mysqlctl: Execute RefreshConfig remotely if requested.

go/cmd/mysqlctld/mysqlctld.go

@@ -98,7 +98,7 @@ func main() {
 		}
 		mysqld.OnTerm(onTermFunc)
 
-		err = mysqld.RefreshConfig()
+		err = mysqld.RefreshConfig(ctx)
 		if err != nil {
 			log.Errorf("failed to refresh config: %v", err)
 			exit.Return(1)

go/vt/mysqlctl/backup.go

@@ -321,7 +321,7 @@ func backup(ctx context.Context, mysqld MysqlDaemon, logger logutil.Logger, bh b
 	usable := backupErr == nil
 
 	// Try to restart mysqld
-	err = mysqld.RefreshConfig()
+	err = mysqld.RefreshConfig(ctx)
 	if err != nil {
 		return usable, fmt.Errorf("can't refresh mysqld config: %v", err)
 	}

go/vt/mysqlctl/fakemysqldaemon/fakemysqldaemon.go

@@ -190,7 +190,7 @@ func (fmd *FakeMysqlDaemon) ReinitConfig(ctx context.Context) error {
 }
 
 // RefreshConfig is part of the MysqlDaemon interface
-func (fmd *FakeMysqlDaemon) RefreshConfig() error {
+func (fmd *FakeMysqlDaemon) RefreshConfig(ctx context.Context) error {
 	return nil
 }
 

go/vt/mysqlctl/grpcmysqlctlclient/client.go

@@ -91,6 +91,14 @@ func (c *client) ReinitConfig(ctx context.Context) error {
 	})
 }
 
+// RefreshConfig is part of the MysqlctlClient interface.
+func (c *client) RefreshConfig(ctx context.Context) error {
+	return c.withRetry(ctx, func() error {
+		_, err := c.c.RefreshConfig(ctx, &mysqlctlpb.RefreshConfigRequest{})
+		return err
+	})
+}
+
 // Close is part of the MysqlctlClient interface.
 func (c *client) Close() {
 	c.cc.Close()

go/vt/mysqlctl/grpcmysqlctlserver/server.go

@@ -54,6 +54,11 @@ func (s *server) ReinitConfig(ctx context.Context, request *mysqlctlpb.ReinitCon
 	return &mysqlctlpb.ReinitConfigResponse{}, s.mysqld.ReinitConfig(ctx)
 }
 
+// RefreshConfig implements the server side of the MysqlctlClient interface.
+func (s *server) RefreshConfig(ctx context.Context, request *mysqlctlpb.RefreshConfigRequest) (*mysqlctlpb.RefreshConfigResponse, error) {
+	return &mysqlctlpb.RefreshConfigResponse{}, s.mysqld.RefreshConfig(ctx)
+}
+
 // StartServer registers the Server for RPCs.
 func StartServer(s *grpc.Server, mysqld *mysqlctl.Mysqld) {
 	mysqlctlpb.RegisterMysqlCtlServer(s, &server{mysqld})

go/vt/mysqlctl/mysql_daemon.go

@@ -39,7 +39,7 @@ type MysqlDaemon interface {
 	Shutdown(ctx context.Context, waitForMysqld bool) error
 	RunMysqlUpgrade() error
 	ReinitConfig(ctx context.Context) error
-	RefreshConfig() error
+	RefreshConfig(ctx context.Context) error
 	Wait(ctx context.Context) error
 
 	// GetMysqlPort returns the current port mysql is listening on.

go/vt/mysqlctl/mysqlctlclient/interface.go

@@ -42,6 +42,9 @@ type MysqlctlClient interface {
 	// ReinitConfig calls Mysqld.ReinitConfig remotely.
 	ReinitConfig(ctx context.Context) error
 
+	// RefreshConfig calls Mysqld.RefreshConfig remotely.
+	RefreshConfig(ctx context.Context) error
+
 	// Close will terminate the connection. This object won't be used anymore.
 	Close()
 }

go/vt/mysqlctl/mysqld.go

@@ -637,7 +637,18 @@ func getMycnfTemplates(root string) []string {
 // RefreshConfig attempts to recreate the my.cnf from templates, and log and
 // swap in to place if it's updated. It keeps a copy of the last version in case fallback is required.
 // Should be called from a stable replica, server_id is not regenerated.
-func (mysqld *Mysqld) RefreshConfig() error {
+func (mysqld *Mysqld) RefreshConfig(ctx context.Context) error {
+	// Execute as remote action on mysqlctld if requested.
+	if *socketFile != "" {
+		log.Infof("executing Mysqld.RefreshConfig() remotely via mysqlctld server: %v", *socketFile)
+		client, err := mysqlctlclient.New("unix", *socketFile)
+		if err != nil {
+			return fmt.Errorf("can't dial mysqlctld: %v", err)
+		}
+		defer client.Close()
+		return client.RefreshConfig(ctx)
+	}
+
 	log.Info("Checking for updates to my.cnf")
 	root, err := vtenv.VtRoot()
 	if err != nil {

proto/mysqlctl.proto

@@ -41,10 +41,15 @@ message ReinitConfigRequest{}
 
 message ReinitConfigResponse{}
 
+message RefreshConfigRequest{}
+
+message RefreshConfigResponse{}
+
 // MysqlCtl is the service definition
 service MysqlCtl {
   rpc Start(StartRequest) returns (StartResponse) {};
   rpc Shutdown(ShutdownRequest) returns (ShutdownResponse) {};
   rpc RunMysqlUpgrade(RunMysqlUpgradeRequest) returns (RunMysqlUpgradeResponse) {};
   rpc ReinitConfig(ReinitConfigRequest) returns (ReinitConfigResponse) {};
+  rpc RefreshConfig(RefreshConfigRequest) returns (RefreshConfigResponse) {};
 }

test/tablet.py

@@ -571,11 +571,15 @@ def start_vttablet(
 
       # When vttablet restores from backup, it will re-generate the .cnf file.
       # So we need to have EXTRA_MY_CNF set properly.
-      all_extra_my_cnf = get_all_extra_my_cnf(None)
-      if all_extra_my_cnf:
-        if not extra_env:
-          extra_env = {}
-        extra_env['EXTRA_MY_CNF'] = ':'.join(all_extra_my_cnf)
+      # When using mysqlctld, only mysqlctld should need EXTRA_MY_CNF.
+      # If any test fails without giving EXTRA_MY_CNF to vttablet,
+      # it means we missed some call that should run remotely on mysqlctld.
+      if not self.use_mysqlctld:
+        all_extra_my_cnf = get_all_extra_my_cnf(None)
+        if all_extra_my_cnf:
+          if not extra_env:
+            extra_env = {}
+          extra_env['EXTRA_MY_CNF'] = ':'.join(all_extra_my_cnf)
 
     if extra_args:
       args.extend(extra_args)