node-migrate state storage for MongoDB


This is a state storage implementation for the node-migrate framework. It will store your migation state in a MongoDB collection called migrations which contains a single document.

In case you’re using node-migrate for migrating your MongoDB, it makes sense to keep the state within the database itself, instead of a separate file which is used by node-migrate per default.

Installation

``shell
$ yarn add @nodepit/migrate-state-store-mongodb
`

Usage

Either create a wrapper script such as run-migrations.ts which calls the migration API like so:

`javascript
import * as migrate from 'migrate';
import { MongoStateStore } from '@nodepit/migrate-state-store-mongodb';

migrate.load({
stateStore: new MongoStateStore(MONGODB_HOST),
// further configuration …
}, (err, set) => {
// your code …
});
`

Per default, the migrations are stored in a collection called migrations. If you want to customize the collection name, instantiate the MongoStateStore with an object instead:


`javascript
new MongoStateStore({ uri: MONGODB_HOST, collectionName: 'custom-migrations-collection' });
`

Synchronization

If you’re running in a clustered environments with more than one node, there will likely be concurrency issues when more than one node tries to run a migration (also see here). The plugin provides a locking mechanism which ensures that only one node can run migrations at a given time (and other ones will just wait until the migration has finished). For this, initialize MongoStateStore with a lockCollectionName:

`javascript
new MongoStateStore({
uri: MONGODB_HOST,
collectionName: 'migrations',
lockCollectionName: 'migrationlock'
});
`

… then use the synchronizedUp function instead of calling migrate.load and set.up directly to ensure that the migration is only run on one instance at a time:

`javascript
import { MongoStateStore, synchronizedUp } from '@nodepit/migrate-state-store-mongodb';

await synchronizedUp({ stateStore: mongoStateStore });
`

CLI Usage

Alternatively, you can also pass the store on the migrate CLI using the --store flag. For that, create a a file which has as default export a configured subclass with a zero-arg constructor of the MongoStateStore. See here for details. You can then call migrate up --store=./my-store.js. Locking is not available in this case.

Development

Install NPM dependencies with yarn.

To execute the tests, run the test task.

For the best development experience, make sure that your editor supports ESLint and EditorConfig.

Releasing to NPM

Commit all changes and run the following:

`shell
$ npm login
$ npm version
$ npm publish --access public
`

… where is one of patch, minor, or major. This will update the package.json`, and create a tagged Git commit with the version number.

Contributing

Pull requests are very welcome. Feel free to discuss bugs or new features by opening a new issue.

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