nats-io/nats-server · error

bad consumer config

Error message

bad consumer config

What it means

Validation guard in memStore.ConsumerStore: consumer creation was attempted with a nil ConsumerConfig or an empty consumer name; both are required to instantiate a consumerMemStore.

Source

Thrown at server/memstore.go:2600

type consumerMemStore struct {
	mu     sync.Mutex
	ms     StreamStore
	name   string
	cfg    ConsumerConfig
	state  ConsumerState
	closed bool
}

func (ms *memStore) ConsumerStore(name string, _ time.Time, cfg *ConsumerConfig) (ConsumerStore, error) {
	if ms == nil {
		return nil, fmt.Errorf("memstore is nil")
	}
	if ms.isClosed() {
		return nil, ErrStoreClosed
	}
	if cfg == nil || name == _EMPTY_ {
		return nil, fmt.Errorf("bad consumer config")
	}
	o := &consumerMemStore{ms: ms, name: name, cfg: *cfg}
	ms.AddConsumer(o)
	return o, nil
}

func (ms *memStore) AddConsumer(o ConsumerStore) error {
	ms.mu.Lock()
	ms.consumers = append(ms.consumers, o)
	ms.mu.Unlock()
	return nil
}

func (ms *memStore) RemoveConsumer(o ConsumerStore) error {
	ms.mu.Lock()
	for i, cfs := range ms.consumers {
		if o == cfs {
			ms.consumers = append(ms.consumers[:i], ms.consumers[i+1:]...)

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Provide a non-empty durable/name and a fully populated ConsumerConfig when creating the consumer
2. Validate consumer add requests at the JetStream API layer before they reach the store

When it happens

Trigger: Thrown at server/memstore.go:2600 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/30f58b5aa59c99b1. Report an issue: GitHub.