Migrating from prometheus-net to OpenTelemetry .NET

[joacar]

Hi

Currently I'm using the promtheus-net package which is added as a middleware and metrics are exported. The name of the metrics are

• http_requests_received_total
• http_requests_in_progress
• http_request_duration_seconds_{sum,count,bucket}

In OT the only one I can see is http_server_duration_ms. What do I need to do to make in progress and total available? Looking at the code it does seem to hook into the HttpRequestIn events in diagnostic listener. Perhaps I need to manually add the source System.Net.Http?
If there is any source mentioning how to migrate from prometheus-net to OT I would be very happy. If not, I might create one :)

I found this that is related but doesn't answer my question.

Thanks

[cijothomas]

What do I need to do to make in progress and total available?

The metrics from OTel follow OTel conventions.

1. Total request - is part of the http.server.duration (its a histogram, so you can get count)
2. In-progress is not yet implemented. Its part of the Otel metric conventions, but we just haven't implemented it.

The names/dimensions etc. will quite likely be different from Prometheus.NET. (I'd suggest to look into using Otel-Collector, which might have something to rename metrics etc, so that you get same names, if that is what you are looking for).

[joacar]

Perfect thank you! Yeah I haven't thought about naming, my concern now is to get the experimental app show same data in Grafana as the others. Then whether to change in OT or move to use new naming is a later question :)
Do you need someone to take a look at implementing it? In one of my applications I wrote my own prometheus-net based on DiagnosticListener instead of middleware, I guess this is the way it should be treated in OT as well.

Cheers

[cijothomas]

@vishweshbankwar can help give some pointers, if you are interested in helping us add the in-progress counter. (most of the infra is already there, but have to incorporate)