package opentelemetry-client-cohttp-lwt

Opentelemetry

This project provides an API for instrumenting server software using opentelemetry, as well as connectors to talk to opentelemetry software such as jaeger.

• library opentelemetry should be used to instrument your code and possibly libraries. It doesn't communicate with anything except a backend (default: dummy backend)

• library opentelemetry-client-ocurl is a backend that communicates via http+protobuf with some collector (otelcol, datadog-agent, etc.)

License

MIT

Features

• [x] basic traces

• [x] basic metrics

• [x] basic logs

• [ ] nice API

• [x] interface with lwt

• [x] sync collector relying on ocurl

  • [x] batching, perf, etc.

• [ ] async collector relying on ocurl-multi

• [ ] interface with logs (carry context around)

Use

For now, instrument manually:

module Otel = Opentelemetry
let (let@) f x = f x

let foo () =
  let@ scope = Otel.Trace.with_  "foo"
      ~attrs:["hello", `String "world"] in
  do_work();
  Otel.Metrics.(
    emit [
      gauge ~name:"foo.x" [int 42];
    ]);
  do_more_work();
  ()

let main () =
  Otel.Globals.service_name := "my_service";
  Otel.GC_metrics.basic_setup();

  Opentelemetry_client_ocurl.with_setup () @@ fun () ->
  (* … *)
  foo ();
  (* … *)

Configuration

The library is configurable via Opentelemetry.Config, via the standard opentelemetry env variables, or with some custom environment variables.

• OTEL_EXPORTER_OTLP_ENDPOINT sets the http endpoint to send signals to

• OTEL_OCAML_DEBUG=1 to print some debug messages from the opentelemetry library ide

• OTEL_RESOURCE_ATTRIBUTES sets a comma separated list of custom resource attributes

Collector opentelemetry-client-ocurl

This is a synchronous collector that uses the http+protobuf format to send signals (metrics, traces, logs) to some other collector (eg. otelcol or the datadog agent).

Collector opentelemetry-client-cohttp-lwt

This is a Lwt-friendly collector that uses cohttp to send signals to some other collector (e.g. otelcol). It must be run inside a Lwt_main.run scope.

Opentelemetry-trace

The optional library opentelemetry.trace, present if trace is installed, provides a collector for trace. This collector forwards and translates events from trace into opentelemetry. It's only useful if there also is also a OTEL collector.

License

MIT

Semantic Conventions

Not supported yet.

• [ ] metrics

• [ ] traces

• [ ] resources