Change Details

Could benefit from server-sent events

**Front-end** Build a static web page printing notifications in real-time. Traditionally, this uses websockets, but here we could use the [[ https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events | server-sent events API ]] to simplify a lot the design. This page could be added as a subpage of https://infra.nasqueron.org (rINFRAWWW). If so: * HTML content should be added to [[ https://devcentral.nasqueron.org/source/infra-www/browse/main/src/pages/ | src/pages ]] * JavaScript code should be added to [[ https://devcentral.nasqueron.org/source/infra-www/browse/main/src/assets/js/ | src/assets/js ]] If we don't use JavaScript, it should be trivial to convert TypeScript/CoffeScript/whatever into JS code, as we've full control with Gulp of the build process. We just need to remember we'll also need a generic way to express the idea "compile that app into js" in upsection (rUPSECTION), so if anything else than JS is used, document it at T1654. **Back-end** A small microservice to get the notifications and push them to the front-end This service could get notifications either: * by directly connecting to RabbitMQ (probably the easiest), see https://www.rabbitmq.com/devtools.html for links to relevant libraries * using delivery API described at T1210 (but that one is NOT real-time, it's for regular query polling like every N seconds) MDN provides an example of the SSE workflow: https://github.com/mdn/dom-examples/tree/master/server-sent-events The back-end can be programmed in any language, as we deploy API endpoints as separate autonomous microservices: * If you use Rust, some newer APIs are prepared with Rocket and our Limiting Factor framework (rLF) like rAPIREG * If you use Python, the `notifications` CLI command successfully uses Pika to connect to RabbitMQ, see rNOTIFCLI **Deployment** 1. Create RabbbitMQ user and store credentials to Vault or through Zemke-Rhyme (Dereckson can help here) 2. Deploy back-end as a Docker container by adding it to rOPS (pillar/paas/docker.sls + roles/paas-docker/containers) 3. Add nginx configuration for api.nasqueron.org, that's in rOPS roles/webserver-legacy/nginx 4. Publish front-end, for rINFRAWWW, there is a job on Jenkins CD for that **Final architecture** A notification would reach the web page by this path: {GitHub, Jenkins, Phabricator, Docker Hub, etc.} -> Notifications Center -> RabbitMQ -> this new back-end service -> this new front-end page