@twindyorg/knex-migrator

knex-migrator

Database migration tool for knex.

Supported Databases

MySQL, Sqlite3

Note: Replicas are unsupported, because knex doesn't support them.

Features

• Locks for concurrency
• Full rollback to latest version
• Full CLI and JS API
• Hooks
• Differentiation between database initialisation and migration
  • Support for a database schema, like we use in Ghost
• Support for database creation

Other migration tools

Knex Migrations

Read here what the major downsides of knex migrations are.

DB-Migrate

Latest version uses autocommit to handle database migrations, which does not solve the problem of DDL/DML statements in MySQL. If you are interested in why, continue reading here.

Furthermore they don't support a full set of features e.g. full atomic rollbacks.

Installation

npm install -g knex-migrator
npm install knex-migrator --save
yarn add knex-migrator

MigratorConfig

knex-migrator requires a config file. Please provide a file named MigratorConfig.js in your project root.

module.exports = {
    database: {
        client: 'mysql',
        connection: {
            host: '127.0.0.1',
            user: 'user',
            password: 'password',
            charset: 'utf8',
            database: 'ghost'
        }
    },
    migrationPath: process.cwd() + '/core/server/data/migrations',
    currentVersion: 'your-current-database/project-version',
    subfolder: 'upgrades'  [default: versions]
}

module.exports = {
    database: {
        client: 'sqlite3',
        connection: {
            filename: 'path/to/your.db'
        }
    },
    migrationPath: process.cwd() + '/core/server/data/migrations',
    currentVersion: 'your-current-database-version'
}

Note that if you are using the Ghost-CLI the migrationPath parameter should point to the current directory:

migrationPath: process.cwd() + '/current/core/server/data/migrations'

API

CLI

knex-migrator help
knex-migrator health [shows the database health]

knex-migrator init [initialises your database based on your init scripts]
knex-migrator init --skip 1
knex-migrator init --only 1
knex-migrator init --mgpath <path-to-MigratorConfig.js>

knex-migrator migrate [migrates your database to latest state, rolls back if an error happens]
knex-migrator migrate --v 1.2
knex-migrator migrate --v 1.2 --force [doesn't matter which current version you are on, we force executing the version]
knex-migrator migrate --init [avoids running `init`, a combined command]
knex-migrator migrate --init --mgpath <path-to-MigratorConfig.js>

knex-migrator reset [resets your database]
knex-migrator reset --force [resets your database and ignores the migration lock]

knex-migrator rollback
knex-migrator rollback --force
knex-migrator rollback --force --v 1.20.0

JS

var KnexMigrator = require('knex-migrator');
var knexMigrator = new KnexMigrator({
    knexMigratorFilePath: 'path-to-migrator-config-file' [optional]
    // or
    knexMigratorConfig: { ... } [optional]
});

// check your database health
knexMigrator.isDatabaseOK()
  .then(function() {
     // database is OK
  })
  .catch(function(err) {
     // err contains a specific code, based on that code you decide (err.code)

     // database is not initialised?
     knexMigrator.init();

     // database is not migrated?
     knexMigrator.migrate();
  });

Hooks

Knex-migrator offers you to hook into the process of executing scripts. The hooks won't work for initialisation right now. All hooks are optional. Hooks need to live in the migrationPath you have offered.

You can disable the hooks passing:

knexMigrator.init({
  disableHooks: true,           [optional]
  noScripts: true | false       [optional]
});

The folder name must be hooks - this is not configureable right now. Please create an index.js file to export your functions.

hook	description
before	is called before anything happens
beforeEach	is called before each migration script
after	is called after everything happened
afterEach	is called after each migration script
shutdown	is called before the migrator shuts down [no database access]

index.js

exports.before = require('./before');
exports.beforeEach = = require('./before');

Migration Folder Example

• hooks
  • migrate
    • before.js
    • index.js
  • init
    • after.js
    • index.js
• init
  • 1-create-tables.js
  • 2-seed.js
• versions
  • 1.0
    • 1-update-user.js
    • 2-change-permissions.js

Migration Files

Transactions

You can enable transactions per migration script.

module.exports.config = {
  transaction: true
}

Example

var Promise = require('bluebird');
module.exports.up = function(options) {
  var connection = options.connection;

  ...

  return Promise.resolve();
};

module.exports.down = function(options) {
  var connection = options.connection;

  ...

  return Promise.resolve();
}

Important

Don't mix DDL/DML statements in a migration script. In MySQL DDL statements use implicit commits. Furthermore it's highly recommended to write both the up and the down function to ensure a full rollback.

Knowledge Base

Shutdown during migrations

If your process dies while migrations are running, knex-migrator won't be able to release the migration lock. To release to lock you can run knex-migrator rollback. But it's recommended to check your database first to see in which state it is. You can check the tables migrations and migrations_lock. The rollback will rollback any migrations which were executed on your current project version.

Sqlite and Locks

Sqlite does not support read locks by default. That's why locks/concurrency is not supported atm.

Debug

DEBUG=knex-migrator:* knex-migrator health

Test

• yarn lint run just eslint
• yarn test run lint && tests
• NODE_ENV=testing-mysql yarn test to test with MySQL

Publish

• yarn ship

Copyright & License

Copyright (c) 2017-2018 Ghost Foundation - Released under the MIT license.