Transactional Email Microservice for Zeebe

Send templated transactional emails using Amazon SES from BPMN processes in Zeebe.io.

Watch me code this project from scratch live on YouTube:

• Part 1
• Part 2

A common task in any modern business is to send a transactional email: a welcome email, a password reset email, a receipt.

This task worker services tasks of type email:send. The task should have a custom header with a key email:template with the name of the template to use. The template is used to generate plain-text and HTML email bodies with the variables from the job bound. The compiled email is then sent to the recipient using AWS SES.

The worker fetches email, firstName, and lastName variables from the broker.

This worker is not intended to be used as-is, as a drop-in task worker, but rather as a POC to give you an idea on how to code something like this up for your system. Making a general-purpose, reusable service takes a lot of work, and requires a lot of abstract configuration. For example: should it support Mailgun? Sendgrid? What templating variables should it support and how should it support them?

You can use this as a starter for your own transactional mail microservice, and structure it to fit your use-case.

To Run

1. Start a local Zeebe broker using the zeebe-docker-compose docker images (or set the environment variable ZEEBE_ADDRESS to point to your existing broker, or set the variables to connect to Camunda Cloud).
2. Clone this repo.
3. Run npm i && npm i -g pino-pretty to install deps.
4. Get your AWS SES credentials (Google it).
5. Put them in the environment:

export ZEEBE_TXES_FROM_EMAIL=<your authorised sending address>
export ZEEBE_TXES_AWS_SES_KEY=<AWS SES credential key>
export ZEEBE_TXES_AWS_SES_SECRET=<AWS SES credential secret>

6. Start the microservice: npm run start:dev | pino-pretty
7. Open the url http://localhost:3000/[email protected]/yourFirstName/yourLastName

(Obviously substituting the values in the URL).

You should receive a welcome email in your inbox from the microservice.

Watch the videos for more insight, or just read the code. Or why not both?

Packages used in this POC:

• @payk/nestjs-zeebe - A zeebe transport and client for NestJS.
• @payk/nestjs-winston - Winston for NestJS has never been this easy!
• micromustache - A secure, fast and lightweight template engine with some handy additions.
• mailgen - A Node.js package that generates clean, responsive HTML e-mails for sending transactional mail.
• node-ses - A simple and reliable Node.js mail for sending mail through Amazon SES.

A progressive Node.js framework for building efficient and scalable server-side applications, heavily inspired by Angular.

Description

Nest framework TypeScript starter repository.

Installation

$ npm install

Running the app

# development
$ npm run start

# watch mode
$ npm run start:dev

# production mode
$ npm run start:prod

Test

# unit tests
$ npm run test

# e2e tests
$ npm run test:e2e

# test coverage
$ npm run test:cov

Support

Nest is an MIT-licensed open source project. It can grow thanks to the sponsors and support by the amazing backers. If you'd like to join them, please read more here.

Stay in touch

• Author - Kamil Myśliwiec
• Website - https://nestjs.com
• Twitter - @nestframework

License

Nest is MIT licensed.