node-mongodb-migrations

Abstract migration framework for node.

Forked from ikatun/node-migrate, in turn forked from tj/node-migrate.

Can store migrations information both in a file or in a mongodb collection (useful for enviroments with multiple instanced servers).

Uses native mongodb promises (in the past it used then-mongo and before that promised-mongo as promised-based mongo libraries).

Installation

$ npm install node-mongodb-migrations

Usage

Usage: migrate [options] [command]

Options:

   -c, --chdir <path>      change the working directory
   --state-file <path>     set path to state file (migrations/.migrate)
   --state-mongo <format>  name of env variable containing the mongo connection string
   --template-file <path>  set path to template file to use for new migrations
   --date-format <format>  set a date format to use for new migration filenames

NOTE: if both --state-mongo and --state-file options are specified while migrations collection is empty, the state file is migrated to the migrations collection before migration is initiated. If migrations collection contains migration state, state-file is ignored.
This behaviour can be used for seamless switching from https://github.com/tj/node-migrate (which at the time of this fork did not support persisting of state file to mongo collection).

Commands:

   down   [name]    migrate down till given migration
   rollback         migrate down the last applied migration
   up     [name]    migrate up till given migration (the default command)
   create [title]   create a new migration file with optional [title]

Programmatic usage

var migrate = require('node-mongodb-migrations');
var set = migrate.load('migration/.migrate', 'migration');
 
set.up(function (err) {
  if (err) throw err;
 
  console.log('Migration completed');
});

Creating Migrations

To create a migration, execute migrate create with an optional title. node-mongodb-migrationse will create a node module within ./migrations/ which contains the following two exports:

exports.up = function(next){
  next();
};
 
exports.down = function(next){
  next();
};

All you have to do is populate these, invoking next() when complete, and you are ready to migrate!

For example:

$ migrate create add-pets
$ migrate create add-owners

The first call creates ./migrations/{timestamp in milliseconds}-add-pets.js, which we can populate:

var db = require('./db');
 
exports.up = function(next){
  db.rpush('pets', 'tobi');
  db.rpush('pets', 'loki');
  db.rpush('pets', 'jane', next);
};
 
exports.down = function(next){
  db.rpop('pets');
  db.rpop('pets');
  db.rpop('pets', next);
};

The second creates ./migrations/{timestamp in milliseconds}-add-owners.js, which we can populate:

var db = require('./db');
 
exports.up = function(next){
  db.rpush('owners', 'taylor');
  db.rpush('owners', 'tj', next);
};
 
exports.down = function(next){
  db.rpop('owners');
  db.rpop('owners', next);
};

Running Migrations

When first running the migrations, all will be executed in sequence.

$ migrate
up : migrations/1316027432511-add-pets.js
up : migrations/1316027432512-add-jane.js
up : migrations/1316027432575-add-owners.js
up : migrations/1316027433425-coolest-pet.js
migration : complete

Subsequent attempts will simply output "complete", as they have already been executed in this machine. node-mongodb-migrations knows this because it stores the current state in ./migrations/.migrate which is typically a file that SCMs like GIT should ignore.

$ migrate
migration : complete

If we were to create another migration using migrate create, and then execute migrations again, we would execute only those not previously executed:

$ migrate
up : migrates/1316027433455-coolest-owner.js

You can also run migrations incrementally by specifying a migration.

$ migrate up 1316027433425-coolest-pet.js
up : migrations/1316027432511-add-pets.js
up : migrations/1316027432512-add-jane.js
up : migrations/1316027432575-add-owners.js
up : migrations/1316027433425-coolest-pet.js
migration : complete

This will run up-migrations upto (and including) 1316027433425-coolest-pet.js. Similarly you can run down-migrations upto (and including) a specific migration, instead of migrating all the way down.

$ migrate down 1316027432512-add-jane.js
down : migrations/1316027432575-add-owners.js
down : migrations/1316027432512-add-jane.js
migration : complete

API

migrate.load(stateFile, migrationsDirectory)

Returns a Set populated with migration scripts from the migrationsDirectory and state loaded from stateFile.

Set.up([migration, ]cb)

Migrates up to the specified migration or, if none is specified, to the latest migration. Calls the callback cb, possibly with an error err, when done.

Set.down([migration, ]cb)

Migrates down to the specified migration or, if none is specified, to the first migration. Calls the callback cb, possibly with an error err, when done.