hook names; added on-stop-replication hook

go/base/context.go

@@ -92,6 +92,7 @@ type MigrationContext struct {
 	InitiallyDropGhostTable bool
 	CutOverType             CutOver
 
+	Hostname                  string
 	TableEngine               string
 	RowsEstimate              int64
 	UsedRowsEstimateMethod    RowsEstimateMethod

go/cmd/gh-ost/main.go

@@ -189,6 +189,7 @@ func main() {
 	migrator := logic.NewMigrator()
 	err := migrator.Migrate()
 	if err != nil {
+		migrator.ExecOnFailureHook()
 		log.Fatale(err)
 	}
 	log.Info("Done")

go/logic/hooks.go

@@ -15,6 +15,20 @@ import (
 	"github.com/openark/golib/log"
 )
 
+const (
+	onStartup            = "gh-ost-on-startup"
+	onValidated          = "gh-ost-on-validated"
+	onAboutToRowCopy     = "gh-ost-on-about-row-copy"
+	onRowCopyComplete    = "gh-ost-on-row-copy-complete"
+	onBeginPostponed     = "gh-ost-on-begin-postponed"
+	onAboutToCutOver     = "gh-ost-on-about-cut-over"
+	onInteractiveCommand = "gh-ost-on-interactive-command"
+	onSuccess            = "gh-ost-on-success"
+	onFailure            = "gh-ost-on-failure"
+	onStatus             = "gh-ost-on-status"
+	onStopReplication    = "gh-ost-on-stop-replication"
+)
+
 type HooksExecutor struct {
 	migrationContext *base.MigrationContext
 }
@@ -29,7 +43,7 @@ func (this *HooksExecutor) initHooks() error {
 	return nil
 }
 
-func (this *HooksExecutor) applyEnvironmentVairables() []string {
+func (this *HooksExecutor) applyEnvironmentVairables(extraVariables ...string) []string {
 	env := os.Environ()
 	env = append(env, fmt.Sprintf("GH_OST_DATABASE_NAME=%s", this.migrationContext.DatabaseName))
 	env = append(env, fmt.Sprintf("GH_OST_TABLE_NAME=%s", this.migrationContext.OriginalTableName))
@@ -37,13 +51,20 @@ func (this *HooksExecutor) applyEnvironmentVairables() []string {
 	env = append(env, fmt.Sprintf("GH_OST_OLD_TABLE_NAME=%s", this.migrationContext.GetOldTableName()))
 	env = append(env, fmt.Sprintf("GH_OST_DDL=%s", this.migrationContext.AlterStatement))
 	env = append(env, fmt.Sprintf("GH_OST_ELAPSED_SECONDS=%f", this.migrationContext.ElapsedTime().Seconds()))
+	env = append(env, fmt.Sprintf("GH_OST_MIGRATED_HOST=%s", this.migrationContext.ApplierConnectionConfig.ImpliedKey.Hostname))
+	env = append(env, fmt.Sprintf("GH_OST_INSPECTED_HOST=%s", this.migrationContext.InspectorConnectionConfig.ImpliedKey.Hostname))
+	env = append(env, fmt.Sprintf("GH_OST_EXECUTING_HOST=%s", this.migrationContext.Hostname))
+
+	for _, variable := range extraVariables {
+		env = append(env, variable)
+	}
 	return env
 }
 
-// executeHook executes a command with arguments, and set relevant environment variables
-func (this *HooksExecutor) executeHook(hook string, arguments ...string) error {
-	cmd := exec.Command(hook, arguments...)
-	cmd.Env = this.applyEnvironmentVairables()
+// executeHook executes a command, and sets relevant environment variables
+func (this *HooksExecutor) executeHook(hook string, extraVariables ...string) error {
+	cmd := exec.Command(hook)
+	cmd.Env = this.applyEnvironmentVairables(extraVariables...)
 
 	if err := cmd.Run(); err != nil {
 		return log.Errore(err)
@@ -60,13 +81,13 @@ func (this *HooksExecutor) detectHooks(baseName string) (hooks []string, err err
 	return hooks, err
 }
 
-func (this *HooksExecutor) executeHooks(baseName string) error {
+func (this *HooksExecutor) executeHooks(baseName string, extraVariables ...string) error {
 	hooks, err := this.detectHooks(baseName)
 	if err != nil {
 		return err
 	}
 	for _, hook := range hooks {
-		if err := this.executeHook(hook); err != nil {
+		if err := this.executeHook(hook, extraVariables...); err != nil {
 			return err
 		}
 	}
@@ -74,41 +95,47 @@ func (this *HooksExecutor) executeHooks(baseName string) error {
 }
 
 func (this *HooksExecutor) onStartup() error {
-	return nil
+	return this.executeHooks(onStartup)
 }
 
 func (this *HooksExecutor) onValidated() error {
-	return nil
+	return this.executeHooks(onValidated)
 }
 
 func (this *HooksExecutor) onAboutToRowCopy() error {
-	return nil
+	return this.executeHooks(onAboutToRowCopy)
 }
 
 func (this *HooksExecutor) onRowCopyComplete() error {
-	return nil
+	return this.executeHooks(onRowCopyComplete)
 }
 
 func (this *HooksExecutor) onBeginPostponed() error {
-	return nil
+	return this.executeHooks(onBeginPostponed)
 }
 
 func (this *HooksExecutor) onAboutToCutOver() error {
-	return nil
+	return this.executeHooks(onAboutToCutOver)
 }
 
 func (this *HooksExecutor) onInteractiveCommand(command string) error {
-	return nil
+	v := fmt.Sprintf("GH_OST_COMMAND='%s'", command)
+	return this.executeHooks(onInteractiveCommand, v)
 }
 
 func (this *HooksExecutor) onSuccess() error {
-	return nil
+	return this.executeHooks(onSuccess)
 }
 
 func (this *HooksExecutor) onFailure() error {
-	return nil
+	return this.executeHooks(onFailure)
 }
 
 func (this *HooksExecutor) onStatus(statusMessage string) error {
-	return nil
+	v := fmt.Sprintf("GH_OST_STATUS='%s'", statusMessage)
+	return this.executeHooks(onStatus, v)
+}
+
+func (this *HooksExecutor) onStopReplication() error {
+	return this.executeHooks(onStopReplication)
 }

go/logic/migrator.go

@@ -58,7 +58,6 @@ type Migrator struct {
 	server           *Server
 	hooksExecutor    *HooksExecutor
 	migrationContext *base.MigrationContext
-	hostname         string
 
 	tablesInPlace              chan bool
 	rowCopyComplete            chan bool
@@ -375,7 +374,7 @@ func (this *Migrator) validateStatement() (err error) {
 func (this *Migrator) Migrate() (err error) {
 	log.Infof("Migrating %s.%s", sql.EscapeName(this.migrationContext.DatabaseName), sql.EscapeName(this.migrationContext.OriginalTableName))
 	this.migrationContext.StartTime = time.Now()
-	if this.hostname, err = os.Hostname(); err != nil {
+	if this.migrationContext.Hostname, err = os.Hostname(); err != nil {
 		return err
 	}
 
@@ -473,6 +472,12 @@ func (this *Migrator) Migrate() (err error) {
 	return nil
 }
 
+// ExecOnFailureHook executes the onFailure hook, and this method is provided as the only external
+// hook access point
+func (this *Migrator) ExecOnFailureHook() (err error) {
+	return this.hooksExecutor.onFailure()
+}
+
 // cutOver performs the final step of migration, based on migration
 // type (on replica? bumpy? safe?)
 func (this *Migrator) cutOver() (err error) {
@@ -516,6 +521,7 @@ func (this *Migrator) cutOver() (err error) {
 		// and swap the tables.
 		// The difference is that we will later swap the tables back.
 		log.Debugf("testing on replica. Stopping replication IO thread")
+		this.hooksExecutor.onStopReplication()
 		if err := this.retryOperation(this.applier.StopReplication); err != nil {
 			return err
 		}
@@ -909,7 +915,7 @@ func (this *Migrator) printMigrationStatusHint(writers ...io.Writer) {
 	fmt.Fprintln(w, fmt.Sprintf("# Migrating %+v; inspecting %+v; executing on %+v",
 		*this.applier.connectionConfig.ImpliedKey,
 		*this.inspector.connectionConfig.ImpliedKey,
-		this.hostname,
+		this.migrationContext.Hostname,
 	))
 	fmt.Fprintln(w, fmt.Sprintf("# Migration started at %+v",
 		this.migrationContext.StartTime.Format(time.RubyDate),