1.7 KiB
1.7 KiB
Migrate
Migrate is a Go library for doing migrations. It's stupidly simple and gets out of your way.
Features
- It's only dependency is
database/sql. - It supports any type of migration you want to run (e.g. raw sql, or Go code).
- It doesn't provide a command. It's designed to be embedded in projects and used exclusively as a library.
Usage
migrations := []migrate.Migration{
{
ID: 1,
Up: func(tx *sql.Tx) error {
_, err := tx.Exec("CREATE TABLE people (id int)")
return err
},
Down: func(tx *sql.Tx) error {
_, err := tx.Exec("DROP TABLE people")
return err
},
},
{
ID: 2,
// For simple sql migrations, you can use the migrate.Queries
// helper.
Up: migrate.Queries([]string{
"ALTER TABLE people ADD COLUMN first_name text",
}),
Down: func(tx *sql.Tx) error {
// It's not possible to remove a column with
// sqlite.
_, err := tx.Exec("SELECT 1 FROM people")
return err
},
},
}
db, _ := sql.Open("sqlite3", ":memory:")
_ = migrate.Exec(db, migrate.Up, migrations...)
Locking
All migrations are run in a transaction, but if you attempt to run a single long running migration concurrently, you could run into a deadlock. For Postgres connections, migrate can use pg_advisory_lock to ensure that only 1 migration is run at a time.
To use this, simply instantiate a Migrator instance using migrate.NewPostgresMigrator:
migrator := NewPostgresMigrator(db)
_ = migrator.Exec(migrate.Up, migrations...)