grpc-js: Fix handling of grpc.enable_channelz option

packages/grpc-js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@grpc/grpc-js",
-  "version": "1.4.2",
+  "version": "1.4.3",
   "description": "gRPC Library for Node - pure JS implementation",
   "homepage": "https://grpc.io/",
   "repository": "https://github.com/grpc/grpc-node/tree/master/packages/grpc-js",

packages/grpc-js/src/subchannel.ts

@@ -832,6 +832,7 @@ export class Subchannel {
         headersString
     );
     const streamSession = this.session;
+    let statsTracker: SubchannelCallStatsTracker;
     if (this.channelzEnabled) {
       this.callTracker.addCallStarted();
       callStream.addStatusWatcher(status => {
@@ -851,16 +852,22 @@ export class Subchannel {
           }
         }
       });
-      callStream.attachHttp2Stream(http2Stream, this, extraFilters, {
+      statsTracker = {
         addMessageSent: () => {
           this.messagesSent += 1;
           this.lastMessageSentTimestamp = new Date();
         },
         addMessageReceived: () => {
           this.messagesReceived += 1;
         }
-      });
+      }
+    } else {
+      statsTracker = {
+        addMessageSent: () => {},
+        addMessageReceived: () => {}
+      }
     }
+    callStream.attachHttp2Stream(http2Stream, this, extraFilters, statsTracker);
   }
 
   /**

packages/grpc-js/test/test-channelz.ts

@@ -286,4 +286,36 @@ describe('Channelz', () => {
       });
     });
   });
+});
+
+describe('Disabling channelz', () => {
+  let testServer: grpc.Server;
+  let testClient: ServiceClient;
+  beforeEach((done) => {
+    testServer = new grpc.Server({'grpc.enable_channelz': 0});
+    testServer.addService(TestServiceClient.service, testServiceImpl);
+    testServer.bindAsync('localhost:0', grpc.ServerCredentials.createInsecure(), (error, port) => {
+      if (error) {
+        done(error);
+        return;
+      }
+      testServer.start();
+      testClient = new TestServiceClient(`localhost:${port}`, grpc.credentials.createInsecure(), {'grpc.enable_channelz': 0});
+      done();
+    });
+  });
+
+  afterEach(() => {
+    testClient.close();
+    testServer.forceShutdown();
+  });
+
+  it('Should still work', (done) => {
+    const deadline = new Date();
+    deadline.setSeconds(deadline.getSeconds() + 1);
+    testClient.unary({}, {deadline}, (error: grpc.ServiceError, value: unknown) => {
+      assert.ifError(error);
+      done();
+    });
+  });
 });