codemao-migrate-mongo

migrate-mongo

A database migration tool for MongoDB in Node.

Installation

$ npm install -g migrate-mongo

Usage

$ migrate-mongo
Usage: migrate-mongo [options] [command]


  Commands:

    init                  initialize a new migration project
    create [description]  create a new database migration with the provided description
    up [options]          run all unapplied database migrations
    down [options]        undo the last applied database migration
    status [options]      print the changelog of the database

  Options:

    -h, --help     output usage information
    -V, --version  output the version number

Quickstart

Initialize a new project

Create a directory where you want to store your migrations for your mongo database (eg. 'albums' here) and cd into it

$ mkdir albums-migrations
$ cd albums-migrations

Initialize a new migrate-mongo project

$ migrate-mongo init
Initialization successful. Please edit the generated config.js file

The above command did two things:

1. create a sample 'config.js' file and
2. create a 'migrations' directory

Edit the config.js file. Make sure you change the mongodb url:

'use strict';
 
// In this file you can configure migrate-mongo
 
module.exports = {
 
  mongodb: {
    // TODO You MUST edit this connection url to your MongoDB database:
    url: 'mongodb://localhost:27017/YOURDATABASENAME',
 
    // uncomment and edit to specify Mongo client connect options (eg. increase the timeouts)
    // see https://mongodb.github.io/node-mongodb-native/2.2/api/MongoClient.html
    //
    // options: {
    //   connectTimeoutMS: 3600000, // 1 hour
    //   socketTimeoutMS: 3600000, // 1 hour
    // }
  },
 
  // The migrations dir, can be an relative or absolute path. Only edit this when really necessary.
  migrationsDir: 'migrations',
 
  // The mongodb collection where the applied changes are stored. Only edit this when really necessary.
  changelogCollectionName: 'changelog',
 
};

Creating a new migration script

To create a new database migration script, just run the migrate-mongo create [description] command.

For example:

$ migrate-mongo create blacklist_the_beatles
Created: migrations/20160608155948-blacklist_the_beatles.js

A new migration file is created in the 'migrations' directory:

'use strict';
 
module.exports = {
 
  up(db, next) {
    // TODO write your migration here
    next();
  },
 
  down(db, next) {
    // TODO write the statements to rollback your migration (if possible)
    next();
  }
 
};

Edit this content so it actually performs changes to your database. Don't forget to write the down part as well. The db object contains the official MongoDB db object

An example:

'use strict';
 
module.exports = {
 
  up(db, next) {
    db.collection('albums').update({artist: 'The Beatles'}, {$set: {blacklisted: true}}, next);
  },
 
  down(db, next) {
    db.collection('albums').update({artist: 'The Beatles'}, {$set: {blacklisted: false}}, next);
  }
};

The up/down implementation can use either callback-style or return a Promise.

'use strict';
 
module.exports = {
 
  up(db) {
    return db.collection('albums').update({artist: 'The Beatles'}, {$set: {blacklisted: true}});
  },
 
  down(db) {
    return db.collection('albums').update({artist: 'The Beatles'}, {$set: {blacklisted: false}});
  }
};

Make sure the implementation matches the function signature.

• function up(db) { /* */ } should return Promise
• function up(db, next) { /* */ } should callback next

Checking the status of the migrations

At any time, you can check which migrations are applied (or not)

$ migrate-mongo status
┌─────────────────────────────────────────┬────────────┐
│ Filename                                │ Applied At │
├─────────────────────────────────────────┼────────────┤
│ 20160608155948-blacklist_the_beatles.js │ PENDING    │
└─────────────────────────────────────────┴────────────┘
 

Migrate up

This command will apply all pending migrations

$ migrate-mongo up
MIGRATED UP: 20160608155948-blacklist_the_beatles.js

If an an error occurred, it will stop and won't continue with the rest of the pending migrations

If we check the status again, we can see the last migration was successfully applied:

$ migrate-mongo status
┌─────────────────────────────────────────┬──────────────────────────┐
│ Filename                                │ Applied At               │
├─────────────────────────────────────────┼──────────────────────────┤
│ 20160608155948-blacklist_the_beatles.js │ 2016-06-08T20:13:30.415Z │
└─────────────────────────────────────────┴──────────────────────────┘

Migrate down

With this command, migrate-mongo will revert (only) the last applied migration

$ migrate-mongo down
MIGRATED DOWN: 20160608155948-blacklist_the_beatles.js

If we check the status again, we see that the reverted migration is pending again:

$ migrate-mongo status
┌─────────────────────────────────────────┬────────────┐
│ Filename                                │ Applied At │
├─────────────────────────────────────────┼────────────┤
│ 20160608155948-blacklist_the_beatles.js │ PENDING    │
└─────────────────────────────────────────┴────────────┘

Using a custom config file

All actions (except init) accept an optional -f or --file option to specify a path to a custom config file. By default, migrate-mongo will look for a config.js config file in of the current directory.

Example:

$ migrate-mongo status -f '~/configs/albums-migrations.js'
┌─────────────────────────────────────────┬────────────┐
│ Filename                                │ Applied At │
├─────────────────────────────────────────┼────────────┤
│ 20160608155948-blacklist_the_beatles.js │ PENDING    │
└─────────────────────────────────────────┴────────────┘