Gormigrate

Gormigrate is a migration helper for Gorm. Gorm already have useful migrate functions, just misses proper schema versioning and rollback cababilities.

Supported databases

It supports the databases Gorm supports:

• PostgreSQL
• MySQL
• SQLite
• Microsoft SQL Server

Installing

go get -u gopkg.in/gormigrate.v1

Usage

package main

import (
	"log"

	"gopkg.in/gormigrate.v1"
	"github.com/jinzhu/gorm"
	_ "github.com/jinzhu/gorm/dialects/sqlite"
)

type Person struct {
	gorm.Model
	Name string
}

type Pet struct {
	gorm.Model
	Name     string
	PersonID int
}

func main() {
	db, err := gorm.Open("sqlite3", "mydb.sqlite3")
	if err != nil {
		log.Fatal(err)
	}
	if err = db.DB().Ping(); err != nil {
		log.Fatal(err)
	}

	db.LogMode(true)

	m := gormigrate.New(db, gormigrate.DefaultOptions, []*gormigrate.Migration{
		{
			ID: "201608301400",
			Migrate: func(tx *gorm.DB) error {
				return tx.AutoMigrate(&Person{}).Error
			},
			Rollback: func(tx *gorm.DB) error {
				return tx.DropTable("people").Error
			},
		},
		{
			ID: "201608301430",
			Migrate: func(tx *gorm.DB) error {
				return tx.AutoMigrate(&Pet{}).Error
			},
			Rollback: func(tx *gorm.DB) error {
				return tx.DropTable("pets").Error
			},
		},
	})

    err = m.Migrate()
    if err == nil {
		log.Printf("Migration did run successfully")
    } else {
		log.Printf("Could not migrate: %v", err)
    }
}

Having a separated function for initializing the schema

If you have a lot of migrations, it can be a pain to run all them, as example, when you are deploying a new instance of the app, in a clean database. To prevent this, you can set a function that will run if no migration was run before (in a new clean database). Remember to create everything here, all tables, foreign keys and what more you need in your app.

m := gormigrate.New(db, gormigrate.DefaultOptions, []*gormigrate.Migration{
    // you migrations here
})

m.InitSchema(func(tx *gorm.DB) error {
	err := tx.AutoMigrate(
		&Person{},
		&Pet{},
		// all other tables of you app
	)
	if err != nil {
		return err
	}

	if err := tx.Model(Pet{}).AddForeignKey("person_id", "people (id)", "RESTRICT", "RESTRICT").Error; err != nil {
		return err
	}
	// all other foreign keys...
	return nil
})

Options

This is the options struct, in case you don't want the defaults:

type Options struct {
	// Migrations table name. Default to "migrations".
	TableName string
	// The of the column that stores the id of migrations. Defaults to "id".
	IDColumnName string
	// UseTransaction makes Gormigrate execute migrations inside a single transaction.
	// Keep in mind that not all databases support DDL commands inside transactions.
	// Defaults to false.
	UseTransaction bool
}