Go Concurrency Patterns Skill

Go Concurrency Patterns

Production patterns for Go concurrency including goroutines, channels, synchronization primitives, and context management.

When to Use This Skill

Building concurrent Go applications
Implementing worker pools and pipelines
Managing goroutine lifecycles
Using channels for communication
Debugging race conditions
Implementing graceful shutdown

Core Concepts

1. Go Concurrency Primitives

| Primitive | Purpose | | ----------------- | -------------------------------- | | goroutine | Lightweight concurrent execution | | channel | Communication between goroutines | | select | Multiplex channel operations | | sync.Mutex | Mutual exclusion | | sync.WaitGroup | Wait for goroutines to complete | | context.Context | Cancellation and deadlines |

2. Go Concurrency Mantra

Don't communicate by sharing memory;
share memory by communicating.

Quick Start

package main

import (
    "context"
    "fmt"
    "sync"
    "time"
)

func main() {
    ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
    defer cancel()

    results := make(chan string, 10)
    var wg sync.WaitGroup

    // Spawn workers
    for i := 0; i < 3; i++ {
        wg.Add(1)
        go worker(ctx, i, results, &wg)
    }

    // Close results when done
    go func() {
        wg.Wait()
        close(results)
    }()

    // Collect results
    for result := range results {
        fmt.Println(result)
    }
}

func worker(ctx context.Context, id int, results chan<- string, wg *sync.WaitGroup) {
    defer wg.Done()

    select {
    case <-ctx.Done():
        return
    case results <- fmt.Sprintf("Worker %d done", id):
    }
}

Detailed patterns and worked examples

Detailed pattern documentation lives in references/details.md. Read that file when the navigation tier above is insufficient.

Best Practices

Do's

Use context - For cancellation and deadlines
Close channels - From sender side only
Use errgroup - For concurrent operations with errors
Buffer channels - When you know the count
Prefer channels - Over mutexes when possible

Don'ts

Don't leak goroutines - Always have exit path
Don't close from receiver - Causes panic
Don't use shared memory - Unless necessary
Don't ignore context cancellation - Check ctx.Done()
Don't use time.Sleep for sync - Use proper primitives

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