added on-resurrecting hook

doc/hooks.md

@@ -38,6 +38,7 @@ The full list of supported hooks is best found in code: [hooks.go](https://githu
 
 - `gh-ost-on-startup`
 - `gh-ost-on-validated`
+- `gh-ost-on-resurrecting`
 - `gh-ost-on-rowcount-complete`
 - `gh-ost-on-before-row-copy`
 - `gh-ost-on-status`

go/logic/hooks.go

@@ -20,6 +20,7 @@ import (
 const (
 	onStartup            = "gh-ost-on-startup"
 	onValidated          = "gh-ost-on-validated"
+	onResurrecting       = "gh-ost-on-resurrecting"
 	onRowCountComplete   = "gh-ost-on-rowcount-complete"
 	onBeforeRowCopy      = "gh-ost-on-before-row-copy"
 	onRowCopyComplete    = "gh-ost-on-row-copy-complete"
@@ -112,6 +113,10 @@ func (this *HooksExecutor) onValidated() error {
 	return this.executeHooks(onValidated)
 }
 
+func (this *HooksExecutor) onResurrecting() error {
+	return this.executeHooks(onResurrecting)
+}
+
 func (this *HooksExecutor) onRowCountComplete() error {
 	return this.executeHooks(onRowCountComplete)
 }

go/logic/migrator.go

@@ -303,6 +303,10 @@ func (this *Migrator) applyResurrectedContext() error {
 	this.migrationContext.ApplyResurrectedContext(this.resurrectedContext)
 	atomic.StoreInt64(&this.migrationContext.IsResurrected, 1)
 
+	if err := this.hooksExecutor.onResurrecting(); err != nil {
+		return err
+	}
+
 	return nil
 }
 

resources/hooks-sample/gh-ost-on-resurrecting-hook

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# Sample hook file for gh-ost-on-resurrecting
+
+echo "$(date) gh-ost-on-resurrecting: beginning resurrection on $GH_OST_DATABASE_NAME.$GH_OST_TABLE_NAME" >> /tmp/gh-ost.log