From 964c7a68aabd3e45f87b0d0045bb604e1bd67ae7 Mon Sep 17 00:00:00 2001
From: Michael Lumish <mlumish@google.com>
Date: Tue, 19 Apr 2022 10:21:49 -0700
Subject: [PATCH] grpc-js: Fix double resolver calls in DNS resolver

---
 packages/grpc-js/src/backoff-timeout.ts |  1 +
 packages/grpc-js/src/resolver-dns.ts    | 10 +++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/grpc-js/src/backoff-timeout.ts b/packages/grpc-js/src/backoff-timeout.ts
index dc7be277..f523e259 100644
--- a/packages/grpc-js/src/backoff-timeout.ts
+++ b/packages/grpc-js/src/backoff-timeout.ts
@@ -100,6 +100,7 @@ export class BackoffTimeout {
   }
 
   private runTimer(delay: number) {
+    clearTimeout(this.timerId);
     this.timerId = setTimeout(() => {
       this.callback();
       this.running = false;
diff --git a/packages/grpc-js/src/resolver-dns.ts b/packages/grpc-js/src/resolver-dns.ts
index 47de8dbc..14de2656 100644
--- a/packages/grpc-js/src/resolver-dns.ts
+++ b/packages/grpc-js/src/resolver-dns.ts
@@ -158,7 +158,6 @@ class DnsResolver implements Resolver {
     if (this.ipResult !== null) {
       trace('Returning IP address for target ' + uriToString(this.target));
       setImmediate(() => {
-        this.backoff.reset();
         this.listener.onSuccessfulResolution(
           this.ipResult!,
           null,
@@ -167,6 +166,8 @@ class DnsResolver implements Resolver {
           {}
         );
       });
+      this.backoff.stop();
+      this.backoff.reset();
       return;
     }
     if (this.dnsHostname === null) {
@@ -178,7 +179,11 @@ class DnsResolver implements Resolver {
           metadata: new Metadata(),
         });
       });
+      this.stopNextResolutionTimer();
     } else {
+      if (this.pendingLookupPromise !== null) {
+        return;
+      }
       trace('Looking up DNS hostname ' + this.dnsHostname);
       /* We clear out latestLookupResult here to ensure that it contains the
        * latest result since the last time we started resolving. That way, the
@@ -299,6 +304,7 @@ class DnsResolver implements Resolver {
   }
 
   private startNextResolutionTimer() {
+    clearTimeout(this.nextResolutionTimer);
     this.nextResolutionTimer = setTimeout(() => {
       this.stopNextResolutionTimer();
       if (this.continueResolving) {
@@ -314,10 +320,12 @@ class DnsResolver implements Resolver {
   }
 
   private startResolutionWithBackoff() {
+    if (this.pendingLookupPromise === null) {
       this.continueResolving = false;
       this.startResolution();
       this.backoff.runOnce();
       this.startNextResolutionTimer();
+    }
   }
 
   updateResolution() {