Make it possible to use uwsgi easily

This patch adds a standard /usr/bin/magnum-api-uwsgi script, which we can
use from uwsgi. Without this patch, there's no way to load the application
correctly, with parameters on the command line.

Change-Id: Icdcd1255e7e08d68a5d31672b21127f781d6ac68

magnum/api/app.py

@@ -10,6 +10,7 @@
 #    See the License for the specific language governing permissions and
 #    limitations under the License.
 import os
+import sys
 
 from oslo_config import cfg
 from oslo_log import log
@@ -19,6 +20,7 @@ import pecan
 from magnum.api import config as api_config
 from magnum.api import middleware
 from magnum.common import config as common_config
+from magnum.common import service
 import magnum.conf
 
 CONF = magnum.conf.CONF
@@ -65,3 +67,8 @@ def load_app():
 
 def app_factory(global_config, **local_conf):
     return setup_app()
+
+
+def build_wsgi_app(argv=None):
+    service.prepare_service(sys.argv)
+    return load_app()

setup.cfg

@@ -47,6 +47,9 @@ console_scripts =
     magnum-driver-manage = magnum.cmd.driver_manage:main
     magnum-status = magnum.cmd.status:main
 
+wsgi_scripts =
+    magnum-api-wsgi = magnum.api.app:build_wsgi_app
+
 oslo.config.opts =
     magnum = magnum.opts:list_opts
     magnum.conf = magnum.conf.opts:list_opts