better-migration

Better Migration - Make migrations easy!

This is a simple tool to migrate data. It features some key features:

Easy to write migrations: just implement the function
Out of the box auto-save current version (into a simple text file)
Out of the box locking mechanism to ensure only one migration is running
Customizable version saving and locking mechanism

npm install --save better-migration

Usage

var migration = require('better-migration');

The idea behind this tool is simple:

1. Write a migration script

migration.version('1.0.0', function (cb) {
    // Your migration script, call cb() when done.
    // cb(err) will abort the migration.
    cb();
})

2. Start the migration

This will run your migration scripts one at a time until it reaches the latest version.

migration.start(function (err) {
    // If the error is set, the script failed, and you should probably not continue.
    // Your data is updated to the latest semver version (in this case is 1.0.0)
})

When you need to migrate again, just call migration.set with the new version number, and restart.

Advanced usage

By default, we save the current version into a file, ./version. You may change this:

var migration = require('better-migration');

Optionally, you may set your own functions for setting the version/lock:

// Set the function to get the version
migration.get = function (cb) {
    cb(null, '1.0.0');
};
 
// Set the function to set the version
migration.set = function (v, cb) {
    cb(); // Call when saved
}
 
// Set the function to obtain a lock for migration.
migration.lock = function (cb) {
    // After you acquire the lock, you must return a release function
    // so that we can release the lock after the migration is complete.
    cb(err, release)
}

Contributions welcome!

Credits

This library was initially made by the awesome team of engineers at Diamond.

If you haven't already, make sure you install Diamond!

better-migration