Fix haproxy global maxconn with disabled listeners

global maxconn value is based on the connection-limit of the listeners
of a LB, but it includes the connection-limit of disabled listeners.
Disabled listeners are now skipped.

Closes-Bug: #2024371

Change-Id: I45500d618b307f740b8e692c49f5efdd27dc10a0
(cherry picked from commit 21682f7056)

octavia/common/jinja/haproxy/combined_listeners/jinja_cfg.py

@@ -265,6 +265,8 @@ class JinjaTemplater(object):
         # listeners' connection limits.
         connection_limit_sum = 0
         for listener in listeners:
+            if not listener.enabled:
+                continue
             if listener.protocol in constants.LVS_PROTOCOLS:
                 continue
             if listener.connection_limit and listener.connection_limit > -1:

octavia/tests/unit/common/jinja/haproxy/combined_listeners/test_jinja_cfg.py

@@ -1559,6 +1559,28 @@ class TestHaproxyCfg(base.TestCase):
         self.assertLess(ret['global_connection_limit'],
                         connection_limit_sum)
 
+    def test_transform_with_disabled_listeners(self):
+        in_amphora = sample_configs_combined.sample_amphora_tuple()
+
+        in_listeners = []
+
+        connection_limit_sum = 0
+
+        in_listener = (
+            sample_configs_combined.sample_listener_tuple())
+        connection_limit_sum += constants.HAPROXY_DEFAULT_MAXCONN
+        in_listeners.append(in_listener)
+
+        disabled_listener = (
+            sample_configs_combined.sample_listener_tuple(enabled=False))
+        in_listeners.append(disabled_listener)
+
+        ret = self.jinja_cfg._transform_loadbalancer(
+            in_amphora, in_listeners[0].load_balancer,
+            in_listeners, None, {})
+        self.assertEqual(ret['global_connection_limit'],
+                         connection_limit_sum)
+
     def test_transform_amphora(self):
         in_amphora = sample_configs_combined.sample_amphora_tuple()
         ret = self.jinja_cfg._transform_amphora(in_amphora, {})

releasenotes/notes/fix-haproxy-maxconn-with-disabled-listeners-fa89f762a94b8fe9.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixed the global number of concurrent connections in haproxy when disabling
+    listeners. The connection-limit of disabled listeners was used to compute
+    this value, disabled listeners are now skipped.