Redis-backed background worker example using OptimalBits/bull and throng.
Use the following commands to create a set of containers:
- exposing a port to interact with from the Host
- using a custom network bind to connect the Redis container using its name (the default bridge network does not allow this and a container cannot bind the Host's localhost from Mac see https://docs.docker.com/docker-for-mac/networking/#use-cases-and-workarounds)
- overriding the $REDIS_URL with the Redis container URL
docker run -d --network=my-docker-net -p 6379:6379 --name redis <image name - e.g. redis:5.0.8-alpine>
docker run -d --network=my-docker-net -p 5000:5000 --name nodeserver --env REDIS_URL=redis://redis:6379 <image name - e.g. node-server>
docker run -d --network=my-docker-net --name nodeworker --env REDIS_URL=redis://redis:6379 <image name - e.g. node-worker>
$ brew install redis
$ brew services start redis
npm installnpm start- http://localhost:5000
$ git clone [email protected]:heroku-examples/node-workers-example.git
$ cd node-workers-example
$ heroku create
$ heroku addons:create heroku-redis
$ git push heroku master
$ heroku ps:scale worker=1
$ heroku open
The application is comprised of two process:
web- An Express server that serves the frontend assets, accepts new background jobs, and reports on the status us existing jobsworker- A small node process that listens for and executes incoming jobs
Because these are separate processes, they can be scaled independently based on specific application needs. Read the Process Model article for a more in-depth understanding of Heroku’s process model.
The web process serves the index.html and client.js files which implement a simplified example of a frontend interface that kicks off new jobs and checks in on them.