Do not restart the worker if the ping fails

Author: Ugo Plouviez

src/main/java/com/iexec/worker/PingService.java

@@ -28,10 +28,16 @@ public void pingScheduler() {
         String sessionId = feignClient.ping();
         String currentSessionId = coreConfigurationService.getCoreSessionId();
         if (currentSessionId == null || currentSessionId.isEmpty()){
+            log.info("First ping from the worker, setting the sessionId [coreSessionId:{}]", sessionId);
             coreConfigurationService.setCoreSessionId(sessionId);
             return;
         }
 
+        if(sessionId != null && sessionId.equals("")){
+            log.warn("The worker cannot ping the core!");
+            return;
+        }
+
         if (sessionId != null && !sessionId.equalsIgnoreCase(currentSessionId)){
             // need to reconnect to the core by restarting the worker
             log.warn("Scheduler seems to have restarted [currentSessionId:{}, coreSessionId:{}]", currentSessionId, sessionId);