fix: Do not retrieve the default SA principal when getting an access token (#1839)

* fix: Do not retrieve the default SA account when getting an access token

* chore: Fix the logging tests

Author: lqiu96

oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java

@@ -344,11 +344,6 @@ private String getUniverseDomainFromMetadata() throws IOException {
   /** Refresh the access token by getting it from the GCE metadata server */
   @Override
   public AccessToken refreshAccessToken() throws IOException {
-    // Retrieve the default service account email prior to retrieving the access token
-    if (principal == null) {
-      principal = getDefaultServiceAccount();
-    }
-
     HttpResponse response =
         getMetadataResponse(createTokenUrlWithScopes(), RequestType.ACCESS_TOKEN_REQUEST, true);
     int statusCode = response.getStatusCode();

oauth2_http/javatests/com/google/auth/oauth2/LoggingTest.java

@@ -441,39 +441,9 @@ public void getRequestMetadata_hasAccessToken() throws IOException {
 
     TestUtils.assertContainsBearerToken(metadata, ACCESS_TOKEN);
 
-    assertEquals(6, testAppender.events.size());
-
-    ILoggingEvent defaultServiceAccountRequest = testAppender.events.get(0);
-    assertEquals(
-        "Sending request for universe domain/default service account",
-        defaultServiceAccountRequest.getMessage());
-    assertEquals(3, defaultServiceAccountRequest.getKeyValuePairs().size());
-    for (KeyValuePair kvp : defaultServiceAccountRequest.getKeyValuePairs()) {
-      assertTrue(
-          kvp.key.equals("request.headers")
-              || kvp.key.equals("request.method")
-              || kvp.key.equals("request.url"));
-      if (kvp.key.equals("request.headers")) {
-        assertTrue(isValidJson((String) kvp.value));
-      }
-    }
-    ILoggingEvent defaultServiceAccountResponse = testAppender.events.get(1);
-    assertEquals(
-        "Received response for universe domain/default service account",
-        defaultServiceAccountResponse.getMessage());
-    assertEquals(3, defaultServiceAccountResponse.getKeyValuePairs().size());
-    for (KeyValuePair kvp : defaultServiceAccountResponse.getKeyValuePairs()) {
-      assertTrue(
-          kvp.key.equals("response.headers")
-              || kvp.key.equals("response.status")
-              || kvp.key.equals("response.status.message"));
-    }
-    ILoggingEvent defaultServiceAccountPayload = testAppender.events.get(2);
-    assertEquals(
-        "Received default service account payload", defaultServiceAccountPayload.getMessage());
-    assertEquals(1, defaultServiceAccountPayload.getKeyValuePairs().size());
+    assertEquals(3, testAppender.events.size());
 
-    ILoggingEvent accessTokenRequest = testAppender.events.get(3);
+    ILoggingEvent accessTokenRequest = testAppender.events.get(0);
     assertEquals("Sending request to refresh access token", accessTokenRequest.getMessage());
     assertEquals(3, accessTokenRequest.getKeyValuePairs().size());
     for (KeyValuePair kvp : accessTokenRequest.getKeyValuePairs()) {
@@ -485,7 +455,7 @@ public void getRequestMetadata_hasAccessToken() throws IOException {
         assertTrue(isValidJson((String) kvp.value));
       }
     }
-    ILoggingEvent accessTokenResponse = testAppender.events.get(4);
+    ILoggingEvent accessTokenResponse = testAppender.events.get(1);
     assertEquals("Received response for refresh access token", accessTokenResponse.getMessage());
     assertEquals(3, accessTokenResponse.getKeyValuePairs().size());
     for (KeyValuePair kvp : accessTokenResponse.getKeyValuePairs()) {
@@ -494,7 +464,7 @@ public void getRequestMetadata_hasAccessToken() throws IOException {
               || kvp.key.equals("response.status")
               || kvp.key.equals("response.status.message"));
     }
-    ILoggingEvent accessTokenPayload = testAppender.events.get(5);
+    ILoggingEvent accessTokenPayload = testAppender.events.get(2);
     assertEquals("Response payload for access token", accessTokenPayload.getMessage());
     assertEquals(3, accessTokenPayload.getKeyValuePairs().size());