Go Patterns

Idiomatic Go patterns for Go 1.21+.

Error Handling

if err != nil {
    return fmt.Errorf("failed to process %s: %w", id, err)
}

Interfaces

Small interfaces (1-3 methods). Accept interfaces, return structs.

type Reader interface {
    Read(p []byte) (n int, err error)
}

Table-Driven Tests

tests := []struct{
    name string
    input, want int
}{
    {"positive", 2, 3},
}
for _, tt := range tests {
    t.Run(tt.name, func(t *testing.T) {
        if got := Fn(tt.input); got != tt.want {
            t.Errorf("got %d, want %d", got, tt.want)
        }
    })
}

Concurrency

Always propagate context for cancellation:

func work(ctx context.Context) error {
    select {
    case <-ctx.Done():
        return ctx.Err()
    default:
        // do work
    }
}

Defer for Cleanup

f, err := os.Open(path)
if err != nil { return err }
defer f.Close()