MDC Logging in GoLang

Java's MDC Logging relies on thread local storage, which is not available in GoLang. However, a similar functionality can be achieved by threading a Context through the stack.

Java MDC relies on thread local storage, something Go does not have. The closest thing is to thread a Context through your stack, which is becoming a common practice in Go libraries.

One way to implement this is through a middleware package that adds a request ID to the context of a web request. This ID can then be retrieved and used throughout the stack for logging purposes.

Here's a simple example of a middleware package:

req = req.WithContext(context.WithValue(req.Context(), "requestId", ID))

The request ID can then be retrieved using:

ctx.Value("requestId")

This value can be used in a custom logger function:

func logStuff(ctx context.Context, msg string) {
    log.Println(ctx.Value("requestId"), msg) // call stdlib logger
}

This approach allows for easy tracing of concurrent requests by adding unique IDs to all server logs. There are other possible implementations, but this one provides a straightforward way to achieve MDC-like logging in GoLang.