grpc-js: xds: Add more logging around adding and removing eds and cds watchers

packages/grpc-js/src/load-balancer-cds.ts

@@ -111,14 +111,14 @@ export class CdsLoadBalancer implements LoadBalancer {
     attributes: { [key: string]: unknown }
   ): void {
     if (!isCdsLoadBalancingConfig(lbConfig)) {
-      trace('Discarding address list update with unrecognized config ' + JSON.stringify(lbConfig));
+      trace('Discarding address list update with unrecognized config ' + JSON.stringify(lbConfig, undefined, 2));
       return;
     }
     if (!(attributes.xdsClient instanceof XdsClient)) {
       trace('Discarding address list update missing xdsClient attribute');
       return;
     }
-    trace('Received update with config ' + JSON.stringify(lbConfig));
+    trace('Received update with config ' + JSON.stringify(lbConfig, undefined, 2));
     this.xdsClient = attributes.xdsClient;
     this.latestAttributes = attributes;
 
@@ -128,6 +128,7 @@ export class CdsLoadBalancer implements LoadBalancer {
       this.isWatcherActive &&
       this.latestConfig?.cds.cluster !== lbConfig.cds.cluster
     ) {
+      trace('Removing old cluster watcher for cluster name ' + this.latestConfig!.cds.cluster);
       this.xdsClient.removeClusterWatcher(
         this.latestConfig!.cds.cluster,
         this.watcher
@@ -143,6 +144,7 @@ export class CdsLoadBalancer implements LoadBalancer {
     this.latestConfig = lbConfig;
 
     if (!this.isWatcherActive) {
+      trace('Adding new cluster watcher for cluster name ' + lbConfig.cds.cluster);
       this.xdsClient.addClusterWatcher(lbConfig.cds.cluster, this.watcher);
       this.isWatcherActive = true;
     }
@@ -154,6 +156,7 @@ export class CdsLoadBalancer implements LoadBalancer {
     this.childBalancer.resetBackoff();
   }
   destroy(): void {
+    trace('Destroying load balancer with cluster name ' + this.latestConfig?.cds.cluster);
     this.childBalancer.destroy();
     if (this.isWatcherActive) {
       this.xdsClient?.removeClusterWatcher(

packages/grpc-js/src/load-balancer-eds.ts

@@ -401,7 +401,7 @@ export class EdsLoadBalancer implements LoadBalancer {
       trace('Discarding address list update missing xdsClient attribute');
       return;
     }
-    trace('Received update with config: ' + JSON.stringify(lbConfig));
+    trace('Received update with config: ' + JSON.stringify(lbConfig, undefined, 2));
     this.lastestConfig = lbConfig;
     this.latestAttributes = attributes;
     this.xdsClient = attributes.xdsClient;
@@ -411,6 +411,7 @@ export class EdsLoadBalancer implements LoadBalancer {
     /* If the name is changing, disable the old watcher before adding the new
      * one */
     if (this.isWatcherActive && this.edsServiceName !== newEdsServiceName) {
+      trace('Removing old endpoint watcher for edsServiceName ' + this.edsServiceName)
       this.xdsClient.removeEndpointWatcher(this.edsServiceName!, this.watcher);
       /* Setting isWatcherActive to false here lets us have one code path for
        * calling addEndpointWatcher */
@@ -423,6 +424,7 @@ export class EdsLoadBalancer implements LoadBalancer {
     this.edsServiceName = newEdsServiceName;
 
     if (!this.isWatcherActive) {
+      trace('Adding new endpoint watcher for edsServiceName ' + this.edsServiceName);
       this.xdsClient.addEndpointWatcher(this.edsServiceName, this.watcher);
       this.isWatcherActive = true;
     }
@@ -447,6 +449,7 @@ export class EdsLoadBalancer implements LoadBalancer {
     this.childBalancer.resetBackoff();
   }
   destroy(): void {
+    trace('Destroying load balancer with edsServiceName ' + this.edsServiceName);
     if (this.edsServiceName) {
       this.xdsClient?.removeEndpointWatcher(this.edsServiceName, this.watcher);
     }

packages/grpc-js/src/xds-client.ts

@@ -261,7 +261,6 @@ class EdsState implements XdsStreamState<ClusterLoadAssignment__Output> {
     edsServiceName: string,
     watcher: Watcher<ClusterLoadAssignment__Output>
   ): void {
-    trace('Adding EDS watcher for edsServiceName ' + edsServiceName);
     let watchersEntry = this.watchers.get(edsServiceName);
     let addedServiceName = false;
     if (watchersEntry === undefined) {
@@ -269,6 +268,7 @@ class EdsState implements XdsStreamState<ClusterLoadAssignment__Output> {
       watchersEntry = [];
       this.watchers.set(edsServiceName, watchersEntry);
     }
+    trace('Adding EDS watcher (' + watchersEntry.length + ' ->' + (watchersEntry.length + 1) + ') for edsServiceName ' + edsServiceName);
     watchersEntry.push(watcher);
 
     /* If we have already received an update for the requested edsServiceName,
@@ -298,6 +298,7 @@ class EdsState implements XdsStreamState<ClusterLoadAssignment__Output> {
     if (watchersEntry !== undefined) {
       const entryIndex = watchersEntry.indexOf(watcher);
       if (entryIndex >= 0) {
+        trace('Removed EDS watcher (' + watchersEntry.length + ' -> ' + (watchersEntry.length - 1) + ') for edsServiceName ' + edsServiceName);
         watchersEntry.splice(entryIndex, 1);
       }
       if (watchersEntry.length === 0) {