Terminate telemetry listener once all all client apps have left

Note that this is fine for the ECMWF case but not in general because
it is perfectly leagitimate for all applications to leave and then
later some others to join.

tests/simple_telemetry_listener.c

@@ -69,7 +69,7 @@ char *g_conf_pminfo = NULL;
 /** logging destination */
 int g_conf_logdst = LOGDST_STDOUT;
 /** verbose operation */
-bool g_verbose = true;
+bool g_verbose = false;
 
 
 /** usage */
@@ -353,6 +353,8 @@ event_loop(void)
       MSTRO_SUBSCRIPTION_OPTS_DEFAULT,
       &join_leave_subscription);
   
+  uint32_t joinCount=0;
+  uint32_t leaveCount=0;
   bool done = false;
   
   mstro_nanosec_t starttime = mstro_clock();
@@ -378,6 +380,7 @@ event_loop(void)
 
         switch(tmp->kind) {
           case MSTRO_POOL_EVENT_APP_JOIN:
+            ++joinCount;
             if(g_verbose)
               fprintf(stdout, "Noticed JOIN event of app %s\n",
                       tmp->join.component_name);
@@ -392,6 +395,7 @@ event_loop(void)
             break;
             
           case MSTRO_POOL_EVENT_APP_LEAVE:
+            ++leaveCount;
             if(g_verbose) {
               fprintf(stdout, "Noticed LEAVE event of app %" PRIappid "\n",
                       tmp->leave.appid);
@@ -456,6 +460,10 @@ event_loop(void)
       }
     }
     
+    if((0 < leaveCount) && (joinCount == leaveCount)) {
+        done=true;
+    }
+
     if(mstro_clock()>starttime+DEFAULT_MAX_WAIT) {
       fprintf(stderr, "Waited %" PRIu64 "s and still not done\n",
               DEFAULT_MAX_WAIT/(1000*1000*1000));

[Utz-Uwe Haus]

it would be great to make a command line option to enable/disable this behavior.