index.js

const _ = require('lodash')
const knex = require('knex')
const DatastoreTrailpack = require('trailpack/datastore')

/**
 * Knex integration for Trails. Allows knex to read its configration from the
 * trails datastore config, and auto-migrate on startup.
 */
module.exports = class KnexTrailpack extends DatastoreTrailpack {

  /**
   * Ensure that this trailpack supports the configured migration
   */
  validate () {
    /*
    if (!_.includes([ 'none', 'drop', 'create' ], this.app.config.database.models.migrate)) {
      throw new Error('Migrate must be configured to either "create" or "drop"')
    }
    */
  }

  configure () {
    this.app.config.set('stores.orm', 'knex')
  }

  /**
   * Initialize knex connections, and perform migrations.
   */
  async initialize () {
    super.initialize()

    this.stores = _.mapValues(this.app.config.stores, (store, storeName) => {
      return {
        knex: knex(Object.assign({ }, store)),
        models: _.pickBy(this.app.models, { store: storeName }),
        migrate: store.migrate
      }
    })
    return this.migrate()
  }

  /**
   * Close all database connections
   */
  async unload () {
    return Promise.all(
      _.map(this.stores, store => store.knex.destroy())
    )
  }

  constructor (app) {
    super(app, {
      config: require('./config'),
      api: require('./api'),
      pkg: require('./package')
    })
  }

  /**
   * Migrate schema according to the database configuration
   */
  migrate () {
    const SchemaMigrationService = this.app.services.SchemaMigrationService

    return Promise.all(
      _.map(this.stores, (store, storeName) => {
        if (store.migrate === 'drop') {
          return SchemaMigrationService.drop(store.knex, this.app.models)
            .then(result => SchemaMigrationService.create(store.knex, this.app.models))
        }
        else {
          return SchemaMigrationService[store.migrate](store.knex, this.app.models)
        }
      })
    )
  }
}