MXS-1782: Add listener state to REST API

The state of each individual listener is now displayed in the REST
API. Created common functions for printing the listener state and took
them into use. Added the new state into MaxCtrl output.

include/maxscale/listener.h

@@ -121,4 +121,13 @@ SERV_LISTENER* listener_iterator_init(const struct service* service, LISTENER_IT
  */
 SERV_LISTENER* listener_iterator_next(LISTENER_ITERATOR* iter);
 
+/**
+ * Get listener state as a string
+ *
+ * @param listener Listener to inspect
+ *
+ * @return State of the listener as a string
+ */
+const char* listener_state_to_string(const SERV_LISTENER* listener);
+
 MXS_END_DECLS

maxctrl/lib/list.js

@@ -104,7 +104,8 @@ exports.builder = function(yargs) {
                 return getSubCollection(host, 'services/' + argv.service, 'attributes.listeners', [
                     {'Name': 'id'},
                     {'Port': 'attributes.parameters.port'},
-                    {'Host': 'attributes.parameters.host'}
+                    {'Host': 'attributes.parameters.host'},
+                    {'State': 'attributes.state'}
                 ])
             })
         })

server/core/listener.cc

@@ -527,6 +527,7 @@ json_t* listener_to_json(const SERV_LISTENER* listener)
     }
 
     json_t* attr = json_object();
+    json_object_set_new(attr, CN_STATE, json_string(listener_state_to_string(listener)));
     json_object_set_new(attr, CN_PARAMETERS, param);
 
     if (listener->listener->authfunc.diagnostic_json)
@@ -540,9 +541,9 @@ json_t* listener_to_json(const SERV_LISTENER* listener)
     }
 
     json_t* rval = json_object();
-    json_object_set_new(rval, CN_ATTRIBUTES, attr);
     json_object_set_new(rval, CN_ID, json_string(listener->name));
     json_object_set_new(rval, CN_TYPE, json_string(CN_LISTENERS));
+    json_object_set_new(rval, CN_ATTRIBUTES, attr);
 
     return rval;
 }
@@ -580,3 +581,28 @@ SERV_LISTENER* listener_iterator_next(LISTENER_ITERATOR* iter)
 
     return iter->current;
 }
+
+const char* listener_state_to_string(const SERV_LISTENER* listener)
+{
+    ss_dassert(listener);
+
+    if (listener->listener && listener->listener->session)
+    {
+        switch (listener->listener->session->state)
+        {
+            case SESSION_STATE_LISTENER_STOPPED:
+                return "Stopped";
+
+            case SESSION_STATE_LISTENER:
+                return "Running";
+
+            default:
+                ss_dassert(!true);
+                return "Unknown";
+        }
+    }
+    else
+    {
+        return "Failed";
+    }
+}

server/core/service.cc

@@ -1626,10 +1626,7 @@ dListListeners(DCB *dcb)
                            listener->name, service->name, listener->protocol,
                            (listener && listener->address) ? listener->address : "*",
                            listener->port,
-                           (!listener->listener ||
+                           listener_state_to_string(listener));
-                            !listener->listener->session ||
-                            listener->listener->session->state == SESSION_STATE_LISTENER_STOPPED) ?
-                           "Stopped" : "Running");
             }
         }
         service = service->next;
@@ -2099,10 +2096,7 @@ serviceListenerRowCallback(RESULTSET *set, void *data)
     resultset_row_set(row, 2, (lptr && lptr->address) ? lptr->address : "*");
     sprintf(buf, "%d", lptr->port);
     resultset_row_set(row, 3, buf);
-    resultset_row_set(row, 4,
+    resultset_row_set(row, 4, listener_state_to_string(lptr));
-                      (!lptr->listener || !lptr->listener->session ||
-                       lptr->listener->session->state == SESSION_STATE_LISTENER_STOPPED) ?
-                      "Stopped" : "Running");
     spinlock_release(&service_spin);
     return row;
 }