moleculer-context-db

A database integrator for injecting a transaction safe database session into the context of the action. Currently, this only has built in support for Mikro-ORM, and in that only SQL databases have been tested. Mongo support is experimental.

Setup

Installation

To install with npm

npm install moleculer-context-db

moleculer and @mikro-orm/core are peer dependecies and need to be installed separately.

Importing

ES6 style

import { MikroConnector, DatabaseContextManager } from 'moleculer-context-db';

CommonJS

const {
  MikroConnector,
  DatabaseContextManager
} = require('moleculer-context-db');

Configuration

You can create a new MikroConnector as such

const connector = new MikroConnector();

You will also need to install the appropriate database driver, e.g.:

import {MongoDriver} from '@mikro-orm/mongodb';

const connector = new MikroConnector<MongoDriver>();

or

npm i @mikro-orm/sqlite;

const connector = new MikroConnector();

You will then need to initialize the connector

await connector.init({
  type: 'sqlite', // or use 'mongo' for mongodb
  dbName: ':memory',
  entities: [YourEntity1, YourEntity2],
  cache: {
    enabled: false
  }
});

For mongo support, you will need to do:

await connector.init({
  type: 'mongo', // or use 'mongo' for mongodb
  dbName: <name_of_db>,
  clientUrl: <mongo_url>
  entities: [YourEntity1, YourEntity2],
  cache: {
    enabled: false
  },
  implicitTransactions: <true/false> // needs to be true if you are running a replica set needing transaction support
});

You can use all available options for MikroORM.init()

Usage

To use, simply instantiate a DatabaseContextManager with the connector and then add the result of the middleware method to your broker's middleware

const dbContextManager: DatabaseContextManager = new DatabaseContextManager(
  connector
);

yourMoleculerBroker.middlewares.add(DatabaseContextManager.middleware());

The above statement will wrap all local actions with a Mikro-ORM transaction.