NestJS BullMQ Implementation

Priority: P0 (Standard)

Implement type-safe, robust background jobs using the Producer-Consumer pattern with @nestjs/bullmq.

Structure

text
1src/modules/{feature}/
2├── {feature}-queue.service.ts  # Producer: Schedules jobs
3├── {feature}.processor.ts      # Consumer: Processes jobs
4└── {feature}.module.ts         # Config: Registers queues

Implementation Guidelines

• Use Producers: create a dedicated QueueService to wrap queue.add().
• Use Consumers: extend WorkerHost and decorate with @Processor(QUEUE_NAME).
• Enforce Types: Define interfaces for JobData to ensure payload safety.
• Manage Lifecycle: Set removeOnComplete: true to prevent Redis memory bloat.
• Handle Errors: Use removeOnFail limit or Dead Letter Queues (DLQ) for debugging.
• Unique IDs: Provide deterministic jobId if you need to cancel/deduplicate jobs later.

Anti-Patterns

• No Strings: Define queue names as constants, not inline strings.
• No Heavy Logic: Do not put complex business logic in QueueService; only schedule.
• Avoid Implicit cleanup: Always configure job cleanup policies explicitly.
• No Direct Redis: Use InjectQueue annotations, avoided raw Redis commands.

Reference & Examples

For complete code patterns: references/patterns.md