Adonis v4 Multi Tenancy Example

example-model.js

'use strict'

/** @type {typeof import('@adonisjs/lucid/src/Lucid/Model')} */
const Model = use('Model')

class ExampleModel extends Model {
  /**
   * Add traits
   */
  static boot () {
    super.boot();
    this.addTrait('Tenant');
  }
}

module.exports = ExampleModel

index.js

const Customer = use ('App/Models/Customer')
const ExampleModel = use ('App/Models/ExampleModel')
const TenantManager = use('Service/TenantManager')

// Update a standard model
async function standardExample (customerId, exampleId, data) {
  const customer = await Customer.find(customerId);
  const tenant = await TenantManager.connect(customer);
  await tenant.perform(async (TenantExampleModel) => {
     const newExample = new TenantExampleModel();
     newExample.merge(data);
     await newExample.save();
  }, ExampleModel);
}

// Do something more complicated
async function rawExample (customerId, inserts) {
  const customer = await Customer.find(customerId);
  const tenant = await TenantManager.connect(customer);
  // Using the tenant perform the inserts
  await tenant.perform(async (connection) => {
    await connection.transaction(async (trx) => {
      // Create raw query to do bulk inserts for timescaledb
      await trx.raw(util.format(
        '%s ON CONFLICT ("uniqueId") DO NOTHING',
        trx
          .from(ExampleModel.table)
          .insert(inserts)
          .toString()
      ));
    });
  });
}

manager.js

'use strict'

const Tenant = require('./Tenant');

/** @typedef {import('app/Models/Customer')} Customer */
const Customer = use('App/Models/Customer');

class Manager {
  /**
   * Construct the manager class
   *
   * @param {Config} Config
   * @param {Database} Database
   */
  constructor (Config, Database) {
    this.config = Config;
    this.defaults = Config.get('database.tenant');
    this.databaseManager = Database;
    this.tenants = {};
  }

  /**
   * Check for expired connections and close them
   */
  expire = () => {
    const now = new Date();
    Object.values(this.tenants)
      .filter(tenant => tenant.expires > now.getTime())
      .forEach(tenant => this.disconnect(tenant.customerId));
  }

  /**
   * Get a fresh expiry date (future date, +60 seconds)
   */
  getExpiryDate () {
    return (new Date()).getTime() + (60 * 1000);
  }

  /**
   * Connect to the tenant database using the given customer
   *
   * @param {Customer} customer
   */
  async connect (customer) {
    return this.createConnection(customer);
  }

  /**
   * Create a connection to the tenant database for the customer record
   *
   * @param {Customer} customer
   * @param {Number} customer.id
   * @param {String} customer.database
   */
  createConnection ({ id: customerId, database }) {
    if (this.tenants[database]) {
      return this.tenants[database].tenant;
    }
    const { defaults } = this;
    // Locate the customer record and populate the config with the customer connection information
    const connectionConfig = { ...defaults };
    connectionConfig.connection.database = database;
    this.config.set(`database.${database}`, connectionConfig);

    // Use the database manager to establish a connection to the database
    const dbConnection = this.databaseManager.connection(database);

    const tenant = new Tenant(database, dbConnection, this);

    this.tenants[database] = {
      tenant,
      database,
      customerId,
      expires: this.getExpiryDate(),
    };

    return tenant;
  }

  /**
   * Ping the connection to update the expiry time
   *
   * @param {String} connection
   */
  ping (database) {
    if (!this.tenants[database]) {
      return;
    }
    // Update last used
    this.tenants[database].expires = this.getExpiryDate();
  }

  /**
   * Disconnect the tenant database for the given customer id
   *
   * @param {Number} customerId
   */
  async disconnect (customerId) {
    const { database } = await Customer.findOrFail(customerId);
    delete this.tenants[database];
    this.close(database);
  }

  /**
   * Closes the connection
   *
   * @param {String} connection
   */
  close (connection) {
    try {
      this.databaseManager.close([connection]);
    } catch (err) {
      // Ignore
    }
  }

  /**
   * Establishes a connection, this opens any that were closed before
   *
   * @param {String} connection
   */
  establish (connection) {
    return this.databaseManager.connection(connection);
  }
}

module.exports = Manager;

tenant.js

class Tenant {
  /**
   * Create the tenant class which is responsible for performing database actions with
   * tenant models
   *
   * @param {String} connection
   * @param {Manager} manager
   */
  constructor (dbName, dbConnection, manager) {
    this.dbName = dbName;
    this.dbConnection = dbConnection;
    this.manager = manager;
  }

  /**
   * Captures the models standard connection so it can be restored once the
   * tenant database actions have been performed
   *
   * @param {Array} models
   */
  capture (models) {
    const { dbName } = this;
    this.dbConnection = this.manager.establish(dbName);

    models.forEach(model => {
      model.previousConnection = model.connection;
      model.connection = dbName;
    });
  }

  /**
   * Restores the connection on the model
   *
   * @param {Array} models
   */
  release (models) {
    const { dbName } = this;
    // Put the previous connection back on the model
    models.forEach(model => {
      model.connection = model.previousConnection;
      model.previousConnection = null;
    });

    this.manager.ping(dbName);
  }

  /**
   * Captures the passed in models so they can be used on the tenant database, this will pass all of
   * the given models to the callback as arguments, these will all be configured so they will work
   * with the tenant database
   *
   * @param {Function} callback
   * @param  {...Model} models
   */
  async perform (callback, ...models) {
    this.capture(models);
    const result = await callback(...models, this.dbConnection);
    this.release(models);
    return result;
  }

  /**
   * Saves the model in the tenant database
   *
   * @param {Model} model
   */
  async save (model) {
    this.capture([model]);
    const result = await model.save();
    this.release([model]);
    return result;
  }

  /**
   * Finds the model from the tenant database, the model will not have the tenant connection when
   * returned and further actions must be used with the Tenant.perform or Tenant.save methods
   *
   * @param {Model} model
   * @param {any} value
   */
  async find(model, value) {
    this.capture([model]);
    const found = await model.find(value);
    this.release([model]);
    return found;
  }

  /**
   * Finds the model from the tenant database by key and value, the model will not have the tenant connection when
   * returned and further actions must be used with the Tenant.perform or Tenant.save methods
   *
   * @param {Model} model
   * @param {String} key
   * @param {any} value
   */
  async findBy(model, key, value) {
    this.capture([model]);
    const found = await model.findBy(key, value);
    this.release([model]);
    return found;
  }
}

module.exports = Tenant;

tenent-model-trait.js

'use strict'

class Tenant {
  register (Model) {
    Object.defineProperties(Model, {
      // Handles updating the connection used by the model
      connection: {
        get: () => this.connection,
        set: (connection) => this.connection = connection,
      },
      // Handles storing the previous connection
      previousConnection: {
        get: () => this.previousConnection,
        set: (prev) => this.previousConnection = prev,
      }
    })
  }
}

module.exports = Tenant

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