Add extensions for API v2 controllers

Controllers (and API endpoints) should be able to be selected using
configuration flags, as we do for plugins

TODO:
 - Extra Hooks to be configured using stevedore

Implements blueprint: pecan-wsme
Implements blueprint: api-extensions

Change-Id: I12f1bc1accbc870aacb0d1e08c9e0d08223c4b18

climate/api/v2/controllers/__init__.py

@@ -16,24 +16,58 @@
 """Version 2 of the API.
 """
 
+from oslo.config import cfg
 import pecan
+from pecan import rest
+from stevedore import enabled
 
-from climate.api.v2.controllers import host
-from climate.api.v2.controllers import lease
-from climate.openstack.common.gettextutils import _  # noqa
+from climate import exceptions
+from climate.openstack.common.gettextutils import _
 from climate.openstack.common import log as logging
 
 LOG = logging.getLogger(__name__)
 
+api_opts = [
+    cfg.ListOpt('api_v2_controllers',
+                default=['oshosts', 'leases'],
+                help='API extensions to use'),
+]
 
-class V2Controller(pecan.rest.RestController):
+CONF = cfg.CONF
+CONF.register_opts(api_opts, 'api')
+
+
+class V2Controller(rest.RestController):
     """Version 2 API controller root."""
 
-    _routes = {'os-hosts': 'oshosts',
-               'oshosts': 'None'}
+    _routes = {}
 
-    leases = lease.LeasesController()
-    oshosts = host.HostsController()
+    def _log_missing_plugins(self, names):
+        for name in names:
+            if name not in self.extension_manager.names():
+                LOG.error(_("API Plugin %s was not loaded") % name)
+
+    def __init__(self):
+        extensions = []
+
+        self.extension_manager = enabled.EnabledExtensionManager(
+            check_func=lambda ext: ext.name in CONF.api.api_v2_controllers,
+            namespace='climate.api.v2.controllers.extensions',
+            invoke_on_load=True
+        )
+        self._log_missing_plugins(CONF.api.api_v2_controllers)
+
+        for ext in self.extension_manager.extensions:
+            try:
+                setattr(self, ext.obj.name, ext.obj)
+            except TypeError:
+                raise exceptions.ClimateException(
+                    _("API name must be specified for "
+                        "extension {0}").format(ext.name))
+            self._routes.update(ext.obj.extra_routes)
+            extensions.append(ext.obj.name)
+
+        LOG.debug(_("Loaded extensions: {0}").format(extensions))
 
     @pecan.expose()
     def _route(self, args):
@@ -44,7 +78,12 @@ class V2Controller(pecan.rest.RestController):
         """
 
         try:
-            args[0] = self._routes.get(args[0], args[0])
+            route = self._routes.get(args[0], args[0])
+            if route is None:
+                # NOTE(sbauza): Route must map to a non-existing controller
+                args[0] = 'http404-nonexistingcontroller'
+            else:
+                args[0] = route
         except IndexError:
             LOG.error(_("No args found on V2 controller"))
         return super(V2Controller, self)._route(args)

climate/api/v2/controllers/extensions/__init__.py

@@ -0,0 +1,63 @@
+# Copyright (c) 2014 Bull.
+#
+# 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 abc
+
+from oslo.config import cfg
+from pecan import rest
+
+from climate.openstack.common import log as logging
+
+LOG = logging.getLogger(__name__)
+CONF = cfg.CONF
+
+
+class BaseController(rest.RestController):
+    __metaclass__ = abc.ABCMeta
+
+    """Mandatory API method name."""
+    name = None
+
+    """Optional extra routes to add.
+    Dict of key/value pairs, where :
+        key : API method name redirect (public URL)
+        value : redirect target (can be None for routing to HTTP 404)
+    """
+    extra_routes = {}
+
+    @abc.abstractmethod
+    def get_one(self, resource_id):
+        """Get a single resource."""
+        pass
+
+    @abc.abstractmethod
+    def get_all(self):
+        """Get all resources."""
+        pass
+
+    @abc.abstractmethod
+    def post(self, resource):
+        """Create a resource."""
+        pass
+
+    @abc.abstractmethod
+    def put(self, resource):
+        """Update a resource."""
+        pass
+
+    @abc.abstractmethod
+    def delete(self, resource_id):
+        """Delete a single resource."""
+        pass

climate/api/v2/controllers/extensions/host.py

@@ -14,11 +14,11 @@
 # limitations under the License.
 
 import pecan
-from pecan import rest
 from wsme import types as wtypes
 import wsmeext.pecan as wsme_pecan
 
 from climate.api.v2.controllers import base
+from climate.api.v2.controllers import extensions
 from climate.api.v2.controllers import types
 from climate import exceptions
 from climate.openstack.common.gettextutils import _  # noqa
@@ -95,10 +95,14 @@ class Host(base._Base):
                    )
 
 
-class HostsController(rest.RestController):
+class HostsController(extensions.BaseController):
     """Manages operations on hosts.
     """
 
+    name = 'oshosts'
+    extra_routes = {'os-hosts': 'oshosts',
+                    'oshosts': None}
+
     @policy.authorize('oshosts', 'get')
     @wsme_pecan.wsexpose(Host, types.IntegerType())
     def get_one(self, id):

climate/api/v2/controllers/extensions/lease.py

@@ -14,11 +14,11 @@
 # limitations under the License.
 
 import pecan
-from pecan import rest
 from wsme import types as wtypes
 import wsmeext.pecan as wsme_pecan
 
 from climate.api.v2.controllers import base
+from climate.api.v2.controllers import extensions
 from climate.api.v2.controllers import types
 from climate import exceptions
 from climate.manager import service
@@ -87,10 +87,12 @@ class Lease(base._Base):
                    )
 
 
-class LeasesController(rest.RestController):
+class LeasesController(extensions.BaseController):
     """Manages operations on leases.
     """
 
+    name = 'leases'
+
     @policy.authorize('leases', 'get')
     @wsme_pecan.wsexpose(Lease, types.UuidType())
     def get_one(self, id):

contrib/devstack/lib/blazar

@@ -104,6 +104,8 @@ function configure_climate() {
 
     iniset $CLIMATE_CONF_FILE manager plugins basic.vm.plugin,physical.host.plugin
 
+    iniset $CLIMATE_CONF_FILE api api_v2_controllers oshosts,leases
+
     iniset $CLIMATE_CONF_FILE database connection `database_connection_url climate`
 
     iniset $CLIMATE_CONF_FILE DEFAULT use_syslog $SYSLOG

doc/source/restapi/rest_api_v2.rst

@@ -35,10 +35,10 @@ Lease is the main abstraction for the user in the Climate case. Lease means
 some kind of contract where start time, end time and resources to be reserved
 are mentioned.
 
-.. rest-controller:: climate.api.v2.controllers.lease:LeasesController
+.. rest-controller:: climate.api.v2.controllers.extensions.lease:LeasesController
    :webprefix: /v2/leases
 
-.. autotype:: climate.api.v2.controllers.lease.Lease
+.. autotype:: climate.api.v2.controllers.extensions.lease.Lease
    :members:
 
 
@@ -50,8 +50,8 @@ are mentioned.
 Host is the abstraction for a computehost in the Climate case. Host means
 a specific type of resource to be allocated.
 
-.. rest-controller:: climate.api.v2.controllers.host:HostsController
+.. rest-controller:: climate.api.v2.controllers.extensions.host:HostsController
    :webprefix: /v2/os-hosts
 
-.. autotype:: climate.api.v2.controllers.host.Host
+.. autotype:: climate.api.v2.controllers.extensions.host.Host
    :members:

etc/climate/climate.conf.sample

@@ -448,6 +448,16 @@
 #image_prefix=reserved_
 
 
+[api]
+
+#
+# Options defined in climate.api.v2.controllers
+#
+
+# API extensions to use (list value)
+#api_v2_controllers=oshosts,leases
+
+
 [database]
 
 #

setup.cfg

@@ -37,6 +37,10 @@ climate.resource.plugins =
     physical.host.plugin=climate.plugins.oshosts.host_plugin:PhysicalHostPlugin
     basic.vm.plugin=climate.plugins.instances.vm_plugin:VMPlugin
 
+climate.api.v2.controllers.extensions =
+    oshosts=climate.api.v2.controllers.extensions.host:HostsController
+    leases=climate.api.v2.controllers.extensions.lease:LeasesController
+
 [build_sphinx]
 all_files = 1
 build-dir = doc/build