Prometheus.Tools

unofficial .NET Core tools for prometheus metrics

Suggestions for improvements or additional tools are most welcome!

Installation

Install the Prometheus.Tools nuget package

Install-Package Prometheus.Tools

Usage

Middleware

The middleware is designed to enable easy metrics logging of request durations.

The package is currently depending on the Prometheus.Client nuget package. Information on how to use it can be found here: https://github.com/phnx47/Prometheus.Client

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IApplicationLifetime appLifetime)
{
    var options = new PrometheusOptions();
    options.MapPath = "metrics";
    options.Collectors.Add(new DotNetStatsCollector());
    app.UsePrometheusServer(options);

    app.UsePrometheusMiddleware(c =>
    {
        c.ExcludeRoutes.Add("swagger");
    });
}

In the above example any routes with swagger will be excluded from the metrics and not be logged. If you do not want to exclude any routes replace it with the below line instead:

    app.UsePrometheusMiddleware();

To exclude several routes:

    app.UsePrometheusMiddleware(c =>
    {
        c.ExcludeRoutes.AddRange(new[] { "swagger", "Values" });
    });

Excepted metrics out

# HELP http_response_time_milliseconds Request duration in milliseconds
# TYPE http_response_time_milliseconds SUMMARY
http_response_time_milliseconds_sum{method="GET",route="/quality/api/values",statuscode="200"} 620
http_response_time_milliseconds_count{method="GET",route="/api/values",statuscode="200"} 25
http_response_time_milliseconds{method="GET",route="/api/values",statuscode="200",quantile="0.5"} 17
http_response_time_milliseconds{method="GET",route="/api/values",statuscode="200",quantile="0.9"} 22
http_response_time_milliseconds{method="GET",route="/api/values",statuscode="200",quantile="0.99"} 22

MvcFilter

An ActionFilter is available and provides more accurate information than the PrometheusMiddleware in form of the controller and action being called. The con is that the metrics are closer to the action and therefore you will get faster request duration metrics from the filter, than you will from the middleware.

public void ConfigureServices(IServiceCollection services)
{
    var prometheusOptions = new PrometheusMiddlewareOptions();
    prometheusOptions.ExcludeRoutes.Add("swagger");

    services.AddMvc(options =>
    {
        options.Filters.Add(new PrometheusActionFilter(prometheusOptions));
    });
}

Expected metrics output

# HELP http_response_time_milliseconds_v2 Request duration in milliseconds
# TYPE http_response_time_milliseconds_v2 SUMMARY
http_response_time_milliseconds_sum{method="GET",controller="Values",action="Get",statuscode="200"} 80
http_response_time_milliseconds_count{method="GET",controller="Values",action="Get",statuscode="200"} 5
http_response_time_milliseconds{method="GET",controller="Values",action="Get",statuscode="200",quantile="0.5"} 15
http_response_time_milliseconds{method="GET",controller="Values",action="Get",statuscode="200",quantile="0.9"} 16
http_response_time_milliseconds{method="GET",controller="Values",action="Get",statuscode="200",quantile="0.99"} 17