*: add debug

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

clientv3/balancer.go

@@ -16,6 +16,7 @@ package clientv3
 
 import (
 	"context"
+	"fmt"
 	"net/url"
 	"strings"
 	"sync"
@@ -291,27 +292,33 @@ func (b *simpleBalancer) up(addr grpc.Address) (func(error), bool) {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
+	fmt.Println("simpleBalancer up:", addr)
 	// gRPC might call Up after it called Close. We add this check
 	// to "fix" it up at application layer. Otherwise, will panic
 	// if b.upc is already closed.
 	if b.closed {
+		fmt.Println("simpleBalancer up closed:", addr, b.closed)
 		return func(err error) {}, false
 	}
 	// gRPC might call Up on a stale address.
 	// Prevent updating pinAddr with a stale address.
 	if !hasAddr(b.addrs, addr.Addr) {
+		fmt.Println("simpleBalancer up !hasAddr:", addr, "/", b.addrs)
 		return func(err error) {}, false
 	}
 	if b.pinAddr != "" {
+		fmt.Println("simpleBalancer up b.pinAddr != '':", addr, "/", b.pinAddr)
 		return func(err error) {}, false
 	}
 	// notify waiting Get()s and pin first connected address
 	close(b.upc)
 	b.downc = make(chan struct{})
 	b.pinAddr = addr.Addr
+	fmt.Println("simpleBalancer up pinned:", addr)
 	// notify client that a connection is up
 	b.readyOnce.Do(func() { close(b.readyc) })
 	return func(err error) {
+		fmt.Println("simpleBalancer up error:", addr, err)
 		b.mu.Lock()
 		b.upc = make(chan struct{})
 		close(b.downc)

clientv3/health_balancer.go

@@ -16,6 +16,7 @@ package clientv3
 
 import (
 	"context"
+	"fmt"
 	"sync"
 	"time"
 
@@ -174,6 +175,7 @@ func (hb *healthBalancer) mayPin(addr grpc.Address) bool {
 	skip := len(hb.addrs) == 1 || len(hb.unhealthy) == 0
 	_, bad := hb.unhealthy[addr.Addr]
 	hb.mu.RUnlock()
+	fmt.Println("mayPin:", addr, skip, bad)
 	if skip || !bad {
 		return true
 	}