Why prom-client is not showing registered metrics in the metrics endpoint?

Question

I have just registered some metrics in a NestJS application, through a typescript decorator. I use the prom-client package, but although I can log the metrics registered, the endpoint is not exposing those, and the Prometheus docker instance that I use to show all metrics, are not showing those neither.

how can I do to view registered metrics in /metrics endpoint and the Prometheus dashboard?

Answer 1

I solved passing to the custom metric in the constructor options the registry that will be used as follow:

new Counter({ name, help, registers: [registerOn] })

where registerOn is a reference of the register instance (from prom-client) used in the main module (because the metrics registered in different modules are registered in different registry instances)