This fixes issue #34. Using the wrong hostname.

replication/binlogsyncer.go

@@ -3,6 +3,7 @@ package replication
 import (
 	"encoding/binary"
 	"fmt"
+	"os"
 	"sync"
 	"time"
 
@@ -25,10 +26,11 @@ type BinlogSyncer struct {
 	c        *client.Conn
 	serverID uint32
 
-	host     string
-	port     uint16
-	user     string
-	password string
+	localhost string
+	host      string
+	port      uint16
+	user      string
+	password  string
 
 	masterID uint32
 
@@ -62,6 +64,21 @@ func NewBinlogSyncer(serverID uint32, flavor string) *BinlogSyncer {
 	return b
 }
 
+// LocalHostname returns the hostname that register slave would register as.
+func (b *BinlogSyncer) LocalHostname() string {
+
+	if b.localhost == "" {
+		h, _ := os.Hostname()
+		return h
+	}
+	return b.localhost
+}
+
+// SetLocalHostname set's the hostname that register salve would register as.
+func (b *NewBinlogSyncer) SetLocalHostname(name string) {
+	b.localhost = name
+}
+
 func (b *BinlogSyncer) Close() {
 	b.m.Lock()
 	defer b.m.Unlock()
@@ -222,11 +239,9 @@ func (b *BinlogSyncer) EnableSemiSync() error {
 	}
 
 	_, err := b.c.Execute(`SET @rpl_semi_sync_slave = 1;`)
-
 	if err != nil {
 		b.semiSyncEnabled = true
 	}
-
 	return errors.Trace(err)
 }
 
@@ -402,7 +417,10 @@ func (b *BinlogSyncer) writeBinlogDumpMariadbGTIDCommand(gset GTIDSet) error {
 func (b *BinlogSyncer) writeRegisterSlaveCommand() error {
 	b.c.ResetSequence()
 
-	data := make([]byte, 4+1+4+1+len(b.host)+1+len(b.user)+1+len(b.password)+2+4+4)
+	hostname := b.LocalHostname()
+
+	// This should be the name of slave host not the host we are connecting to.
+	data := make([]byte, 4+1+4+1+len(hostname)+1+len(b.user)+1+len(b.password)+2+4+4)
 	pos := 4
 
 	data[pos] = COM_REGISTER_SLAVE
@@ -411,9 +429,10 @@ func (b *BinlogSyncer) writeRegisterSlaveCommand() error {
 	binary.LittleEndian.PutUint32(data[pos:], b.serverID)
 	pos += 4
 
-	data[pos] = uint8(len(b.host))
+	// This should be the name of slave hostname not the host we are connecting to.
+	data[pos] = uint8(len(hostname))
 	pos++
-	n := copy(data[pos:], b.host)
+	n := copy(data[pos:], hostname)
 	pos += n
 
 	data[pos] = uint8(len(b.user))