Uses paste.deploy to make application running configurable. This includes the ability to swap out middlewares, define new endpoints, and generally move away from having code to build wsgi routers and middleware chains into a configurable, extensible method for running wsgi servers.

1 files changed, 109 insertions, 0 deletions

diff --git a/bin/nova-api-paste b/bin/nova-api-paste
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+#!/usr/bin/env python
+# pylint: disable-msg=C0103
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# 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.
+
+"""Starter script for Nova API."""
+
+import gettext
+import logging
+import os
+import sys
+
+from paste import deploy
+
+# If ../nova/__init__.py exists, add ../ to Python search path, so that
+# it will override what happens to be installed in /usr/(local/)lib/python...
+possible_topdir = os.path.normpath(os.path.join(os.path.abspath(sys.argv[0]),
+                                   os.pardir,
+                                   os.pardir))
+if os.path.exists(os.path.join(possible_topdir, 'nova', '__init__.py')):
+    sys.path.insert(0, possible_topdir)
+
+gettext.install('nova', unicode=1)
+
+from nova import flags
+from nova import wsgi
+
+LOG = logging.getLogger('nova.api')
+LOG.setLevel(logging.DEBUG)
+LOG.addHandler(logging.StreamHandler())
+
+FLAGS = flags.FLAGS
+
+API_ENDPOINTS = ['ec2', 'openstack']
+
+
+def load_configuration(paste_config):
+    """Load the paste configuration from the config file and return it."""
+    config = None
+    # Try each known name to get the global DEFAULTS, which will give ports
+    for name in API_ENDPOINTS:
+        try:
+            config = deploy.appconfig("config:%s" % paste_config, name=name)
+        except LookupError:
+            pass
+        if config:
+            verbose = config.get('verbose', None)
+            if verbose:
+                FLAGS.verbose = int(verbose) == 1
+                if FLAGS.verbose:
+                    logging.getLogger().setLevel(logging.DEBUG)
+            return config
+    LOG.debug(_("Paste config at %s has no secion for known apis"),
+              paste_config)
+    print _("Paste config at %s has no secion for any known apis") % \
+          paste_config
+    os.exit(1)
+
+
+def launch_api(paste_config_file, section, server, port, host):
+    """Launch an api server from the specified port and IP."""
+    LOG.debug(_("Launching %s api on %s:%s"), section, host, port)
+    app = deploy.loadapp('config:%s' % paste_config_file, name=section)
+    server.start(app, int(port), host)
+
+
+def run_app(paste_config_file):
+    LOG.debug(_("Using paste.deploy config at: %s"), configfile)
+    config = load_configuration(paste_config_file)
+    LOG.debug(_("Configuration: %r"), config)
+    server = wsgi.Server()
+    ip = config.get('host', '0.0.0.0')
+    for api in API_ENDPOINTS:
+        port = config.get("%s_port" % api, None)
+        if not port:
+            continue
+        host = config.get("%s_host" % api, ip)
+        launch_api(configfile, api, server, port, host)
+    LOG.debug(_("All api servers launched, now waiting"))
+    server.wait()
+
+
+if __name__ == '__main__':
+    FLAGS(sys.argv)
+    configfiles = ['/etc/nova/nova-api.conf']
+    if os.path.exists(os.path.join(possible_topdir, 'nova', '__init__.py')):
+        configfiles.insert(0,
+                       os.path.join(possible_topdir, 'etc', 'nova-api.conf'))
+    for configfile in configfiles:
+        if os.path.exists(configfile):
+            run_app(configfile)
+            break
+        else:
+            LOG.debug(_("Skipping missing configuration: %s"), configfile)