mongo-up
A database migration tool for MongoDB in Node. This project was forked from migrate-mongo, and enhanced with the capability to
have "run always" scripts before or after the deployment. This is convenient when applying indexes or other structures that should
always be run idempotently.
Installation
$ npm install -g mongo-up
CLI Usage
$ mongo-up
Usage: mongo-up [options] [command]
Commands:
init initialize a new migration project
create [description] create a new database migration with the provided description
create-before [description] create a new database script that always runs before migrations with the provided description
create-after [description] create a new database script that always runs after migrations 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
Make sure you have Node.js 7.6.0 (or higher) installed.
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 mongo-up project
$ mongo-up init
Initialization successful. Please edit the generated mongo-up-config.js file
The above command did two things:
- create a sample 'mongo-up-config.js' file and
- create a 'migrations' directory
Edit the mongo-up-config.js file.
An object or Promise can be returned. A Promise would be returned if you need to call an external API like the AWS SDK to get configuration information.
Static file example
Make sure you change the mongodb url:
module.exports = {
mongodb: {
url: "mongodb://localhost:27017",
databaseName: "YOURDATABASENAME",
options: {
useNewUrlParser: true
}
},
migrationsDir: "migrations",
beforeDir: "before",
afterDir: "after",
changelogCollectionName: "changelog"
};
Promise example
const AWS = require('aws-sdk')
const ssm = new AWS.SSM()
const params = {
Name: process.env.MONGO_CONNECTION_KEY,
WithDecryption: true
}
module.exports = ssm.getParameter(params).promise().then(data => {
const url = data.Parameter.Value
const dbName = url.split("?")[0].split("/").pop()
const mongoSettings = {
url: data.Parameter.Value,
databaseName: dbName,
options: {
useNewUrlParser: true
}
}
return {
mongodb: mongoSettings,
beforeDir: "before",
migrationsDir: "migrations",
afterDir: "after",
changelogCollectionName: "changelog"
}
})
Creating a new migration script
To create a new database migration script, just run the mongo-up create [description]
command.
For example:
$ mongo-up create blacklist_the_beatles
Created: migrations/20160608155948-blacklist_the_beatles.js
A new migration file is created in the 'migrations' directory:
module.exports = {
up(db) {
},
down(db) {
}
};
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
There are 3 options to implement the up
and down
functions of your migration:
- Return a Promise
- Use async-await
- Call a callback (deprecated)
Always make sure the implementation matches the function signature:
function up(db) { /* */ }
should return Promise
function async up(db) { /* */ }
should contain await
keyword(s) and return Promise
function up(db, next) { /* */ }
should callback next
Example 1: Return a Promise
module.exports = {
up(db) {
return db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: true}});
},
down(db) {
return db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: false}});
}
};
Example 2: Use async & await
Async & await is especially useful if you want to perform multiple operations against your MongoDB in one migration.
module.exports = {
async up(db) {
await db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: true}});
await db.collection('albums').updateOne({artist: 'The Doors'}, {$set: {stars: 5}});
},
async down(db) {
await db.collection('albums').updateOne({artist: 'The Doors'}, {$set: {stars: 0}});
await db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: false}});
},
};
Example 3: Call a callback (deprecated)
Callbacks are supported for backwards compatibility.
New migration scripts should be written using Promises and/or async & await. It's easier to read and write.
module.exports = {
up(db, callback) {
return db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: true}}, callback);
},
down(db, callback) {
return db.collection('albums').updateOne({artist: 'The Beatles'}, {$set: {blacklisted: false}}, callback);
}
};
Creating a new 'before' or 'after' script
To create a new database before or after script, just run mongo-up create-before [description]
or
mongo-up create-after [description]
. As the names imply, these scripts get
run each time either before or after the database migration is run.
These scripts are good for tasks like ensuring indexes on each migration run.
For example:
$ mongo-up create-after blacklist_the_beatles_idx
Created: after/20160608155948-blacklist_the_beatles_idx.js
A new migration file is created in the 'before' or 'after' directory.
Always scripts only contain an 'up' as they are not a migration.
module.exports = {
up(db) {
}
};
Checking the status of the migrations
At any time, you can check which migrations are applied (or not)
$ mongo-up status
┌─────────────────────────────────────────┬────────────┐
│ Filename │ Applied At │
├─────────────────────────────────────────┼────────────┤
│ 20160608155948-blacklist_the_beatles.js │ PENDING │
└─────────────────────────────────────────┴────────────┘
Migrate up
This command will apply all pending migrations
$ mongo-up 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:
$ mongo-up status
┌─────────────────────────────────────────┬──────────────────────────┐
│ Filename │ Applied At │
├─────────────────────────────────────────┼──────────────────────────┤
│ 20160608155948-blacklist_the_beatles.js │ 2016-06-08T20:13:30.415Z │
└─────────────────────────────────────────┴──────────────────────────┘
Migrate down
With this command, mongo-up will revert (only) the last applied migration
$ mongo-up down
MIGRATED DOWN: 20160608155948-blacklist_the_beatles.js
If we check the status again, we see that the reverted migration is pending again:
$ mongo-up 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, mongo-up will look for a mongo-up-config.js
config file in of the current directory.
Example:
$ mongo-up status -f '~/configs/albums-migrations.js'
┌─────────────────────────────────────────┬────────────┐
│ Filename │ Applied At │
├─────────────────────────────────────────┼────────────┤
│ 20160608155948-blacklist_the_beatles.js │ PENDING │
└─────────────────────────────────────────┴────────────┘
API Usage
const {
init,
create,
database,
config,
up,
down,
status
} = require('mongo-up');
init() → Promise
Initialize a new mongo-up project
await init();
The above command did two things:
- create a sample
mongo-up-config.js
file and - create a
migrations
directory
Edit the mongo-up-config.js
file. Make sure you change the mongodb url.
create(description) → Promise<fileName>
For example:
const fileName = await create('blacklist_the_beatles');
console.log('Created:', fileName);
A new migration file is created in the migrations
directory.
create-before(description) → Promise<fileName>
For example:
const fileName = await create-before('blacklist_the_beatles_before');
console.log('Created:', fileName);
A new always-before file is created in the before
directory.
create-after(description) → Promise<fileName>
For example:
const fileName = await create-after('blacklist_the_beatles_after');
console.log('Created:', fileName);
A new always-after file is created in the after
directory.
database.connect() → Promise<MongoDb>
Connect to a mongo database using the connection settings from the mongo-up-config.js
file.
const db = await database.connect();
config.read() → Promise<JSON>
Read connection settings from the mongo-up-config.js
file.
const mongoConnectionSettings = await config.read();
up(MongoDb) → Promise<Array<fileName>>
Apply all pending migrations
const db = await database.connect();
const migrated = await up(db);
migrated.forEach(fileName => console.log('Migrated:', fileName));
If an an error occurred, the Promise will reject and won't continue with the rest of the pending migrations.
down(MongoDb) → Promise<Array<fileName>>
Revert (only) the last applied migration
const db = await database.connect();
const migratedDown = await down(db);
migratedDown.forEach(fileName => console.log('Migrated Down:', fileName));
status(MongoDb) → Promise<Array<{ fileName, appliedAt }>>
Check which migrations are applied (or not.
const db = await database.connect();
const migrationStatus = await status(db);
migrationStatus.forEach(({ fileName, appliedAt }) => console.log(fileName, ':', appliedAt));
db.close() → Promise
Close the database connection
const db = await database.connect();
await db.close()