reset process env and add trace log

Author: gkampitakis

packages/grpc-js/gulpfile.ts

@@ -91,11 +91,17 @@ const testWithAlternativeResolver = checkTask(() => {
   );
 });
 
+const resetEnv = () => {
+  process.env.GRPC_NODE_USE_ALTERNATIVE_RESOLVER = 'false';
+  return Promise.resolve();
+};
+
 const test = gulp.series(
   install,
   copyTestFixtures,
   runTests,
-  testWithAlternativeResolver
+  testWithAlternativeResolver,
+  resetEnv
 );
 
 export { install, lint, clean, cleanAll, compile, test };

packages/grpc-js/src/resolver-dns.ts

@@ -73,7 +73,7 @@ class DnsResolver implements Resolver {
   private isNextResolutionTimerRunning = false;
   private isServiceConfigEnabled = true;
   private returnedIpResult = false;
-  private independentResolver = new dns.Resolver();
+  private alternativeResolver = new dns.Resolver();
 
   constructor(
     private target: GrpcUri,
@@ -82,7 +82,7 @@ class DnsResolver implements Resolver {
   ) {
     trace('Resolver constructed for target ' + uriToString(target));
     if (target.authority) {
-      this.independentResolver.setServers([target.authority]);
+      this.alternativeResolver.setServers([target.authority]);
     }
     const hostPort = splitHostPort(target.path);
     if (hostPort === null) {
@@ -297,9 +297,11 @@ class DnsResolver implements Resolver {
 
   private async lookup(hostname: string): Promise<TcpSubchannelAddress[]> {
     if (GRPC_NODE_USE_ALTERNATIVE_RESOLVER) {
+      trace('Using alternative DNS resolver.');
+
       const records = await Promise.allSettled([
-        this.independentResolver.resolve4(hostname),
-        this.independentResolver.resolve6(hostname),
+        this.alternativeResolver.resolve4(hostname),
+        this.alternativeResolver.resolve6(hostname),
       ]);
 
       if (records.every(result => result.status === 'rejected')) {
@@ -328,7 +330,8 @@ class DnsResolver implements Resolver {
 
   private async resolveTxt(hostname: string): Promise<string[][]> {
     if (GRPC_NODE_USE_ALTERNATIVE_RESOLVER) {
-      return this.independentResolver.resolveTxt(hostname);
+      trace('Using alternative DNS resolver.');
+      return this.alternativeResolver.resolveTxt(hostname);
     }
 
     return dns.resolveTxt(hostname);