What is goroutine leak and how to prevent it

Concurrency Core
2026-04-17T12:05:42+00:00
A goroutine leak is a non-terminating goroutine that consumes resources, prevented by ensuring clear exit conditions via context cancellation or channel closure.

A goroutine leak occurs when a goroutine is started but never terminates, typically because it is blocked indefinitely on a channel send or receive, causing memory and CPU usage to grow until the program crashes. Prevent leaks by ensuring every goroutine has a clear exit condition, such as using a context.Context to signal cancellation or closing channels to unblock receivers. Use runtime/pprof to profile active goroutines and identify stuck routines:

import (
    "context"
    "runtime/pprof"
    "time"
)

func worker(ctx context.Context) {
    select {
    case <-ctx.Done():
        return // Exit on cancellation
    case <-time.After(time.Second):
        // Do work
    }
}

func main() {
    ctx, cancel := context.WithCancel(context.Background())
    go worker(ctx)
    
    // Profile goroutines
    pprof.Lookup("goroutine").WriteTo(os.Stdout, 2)
    cancel()
}