Prometheus .NET Client
This is an experimental version (unofficial)
It's tested on Windows/.NET4 and Ubuntu/Mono 3.12.1.
See prometheus here
Installation
Nuget package: prometheus-net
Install-Package prometheus-net
Instrumenting
Four types of metric are offered: Counter, Gauge, Summary and Histogram. See the documentation on metric types and instrumentation best practices on how to use them.
Counter
Counters go up, and reset when the process restarts.
var counter = Metrics.CreateCounter("myCounter", "some help about this");
counter.Inc(5.5);
Gauge
Gauges can go up and down.
var gauge = Metrics.CreateGauge("gauge", "help text");
gauge.Inc(3.4);
gauge.Dec(2.1);
gauge.Set(5.3);
Summary
Summaries track the size and number of events.
var summary = Metrics.CreateSummary("mySummary", "help text");
summary.Observe(5.3);
Histogram
Histograms track the size and number of events in buckets. This allows for aggregatable calculation of quantiles.
var hist = Metrics.CreateHistogram("my_histogram", "help text", buckets: new[] { 0, 0.2, 0.4, 0.6, 0.8, 0.9 });
hist.Observe(0.4);
The default buckets are intended to cover a typical web/rpc request from milliseconds to seconds.
They can be overridden passing in the buckets
argument.
Labels
All metrics can have labels, allowing grouping of related time series.
See the best practices on naming and labels.
Taking a counter as an example:
var counter = Metrics.CreateCounter("myCounter", "help text", labelNames: new []{ "method", "endpoint"});
counter.Labels("GET", "/").Inc();
counter.Labels("POST", "/cancel").Inc();
HTTP handler
Metrics are usually exposed over HTTP, to be read by the Prometheus server.
var metricServer = new MetricServer(port: 1234);
metricServer.Start();
Unit testing
For simple usage the API uses static classes, which - in unit tests - can cause errors like this: "A collector with name '' has already been registered!"
To address this you can add this line to your test setup:
DefaultCollectorRegistry.Instance.Clear();