From 701f02f90aac03f6ddf958e77fbc55a66aa92ecd Mon Sep 17 00:00:00 2001
From: Denis Issoupov <dissoupov@salesforce.com>
Date: Mon, 13 Jul 2020 09:05:06 -0700
Subject: [PATCH] 12125: panic: zap.Logger is nil in Embed client

---
 clientv3/client.go                  |  8 +++++++-
 clientv3/client_test.go             | 13 +++++++++++++
 etcdserver/api/v3client/v3client.go |  4 ++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/clientv3/client.go b/clientv3/client.go
index ed4a98677..3e33e956c 100644
--- a/clientv3/client.go
+++ b/clientv3/client.go
@@ -112,7 +112,7 @@ func New(cfg Config) (*Client, error) {
 // service interface implementations and do not need connection management.
 func NewCtxClient(ctx context.Context) *Client {
 	cctx, cancel := context.WithCancel(ctx)
-	return &Client{ctx: cctx, cancel: cancel}
+	return &Client{ctx: cctx, cancel: cancel, lg: zap.NewNop()}
 }
 
 // NewFromURL creates a new etcdv3 client from a URL.
@@ -125,6 +125,12 @@ func NewFromURLs(urls []string) (*Client, error) {
 	return New(Config{Endpoints: urls})
 }
 
+// WithLogger sets a logger
+func (c *Client) WithLogger(lg *zap.Logger) *Client {
+	c.lg = lg
+	return c
+}
+
 // Close shuts down the client's etcd connections.
 func (c *Client) Close() error {
 	c.cancel()
diff --git a/clientv3/client_test.go b/clientv3/client_test.go
index e4daf0abd..232aa441c 100644
--- a/clientv3/client_test.go
+++ b/clientv3/client_test.go
@@ -166,3 +166,16 @@ func TestCloseCtxClient(t *testing.T) {
 		t.Errorf("failed to Close the client. %v", err)
 	}
 }
+
+func TestWithLogger(t *testing.T) {
+	ctx := context.Background()
+	c := NewCtxClient(ctx)
+	if c.lg == nil {
+		t.Errorf("unexpected nil in *zap.Logger")
+	}
+
+	c.WithLogger(nil)
+	if c.lg != nil {
+		t.Errorf("WithLogger should modify *zap.Logger")
+	}
+}
diff --git a/etcdserver/api/v3client/v3client.go b/etcdserver/api/v3client/v3client.go
index f2a401224..f93474fe7 100644
--- a/etcdserver/api/v3client/v3client.go
+++ b/etcdserver/api/v3client/v3client.go
@@ -29,6 +29,10 @@ import (
 // to the etcd server through its api/v3rpc function interfaces.
 func New(s *etcdserver.EtcdServer) *clientv3.Client {
 	c := clientv3.NewCtxClient(context.Background())
+	lg := s.Logger()
+	if lg != nil {
+		c.WithLogger(lg)
+	}
 
 	kvc := adapter.KvServerToKvClient(v3rpc.NewQuotaKVServer(s))
 	c.KV = clientv3.NewKVFromKVClient(kvc, c)