clientv3: add more health balancer debugging logs

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

clientv3/balancer.go

@@ -310,7 +310,7 @@ func (b *simpleBalancer) up(addr grpc.Address) (func(error), bool) {
 	b.downc = make(chan struct{})
 	b.pinAddr = addr.Addr
 	if logger.V(4) {
-		logger.Infof("clientv3: balancer pins endpoint to %s", addr.Addr)
+		logger.Infof("clientv3/balancer: pin %s", addr.Addr)
 	}
 	// notify client that a connection is up
 	b.readyOnce.Do(func() { close(b.readyc) })
@@ -321,7 +321,7 @@ func (b *simpleBalancer) up(addr grpc.Address) (func(error), bool) {
 		b.pinAddr = ""
 		b.mu.Unlock()
 		if logger.V(4) {
-			logger.Infof("clientv3: unpin %s (%v)", addr.Addr, err)
+			logger.Infof("clientv3/balancer: unpin %s (%v)", addr.Addr, err)
 		}
 	}, true
 }

clientv3/health_balancer.go

@@ -139,6 +139,9 @@ func (hb *healthBalancer) updateUnhealthy(timeout time.Duration) {
 			for k, v := range hb.unhealthy {
 				if time.Since(v) > timeout {
 					delete(hb.unhealthy, k)
+					if logger.V(4) {
+						logger.Infof("clientv3/balancer: removes %s from unhealthy after %v", k, timeout)
+					}
 				}
 			}
 			hb.mu.Unlock()
@@ -181,13 +184,16 @@ func (hb *healthBalancer) mayPin(addr grpc.Address) bool {
 		hb.mu.Lock()
 		delete(hb.unhealthy, addr.Addr)
 		hb.mu.Unlock()
+		if logger.V(4) {
+			logger.Infof("clientv3/balancer: %s is healthy", addr.Addr)
+		}
 		return true
 	}
 	hb.mu.Lock()
 	hb.unhealthy[addr.Addr] = time.Now()
 	hb.mu.Unlock()
 	if logger.V(4) {
-		logger.Infof("clientv3: %s becomes unhealthy", addr.Addr)
+		logger.Infof("clientv3/balancer: %s becomes unhealthy", addr.Addr)
 	}
 	return false
 }