Add metrics exposure to kuzzle core

[kuzzle]

Feature Description

Kuzzle is a backend. Each backend is intended to be deployed in scalable environments. These environments create a need for monitoring and metrology.

It is possible today to use Kuzzle with one of the technologies already implemented in the monitoring world:

https://github.com/kuzzleio/kuzzle-plugin-prometheus

But we want to push the approach even further.
So we decided to implement a native way in Kuzzle to monitor the backend and make it accessible for the most standard tools of today, but also to open the field for future implementations.

The first technologies to be made available will be:

https://prometheus.io/ and https://opentelemetry.io/

Example Use Case

When installing Kuzzle on a docker-compose or docker swarm, or even Kubernetes we need monitoring.

For some of our infrastructures, we need a native way (without plugin installation) to be able to perform these actions.

The tools we use are not always the classic prometheus \/ Grafana and for that we need a system that is extensible to use other tools and formats

Possible Solution (optional)

• Create a new service

  • A new onAsk \/ ask

  • Have a metrics controller that relies on the metrics service

  • Have a route to get the metrics

In the metrics controller there will be an onAsk that will aggregate information from the core

Add a categorisation level

• Internal level

• Plugin level

Have a separation in the metrics

• http or websocket protocol metrics

Allow users to add new metrics via the framework

• Have a map (or something in RAM) to allow to collect information when calling the metrics\/get route of the controller

• Persist some snapshots with an ID in RAM (the last n) - If there is ever a hole in a graph, we need to be able to browse these snapshots.

Add a function that would format the metrics according to formats supported by Kuzzle.

• Prometheus

• OpenTelemetry

• JSON

---

Point of attention in the code

index.js level controller

In the funnel, import the controller

set the controller in the funnel

httpsRoutes -> add the new routes after the others

Spec OpenAPI → openapi\/component\/

Do the tests with Jest in api\/controller\/

[kuzzle]

Link to feature: https://kuzzle.productboard.com/feature-board/planning/features/20053272

[rolljee]

Followed on JIRA