nats-io/nats-server · error

bad consumer config

Error message

bad consumer config

What it means

Returned by (*fileStore).ConsumerStore when the provided ConsumerConfig is nil or the consumer name is an empty string. The file store cannot create a consumer without a valid name and configuration, so it refuses. This is a caller-contract validation error inside the store layer.

Source

Thrown at server/filestore.go:13335

	hh      *highwayhash.Digest64
	state   ConsumerState
	fch     chan struct{}
	qch     chan struct{}
	flusher bool
	writing bool
	dirty   bool
	closed  bool
}

func (fs *fileStore) ConsumerStore(name string, created time.Time, cfg *ConsumerConfig) (ConsumerStore, error) {
	if fs == nil {
		return nil, fmt.Errorf("filestore is nil")
	}
	if fs.isClosed() {
		return nil, ErrStoreClosed
	}
	if cfg == nil || name == _EMPTY_ {
		return nil, fmt.Errorf("bad consumer config")
	}

	// We now allow overrides from a stream being a filestore type and forcing a consumer to be memory store.
	if cfg.MemoryStorage {
		// Create directly here.
		o := &consumerMemStore{ms: fs, name: name, cfg: *cfg}
		if err := fs.AddConsumer(o); err != nil {
			return nil, err
		}
		return o, nil
	}

	odir := filepath.Join(fs.fcfg.StoreDir, consumerDir, name)
	if err := os.MkdirAll(odir, defaultDirPerms); err != nil {
		return nil, fmt.Errorf("could not create consumer directory - %v", err)
	}
	csi := &FileConsumerInfo{Name: name, Created: created, ConsumerConfig: *cfg}
	o := &consumerFileStore{

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Ensure the consumer create request includes a valid durable name and full ConsumerConfig.
2. Inspect the stream's consumer directory meta files; restore missing/corrupt JetStreamMetaFile entries from backup.
3. Re-create the consumer via the JetStream API after fixing the request.
4. Remove orphaned consumer directories whose config cannot be loaded, then re-add the consumer.

Example fix

// before
fs.ConsumerStore("", created, nil)
// after
fs.ConsumerStore("my-durable", created, &ConsumerConfig{Durable: "my-durable", AckPolicy: AckExplicit})

func validConsumerReq(name string, cfg *ConsumerConfig) bool {
    return name != "" && cfg != nil && cfg.Durable == name
}

func cfgOk(cfg *ConsumerConfig) bool { return cfg != nil }

if err != nil {
    if strings.Contains(err.Error(), "bad consumer config") {
        // fix request: supply durable name and full ConsumerConfig, then retry
    }
}

When it happens

Trigger: Calling ConsumerStore with cfg == nil or name == ""; internally this means JetStream attempted to materialize a consumer without a valid name/config, typically from a corrupted or hand-edited consumer meta file or an API request missing required fields.

Common situations: Malformed consumer create API requests missing the durable name/stream config; restored or manually edited JetStream meta files missing ConsumerConfig; bugs in tooling that manipulates stream state.

Related errors

• bad ack floor for consumer
• could not create consumer directory - %v
• bad ack floor for stream
• bad pending entry, sequence [%d] out of range
• uncompressed buffer is too short

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/10e5679898134cf6. Report an issue: GitHub.