truss

truss /trŭs/

n. A rigid framework, as of wooden beams or metal bars, designed to support a structure, such as a roof.

v. to support, strengthen, or stiffen by or as if by a truss.

Truss is a simple golang mysql schema management library that provides the following features:

• truss.Connect returns a *sql.DB for a production use.
• truss.Migrate schema management via migration queries (roll forward only).
• truss.ConnectForTesting returns testing *sql.DB for a temp database with the current schema.
• truss.TestSchema provides a snapshot of the current schema for explicit tracking of changes and to quickly view the current state.

TL;DR

Common usage is to use truss in your db package:

Define a simple slice of migration queries in db/migrations.go.

package db

// migrations is an append-only list of all migrations over time.
var migrations = []string{`

CREATE TABLE users (
  id BIGINT NOT NULL AUTO_INCREMENT,
  name VARCHAR(255) NOT NULL,
  type INT NOT NULL,

  PRIMARY KEY (id),
  INDEX by_name (name)
);`, `

ALTEST TABLE users ADD COLUMN surname VARCHAR(255) AFTER name;
`,
}

Ensure the latest schema is applied on startup and in tests in db/db.go.

// Connect returns a database connection and ensures latest migrations are applied
func Connect(uri string) (*sql.DB, error) {
	dbc, err := truss.Connect(uri)
	if err != nil {
		return nil, err
	}

	err = truss.Migrate(context.Background(), dbc, migrations)
	if err != nil {
		return nil, err
	}

	return dbc, nil
}

// ConnectForTesting returns a database connection for a temp database with latest schema. 
func ConnectForTesting(t *testing.T) *sql.DB {
	return truss.ConnectForTesting(t, migrations...)
}

Maintain an explicit snapshot of the latest schema in migrations_test.go.

package db

var update = flag.Bool("update", false, "update schema file")

//go:generate go test -update -run=TestSchema

func TestSchema(t *testing.T) {
	truss.TestSchema(t, "schema.sql", *update, migrations...)
}

Which will generate the following db/schema.sql file that is checked into the git.

-- Schema generated by truss. DO NOT EDIT.

CREATE TABLE `users` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `surname` varchar(255),
  `type` int(11) NOT NULL,
  `created_at` datetime(3) NOT NULL,
  PRIMARY KEY (`id`),
  KEY `by_name` (`name`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4

CREATE TABLE `migrations` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `query_hash` char(64) NOT NULL,
  `schema_hash` char(64) NOT NULL,
  `created_at` datetime(3) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4