From 120728e1f775e40a2a764341939b78d666b08260 Mon Sep 17 00:00:00 2001
From: Fabian Holler <fabian.holler@simplesurance.de>
Date: Thu, 25 Jul 2019 22:25:20 +0200
Subject: [PATCH] client: log balancer info messages only for verbosity level
 >=2 (#2908)

The pickfirstBalancer and baseBalancer are logging a lot of messages under normal operation.  Those messages can not be associated to a server connection because no connection address is part of the messages. They are messages that are only useful when debugging issues.

Only log them when the verbose level is at least 2, to reduce the amount of log messages under normal operation.
---
 balancer/base/balancer.go | 12 +++++++++---
 pickfirst.go              | 16 ++++++++++++----
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/balancer/base/balancer.go b/balancer/base/balancer.go
index e587d8d11..1af88f0a3 100644
--- a/balancer/base/balancer.go
+++ b/balancer/base/balancer.go
@@ -73,7 +73,9 @@ func (b *baseBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error)
 func (b *baseBalancer) UpdateClientConnState(s balancer.ClientConnState) {
 	// TODO: handle s.ResolverState.Err (log if not nil) once implemented.
 	// TODO: handle s.ResolverState.ServiceConfig?
-	grpclog.Infoln("base.baseBalancer: got new ClientConn state: ", s)
+	if grpclog.V(2) {
+		grpclog.Infoln("base.baseBalancer: got new ClientConn state: ", s)
+	}
 	// addrsSet is the set converted from addrs, it's used for quick lookup of an address.
 	addrsSet := make(map[resolver.Address]struct{})
 	for _, a := range s.ResolverState.Addresses {
@@ -127,10 +129,14 @@ func (b *baseBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectiv
 
 func (b *baseBalancer) UpdateSubConnState(sc balancer.SubConn, state balancer.SubConnState) {
 	s := state.ConnectivityState
-	grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
+	if grpclog.V(2) {
+		grpclog.Infof("base.baseBalancer: handle SubConn state change: %p, %v", sc, s)
+	}
 	oldS, ok := b.scStates[sc]
 	if !ok {
-		grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
+		if grpclog.V(2) {
+			grpclog.Infof("base.baseBalancer: got state changes for an unknown SubConn: %p, %v", sc, s)
+		}
 		return
 	}
 	b.scStates[sc] = s
diff --git a/pickfirst.go b/pickfirst.go
index d1e38aad7..ed05b02ed 100644
--- a/pickfirst.go
+++ b/pickfirst.go
@@ -51,14 +51,18 @@ type pickfirstBalancer struct {
 
 func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err error) {
 	if err != nil {
-		grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
+		if grpclog.V(2) {
+			grpclog.Infof("pickfirstBalancer: HandleResolvedAddrs called with error %v", err)
+		}
 		return
 	}
 	if b.sc == nil {
 		b.sc, err = b.cc.NewSubConn(addrs, balancer.NewSubConnOptions{})
 		if err != nil {
 			//TODO(yuxuanli): why not change the cc state to Idle?
-			grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+			if grpclog.V(2) {
+				grpclog.Errorf("pickfirstBalancer: failed to NewSubConn: %v", err)
+			}
 			return
 		}
 		b.cc.UpdateBalancerState(connectivity.Idle, &picker{sc: b.sc})
@@ -70,9 +74,13 @@ func (b *pickfirstBalancer) HandleResolvedAddrs(addrs []resolver.Address, err er
 }
 
 func (b *pickfirstBalancer) HandleSubConnStateChange(sc balancer.SubConn, s connectivity.State) {
-	grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+	if grpclog.V(2) {
+		grpclog.Infof("pickfirstBalancer: HandleSubConnStateChange: %p, %v", sc, s)
+	}
 	if b.sc != sc {
-		grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+		if grpclog.V(2) {
+			grpclog.Infof("pickfirstBalancer: ignored state change because sc is not recognized")
+		}
 		return
 	}
 	if s == connectivity.Shutdown {