Merge pull request #36 from boschrexroth/bugfix/missing_subscription

fix: improve diagnostics for misconfigured subscriptions. E.g. when a…

README.md

@@ -93,6 +93,7 @@ Any use of the source code and related documents of this repository in applicati
 * 2021-10-22: 1.8.11 - fix: prevent "Failed login attempts" after flow gets redeployed with correct credentials (Bug392030).
 * 2021-10-22: 1.8.12 - fix: make subscription to properly report error and reconnect when authorization token expires (Bug405282).
 * 2022-01-27: 1.8.13 - refactor: update dependency versions. No functional change.
+* 2022-03-02: 1.8.14 - fix: improve diagnostics for misconfigured subscriptions. E.g. when a single node of a subscription is missing (Bug449366).
 
 ## About
 

ctrlx-config-subscription.js

@@ -24,7 +24,7 @@
  *
  */
 
-
+ const CtrlxProblemError = require('./lib/CtrlxProblemError');
 
 module.exports = function(RED) {
   'use strict';
@@ -110,6 +110,8 @@ module.exports = function(RED) {
         } else {
           node.subscription = subscription;
 
+
+
           // This is the handler function which dispatches incoming update messages to the nodes.
           node.subscription.on('update', (data, lastEventId) => {
             Object.values(node.users).forEach((element) => {
@@ -119,23 +121,45 @@ module.exports = function(RED) {
             });
           });
 
-          // This is the handler which is called on error. E.g. on authorization errors
+
+
+          // This is the handler which is called on error. E.g. on authorization errors of the whole subscription
+          // or when a single node address has a problem.
           node.subscription.on('error', (err) => {
 
-            // Distribute the error to all registered nodes.
-            Object.values(node.users).forEach((element) => {
-              element.callback(err);
-            });
+            let isSingleNodeError = false;
 
-            // To recover from the error state, let's reset the subscription.
-            node.dirty = true;
-            setTimeout(() => {
-              node.updateSubscription();
-            }, 2000);
+            // Check if we have an error, that is only attached to a single node and
+            // not to the whole subscription
+            if (err instanceof CtrlxProblemError && err._instance) {
+
+              // Distribute the error to actual node.
+              Object.values(node.users).forEach((element) => {
+                if (element.path === err._instance) {
+                  element.callback(err);
+                  isSingleNodeError = true;
+                }
+              });
+
+            }
+
+            if (!isSingleNodeError) {
+              // Distribute the error to all registered nodes.
+              Object.values(node.users).forEach((element) => {
+                element.callback(err);
+              });
+
+              // To recover from the error state, let's reset the subscription.
+              node.dirty = true;
+              setTimeout(() => {
+                node.updateSubscription();
+              }, 2000);
+            }
 
           });
 
 
+
           // This is the handler if the connection gets closed by the server.
           node.subscription.on('end', () => {
 

ctrlx-datalayer-subscribe.js

@@ -24,6 +24,8 @@
  *
  */
 
+const CtrlxProblemError = require('./lib/CtrlxProblemError');
+
 
  module.exports = function(RED) {
   'use strict';
@@ -67,8 +69,13 @@
       node.configSubscription.register(node, node.path, (err, data, lastEventId) => {
 
         if (err) {
-          node.status({fill: 'red', shape: 'ring', text: 'subscription failed'});
-          node.error(err.message);
+          if (err.message) {
+            node.status({fill: 'red', shape: 'ring', text: `subscription failed: ${err.message}`});
+            node.error(err.message);
+          } else {
+            node.status({fill: 'red', shape: 'ring', text: `subscription failed`});
+            node.error('unknown error');
+          }
         } else {
           node.eventCounter++;
           node.status({fill: 'green', shape: 'dot', text: `received data #${node.eventCounter}`});

lib/CtrlxDatalayerSubscription.js

@@ -29,6 +29,7 @@
 const EventSource = require('launchdarkly-eventsource').EventSource;
 const EventEmitter = require("events").EventEmitter;
 const CtrlxDatalayer = require('./CtrlxDatalayerV2');
+const CtrlxProblemError = require('../lib/CtrlxProblemError');
 const debug = require('debug')('ctrlxcore:datalayer:subscription');
 const debugUpdate = require('debug')('ctrlxcore:datalayer:subscription:update');
 
@@ -193,12 +194,30 @@ class CtrlxDatalayerSubscription extends EventEmitter {
       };
 
       // @ts-ignore
-      this._es.onerror = (err) => {
-        debug(`onerror(${err.message})`);
+      this._es.onerror = (e) => {
+        debug(`onerror(${e.type})`);
+
+        if (e.data !== 'undefined') {
+
+          // The error is of type 'MessageEvent'. This means, that not the stream has an error, but
+          // an 'error' message is send over the stream (in contrast to an 'update' message if everything is fine).
+          // This could mean, that one of the subscribed nodes might have a problem.
+          // For a 'MessageEvent' of type 'error', we expect a 'Problem' object to be transferred in the 'data' element.
+          let err = CtrlxProblemError.fromHttpResponse(e.data.status, e.data);
+
+          if (this.listeners('error').length > 0) {
+            this.emit('error', err);
+          }
+
+        } else {
+
+          // The error is of type Event or Error. The subscription might be broken.
+          if (this.listeners('error').length > 0) {
+            this.emit('error', e);
+          }
 
-        if (this.listeners('error').length > 0) {
-          this.emit('error', err);
         }
+
       };
 
       this._es.addEventListener('update', (e) => {