ComeOnOliver Golang Logging Standards
Priority: P1 (STANDARD)
Principles
- Structured Logging: Use JSON or structured text. Readable by machines and humans.
- Leveled Logging: Debug, Info, Warn, Error.
- Contextual: Include correlation IDs (TraceID, RequestID) in logs.
- No
log.Fatal: Avoid terminating app inside libraries. Return error instead. Onlymainshould exit.
Libraries
log/slog(Recommended): Stdlib since Go 1.21. Fast, structured, zero-dep.- Zap (
uber-go/zap): High performance, good if pre-1.21 or extreme throughput needed. - Zerolog: Zero allocation, fast JSON logger.
Guidelines
- Initialize logger at startup.
- Inject logger or use a global singleton configured at startup (pragmatic choice).
- Use
slog.Attrfor structured data.
References
- Slog Patterns
Anti-Patterns
- No fmt.Println in production: Use slog or zap for structured, leveled logging.
- No log.Fatal in libraries: Return errors; only main() should call os.Exit.
- No unstructured log strings: Include correlation IDs and structured fields via slog.Attr.