Stage 3 · Build
Caching, Queues & Background Jobs
Worker Pools
Build bounded Go workers with channels, context cancellation, retries, and dead-letter queues.
8 min readBuilding Backend ApplicationsBuild
Why Worker Pools
Unbounded goroutines exhaust memory and overwhelm downstream services. Worker pools limit concurrency, provide backpressure, and enable graceful shutdown. Every background processing system needs bounded concurrency.
Channel-Based Workers
Gobasic-worker-pool.go
28 linesLn 1, Col 1Go
The jobs channel distributes work. Workers read from the channel and write results. The WaitGroup ensures all workers finish before closing the results channel.
Context Cancellation
Goworkers-with-context-cancellation.go
23 linesLn 1, Col 1Go
The select statement checks both the jobs channel and the context. When the context is cancelled (e.g., SIGTERM), workers stop processing new jobs and exit gracefully.
Retries
Goretry-with-exponential-backoff.go
30 linesLn 1, Col 1Go
Exponential backoff increases the wait time between retries. This gives the downstream service time to recover. Only retry on transient errors, not validation errors.
Dead-Letter Queues
Godead-letter-queue-pattern.go
32 linesLn 1, Col 1Go
The dead-letter queue captures jobs that cannot be processed after retries. This prevents poison messages from blocking the queue. Review DLQ items manually or with automated alerts.
Graceful Shutdown
Goworker-pool-with-graceful-shutdown.go
35 linesLn 1, Col 1Go
On SIGTERM, cancel the context and close the jobs channel. Workers finish current jobs and exit. Wait for all results before exiting.
Set worker count based on workload
Too few workers and jobs queue up. Too many and you overwhelm downstream services. Start with 2x CPU cores for CPU-bound work and 10x for I/O-bound work. Monitor queue depth and adjust.
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