prometheus-net "extended"

This repo is a fork of https://github.com/prometheus-net/prometheus-net

Changes on this repo:

Use common class(hierarchy) to represent additional parameters to add to default metrics (asp.net pipeline)
Allow to add static label

All code changes are in "Prometheus.AspNetCore\HttpMetrics"

How to add custom labels

We can add two custom labels:

1- Route Parameter label This is an existing implementation, changes are just around how to declare route parameter

2- Static label parameter This is something missing in original library. My use case is to identify metrics based on machine groups, ex: cluster, hubs, etc.

sample code

app.UseHttpMetrics(options =>
                    {
                        // add label "cluster" for all metrics
                        options.AddRouteParameter(new HttpStaticParameterMapping("cluster", "western_europe"));
                        // add label "myparam" only for duration
                        options.RequestDuration.AdditionalParameters.Add(new HttpRouteParameterMapping("myparam"));
                        // add label "method_param" only for counts
                        options.RequestCount.AdditionalParameters.Add(new HttpRouteParameterMapping("method", "method_param"));
                    });

How to test:

Launch tester Tester.Netcore

Request url: "http://127.0.0.1:21881/api/dummy/abc/method1"

According configuration above, we are adding the static label cluster="western_europe" to all metrics, myparam label to duration metrics and method_param to total count metric, which cover all 3 cases on custom label on default metrics.

Metrics will looks as:

alfhv/prometheus-net

prometheus-net "extended"