east

east

east - node.js database migration tool for different databases (extensible via adapters) with transpiled languages support (e.g. TypeScript).

east connects to the db using particular adapter (mongodb, sqlite, postgres, mysql, couchbase, couchdb), keeps track of executed migrations by storing their names inside db and makes connect to the db available inside migrate and rollback functions. east encourages you to use for migrations driver/syntax with which you are already familiar with (apparently you use it for work with db at your application) and doesn't provide universal api for working with any kind of database.

Following subjects described below:

• Node.js compatibility
• Installation
• Changelog
• Cli usage
• Library usage
• Adapters
• Plugins
• Creating own adapter
• TypeScript and other transpiled languages support
• ECMAScript Modules support
• License

Node.js compatibility

east itself requires node.js >= 10.17.0 to work.

Please note that particular adapter may have other requirements (see documentation for specific adapter).

Installation

npm install east -g

alternatively you could install it locally

Changelog

All notable changes to this project documented in CHANGELOG.md.

Cli usage

At your project dir run

east init

after that you can create, migrate, rollback your migrations.

Run east -h to see all commands:

Usage: east [options] [command]

Options:
  -V, --version                       output the version number
  --adapter <name>                    which db adapter to use
  --config <path>                     config file to use
  --timeout <timeout>                 timeout for migrate/rollback
  --template <path>                   path to template for new migrations
  --dir <dir>                         dir where migration executable files are stored (default: "./migrations")
  --source-dir <dir>                  dir where migration source files are stored, equal to --dir by default
  --migration-extension <ext>         migration executable files extension name (default: "js")
  --source-migration-extension <ext>  migration source files extension name, equal to --migration-extension by default
  --url <url>                         db connect url
  --trace                             verbose mode (includes error stack trace)
  --silent                            prevent output of detailed log
  --es-modules                        config, migrations, adapter and plugins could be provided as ES Modules with this flag
  --no-exit                           require a clean shutdown of the event loop: process.exit will not be called at the end
  -h, --help                          display help for command

Commands:
  init                                initialize migration system
  create <basename>                   create new migration based on template
  migrate [options] [migrations...]   run all or selected migrations
  rollback [options] [migrations...]  rollback all or selected migrations
  list [options] [status]             list migration with selected status ("new", "executed" or "all"), "new" by default
  *
  help [command]                      display help for command

run east <command> -h to see detailed command help.

All options described above can be set via command line or at .eastrc file located at current directory, e.g.:

{
	"dir": "./dbmigration",
	"template": "./lib/node/utils/customMigrationTemplate.js"
}

.eastrc also can be a regular commonjs module (instead of json file):

var path = require('path');

module.exports = {
    dir: path.join(__dirname, 'dbmigration'),
    template: './lib/node/utils/customMigrationTemplate.js'
};

east also supports config as ECMAScript module, config could be:

import path from 'path';

export const dir = path.resolve('dbmigration');
export const template = path.resolve('./lib/node/utils/customMigrationTemplate.js');

See ECMAScript Modules support for details.

create

east create doSomething

produces something like this

New migration "1_doSomething" created at "migrations/1_doSomething.js"

the created file will contain

exports.tags = [];

exports.migrate = async (client) => {

};

exports.rollback = async (client) => {

};

• client represents a connection to the current db and it's determined by the adapter (see adapters section)
• done callback may be defined as second argument - should be called at the end of the migration (if any error occures you can pass it as the first argument)
• rollback function is optional and may be omitted

Migration file is a regular node.js module and allows migrating any database e.g.

// include your database wrapper which you already use in app
const db = require('./db');

exports.migrate = async (client) => {
    await db.connect();
    await db.things.insert({_id: 1, name: 'apple', color: 'red'});
};

exports.rollback = async (client) => {
    await db.connect();
    await db.things.remove({_id: 1});
};

or you can use a special adapter for database (see adapters section).

Migration file number format

The default format for migration file names is to prepend a number to the filename which is incremented with every new file. This creates migration files such as "migrations/1_doSomething.js", "migrations/2_doSomethingElse.js".

If you prefer your files to be created with a date-time instead of sequential numbers, you can set the migrationNumberFormat configuration parameter in your .eastrc to "dateTime":

{
    "migrationNumberFormat": "dateTime"
}

This will create migration files with date-time prefix in YYYYMMDDhhmmss format (e.g. "migrations/20190720172730_doSomething.js").

For the default behavior, you can omit the migrationNumberFormat configuration option or set it to:

{
    "migrationNumberFormat": "sequentialNumber"
}

migrate

let's create one more migration

east create doSomethingElse

then executes both of them

east migrate

it sequentially executes all new migrations and produces

target migrations:
    1_doSomething
    2_doSomethingElse
migrate "1_doSomething"
migration done
migrate "2_doSomethingElse"
migration done

selected migrations can be executed by passing their names (or numbers or basenames or paths) as an argument

east migrate 1_doSomething 2

in our case this command will skip all of them

skip "1_doSomething" because it's already executed
skip "2_doSomethingElse" because it's already executed
nothing to migrate

you can pass --force option to execute already executed migrations. This is useful while you develop and test your migration.

You also can export tags array from migration and then run only migrations that satisfy the expression specified by --tag option. The expression consists of tag names and boolean operators &, | and !. For example, the following command will run all migrations that have "tag1" tag and do not have "tag2" tag:

east migrate --tag 'tag1 & !tag2'

rollback

rollback has similar to migrate command syntax but executes rollback function from the migration file

east rollback

will produce

target migrations:
    2_doSomethingElse
    1_doSomething
rollback "2_doSomethingElse"
migration successfully rolled back
rollback "1_doSomething"
migration successfully rolled back

list

east list

shows new migrations e.g.

new migrations:
     1_doSomething
     2_doSomethingElse

target status could be specified as an argument e.g.

east list executed

Library usage

east exposes MigrationManager class (descendant of EventEmitter) which for example can be used to migrate your database from node.js app without using east cli:

const {MigrationManager} = require('east');

const main = async () => {
    const migrationManager = new MigrationManager();

    // log target migrations before execution
    migrationManager.once('beforeMigrateMany', (migrationNames) => {
        console.log('Target migrations: ', migrationNames);
    });

    await migrationManager.configure();

    try {
        await migrationManager.connect();
        // select for migration all not executed migrations
        await migrationManager.migrate({status: 'new'});
    }
    finally {
        await migrationManager.disconnect();
    }
}

main().catch((err) => {
    console.error('Some error occurred: ', err.stack || err);
});

MigrationManager methods:

• configure(params) - configures migration process, accepts object with parameters (dir, adapter, etc) and merges it with loaded config (when loadConfig param is truthy - true by default). Returns Promise. This method should be called before any other methods.

• getParams() - returns Promise with parameters used by migration process after configuration(configure method).

• init() - initiates migration process for a project. Should be called once per project. Returns Promise.

• isInitialized() - checks whether init was made or not. Returns Promise.

• create(basename) - creates migration, returns Promise with migration object.

• getMigrationPath(name, migrationFileType) - returns an absolute path of the migration file on disk by the name of the migration, migrationFileType can be one of "executable" or "source" ("executable" by default). Returns Promise.

• connect() - connects to database management system (if supposed by adapter). Returns Promise.

• getMigrationNames({migrations, status, tag, reverseOrderResult}) - returns migrations names, following options are provided:

  • migrations - array of target migrations, each migration could be defined by basename, full name, path or number.
  • status - status to filter migrations, supported statuses are: "new", "executed" and "all".
  • tag - tag expression to filter migrations e.g. "tag1 & !tag2"
  • reverseOrderResult - if true then result array will be reversed.

migrations and status are mutually exclusive. If migrations, status not provided then all migrations will be processed (e.g. filtered by tag and returned).

• migrate({migrations, status, tag, force}) - executes target migrations. Target migration could be defined by migrations, status, tag options (see it's description at getMigrationNames method). By default migrations with status "new" are chosen. Returns Promise. force flag allows to execute already executed migrations.

• rollback({migrations, status, tag, force}) - rollbacks target migrations. Target migration could be defined by migrations, status, tag options (see it's description at getMigrationNames method). By default migrations with status "executed" are chosen. Returns Promise. force flag allows to rollback not executed migrations.

• disconnect() - disconnects from database management system (if supposed by adapter). Returns Promise.

MigrationManager events:

• beforeMigrateOne({migration})
• afterMigrateOne({migration})
• beforeMigrateMany({migrationNames})
• afterMigrateMany({migrationNames})
• beforeRollbackOne({migration})
• afterRollbackOne({migration})
• beforeRollbackMany({migrationNames})
• afterRollbackMany({migrationNames})
• onSkipMigration({migration, reason})

Adapters

adapter determines where executed migration names will be stored and what will be passed to migrate and rollback function as client. Default adapter stores executed migration names at file .migrations which is located at migrations executables directory and passes null as client.

Other adapters:

• mongodb
• sqlite
• postgres
• mysql
• couchbase
• couchdb
• dynamodb

Plugins

East functionality could be extended by using plugins, for usage instructions see plugin page:

• migration duration logger
• migration progress indicator helper

Creating own adapter

For writing your own adapter you should implement methods for connection, mark transaction as executed, etc see details inside built-in adapter and other adapters. See TypeScript support for the details on the required adapter interface.

You also can run migrator tests from current repository against your adapter:

• Clone current repository
• Change current directory to it
• Create file .eastrc with path and parameters for your adapter e.g.

{
    "adapter": "../../east-mysql/lib/adapter",
    "url": "mysql://user:password@localhost/east_test_db",
    "createDbOnConnect": true
}

• Run NODE_EAST_TEST_LOAD_CONFIG=1 npm run testSpecified test/01-migrator -- --jobs=1 at root of the cloned repository.

TypeScript and other transpiled languages support

east allows you to opt-in writing and executing your migrations with any transpiled languages, while by default it uses a single dir called "migrations" and looks for ".js" files in it.

You can configure separate executable and source files directories as well as separate executable and source files extensions with --dir, --source-dir, --migration-extension, --source-migration-extension respectively.

By default if you specify only --dir and/or --migration-extension, then --source-dir and/or --source-migration-extension will be equal to it, however it doesn't work on the other way around, e.g. if you specify

--source-dir mySourceDir --source-migration-extension ts

then --dir and --migration-extension will have migrations and js values by default, so it is recommended to specify at least --dir, --source-dir and --source-migration-extension when you are building a transpiled language.

If you use TypeScript you can run east with ts-node if you don't want to transpile you migration scripts before running them:

ts-node $(which east) migrate

Just be sure to specify --migration-extension ts so that east does look for TypeScript files when require()-ing the migration scripts.

TypeScript typings

east exposes TypeScript declarations of the Adapter, MigrationManager and other related interfaces.

You can access it by importing the interfaces from east module itself:

import { DbClient } from 'some-mainstream-db';
import type { Adapter, AdapterConstructor } from 'east';

class MyAdapter implements Adapter<DbClient> {
	// go to definition of Adapter interface for documentation on required methods
	// you can also leverage your ide features to generate
	// stub method impementations here
}

// type-check the class static type (i.e. its constructor)
const _: AdpaterConstructor<DbClient> = MyAdapter;

export = MyAdapter;

ECMAScript Modules support

east provides support for es modules by --es-modules cli flag. With this flag config, migrations, adapter and plugins will be loaded using import expression. It allows to provide those entities like commonjs or es modules, e.g. .eastrc.mjs:

import path from 'path';
export const dir = path.resolve('dbmigration');
export const template = path.resolve('./lib/node/utils/customMigrationTemplate.js');

Please note, that you need to enable nodejs es modules support (use mjs extension for module or package.json with type "module", etc - see nodejs esm docs for details).

Config presented above could be used like this:

east --config .eastrc.mjs --es-modules list

When migration files as es module are desired --migration-extension and --source-migration-extension set to "mjs" could be used.

License

MIT