etcdserver/api/etcdhttp: support structured logging

Signed-off-by: Gyuho Lee <gyuhox@gmail.com>

etcdserver/api/etcdhttp/base.go

@@ -29,6 +29,7 @@ import (
 	"github.com/coreos/etcd/version"
 
 	"github.com/coreos/pkg/capnslog"
+	"go.uber.org/zap"
 )
 
 var (
@@ -88,13 +89,13 @@ func logHandleFunc(w http.ResponseWriter, r *http.Request) {
 
 	d := json.NewDecoder(r.Body)
 	if err := d.Decode(&in); err != nil {
-		WriteError(w, r, httptypes.NewHTTPError(http.StatusBadRequest, "Invalid json body"))
+		WriteError(nil, w, r, httptypes.NewHTTPError(http.StatusBadRequest, "Invalid json body"))
 		return
 	}
 
 	logl, err := capnslog.ParseLevel(strings.ToUpper(in.Level))
 	if err != nil {
-		WriteError(w, r, httptypes.NewHTTPError(http.StatusBadRequest, "Invalid log level "+in.Level))
+		WriteError(nil, w, r, httptypes.NewHTTPError(http.StatusBadRequest, "Invalid log level "+in.Level))
 		return
 	}
 
@@ -133,27 +134,66 @@ func allowMethod(w http.ResponseWriter, r *http.Request, m string) bool {
 // WriteError logs and writes the given Error to the ResponseWriter
 // If Error is an etcdErr, it is rendered to the ResponseWriter
 // Otherwise, it is assumed to be a StatusInternalServerError
-func WriteError(w http.ResponseWriter, r *http.Request, err error) {
+func WriteError(lg *zap.Logger, w http.ResponseWriter, r *http.Request, err error) {
 	if err == nil {
 		return
 	}
 	switch e := err.(type) {
 	case *v2error.Error:
 		e.WriteTo(w)
+
 	case *httptypes.HTTPError:
 		if et := e.WriteTo(w); et != nil {
-			plog.Debugf("error writing HTTPError (%v) to %s", et, r.RemoteAddr)
+			if lg != nil {
+				lg.Debug(
+					"failed to write v2 HTTP error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", e.Error()),
+					zap.Error(et),
+				)
+			} else {
+				plog.Debugf("error writing HTTPError (%v) to %s", et, r.RemoteAddr)
+			}
 		}
+
 	default:
 		switch err {
-		case etcdserver.ErrTimeoutDueToLeaderFail, etcdserver.ErrTimeoutDueToConnectionLost, etcdserver.ErrNotEnoughStartedMembers, etcdserver.ErrUnhealthy:
-			mlog.MergeError(err)
+		case etcdserver.ErrTimeoutDueToLeaderFail, etcdserver.ErrTimeoutDueToConnectionLost, etcdserver.ErrNotEnoughStartedMembers,
+			etcdserver.ErrUnhealthy:
+			if lg != nil {
+				lg.Warn(
+					"v2 response error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", err.Error()),
+				)
+			} else {
+				mlog.MergeError(err)
+			}
+
 		default:
-			mlog.MergeErrorf("got unexpected response error (%v)", err)
+			if lg != nil {
+				lg.Warn(
+					"unexpected v2 response error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", err.Error()),
+				)
+			} else {
+				mlog.MergeErrorf("got unexpected response error (%v)", err)
+			}
 		}
+
 		herr := httptypes.NewHTTPError(http.StatusInternalServerError, "Internal Server Error")
 		if et := herr.WriteTo(w); et != nil {
-			plog.Debugf("error writing HTTPError (%v) to %s", et, r.RemoteAddr)
+			if lg != nil {
+				lg.Debug(
+					"failed to write v2 HTTP error",
+					zap.String("remote-addr", r.RemoteAddr),
+					zap.String("internal-server-error", err.Error()),
+					zap.Error(et),
+				)
+			} else {
+				plog.Debugf("error writing HTTPError (%v) to %s", et, r.RemoteAddr)
+			}
 		}
 	}
 }