log

ctx/log

Structured logging utilities built on top of ctx.C.

• Log messages are emitted as JSON Lines (Line.JSON()) and always include the tags stored in the originating context.
• log.Errorf, log.Warnf, log.Infof, and log.Debugf mirror the standard library's formatting helpers but understand ctx.Error values so stack traces and tagged contexts are captured automatically.
• Attach a custom sink with log.WithLogger(ctx, func(Line)); tests can use log.WithLoggerAndHelper to hook into t.Helper() and keep backtraces clean.
• Implement log.Loggable on your types to tweak how they appear in structured logs and to add/remove tags dynamically.

See the root ctx package README for an overview of tagging and error helpers that work hand-in-hand with the logger.