Ensuring Message Ordering in NATS: A Kafka-like Approach

Lease-based Consumer Coordination

Consumers use a lease mechanism to claim exclusive ownership of partitions:

type LeaseInfo struct {
    Owned     bool
    Revision  uint64
    Value     leaseValue
}

type leaseValue struct {
    WorkerID   string    `json:"worker_id"`
    ExpiresAt  time.Time `json:"expires_at"`
}

Each consumer:

1. Attempts to claim partitions through the lease store
2. Regularly renews leases to maintain ownership
3. Releases leases during graceful shutdown
4. Automatically expires leases when consumers fail