Sub-loggers & Context

Sub-loggers

Create sub-loggers with preset fields using the With() context builder:

logger := clog.With().Str("component", "auth").Logger()
logger.Info().Str("user", "john").Msg("Authenticated")
// INF ℹ️ Authenticated component=auth user=john

Context fields support the same typed methods as events.

Context Propagation

Store a logger in a context.Context and retrieve it deeper in the call stack:

logger := clog.With().Str("request_id", "abc-123").Logger()
ctx := logger.WithContext(ctx)

// later, in any function that receives ctx:
clog.Ctx(ctx).Info().Msg("Handling request")
// INF ℹ️ Handling request request_id=abc-123

Ctx returns clog.Default when the context is nil or contains no logger, so it is always safe to call.

A package-level WithContext convenience stores clog.Default:

ctx := clog.WithContext(ctx) // stores clog.Default