Add rate limiting middleware

- Add rate limiting config options. Only the ones that we might want
  to change have been added as config options for now.

- Remove statsd options from watcher middleware. Since the defaults
  values are being used it's better to use them for both watcher MW as
  well as rate limiting MW, rather than definining statsd options for
  each of the middlewares. If in the future we need to set non-default
  options we can create a dedicated statsd config option group that
  all middlewares are getting their statsd config from.

custom-requirements.txt

@@ -11,5 +11,6 @@ uwsgi-shortmsecs
 raven
 -e git+https://github.com/sapcc/octavia-f5-provider-driver.git@stable/yoga-m3#egg=octavia-f5-provider-driver
 git+https://github.com/sapcc/openstack-watcher-middleware.git#egg=watcher-middleware
+git+https://github.com/sapcc/openstack-rate-limit-middleware.git#egg=rate-limit-middleware
 git+https://github.com/sapcc/openstack-audit-middleware.git@master#egg=audit-middleware
 git+https://github.com/sapcc/openstack-uwsgi-middleware.git@main#egg=uwsgi-middleware

octavia/api/app.py

@@ -14,6 +14,7 @@
 
 import sys
 
+import rate_limit as ratelimitmiddleware
 # Try using custom auditmiddleware
 try:
     import auditmiddleware as audit_middleware
@@ -86,16 +87,33 @@ def setup_app(pecan_config=None, debug=False, argv=None):
 def _wrap_app(app):
     """Wraps wsgi app with additional middlewares."""
 
-    # This needs to be the first middleware (and the last in the chain)
+    # UWSGI needs to be the first middleware (and the last in the chain)
     try:
         from uwsgi_middleware import uwsgi
         app = uwsgi.Uwsgi(app)
     except (EnvironmentError, OSError, ImportError) as e:
         LOG.debug("Could not load uwsgi middleware: %s", e)
 
+    # Inject Request ID
     app = request_id.RequestId(app)
 
     if CONF.audit.enabled:
+
+        # rate limiting - depends on audit middleware, therefore must stand
+        # before it in order to appear after it in the chain
+        app = ratelimitmiddleware.OpenStackRateLimitMiddleware(
+                app,
+                config_file=CONF.rate_limiting.config_file,
+                service_type=CONF.rate_limiting.service_type,
+                rate_limit_by=CONF.rate_limiting.rate_limit_by,
+                max_sleep_time_seconds=CONF.rate_limiting.max_sleep_time_seconds,
+                backend_host=CONF.rate_limiting.backend_host,
+                backend_port=CONF.rate_limiting.backend_port,
+                backend_max_connections=CONF.rate_limiting.backend_max_connections,
+                backend_timeout_seconds=CONF.rate_limiting.backend_timeout_seconds,
+                )
+
+        # audit middleware
         try:
             app = audit_middleware.AuditMiddleware(
                 app,

octavia/common/config.py

@@ -822,6 +822,32 @@
                        'using tagged statsd metrics.')),
 ]
 
+rate_limiting_opts = [
+    cfg.StrOpt('config_file', default="/etc/octavia/ratelimit.yaml",
+        help=_('Path to the rate limiting middleware configuration file')),
+    cfg.StrOpt('service_type', default="loadbalancer",
+        help=_('The service type according to CADF specification')),
+    cfg.StrOpt('rate_limit_by',
+        help=_('Per default rate limits are applied based on '
+               '`initiator_project_id`. However, this can also be se to '
+               '`initiator_host_address` or `target_project_id`')),
+    cfg.IntOpt('max_sleep_time_seconds', default=20,
+        help=_('The maximal time a request can be suspended in seconds. '
+                'Instead of immediately returning a rate limit response, '
+                'a request can be suspended until the specified maximum '
+                'duration to fit the configured rate limit. This feature '
+                'can be disabled by setting the max sleep time to 0 seconds.')),
+    cfg.StrOpt('backend_host', default="127.0.0.1",
+        help=_('Redis backend host for rate limiting middleware')),
+    cfg.PortOpt('backend_port', default=6379,
+        help=_('Redis backend port for rate limiting middleware')),
+    cfg.IntOpt('backend_max_connections', default=100,
+        help=_('Maximum connections for redis connection pool.')),
+    cfg.IntOpt('backend_timeout_seconds', default=2,
+        help=_('Timeout for obtaining a connection to the backend. '
+               'It should be >= 1 second. Skips rate limit on timeout.')),
+]
+
 driver_agent_opts = [
     cfg.StrOpt('status_socket_path',
                default='/var/run/octavia/status.sock',
@@ -882,15 +908,6 @@
                help=_('The name of the service according to CADF')),
     cfg.StrOpt('config_file',
                help=_('Path to configuration file')),
-    cfg.StrOpt('statsd_host',
-               default='127.0.0.1',
-               help=_('Host of the StatsD backend')),
-    cfg.StrOpt('statsd_namespace',
-               default='openstack_watcher',
-               help=_('Namespace to use for metrics')),
-    cfg.IntOpt('statsd_port',
-               default=9125,
-               help=_('Port of the StatsD backend')),
     cfg.BoolOpt('target_project_id_from_path',
                 default=False,
                 help=_('Whether to get the target project uid from the path')),
@@ -928,6 +945,7 @@
 cfg.CONF.register_opts(neutron_opts, group='neutron')
 cfg.CONF.register_opts(quota_opts, group='quotas')
 cfg.CONF.register_opts(audit_opts, group='audit')
+cfg.CONF.register_opts(rate_limiting_opts, group='rate_limiting')
 cfg.CONF.register_opts(driver_agent_opts, group='driver_agent')
 
 cfg.CONF.register_opts(local.certgen_opts, group='certificates')