Zero Scale Zeebe

A Zeebe Worker for integration with Serverless (AWS / Azure Web Function / OpenWhisk) or other JSON-based HTTP APIs. Allows you to run workers at zero-scale (nothing running when there is no work).

OK, it's not zero scale, because you need this one worker running. But it is one worker for multiple task types - not one worker per-task type.

This worker is configured via a JSON file containing a map of task types to REST endpoints.

It polls for configured tasks and invokes remote HTTP endpoints via GET or POST.

This configuration file looks like this:

{
  "tasks": {
    "test-task": {
      "url": "http://localhost:3000/getExample?foo=bar&baz=foo",
      "method": "get",
      "headers": { "Content-Type": "application/json" }
    },
    "test-task2": {
      "url": "http://localhost:3000/postExample",
      "method": "post",
      "headers": { "X-My-Custom-Header": "woopWoop" }
    }
  }
}

The map is reloaded every 30 seconds, so the task type mapping can be updated.

Usage

Install dependencies:

npm i

Build:

npm run build

Set the environment variable ZEEBE_TASK_MAP_FILE to point to your JSON map (there is an example in the demo subdirectory).

Then run npm start

Demo

To run the demo:

• Install dependencies:

npm i
npm i -g typescript ts-node

• In Terminal 1 - Start a broker:

cd demo
docker-compose up

• In Terminal 2 - Start the Lambda Emulator REST Server. This server emulates an AWS Lambda / SQS or other endpoint.

cd demo
ts-node server.ts

• In Terminal 3 - Start the Zero-Scale worker:

ZEEBE_TASK_MAP_FILE=../demo/taskmap.json ts-node src/index.ts

• In Terminal 4 - start a workflow:

cd demo
ts-node start-work.ts