code: func BlobpackedRecoveryValue() int {
  	recovery, err := metadata.InstanceAttributeValue("camlistore-recovery")
  	if err != nil {
  		if _, ok := err.(metadata.NotDefinedError); !ok {
  			log.Printf("error getting camlistore-recovery: %v", err)
  		}
  		return 0
  	}
  	if recovery == "" {
  		return 0
  	}
  	mode, err := strconv.Atoi(recovery)
  	if err != nil {
  		log.Printf("invalid int value for \"camlistore-recovery\": %v", err)
  	}
  	return mode
  }
docs: // BlobpackedRecoveryValue returns the blobpacked recovery level (0, 1, 2) from
  // the GCE instance metadata.
  //
  // The return type here is logically a blobpacked.RecoveryMode, but we're not
  // importing that here to save a dependency.