@atlas.js/objection

Object.js service for @atlas.js.

Installation

npm i @atlas.js/objection

You will also need to install one of the supported database drivers on your own.

Usage

Service

The service accepts three configuration options - models, knex and prefetch.

• models: A path to a module, relative to application's root, from which to load database models. Each exported key is expected to a model.
• knex: This object is passed as-is to the underlying Knex client to initialise the connection.
• prefetch: (default true) Determines whether your models' table schemas will be eagerly prefetched on startup to avoid fetching them during actual requests. See Objection.js docs to learn more about this behaviour.

import * as objection from '@atlas.js/objection'
import { Atlas } from '@atlas.js/atlas'

const atlas = new Atlas({
  config: {
    services: {
      database: {
        prefetch: true,
        models: 'path/to/objection-models',
        knex: {
          client: 'mysql',
          connection: {
            host : '127.0.0.1',
            user : 'your_database_user',
            password : 'your_database_password',
            database : 'myapp_test'
          }
        },
      },
    },
  },
})

atlas.service('database', objection.Service)
await atlas.start()

// You have your objection client and all models available here:
atlas.services.database
// A knex instance
atlas.services.database.connection
// Object with all the models you defined, ready for use
atlas.services.database.models

Accessing the Atlas instance

From within your models you can access the Atlas instance as both a static and instance-level property on the models. This is set up as part of the model loading process during the prepare step.

import { Model } from '@atlas.js/objection'

class User extends Model {
  static doThatThing() {
    // this refers to the class, ie. this === User
    this.atlas
  }
  doThisThing() {
    // this refers to the class' instance, ie. this instanceof User === true
    this.atlas
  }
}

MigrationAction

This action contains methods for applying and rolling back your migrations. The migration files must export an up() and down() functions. Both of these functions should return a Promise and their first argument is the knex client.

In addition to using plain JavaScript migration files, you may also organise your migrations into a folder with an index.js file inside, if the migration requires more data or you simply wish to organise the migration in a different way than a single script.

MigrationAction Dependencies

• service:objection: An Objection.js service to use with which to apply/undo the migrations

// index.js
import * as objection from '@atlas.js/objection'
import { Atlas } from '@atlas.js/atlas'

const atlas = new Atlas({
  root: __dirname,
  config: {
    actions: {
      migration: {
        // The path to the module from which all the migrations should be
        // loaded, relative to atlas.root
        module: 'migrations'
      }
    }
  }
})

atlas.action('migration', objection.MigrationAction, {
  aliases: {
    'service:objection': 'database'
  }
})
await atlas.start()

// Available actions:
await atlas.actions.migration.up() // Applies all pending migrations
await atlas.actions.migration.down() // Rolls back last applied migration
await atlas.actions.migration.pending() // Returns names of pending migrations

Running migrations on start

Migrations are not applied automatically on application start. You will need to implement your own hook which implements the afterStart event handler and run the up() method from there.

A simple hook doing just that:

import Hook from '@atlas.js/hook'

export default MigrateHook extends Hook {
  static observes = 'service:objection'

  async afterStart() {
    await this.atlas.actions.migrate.up()
  }
}

License

See the LICENSE file for information.