I'm starting to use prometheus, here's a minor problem I've occured:
The documentation says that CollectorRegistry.create is "mostly useful for testing". However, it happens to be more useful in my case because our projects links multiple libraries that relies on prometheus, and therefore registers metrics I don't want. However, the functor Cohttp uses the CollectRegistry.default to collect data, so I basically have to copy/paste it and just change the registry:
let registry = CollectorRegistry.create ()
module Cohttp (Server : Cohttp_lwt.S.Server) = struct
let callback _conn req _body =
let open Cohttp in
let open Lwt_syntax in
let uri = Request.uri req in
match (Request.meth req, Uri.path uri) with
| `GET, "/metrics" ->
let* data = CollectorRegistry.collect registry in
let body =
Fmt.to_to_string Prometheus_app.TextFormat_0_0_4.output data
in
let headers =
Header.init_with "Content-Type" "text/plain; version=0.0.4"
in
Server.respond_string ~status:`OK ~headers ~body ()
| _ -> Server.respond_error ~status:`Bad_request ~body:"Bad request" ()
end
Maybe it would make sense to add another argument to the functor with the registry? Or potentially adding a new functor Cohttp_with_registry?
Hey,
I'm starting to use prometheus, here's a minor problem I've occured:
The documentation says that
CollectorRegistry.create
is "mostly useful for testing". However, it happens to be more useful in my case because our projects links multiple libraries that relies on prometheus, and therefore registers metrics I don't want. However, the functorCohttp
uses theCollectRegistry.default
to collect data, so I basically have to copy/paste it and just change the registry:Maybe it would make sense to add another argument to the functor with the registry? Or potentially adding a new functor
Cohttp_with_registry
?