[#148] Add trace_id to logs

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

utils/util.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/valyala/fasthttp"
+	"go.uber.org/zap"
 )
 
 // SetContextToRequest adds new context to fasthttp request.
@@ -15,3 +16,34 @@ func SetContextToRequest(ctx context.Context, c *fasthttp.RequestCtx) {
 func GetContextFromRequest(c *fasthttp.RequestCtx) context.Context {
 	return c.UserValue("context").(context.Context)
 }
+
+type ctxReqLoggerKeyType struct{}
+
+// SetReqLog sets child zap.Logger in the context.
+func SetReqLog(ctx context.Context, log *zap.Logger) context.Context {
+	if ctx == nil {
+		return nil
+	}
+	return context.WithValue(ctx, ctxReqLoggerKeyType{}, log)
+}
+
+// GetReqLog returns log if set.
+// If zap.Logger isn't set returns nil.
+func GetReqLog(ctx context.Context) *zap.Logger {
+	if ctx == nil {
+		return nil
+	} else if r, ok := ctx.Value(ctxReqLoggerKeyType{}).(*zap.Logger); ok {
+		return r
+	}
+	return nil
+}
+
+// GetReqLogOrDefault returns log from context, if it exists.
+// If the log is missing from the context, the default logger is returned.
+func GetReqLogOrDefault(ctx context.Context, defaultLog *zap.Logger) *zap.Logger {
+	log := GetReqLog(ctx)
+	if log == nil {
+		log = defaultLog
+	}
+	return log
+}