Print Instead Of Logger (ARCH5157)

Key go.logging.fmt-print-instead-of-logger · Severity warning · Category logging

Writing directly to stdout/stderr with fmt.Println or fmt.Printf bypasses the structured logger that provides levels, structure, and sink routing. Diagnostic output should go through the framework logger.

Incorrect

func handle(req *Request) {
  fmt.Println("processing request", req.ID)
  // ...
}

Correct

func handle(req *Request, log *slog.Logger) {
  log.Info("processing request", "id", req.ID)
  // ...
}

Fix

Use a structured logger (log/slog) instead of fmt.Print*.