grpc-js: Make a few improvements to DNS resolving timing

Author: murgatroid99

packages/grpc-js/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@grpc/grpc-js",
-  "version": "1.9.2",
+  "version": "1.9.3",
   "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/resolver-dns.ts

@@ -175,6 +175,7 @@ class DnsResolver implements Resolver {
       });
       this.backoff.stop();
       this.backoff.reset();
+      this.stopNextResolutionTimer();
       return;
     }
     if (this.dnsHostname === null) {
@@ -339,9 +340,9 @@ class DnsResolver implements Resolver {
   private startResolutionWithBackoff() {
     if (this.pendingLookupPromise === null) {
       this.continueResolving = false;
-      this.startResolution();
       this.backoff.runOnce();
       this.startNextResolutionTimer();
+      this.startResolution();
     }
   }
 

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

@@ -247,6 +247,8 @@ export class ResolvingLoadBalancer implements LoadBalancer {
           configSelector: ConfigSelector | null,
           attributes: { [key: string]: unknown }
         ) => {
+          this.backoffTimeout.stop();
+          this.backoffTimeout.reset();
           let workingServiceConfig: ServiceConfig | null = null;
           /* This first group of conditionals implements the algorithm described
            * in https://github.com/grpc/proposal/blob/master/A21-service-config-error-handling.md