introduce --singleton-table DDL strategy flag

Signed-off-by: Shlomi Noach <2607934+shlomi-noach@users.noreply.github.com>

Author: shlomi-noach

go/vt/schema/ddl_strategy.go

@@ -38,6 +38,7 @@ const (
 	skipTopoFlag           = "skip-topo" // legacy. Kept for backwards compatibility, but unused
 	singletonFlag          = "singleton"
 	singletonContextFlag   = "singleton-context"
+	singletonTableFlag     = "singleton-table"
 	allowZeroInDateFlag    = "allow-zero-in-date"
 	postponeLaunchFlag     = "postpone-launch"
 	postponeCompletionFlag = "postpone-completion"
@@ -177,6 +178,11 @@ func (setting *DDLStrategySetting) IsSingletonContext() bool {
 	return setting.hasFlag(singletonContextFlag)
 }
 
+// IsSingletonTable checks if strategy options include --singleton-table
+func (setting *DDLStrategySetting) IsSingletonTable() bool {
+	return setting.hasFlag(singletonTableFlag)
+}
+
 // IsAllowZeroInDateFlag checks if strategy options include --allow-zero-in-date
 func (setting *DDLStrategySetting) IsAllowZeroInDateFlag() bool {
 	return setting.hasFlag(allowZeroInDateFlag)
@@ -322,6 +328,7 @@ func (setting *DDLStrategySetting) RuntimeOptions() []string {
 		case isFlag(opt, skipTopoFlag): // deprecated flag, parsed for backwards compatibility
 		case isFlag(opt, singletonFlag):
 		case isFlag(opt, singletonContextFlag):
+		case isFlag(opt, singletonTableFlag):
 		case isFlag(opt, allowZeroInDateFlag):
 		case isFlag(opt, postponeLaunchFlag):
 		case isFlag(opt, postponeCompletionFlag):

go/vt/schema/ddl_strategy_test.go

@@ -189,6 +189,8 @@ func TestParseDDLStrategy(t *testing.T) {
 		options              string
 		isDeclarative        bool
 		isSingleton          bool
+		isSingletonContext   bool
+		isSingletonTable     bool
 		isPostponeLaunch     bool
 		isPostponeCompletion bool
 		isInOrderCompletion  bool
@@ -258,6 +260,20 @@ func TestParseDDLStrategy(t *testing.T) {
 			runtimeOptions:   "",
 			isSingleton:      true,
 		},
+		{
+			strategyVariable:   "vitess --singleton-context",
+			strategy:           DDLStrategyVitess,
+			options:            "--singleton-context",
+			runtimeOptions:     "",
+			isSingletonContext: true,
+		},
+		{
+			strategyVariable: "vitess --singleton-table",
+			strategy:         DDLStrategyVitess,
+			options:          "--singleton-table",
+			runtimeOptions:   "",
+			isSingletonTable: true,
+		},
 		{
 			strategyVariable: "online -postpone-launch",
 			strategy:         DDLStrategyOnline,
@@ -387,6 +403,8 @@ func TestParseDDLStrategy(t *testing.T) {
 			assert.Equal(t, ts.options, setting.Options)
 			assert.Equal(t, ts.isDeclarative, setting.IsDeclarative())
 			assert.Equal(t, ts.isSingleton, setting.IsSingleton())
+			assert.Equal(t, ts.isSingletonContext, setting.IsSingletonContext())
+			assert.Equal(t, ts.isSingletonTable, setting.IsSingletonTable())
 			assert.Equal(t, ts.isPostponeCompletion, setting.IsPostponeCompletion())
 			assert.Equal(t, ts.isPostponeLaunch, setting.IsPostponeLaunch())
 			assert.Equal(t, ts.isAllowConcurrent, setting.IsAllowConcurrent())