gddo-server: collect GCE metadata configuration in Viper

Remove the gaAccount global variable in favor of reading from

Minor behavior changes:
- The GA_ACCOUNT environment variable will override the GCE metadata
  ga-account, where before it was not being read on GCE.
- The project ID across the program defaults to the one from GCE
  metadata, overridden by the GCLOUD_PROJECT environment variable or the
  command-line flag.  The GCE logger now uses this project ID instead of
  just considering the GCE metadata.
- The GCE log name can now be set using the gddo_gce_log_name
  environment variable.

Change-Id: I0ed2ae7a5130d63146e9bf2746f22980c8a782b9
Reviewed-by: Tuo Shan <>
3 files changed