Add generic PasteDeploy app and filter factories

These generic factories allow us to dump the copied and pasted
app_factory and filter_factory methods in the codebase.

The main difference is the paste configuration changes from:

  [app:apiv1app]
  paste.app_factory = glance.api.v1:app_factory
  ...
  [filter:cache]
  paste.filter_factory = glance.api.middleware.cache:filter_factory

to this:

  [app:apiv1app]
  paste.app_factory = glance.common.wsgi:app_factory
  glance.app_factory = glance.api.v1:API
  ...
  [filter:cache]
  paste.filter_factory = glance.common.wsgi:filter_factory
  glance.filter_factory = glance.api.middleware.cache:CacheFilter

Apart from reducing code duplication, this will also allow us to have
the generic factories inject other data into the apps and filters.

Change-Id: I1d2be5630ab61d29b8948ff88d58e6e1b11c2e5f

doc/source/configuring.rst

@@ -513,7 +513,8 @@ The cache middleware should be in your ``glance-api.conf`` in a section titled
 ``[filter:cache]``. It should look like this::
 
   [filter:cache]
-  paste.filter_factory = glance.api.middleware.cache:filter_factory
+  paste.filter_factory = glance.common.wsgi:filter_factory
+  glance.filter_factory = glance.api.middleware.cache:CacheFilter
 
 
 For example, suppose your application pipeline in the ``glance-api.conf`` file

etc/glance-api.conf

@@ -214,19 +214,24 @@ pipeline = versionnegotiation context apiv1app
 # pipeline = versionnegotiation authtoken auth-context cachemanage apiv1app
 
 [app:apiv1app]
-paste.app_factory = glance.api.v1.router:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.api.v1.router:API
 
 [filter:versionnegotiation]
-paste.filter_factory = glance.api.middleware.version_negotiation:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.api.middleware.version_negotiation:VersionNegotiationFilter
 
 [filter:cache]
-paste.filter_factory = glance.api.middleware.cache:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.api.middleware.cache:CacheFilter
 
 [filter:cachemanage]
-paste.filter_factory = glance.api.middleware.cache_manage:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.api.middleware.cache_manage:CacheManageFilter
 
 [filter:context]
-paste.filter_factory = glance.common.context:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.common.context:ContextMiddleware
 
 [filter:authtoken]
 paste.filter_factory = keystone.middleware.auth_token:filter_factory
@@ -240,4 +245,5 @@ auth_uri = http://127.0.0.1:5000/
 admin_token = 999888777666
 
 [filter:auth-context]
-paste.filter_factory = keystone.middleware.glance_auth_token:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = keystone.middleware.glance_auth_token:KeystoneContextMiddleware

etc/glance-cache.conf

@@ -40,13 +40,17 @@ registry_port = 9191
 # admin_token = 123
 
 [app:glance-pruner]
-paste.app_factory = glance.image_cache.pruner:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.pruner:Pruner
 
 [app:glance-prefetcher]
-paste.app_factory = glance.image_cache.prefetcher:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.prefetcher:Prefetcher
 
 [app:glance-cleaner]
-paste.app_factory = glance.image_cache.cleaner:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.cleaner:Cleaner
 
 [app:glance-queue-image]
-paste.app_factory = glance.image_cache.queue_image:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.queue_image:Queuer

etc/glance-registry.conf

@@ -57,11 +57,13 @@ pipeline = context registryapp
 # pipeline = authtoken auth-context registryapp
 
 [app:registryapp]
-paste.app_factory = glance.registry.api.v1:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.registry.api.v1:API
 
 [filter:context]
 context_class = glance.registry.context.RequestContext
-paste.filter_factory = glance.common.context:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.common.context:ContextMiddleware
 
 [filter:authtoken]
 paste.filter_factory = keystone.middleware.auth_token:filter_factory
@@ -76,4 +78,5 @@ admin_token = 999888777666
 
 [filter:auth-context]
 context_class = glance.registry.context.RequestContext
-paste.filter_factory = keystone.middleware.glance_auth_token:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = keystone.middleware.glance_auth_token:KeystoneContextMiddleware

etc/glance-scrubber.conf

@@ -35,4 +35,5 @@ registry_host = 0.0.0.0
 registry_port = 9191
 
 [app:glance-scrubber]
-paste.app_factory = glance.store.scrubber:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.store.scrubber:Scrubber

glance/api/cached_images.py

@@ -115,10 +115,3 @@ def create_resource(options):
     deserializer = CachedImageDeserializer()
     serializer = CachedImageSerializer()
     return wsgi.Resource(Controller(options), deserializer, serializer)
-
-
-def app_factory(global_conf, **local_conf):
-    """paste.deploy app factory for creating Cached Images apps"""
-    conf = global_conf.copy()
-    conf.update(local_conf)
-    return Controller(conf)

glance/api/middleware/cache.py

@@ -132,16 +132,3 @@ class CacheFilter(wsgi.Middleware):
             chunks = utils.chunkiter(cache_file)
             for chunk in chunks:
                 yield chunk
-
-
-def filter_factory(global_conf, **local_conf):
-    """
-    Factory method for paste.deploy
-    """
-    conf = global_conf.copy()
-    conf.update(local_conf)
-
-    def filter(app):
-        return CacheFilter(app, conf)
-
-    return filter

glance/api/middleware/cache_manage.py

@@ -70,16 +70,3 @@ class CacheManageFilter(wsgi.Middleware):
 
         logger.info(_("Initialized image cache management middleware"))
         super(CacheManageFilter, self).__init__(app)
-
-
-def filter_factory(global_conf, **local_conf):
-    """
-    Factory method for paste.deploy
-    """
-    conf = global_conf.copy()
-    conf.update(local_conf)
-
-    def filter(app):
-        return CacheManageFilter(app, conf)
-
-    return filter

glance/api/middleware/version_negotiation.py

@@ -121,16 +121,3 @@ class VersionNegotiationFilter(wsgi.Middleware):
             req.environ['api.major_version'] = major_version
             req.environ['api.minor_version'] = minor_version
         return match is not None
-
-
-def filter_factory(global_conf, **local_conf):
-    """
-    Factory method for paste.deploy
-    """
-    conf = global_conf.copy()
-    conf.update(local_conf)
-
-    def filter(app):
-        return VersionNegotiationFilter(app, conf)
-
-    return filter

glance/api/v1/router.py

@@ -56,10 +56,3 @@ class API(wsgi.Router):
                        conditions=dict(method=["PUT"]))
 
         super(API, self).__init__(mapper)
-
-
-def app_factory(global_conf, **local_conf):
-    """paste.deploy app factory for creating Glance API server apps"""
-    conf = global_conf.copy()
-    conf.update(local_conf)
-    return API(conf)

glance/common/context.py

@@ -119,16 +119,3 @@ class ContextMiddleware(wsgi.Middleware):
         req.context = self.make_context(
             auth_tok=auth_tok, user=user, tenant=tenant, roles=roles,
             is_admin=is_admin)
-
-
-def filter_factory(global_conf, **local_conf):
-    """
-    Factory method for paste.deploy
-    """
-    conf = global_conf.copy()
-    conf.update(local_conf)
-
-    def filter(app):
-        return ContextMiddleware(app, conf)
-
-    return filter

glance/common/wsgi.py

@@ -37,6 +37,7 @@ import webob.dec
 import webob.exc
 
 from glance.common import exception
+from glance.common import utils
 
 
 class WritableLogger(object):
@@ -406,3 +407,52 @@ class Resource(object):
             pass
 
         return args
+
+
+def _import_factory(conf, key):
+    return utils.import_class(conf[key].replace(':', '.').strip())
+
+
+def app_factory(global_conf, **local_conf):
+    """A Generic paste.deploy app factory.
+
+    This requires glance.app_factory to be set to a callable which returns a
+    WSGI app when invoked. The format of the name is <module>:<callable> e.g.
+
+      [app:apiv1app]
+      paste.app_factory = glance.common.wsgi:app_factory
+      glance.app_factory = glance.api.v1:API
+
+    The WSGI app constructor must accept a configuration dict as its only
+    argument.
+    """
+    factory = _import_factory(local_conf, 'glance.app_factory')
+
+    conf = global_conf.copy()
+    conf.update(local_conf)
+
+    return factory(conf)
+
+
+def filter_factory(global_conf, **local_conf):
+    """A Generic paste.deploy filter factory.
+
+    This requires glance.filter_factory to be set to a callable which returns a
+    WSGI filter when invoked. The format is <module>:<callable> e.g.
+
+      [filter:cache]
+      paste.filter_factory = glance.common.wsgi:filter_factory
+      glance.filter_factory = glance.api.middleware.cache:CacheFilter
+
+    The WSGI filter constructor must accept a WSGI app and a configuration dict
+    as its only two arguments.
+    """
+    factory = _import_factory(local_conf, 'glance.filter_factory')
+
+    conf = global_conf.copy()
+    conf.update(local_conf)
+
+    def filter(app):
+        return factory(app, conf)
+
+    return filter

glance/image_cache/cleaner.py

@@ -33,9 +33,3 @@ class Cleaner(object):
 
     def run(self):
         self.cache.clean()
-
-
-def app_factory(global_config, **local_conf):
-    conf = global_config.copy()
-    conf.update(local_conf)
-    return Cleaner(conf)

glance/image_cache/prefetcher.py

@@ -88,9 +88,3 @@ class Prefetcher(object):
 
         logger.info(_("Successfully cached all %d images"), num_images)
         return True
-
-
-def app_factory(global_config, **local_conf):
-    conf = global_config.copy()
-    conf.update(local_conf)
-    return Prefetcher(conf)

glance/image_cache/pruner.py

@@ -33,9 +33,3 @@ class Pruner(object):
 
     def run(self):
         self.cache.prune()
-
-
-def app_factory(global_config, **local_conf):
-    conf = global_config.copy()
-    conf.update(local_conf)
-    return Pruner(conf)

glance/image_cache/queue_image.py

@@ -78,9 +78,3 @@ class Queuer(object):
 
         logger.info(_("Successfully queued all %d images"), num_images)
         return True
-
-
-def app_factory(global_config, **local_conf):
-    conf = global_config.copy()
-    conf.update(local_conf)
-    return Queuer(conf)

glance/registry/api/v1/__init__.py

@@ -45,13 +45,3 @@ class API(wsgi.Router):
                        action="index_shared_images")
 
         super(API, self).__init__(mapper)
-
-
-def app_factory(global_conf, **local_conf):
-    """
-    paste.deploy app factory for creating Glance reference implementation
-    registry server apps
-    """
-    conf = global_conf.copy()
-    conf.update(local_conf)
-    return API(conf)

glance/registry/server.py

@@ -1,20 +0,0 @@
-# vim: tabstop=4 shiftwidth=4 softtabstop=4
-
-# Copyright 2010-2011 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.
-
-# NOTE(bcwaldon): This is done as a convenience for people
-# so they don't have to update their paste configs just yet.
-from glance.registry.api.v1 import app_factory

glance/store/scrubber.py

@@ -180,9 +180,3 @@ def write_queue_file(file_path, uri, delete_time):
         f.write('\n'.join([uri, str(int(delete_time))]))
     os.chmod(file_path, 0600)
     os.utime(file_path, (delete_time, delete_time))
-
-
-def app_factory(global_config, **local_conf):
-    conf = global_config.copy()
-    conf.update(local_conf)
-    return Scrubber(conf)

glance/tests/functional/__init__.py

@@ -217,19 +217,25 @@ image_cache_driver = %(image_cache_driver)s
 pipeline = versionnegotiation context %(cache_pipeline)s apiv1app
 
 [app:apiv1app]
-paste.app_factory = glance.api.v1.router:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.api.v1.router:API
 
 [filter:versionnegotiation]
-paste.filter_factory = glance.api.middleware.version_negotiation:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory =
+ glance.api.middleware.version_negotiation:VersionNegotiationFilter
 
 [filter:cache]
-paste.filter_factory = glance.api.middleware.cache:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.api.middleware.cache:CacheFilter
 
 [filter:cache_manage]
-paste.filter_factory = glance.api.middleware.cache_manage:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.api.middleware.cache_manage:CacheManageFilter
 
 [filter:context]
-paste.filter_factory = glance.common.context:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.common.context:ContextMiddleware
 """
 
 
@@ -267,11 +273,13 @@ owner_is_tenant = %(owner_is_tenant)s
 pipeline = context registryapp
 
 [app:registryapp]
-paste.app_factory = glance.registry.api.v1:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.registry.api.v1:API
 
 [filter:context]
 context_class = glance.registry.context.RequestContext
-paste.filter_factory = glance.common.context:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory = glance.common.context:ContextMiddleware
 """
 
 
@@ -302,7 +310,8 @@ registry_host = 0.0.0.0
 registry_port = %(registry_port)s
 
 [app:glance-scrubber]
-paste.app_factory = glance.store.scrubber:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.store.scrubber:Scrubber
 """
 
 

glance/tests/functional/keystone_utils.py

@@ -158,7 +158,9 @@ admin_token = 999888777666
 delay_auth_decision = 1
 
 [filter:keystone_shim]
-paste.filter_factory = keystone.middleware.glance_auth_token:filter_factory
+paste.filter_factory = glance.common.wsgi:filter_factory
+glance.filter_factory =
+ keystone.middleware.glance_auth_token:KeystoneContextMiddleware
 """ % subs
 
 

glance/tests/functional/test_bin_glance_cache_manage.py

@@ -209,16 +209,20 @@ metadata_encryption_key = %(metadata_encryption_key)s
 log_file = %(log_file)s
 
 [app:glance-pruner]
-paste.app_factory = glance.image_cache.pruner:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.pruner:Pruner
 
 [app:glance-prefetcher]
-paste.app_factory = glance.image_cache.prefetcher:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.prefetcher:Prefetcher
 
 [app:glance-cleaner]
-paste.app_factory = glance.image_cache.cleaner:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.cleaner:Cleaner
 
 [app:glance-queue-image]
-paste.app_factory = glance.image_cache.queue_image:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.queue_image:Queuer
 """ % cache_file_options)
             cache_file.flush()
 

glance/tests/functional/test_cache_middleware.py

@@ -338,16 +338,20 @@ metadata_encryption_key = %(metadata_encryption_key)s
 log_file = %(log_file)s
 
 [app:glance-pruner]
-paste.app_factory = glance.image_cache.pruner:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.pruner:Pruner
 
 [app:glance-prefetcher]
-paste.app_factory = glance.image_cache.prefetcher:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.prefetcher:Prefetcher
 
 [app:glance-cleaner]
-paste.app_factory = glance.image_cache.cleaner:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.cleaner:Cleaner
 
 [app:glance-queue-image]
-paste.app_factory = glance.image_cache.queue_image:app_factory
+paste.app_factory = glance.common.wsgi:app_factory
+glance.app_factory = glance.image_cache.queue_image:Queuer
 """ % cache_file_options)
             cache_file.flush()
 

glance/tests/unit/test_config.py

@@ -26,6 +26,7 @@ from glance.api.middleware import version_negotiation
 from glance.api.v1 import images
 from glance.api.v1 import members
 from glance.common import config
+from glance.common import wsgi
 from glance.image_cache import pruner
 
 
@@ -178,7 +179,7 @@ class TestPasteApp(unittest.TestCase):
         self.stubs.Set(os.path, 'join', fake_join)
 
         self.stubs.Set(config, 'setup_logging', lambda *a: None)
-        self.stubs.Set(pruner, 'app_factory', lambda *a: 'pruner')
+        self.stubs.Set(wsgi, 'app_factory', lambda *a, **kw: 'pruner')
 
         conf, app = config.load_paste_app('glance-pruner', {}, [],
                                           'glance-cache')