context.go

package log

import (
	"github.com/Sirupsen/logrus"
	"golang.org/x/net/context"
)

var (
	// G is an alias for GetLogger.
	//
	// We may want to define this locally to a package to get package tagged log
	// messages.
	G = GetLogger

	// L is an alias for the the standard logger.
	L = logrus.NewEntry(logrus.StandardLogger())
)

type loggerKey struct{}

// WithLogger returns a new context with the provided logger. Use in
// combination with logger.WithField(s) for great effect.
func WithLogger(ctx context.Context, logger *logrus.Entry) context.Context {
	return context.WithValue(ctx, loggerKey{}, logger)
}

// GetLogger retrieves the current logger from the context. If no logger is
// available, the default logger is returned.
func GetLogger(ctx context.Context) *logrus.Entry {
	logger := ctx.Value(loggerKey{})

	if logger == nil {
		return L
	}

	return logger.(*logrus.Entry)
}