package google import ( "fmt" "google.golang.org/api/compute/v1" ) const FINGERPRINT_RETRIES = 10 const FINGERPRINT_FAIL = "Invalid fingerprint." // Since the google compute API uses optimistic locking, there is a chance // we need to resubmit our updated metadata. To do this, you need to provide // an update function that attempts to submit your metadata func MetadataRetryWrapper(update func() error) error { attempt := 0 for attempt < FINGERPRINT_RETRIES { err := update() if err != nil && err.Error() == FINGERPRINT_FAIL { attempt++ } else { return err } } return fmt.Errorf("Failed to update metadata after %d retries", attempt) } // Update the metadata (serverMD) according to the provided diff (oldMDMap v // newMDMap). func MetadataUpdate(oldMDMap map[string]interface{}, newMDMap map[string]interface{}, serverMD *compute.Metadata) { curMDMap := make(map[string]string) // Load metadata on server into map for _, kv := range serverMD.Items { // If the server state has a key that we had in our old // state, but not in our new state, we should delete it _, okOld := oldMDMap[kv.Key] _, okNew := newMDMap[kv.Key] if okOld && !okNew { continue } else { curMDMap[kv.Key] = *kv.Value } } // Insert new metadata into existing metadata (overwriting when needed) for key, val := range newMDMap { curMDMap[key] = val.(string) } // Reformat old metadata into a list serverMD.Items = nil for key, val := range curMDMap { v := val serverMD.Items = append(serverMD.Items, &compute.MetadataItems{ Key: key, Value: &v, }) } } // Format metadata from the server data format -> schema data format func MetadataFormatSchema(md *compute.Metadata) map[string]interface{} { newMD := make(map[string]interface{}) for _, kv := range md.Items { newMD[kv.Key] = *kv.Value } return newMD }