Add note about NO_GCE_CHECK to Metadata 404 Error (#205)

lbergelson · chingor13 · commit 108df92031a4 · 2018-11-12T15:44:07.000-08:00
This makes the workaround to issue #204 much easier to discover.
diff --git a/oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java b/oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java
@@ -155,8 +155,9 @@ public AccessToken refreshAccessToken() throws IOException {
     if (statusCode == HttpStatusCodes.STATUS_CODE_NOT_FOUND) {
       throw new IOException(String.format("Error code %s trying to get security access token from"
           + " Compute Engine metadata for the default service account. This may be because"
-          + " the virtual machine instance does not have permission scopes specified.",
-          statusCode));
+          + " the virtual machine instance does not have permission scopes specified."
+          + " It is possible to skip checking for Compute Engine metadata by specifying the environment "
+          + " variable " + DefaultCredentialsProvider.NO_GCE_CHECK_ENV_VAR + "=true.", statusCode));
     }
     if (statusCode != HttpStatusCodes.STATUS_CODE_OK) {
       throw new IOException(String.format("Unexpected Error code %s trying to get security access"
