Prometheus

The Steeltoe prometheus endpoint exposes metrics collected via built-in instrumentation of various aspects of the application in the prometheus format. Similar to the Metrics Endpoint, it automatically configures built-in instrumentation of various aspects of the application.

The metrics collected are the same as those collected by the metrics endpoint.

Configure Settings

The following table describes the settings that you can apply to the endpoint:

Key	Description	Default
Id	The ID of the metrics endpoint.	prometheus
Enabled	Whether to enable the metrics management endpoint.	true

Each setting must be prefixed with Management:Endpoints:Prometheus.

To configure Observers, see Metric Observers

Enable HTTP Access

The default path to the Prometheus endpoint is computed by combining the global Path prefix setting together with the Id setting described in the preceding section. The default path is /actuator/prometheus.

See the HTTP Access section to see the overall steps required to enable HTTP access to endpoints in an ASP.NET Core application.

To add the actuator to the service container and map its route, use the AddPrometheusActuator extension method from ManagementHostBuilderExtensions.

The following example shows how to use the metrics actuator endpoint:

 public static IHost BuildHost(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .AddPrometheusActuator()
            .Build();

Alternatively, first,add the Prometheus actuator to the service container, using the AddPrometheusActuator() extension method from EndpointServiceCollectionExtensions.

Then, add the Prometheus actuator middleware to the ASP.NET Core pipeline, use the Map<PrometheusEndpoint>() extension method from ActuatorRouteBuilderExtensions.

Add NuGet References

To use the Prometheus endpoint, you need to add a reference to Steeltoe.Management.EndpointCore. To add this NuGet to your project, add a PackageReference resembling the following:

<ItemGroup>
...
    <PackageReference Include="Steeltoe.Management.EndpointCore" Version="3.2.0"/>
...
</ItemGroup>

Alternatively, you can use PowerShell:

PM>Install-Package  Steeltoe.Management.EndpointCore