feat: Utilize gcp-metadata's GCP Residency Check

package.json

@@ -22,7 +22,7 @@
     "ecdsa-sig-formatter": "^1.0.11",
     "fast-text-encoding": "^1.0.0",
     "gaxios": "^5.0.0",
-    "gcp-metadata": "^5.2.0",
+    "gcp-metadata": "^5.3.0",
     "gtoken": "^6.1.0",
     "jws": "^4.0.0",
     "lru-cache": "^6.0.0"

src/auth/googleauth.ts

@@ -396,13 +396,18 @@ export class GoogleAuth<T extends AuthClient = JSONClient> {
 
   /**
    * Determines whether the auth layer is running on Google Compute Engine.
+   * Checks for GCP Residency, then fallback to checking if metadata server
+   * is available.
+   *
    * @returns A promise that resolves with the boolean.
    * @api private
    */
   async _checkIsGCE() {
     if (this.checkIsGCE === undefined) {
-      this.checkIsGCE = await gcpMetadata.isAvailable();
+      this.checkIsGCE =
+        gcpMetadata.getGCPResidency() || (await gcpMetadata.isAvailable());
     }
+
     return this.checkIsGCE;
   }
 

test/test.googleauth.ts

@@ -25,6 +25,7 @@ import {
   SECONDARY_HOST_ADDRESS,
   resetIsAvailableCache,
 } from 'gcp-metadata';
+import * as gcpMetadata from 'gcp-metadata';
 import * as nock from 'nock';
 import * as os from 'os';
 import * as path from 'path';
@@ -1137,66 +1138,15 @@ describe('googleauth', () => {
       assert.strictEqual(undefined, client.scope);
     });
 
-    it('_checkIsGCE should set the _isGCE flag when running on GCE', async () => {
-      assert.notStrictEqual(true, auth.isGCE);
-      const scope = nockIsGCE();
-      await auth._checkIsGCE();
-      assert.strictEqual(true, auth.isGCE);
-      scope.done();
-    });
-
-    it('_checkIsGCE should not set the _isGCE flag when not running on GCE', async () => {
-      const scope = nockNotGCE();
-      assert.notStrictEqual(true, auth.isGCE);
-      await auth._checkIsGCE();
-      assert.strictEqual(false as boolean, auth.isGCE);
-      scope.done();
-    });
-
-    it('_checkIsGCE should retry the check for isGCE on transient http errors', async () => {
-      assert.notStrictEqual(true, auth.isGCE);
-      // the first request will fail, the second one will succeed
-      const scopes = [nock500GCE(), nockIsGCE()];
-      await auth._checkIsGCE();
-      assert.strictEqual(true, auth.isGCE);
-      scopes.forEach(s => s.done());
-    });
-
-    it('_checkIsGCE should return false on unexpected errors', async () => {
-      assert.notStrictEqual(true, auth.isGCE);
-      const scope = nock500GCE();
-      assert.strictEqual(await auth._checkIsGCE(), false);
-      assert.strictEqual(auth.isGCE, false);
-      scope.done();
-    });
+    it("_checkIsGCE should be equalivalent should use GCP metadata's checks", async () => {
+      nockNotGCE();
 
-    it('_checkIsGCE should not retry the check for isGCE if it fails with an ENOTFOUND', async () => {
-      assert.notStrictEqual(true, auth.isGCE);
-      const scope = nockNotGCE();
-      await auth._checkIsGCE();
-      assert.strictEqual(false as boolean, auth.isGCE);
-      scope.done();
-    });
-
-    it('_checkIsGCE does not execute the second time when running on GCE', async () => {
-      // This test relies on the nock mock only getting called once.
-      assert.notStrictEqual(true, auth.isGCE);
-      const scope = nockIsGCE();
-      await auth._checkIsGCE();
-      assert.strictEqual(true, auth.isGCE);
-      await auth._checkIsGCE();
-      assert.strictEqual(true, auth.isGCE);
-      scope.done();
-    });
+      const expected = await (gcpMetadata.getGCPResidency() ||
+        gcpMetadata.isAvailable());
 
-    it('_checkIsGCE does not execute the second time when not running on GCE', async () => {
-      assert.notStrictEqual(true, auth.isGCE);
-      const scope = nockNotGCE();
-      await auth._checkIsGCE();
-      assert.strictEqual(false as boolean, auth.isGCE);
+      assert.strict.notEqual(auth.isGCE, true);
       await auth._checkIsGCE();
-      assert.strictEqual(false as boolean, auth.isGCE);
-      scope.done();
+      assert.strictEqual(auth.isGCE, expected);
     });
 
     it('getCredentials should get metadata from the server when running on GCE', async () => {