Fix for #32

- Add a retry loop when the server is down

Client/controllers/clientController.js

@@ -106,8 +106,18 @@ exports.checkIn = async () => {
         if (!runningClientConfig?.id || runningClientConfig.id == 0) {                        
             // ID was not found in the config, creating a new node
             reqOptions = new requestOptions("/nodes/newNode", "POST");                
-            sendHttpRequest(reqOptions, JSON.stringify(runningClientConfig), async (responseObject) => {
-                // Update the client's ID if the server accepted it
+            sendHttpRequest(reqOptions, JSON.stringify(runningClientConfig), async (responseObject) => {                
+                // Check if the server responded
+                if (!responseObject) {
+                    log.WARN("Server did not respond to checkIn. Will wait 60 seconds then try again");
+                    setTimeout(() => {
+                        // Run itself again to see if the server is up now
+                        this.checkIn();
+                    }, 60000);
+                    return
+                }
+
+                // Update the client's ID if the server accepted its
                 if (responseObject.statusCode === 202) {                    
                     runningClientConfig.id = responseObject.body.nodeId;
                     log.DEBUG("Response object from new node: ", responseObject, runningClientConfig);