feat: export context key (#65)

context.go

@@ -4,19 +4,20 @@ import "context"
 
 // WithContext wraps the given logger in context.
 func WithContext(ctx context.Context, logger *Logger) context.Context {
-	return context.WithValue(ctx, loggerContextKey, logger)
+	return context.WithValue(ctx, ContextKey, logger)
 }
 
 // FromContext returns the logger from the given context.
 // This will return the default package logger if no logger
 // found in context.
 func FromContext(ctx context.Context) *Logger {
-	if logger, ok := ctx.Value(loggerContextKey).(*Logger); ok {
+	if logger, ok := ctx.Value(ContextKey).(*Logger); ok {
 		return logger
 	}
 	return defaultLogger
 }
 
-type contextKey struct{}
+type contextKey struct{ string }
 
-var loggerContextKey = contextKey{}
+// ContextKey is the key used to store the logger in context.
+var ContextKey = contextKey{"log"}