Fix WSGI script for gunicorn

The previous patch to add support for apache breaks gunicorn. The gunicorn
setup loads the mistral.api.wsgi module and requires the application
variable be assigned. The support for apache make the assumption that the
mistral.api.wsgi be called as a python script. This patch moves the init
function required by apache to a different location.

Change-Id: Ib5af50a55d3f3bb9d0fa0d1ee6b8e7564f909d70
Closes-Bug: #1689943

mistral/api/app.py

@@ -83,3 +83,12 @@ def setup_app(config=None):
     # Create a CORS wrapper, and attach mistral-specific defaults that must be
     # included in all CORS responses.
     return cors_middleware.CORS(app, cfg.CONF)
+
+
+def init_wsgi():
+    # By default, oslo.config parses the CLI args if no args is provided.
+    # As a result, invoking this wsgi script from gunicorn leads to the error
+    # with argparse complaining that the CLI options have already been parsed.
+    m_config.parse_args(args=[])
+
+    return setup_app()

mistral/api/wsgi.py

@@ -13,17 +13,5 @@
 #    limitations under the License.
 
 from mistral.api import app
-from mistral import config
 
-
-# By default, oslo.config parses the CLI args if no args is provided.
-# As a result, invoking this wsgi script from gunicorn leads to the error
-# with argparse complaining that the CLI options have already been parsed.
-def init_application():
-    config.parse_args(args=[])
-
-    return app.setup_app()
-
-
-if __name__ == '__main__':
-    application = init_application()
+application = app.init_wsgi()

setup.cfg

@@ -38,7 +38,7 @@ console_scripts =
     mistral-db-manage = mistral.db.sqlalchemy.migration.cli:main
 
 wsgi_scripts =
-    mistral-wsgi-api = mistral.api.wsgi:init_application
+    mistral-wsgi-api = mistral.api.app:init_wsgi
 
 mistral.rpc.backends =
     oslo_client = mistral.rpc.oslo.oslo_client:OsloRPCClient