
+
     return control_api

deckhand/control/base.py

@@ -16,9 +16,6 @@ import yaml
 
 import falcon
 from oslo_context import context
-from oslo_log import log as logging
-
-LOG = logging.getLogger(__name__)
 
 
 class BaseResource(object):
@@ -26,6 +23,7 @@ class BaseResource(object):
 
     def on_options(self, req, resp):
         self_attrs = dir(self)
+
         methods = ['GET', 'HEAD', 'POST', 'PUT', 'DELETE', 'PATCH']
         allowed_methods = []
 
@@ -39,7 +37,7 @@ class BaseResource(object):
     def to_yaml_body(self, dict_body):
         """Converts JSON body into YAML response body.
 
-        :dict_body: response body to be converted to YAML.
+        :param dict_body: response body to be converted to YAML.
         :returns: YAML encoding of `dict_body`.
         """
         if isinstance(dict_body, dict):

deckhand/control/middleware.py

@@ -1,40 +0,0 @@
-# Copyright 2017 AT&T Intellectual Property.  All other 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.
-
-import re
-
-import falcon
-
-
-class ContextMiddleware(object):
-
-    def __init__(self, routing_map):
-        self.routing_map = routing_map
-
-    def process_request(self, req, resp):
-        # Determine whether the method is allowed.
-        req_method = req.method
-        req_uri = req.uri
-        found = False
-
-        for route_pattern, allowed_methods in self.routing_map.items():
-            if re.match(route_pattern, req_uri):
-                if req_method not in allowed_methods:
-                    raise falcon.HTTPMethodNotAllowed(allowed_methods)
-                else:
-                    found = True
-                    break
-
-        if not found:
-            raise falcon.HTTPMethodNotAllowed([])

deckhand/control/versions.py

@@ -0,0 +1,30 @@
+# Copyright 2017 AT&T Intellectual Property.  All other 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.
+
+import falcon
+
+from deckhand.control import base as api_base
+
+
+class VersionsResource(api_base.BaseResource):
+
+    def on_get(self, req, resp):
+        resp.body = self.to_yaml_body({
+            'v1.0': {
+                'path': '/api/v1.0',
+                'status': 'stable'
+            }
+        })
+        resp.append_header('Content-Type', 'application/x-yaml')
+        resp.status = falcon.HTTP_200

deckhand/db/sqlalchemy/models.py

@@ -172,13 +172,13 @@ class Document(BASE, DeckhandBase):
 
 def register_models(engine):
     """Create database tables for all models with the given engine."""
-    models = [Bucket, Document, Revision]
+    models = [Bucket, Document, Revision, RevisionTag]
     for model in models:
         model.metadata.create_all(engine)
 
 
 def unregister_models(engine):
     """Drop database tables for all models with the given engine."""
-    models = [Bucket, Document, Revision]
+    models = [Bucket, Document, Revision, RevisionTag]
     for model in models:
         model.metadata.drop_all(engine)

deckhand/tests/unit/control/test_api.py

@@ -47,7 +47,7 @@ class TestApi(test_base.DeckhandTestCase):
         self.assertEqual(mock_falcon_api, result)
 
         mock_falcon.API.assert_called_once_with(
-            request_type=base.DeckhandRequest, middleware=[mock.ANY])
+            request_type=base.DeckhandRequest)
         mock_falcon_api.add_route.assert_has_calls([
             mock.call('/api/v1.0/bucket/{bucket_name}/documents',
                       self.buckets_resource()),