MongoDB

@node-ts/bus-mongodb stores workflow state in MongoDB, using version 7 of the mongodb driver (MongoDB server 4.2 or later). This page covers installing and configuring it.

@node-ts/bus-mongodbSource

Installation

npm

npm i @node-ts/bus-mongodb

pnpm

pnpm add @node-ts/bus-mongodb

yarn

yarn add @node-ts/bus-mongodb

Create a MongodbPersistence and pass it to the bus configuration:

import { Bus } from '@node-ts/bus-core'
import { MongodbConfiguration, MongodbPersistence } from '@node-ts/bus-mongodb'
import { messageTypes } from './message-types.generated'
import { fulfilmentWorkflow } from './workflows/fulfilment-workflow'

const configuration: MongodbConfiguration = {
  connection: 'mongodb://localhost:27017',
  databaseName: 'workflows'
}
const mongodbPersistence = new MongodbPersistence(configuration)

const bus = Bus.configure()
  .withMessageTypes(messageTypes)
  .withPersistence(mongodbPersistence)
  .withWorkflow(fulfilmentWorkflow)
  .build()

// Creates a collection, and indexes for its lookups, for each workflow state
await bus.initialize()
await bus.start()

Configuration

Option	Description
connection	The connection string: a single server, a replica set, or a mongodb+srv connection.
databaseName	The database to create the workflow collections in.

To share a client with the rest of your application, pass your MongoClient as the second constructor argument.

Collections

Each workflow state has a collection, named after its $name with invalid characters removed. initialize() creates the collections, and an index for each field that messages are looked up by. It never drops indexes, so ones you add are safe.

Keys in the state are percent-encoded when stored ($ as %24, . as %2E and % as %25), since MongoDB doesn't allow them in field names, and decoded when read.

Running MongoDB locally

docker run -d -p 27017:27017 mongo

See also

• Workflows
• MongodbConfiguration in the API reference