Background jobs на собеседовании системного аналитика

Зачем background jobs

Long operations не должны block user requests.

Examples:

• Send emails.
• Generate reports.
• Image processing.
• Bulk imports.
• Periodic cleanups.

User submits → return ID quickly → background processes.

Queue technologies

RabbitMQ. Mature AMQP broker.

Redis. Lightweight, in-memory. Used с Celery, Sidekiq, BullMQ.

Kafka. Streaming, but can be queue.

SQS. AWS managed.

Yandex Message Queue. РФ alternative.

Cloud Tasks (GCP), Azure Service Bus.

Worker patterns

Pull-based. Workers poll queue.

while True:
    job = queue.pop()
    if job:
        process(job)

Push-based. Broker pushes к worker.

Sidekiq, RQ, Celery, BullMQ. Common worker frameworks.

Concurrency. Multiple workers parallel. Scale based на queue depth.

Retry strategies

Failed job → retry с backoff.

Attempt 1: 0s.
Attempt 2: 30s.
Attempt 3: 5min.
Attempt 4: 1h.
Stop / DLQ.

Idempotency — make jobs safely retryable.

Poison messages. Bad job loops forever — DLQ after N attempts.

Scheduling

Cron-like. Run job каждые X.

Delayed. Run after N delay (e.g., reminder в 30 days).

Recurring. Daily cleanup, hourly reports.

Tools:

• Celery Beat.
• BullMQ scheduled jobs.
• Cron в k8s.
• Airflow для complex orchestration.

Связанные темы

• Webhook design для SA
• Idempotency key для SA
• Notification system для SA
• Backpressure для SA
• Подготовка к собесу системного аналитика

FAQ

Это официальная информация?

Нет. Статья основана на индустриальных background jobs practices.

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