Why Context Should Be the First Parameter in Go Functions

Context should be the first parameter in Go functions to ensure it is never forgotten and to allow the compiler to enforce its presence in call chains. This convention enables the compiler to detect if a context is missing and allows tools to easily trace context propagation through your codebase.

func HandleRequest(ctx context.Context, w http.ResponseWriter, r *http.Request) {
    // ctx is guaranteed to be present and can be used for timeouts/cancellation
    if err := process(ctx); err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }
}

Placing context first acts like a mandatory 'pass the baton' rule in a relay race. It ensures every function in a chain receives the necessary cancellation and timeout signals before doing any work. If you skip it, the compiler warns you, preventing your program from hanging or leaking resources.