Enable uWSGI deployment of the blazar-api service

This patch adds a WSGI entry point to setup.cfg and enables users to
deploy the blazar-api service as a uWSGI service.

If operators want to deploy blazar-api under their own servers that
support WSGI applications, they can get the WSGI app by calling
blazar.api.wsgi_app.init_app().

If you need more details about WSGI itself, please see the following
link: https://www.python.org/dev/peps/pep-3333/

Patially Implements: blueprint deploy-api-in-wsgi
Change-Id: I1fb02c403c6e588e49fa455969895731b88e5dd7

blazar/api/wsgi_app.py

@@ -0,0 +1,51 @@
+# Copyright (c) 2017 NTT Inc.
+#
+# 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 os
+
+from oslo_config import cfg
+from oslo_log import log as logging
+
+from blazar.api import app as wsgi_app
+from blazar.api.v2 import app as v2_app
+from blazar.utils import service as service_utils
+
+
+CONF = cfg.CONF
+CONF.import_opt('enable_v1_api', 'blazar.config')
+logging.register_options(CONF)
+
+CONFIG_FILES = ['blazar.conf']
+
+
+def _get_config_files(env=None):
+    if env is None:
+        env = os.environ
+    dirname = env.get('OS_BLAZAR_CONFIG_DIR', '/etc/blazar').strip()
+    return [os.path.join(dirname, config_file)
+            for config_file in CONFIG_FILES]
+
+
+def init_app():
+    config_files = _get_config_files()
+    CONF([], project='blazar', prog='blazar-api',
+         default_config_files=config_files)
+    service_utils.prepare_service()
+    if not CONF.enable_v1_api:
+        app = v2_app.make_app()
+    else:
+        app = wsgi_app.VersionSelectorApplication()
+
+    return app

blazar/cmd/api.py

@@ -36,19 +36,12 @@ opts = [
                help='Port that will be used to listen on'),
 ]
 
-api_opts = [
-    cfg.BoolOpt('enable_v1_api',
-                default=True,
-                help='Deploy the v1 API.'),
-]
-
-
 LOG = logging.getLogger(__name__)
 CONF = cfg.CONF
 CONF.register_cli_opts(opts)
-CONF.register_opts(api_opts)
 
 CONF.import_opt('host', 'blazar.config')
+CONF.import_opt('enable_v1_api', 'blazar.config')
 
 
 def main():

blazar/config.py

@@ -66,7 +66,14 @@ os_opts = [
                help='A domain name the os_admin_project_name belongs to')
 ]
 
+api_opts = [
+    cfg.BoolOpt('enable_v1_api',
+                default=True,
+                help='Deploy the v1 API.'),
+]
+
 CONF = cfg.CONF
 CONF.register_cli_opts(cli_opts)
 CONF.register_opts(os_opts)
+CONF.register_opts(api_opts)
 logging.register_options(cfg.CONF)

blazar/opts.py

@@ -32,8 +32,8 @@ def list_opts():
         ('DEFAULT',
          itertools.chain(
              blazar.api.v2.app.auth_opts,
-             blazar.cmd.api.api_opts,
              blazar.cmd.api.opts,
+             blazar.config.api_opts,
              blazar.config.cli_opts,
              blazar.config.os_opts,
              blazar.db.base.db_driver_opts,

setup.cfg

@@ -55,6 +55,9 @@ blazar.api.v2.controllers.extensions =
 oslo.config.opts =
     blazar = blazar.opts:list_opts
 
+wsgi_scripts =
+    blazar-api-wsgi = blazar.api.wsgi_app:init_app
+
 [build_sphinx]
 all_files = 1
 build-dir = doc/build