Add --mysql-wait-timeout flag (#1401)

Author: timvaillancourt

go/cmd/gh-ost/main.go

@@ -51,6 +51,7 @@ func main() {
 	flag.StringVar(&migrationContext.AssumeMasterHostname, "assume-master-host", "", "(optional) explicitly tell gh-ost the identity of the master. Format: some.host.com[:port] This is useful in master-master setups where you wish to pick an explicit master, or in a tungsten-replicator where gh-ost is unable to determine the master")
 	flag.IntVar(&migrationContext.InspectorConnectionConfig.Key.Port, "port", 3306, "MySQL port (preferably a replica, not the master)")
 	flag.Float64Var(&migrationContext.InspectorConnectionConfig.Timeout, "mysql-timeout", 0.0, "Connect, read and write timeout for MySQL")
+	flag.Float64Var(&migrationContext.InspectorConnectionConfig.WaitTimeout, "mysql-wait-timeout", 0.0, "wait_timeout for MySQL sessions")
 	flag.StringVar(&migrationContext.CliUser, "user", "", "MySQL user")
 	flag.StringVar(&migrationContext.CliPassword, "password", "", "MySQL password")
 	flag.StringVar(&migrationContext.CliMasterUser, "master-user", "", "MySQL user on master, if different from that on replica. Requires --assume-master-host")

go/mysql/connection.go

@@ -31,6 +31,7 @@ type ConnectionConfig struct {
 	Timeout              float64
 	TransactionIsolation string
 	Charset              string
+	WaitTimeout          float64
 }
 
 func NewConnectionConfig() *ConnectionConfig {
@@ -51,6 +52,7 @@ func (this *ConnectionConfig) DuplicateCredentials(key InstanceKey) *ConnectionC
 		Timeout:              this.Timeout,
 		TransactionIsolation: this.TransactionIsolation,
 		Charset:              this.Charset,
+		WaitTimeout:          this.WaitTimeout,
 	}
 	config.ImpliedKey = &config.Key
 	return config
@@ -139,6 +141,9 @@ func (this *ConnectionConfig) GetDBUri(databaseName string) string {
 		fmt.Sprintf("readTimeout=%fs", this.Timeout),
 		fmt.Sprintf("writeTimeout=%fs", this.Timeout),
 	}
+	if this.WaitTimeout > 0 {
+		connectionParams = append(connectionParams, fmt.Sprintf("wait_timeout=%fs", this.WaitTimeout))
+	}
 
 	return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?%s", this.User, this.Password, hostname, this.Key.Port, databaseName, strings.Join(connectionParams, "&"))
 }

go/mysql/connection_test.go

@@ -82,6 +82,7 @@ func TestGetDBUri(t *testing.T) {
 	c.User = "gromit"
 	c.Password = "penguin"
 	c.Timeout = 1.2345
+	c.WaitTimeout = 0 // should be ignored
 	c.TransactionIsolation = transactionIsolation
 	c.Charset = "utf8mb4,utf8,latin1"
 
@@ -95,10 +96,11 @@ func TestGetDBUriWithTLSSetup(t *testing.T) {
 	c.User = "gromit"
 	c.Password = "penguin"
 	c.Timeout = 1.2345
+	c.WaitTimeout = 60
 	c.tlsConfig = &tls.Config{}
 	c.TransactionIsolation = transactionIsolation
 	c.Charset = "utf8mb4_general_ci,utf8_general_ci,latin1"
 
 	uri := c.GetDBUri("test")
-	test.S(t).ExpectEquals(uri, `gromit:penguin@tcp(myhost:3306)/test?autocommit=true&interpolateParams=true&charset=utf8mb4_general_ci,utf8_general_ci,latin1&tls=ghost&transaction_isolation="REPEATABLE-READ"&timeout=1.234500s&readTimeout=1.234500s&writeTimeout=1.234500s`)
+	test.S(t).ExpectEquals(uri, `gromit:penguin@tcp(myhost:3306)/test?autocommit=true&interpolateParams=true&charset=utf8mb4_general_ci,utf8_general_ci,latin1&tls=ghost&transaction_isolation="REPEATABLE-READ"&timeout=1.234500s&readTimeout=1.234500s&writeTimeout=1.234500s&wait_timeout=60.000000s`)
 }