go-coding

name	go-coding
description	Expertise in Go (Golang) development, including idiomatic patterns, concurrency, and performance optimization. Use when asked to write, refactor, or debug Go code.

Go Coding Skill

This skill provides instructions for writing idiomatic, efficient, and robust Go code.

Core Principles

• Simplicity: Favor straightforward code over cleverness.
• Explicit over Implicit: Avoid magic; make logic clear.
• Error Handling: Treat errors as values. Always check returned errors.
• Concurrency: Use Goroutines and Channels for concurrent tasks. "Do not communicate by sharing memory; instead, share memory by communicating."

Implementation Guidelines

Project Structure

• Follow standard Go project layout (e.g., cmd/, internal/, pkg/).
• Use go mod init <module-name> to initialize modules.

Formatting and Linting

• Always use gofmt or goimports to format code.
• Use go vet and golangci-lint for static analysis.

Performance

• Use sync.Pool for frequently allocated objects.
• Profile using pprof to identify bottlenecks.
• Be mindful of slice and map allocations; pre-allocate when size is known.

Testing

• Write unit tests using the testing package (_test.go files).
• Use testify or similar for easier assertions if allowed.
• Aim for high test coverage but prioritize critical logic.

Detailed Documentation

• Common Go Code Examples - Reference for web servers, JSON, worker pools, and interfaces.
• Table Test Template - Template for writing idiomatic table-driven tests.

Common Patterns

Error Handling

if err := doSomething(); err != nil {
    return fmt.Errorf("failed to do something: %w", err)
}

Goroutines and WaitGroups

var wg sync.WaitGroup
for i := 0; i < 10; i++ {
    wg.Add(1)
    go func(id int) {
        defer wg.Done()
        process(id)
    }(i)
}
wg.Wait()

Context for Cancellation

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

req, _ := http.NewRequestWithContext(ctx, "GET", url, nil)

Useful Commands

• Build: go build -o app ./cmd/app
• Test: go test ./...
• Run: go run ./cmd/app
• Tidy dependencies: go mod tidy