micro/go-micro · error

Error writing to the store

Error message

Error writing to the store

What it means

evStore.Write writes the constructed store.Record (topic/ID/time-suffixed key, JSON value, TTL expiry) to the underlying store. This error wraps any failure returned by store.Write, meaning the event record could not be persisted.

Source

Thrown at events/store.go:107

	// construct the store record
	bytes, err := json.Marshal(event)
	if err != nil {
		return errors.Wrap(err, "Error mashaling event to JSON")
	}
	// suffix event ID with hour resolution for easy retrieval in batches
	timeSuffix := time.Now().Format("2006010215")

	record := &store.Record{
		// key is such that reading by prefix indexes by topic and reading by suffix indexes by time
		Key:    event.Topic + joinKey + event.ID + joinKey + timeSuffix,
		Value:  bytes,
		Expiry: options.TTL,
	}

	// write the record to the store
	if err := s.store.Write(record); err != nil {
		return errors.Wrap(err, "Error writing to the store")
	}

	return nil
}

func (s *evStore) backupLoop() {
	for {
		err := s.opts.Backup.Snapshot(s.store)
		if err != nil {
			logger.Errorf("Error running backup %s", err)
		}

		time.Sleep(1 * time.Hour)
	}
}

// Backup is an interface for snapshotting the events store to long term storage
type Backup interface {

View on GitHub (pinned to 24529f1404)

Solutions

1. Check errors.Cause(err) for the backend-specific reason
2. Verify the backing store service health, credentials, and available disk/quota
3. Validate the record key (event.Topic + event.ID + time suffix) is acceptable for the backend
4. Retry with backoff for transient backend failures
5. If writes keep failing, fall back to the in-memory store and alert

Example fix

// before
if err := s.store.Write(record); err != nil { return err } // hard fail on transient blip
// after
if err := s.store.Write(record); err != nil {
    return backoff.Retry(func() error { return s.store.Write(record) }, policy)
}

// sanity-check the event before writing
if event == nil || event.Topic == "" || event.ID == "" {
    return errors.New("event missing topic or id")
}
if _, err := json.Marshal(event); err != nil { return err }

err := evStore.Write(event)
if err != nil {
    if strings.Contains(err.Error(), "Error writing to the store") {
        cause := errors.Cause(err)
        // retry transient failures, alert on persistent ones
        log.Printf("store write failed: %v", cause)
    }
    return err
}

When it happens

Trigger: Calling evStore.Write when the backing store rejects the write: remote store backend unreachable or read-only, disk full for file-backed stores, invalid key characters rejected by a custom store implementation, or the store was closed.

Common situations: Redis/cockroach store plugin down or misconfigured credentials; storage quota or disk exhaustion; key containing characters a custom backend forbids; concurrent snapshot (backup) locking the store.

Related errors

• flow %s checkpoint save: %w
• Error reading from store
• Couldn't insert record ${key}
• unsupported statement
• not found

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/2636f78b99ae404d. Report an issue: GitHub.