Merge pull request #905 from github/azure-support

Support Azure Database for MySQL (merge PR)

Author: timvaillancourt

README.md

@@ -65,6 +65,7 @@ Also see:
 - [the fine print](doc/the-fine-print.md)
 - [Community questions](https://github.com/github/gh-ost/issues?q=label%3Aquestion)
 - [Using `gh-ost` on AWS RDS](doc/rds.md)
+- [Using `gh-ost` on Azure Database for MySQL](doc/azure.md)
 
 ## What's in a name?
 

doc/azure.md

@@ -0,0 +1,26 @@
+`gh-ost` has been updated to work with Azure Database for MySQL however due to GitHub does not use it, this documentation is community driven so if you find a bug please [open an issue][new_issue]!
+
+# Azure Database for MySQL
+
+## Limitations
+
+- `gh-ost` runs should be setup use [`--assume-rbr`][assume_rbr_docs] and use `binlog_row_image=FULL`.
+- Azure Database for MySQL does not use same user name suffix for master and replica, so master host, user and password need to be pointed out. 
+
+## Step
+1. Change the replica server's `binlog_row_image` from `MINIMAL` to `FULL`. See [guide](https://docs.microsoft.com/en-us/azure/mysql/howto-server-parameters) on Azure document.
+2. Use your `gh-ost` always with additional 5 parameter
+```{bash}
+gh-ost \
+--azure \
+--assume-master-host=master-server-dns-name \
+--master-user="master-user-name" \
+--master-password="master-password" \
+--assume-rbr \
+[-- other paramters you need]
+```
+
+
+[new_issue]: https://github.com/github/gh-ost/issues/new
+[assume_rbr_docs]: https://github.com/github/gh-ost/blob/master/doc/command-line-flags.md#assume-rbr
+[migrate_test_on_replica_docs]: https://github.com/github/gh-ost/blob/master/doc/cheatsheet.md#c-migratetest-on-replica

doc/command-line-flags.md

@@ -6,6 +6,10 @@ A more in-depth discussion of various `gh-ost` command line flags: implementatio
 
 Add this flag when executing on Aliyun RDS.
 
+###  azure
+
+Add this flag when executing on Azure Database for MySQL.
+
 ### allow-master-master
 
 See [`--assume-master-host`](#assume-master-host).

doc/requirements-and-limitations.md

@@ -41,6 +41,7 @@ The `SUPER` privilege is required for `STOP SLAVE`, `START SLAVE` operations. Th
 - Amazon RDS works, but has its own [limitations](rds.md).
 - Google Cloud SQL works, `--gcp` flag required.
 - Aliyun RDS works, `--aliyun-rds` flag required.
+- Azure Database for MySQL works, `--azure` flag required, and have detailed document about it. (azure.md)
 
 - Multisource is not supported when migrating via replica. It _should_ work (but never tested) when connecting directly to master (`--allow-on-master`)
 

go/base/context.go

@@ -97,6 +97,7 @@ type MigrationContext struct {
 	DiscardForeignKeys       bool
 	AliyunRDS                bool
 	GoogleCloudPlatform      bool
+	AzureMySQL               bool
 
 	config            ContextConfig
 	configMutex       *sync.Mutex

go/base/utils.go

@@ -75,7 +75,8 @@ func ValidateConnection(db *gosql.DB, connectionConfig *mysql.ConnectionConfig,
 	}
 	// AliyunRDS set users port to "NULL", replace it by gh-ost param
 	// GCP set users port to "NULL", replace it by gh-ost param
-	if migrationContext.AliyunRDS || migrationContext.GoogleCloudPlatform {
+	// Azure MySQL set users port to a different value by design, replace it by gh-ost para
+	if migrationContext.AliyunRDS || migrationContext.GoogleCloudPlatform || migrationContext.AzureMySQL {
 		port = connectionConfig.Key.Port
 	} else {
 		portQuery := `select @@global.port`

go/cmd/gh-ost/main.go

@@ -79,6 +79,7 @@ func main() {
 	flag.BoolVar(&migrationContext.SkipStrictMode, "skip-strict-mode", false, "explicitly tell gh-ost binlog applier not to enforce strict sql mode")
 	flag.BoolVar(&migrationContext.AliyunRDS, "aliyun-rds", false, "set to 'true' when you execute on Aliyun RDS.")
 	flag.BoolVar(&migrationContext.GoogleCloudPlatform, "gcp", false, "set to 'true' when you execute on a 1st generation Google Cloud Platform (GCP).")
+	flag.BoolVar(&migrationContext.AzureMySQL, "azure", false, "set to 'true' when you execute on Azure Database on MySQL.")
 
 	executeFlag := flag.Bool("execute", false, "actually execute the alter & migrate the table. Default is noop: do some tests and exit")
 	flag.BoolVar(&migrationContext.TestOnReplica, "test-on-replica", false, "Have the migration run on a replica, not on the master. At the end of migration replication is stopped, and tables are swapped and immediately swap-revert. Replication remains stopped and you can compare the two tables for building trust")

go/logic/applier.go

@@ -89,7 +89,7 @@ func (this *Applier) InitDBConnections() (err error) {
 	if err := this.validateAndReadTimeZone(); err != nil {
 		return err
 	}
-	if !this.migrationContext.AliyunRDS && !this.migrationContext.GoogleCloudPlatform {
+	if !this.migrationContext.AliyunRDS && !this.migrationContext.GoogleCloudPlatform && !this.migrationContext.AzureMySQL {
 		if impliedKey, err := mysql.GetInstanceKey(this.db); err != nil {
 			return err
 		} else {

go/logic/inspect.go

@@ -52,7 +52,7 @@ func (this *Inspector) InitDBConnections() (err error) {
 	if err := this.validateConnection(); err != nil {
 		return err
 	}
-	if !this.migrationContext.AliyunRDS && !this.migrationContext.GoogleCloudPlatform {
+	if !this.migrationContext.AliyunRDS && !this.migrationContext.GoogleCloudPlatform && !this.migrationContext.AzureMySQL {
 		if impliedKey, err := mysql.GetInstanceKey(this.db); err != nil {
 			return err
 		} else {