go-best-practices

Go Best Practices

Code Style

| Rule | Guideline | |------|-----------| | Formatter | gofmt or goimports | | Linter | golangci-lint | | Naming | Short, clear; avoid stuttering | | Comments | Godoc for exported items |

Error Handling

| Rule | Guideline | |------|-----------| | Always check | Never ignore errors | | Wrap context | fmt.Errorf("ctx: %w", err) | | Sentinel errors | var ErrNotFound = errors.New(...) |

func Load(path string) (*Config, error) {
    data, err := os.ReadFile(path)
    if err != nil {
        return nil, fmt.Errorf("load config %s: %w", path, err)
    }
    // ...
}

Project Structure

cmd/appname/main.go
internal/config/
internal/service/
go.mod

Concurrency

| Pattern | Usage | |---------|-------| | context.Context | Cancellation, timeouts | | sync.WaitGroup | Wait for goroutines | | errgroup.Group | Goroutines with errors |

func Process(ctx context.Context, items []Item) error {
    for _, item := range items {
        select {
        case <-ctx.Done():
            return ctx.Err()
        default:
            if err := process(item); err != nil { return err }
        }
    }
    return nil
}

Anti-Patterns

| Avoid | Use Instead | |-------|-------------| | Naked returns | Explicit returns | | panic for errors | Return errors | | Large interfaces | Small, focused | | init() | Explicit init |

Testing (Table-Driven)

func TestParse(t *testing.T) {
    tests := []struct{ name, input string; want int; wantErr bool }{
        {"valid", "42", 42, false},
        {"invalid", "abc", 0, true},
    }
    for _, tt := range tests {
        t.Run(tt.name, func(t *testing.T) {
            got, err := Parse(tt.input)
            if (err != nil) != tt.wantErr { t.Errorf("err=%v, want=%v", err, tt.wantErr) }
            if got != tt.want { t.Errorf("got=%v, want=%v", got, tt.want) }
        })
    }
}