Metrics

The Steeltoe metrics endpoint configures application metrics collection using the open source OpenCensus project. It automatically configures built-in instrumentation of various aspects of the application and exposes the collected metrics via the endpoint.

The following instrumentation is automatically configured:

• CLR Metrics
  • Heap memory, Garbage collections, Thread utilization
• HTTP Client Metrics
  • Request timings & counts
• HTTP Server Metrics
  • Request timings & counts

All of the above metrics are tagged with values specific to the requests being processed; thereby giving multi-dimensional views of the collected metrics.

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	metrics
enabled	Whether to enable the metrics management endpoint	true
ingressIgnorePattern	Regex pattern describing what incoming requests to ignore	See MetricsOptions
egressIgnorePattern	Regex pattern describing what outgoing requests to ignore	See MetricsOptions

Note: Each setting above must be prefixed with management:endpoints:metrics.

Enable HTTP Access

The default path to the Metrics endpoint is computed by combining the global path prefix setting together with the id setting from above. The default path is /actuator/metrics.

The coding steps you take to enable HTTP access to the Metrics endpoint differs depending on the type of .NET application your are developing. The sections which follow describe the steps needed for each of the supported application types.

ASP.NET Core App

To add the Metrics actuator to the service container, use the AddMetricsActuator() extension method from EndpointServiceCollectionExtensions.

To add the Metrics actuator middleware to the ASP.NET Core pipeline, use the UseMetricsActuator() extension method from EndpointApplicationBuilderExtensions.

ASP.NET 4.x App

To add the Metrics actuator endpoint, use the UseMetricsActuator() method from ActuatorConfigurator.

ASP.NET OWIN App

To add the Metrics actuator middleware to the ASP.NET OWIN pipeline, use the UseMetricsActuator() extension method from MetricsEndpointAppBuilderExtensions.

Exporting

By default when you enable metrics collection in your application you do NOT automatically enable exporting of those metrics to a backend system.

The coding steps you take to enable metrics exporting differs depending on what backend system you are targeting and the type of .NET application your are developing. The sections which follow describe the steps needed for each of the backend systems and supported application types.

Add NuGet References

To use the metrics exporters, you need to add a reference to the appropriate Steeltoe NuGet based on the type of the application you are building and what Dependency Injector you have chosen, if any.

The following table describes the available packages:

App Type	Package	Description
All	Steeltoe.Management.ExporterBase	Base functionality, no dependency injection
ASP.NET Core	Steeltoe.Management.ExporterCore	Includes ExporterBase, adds ASP.NET Core DI

To add this type of NuGet to your project, add a PackageReference resembling the following:

<ItemGroup>
...
    <PackageReference Include="Steeltoe.Management.ExporterCore" Version="2.5.2" />
...
</ItemGroup>

or

PM>Install-Package  Steeltoe.Management.ExporterCore -Version 2.5.2

Cloud Foundry Forwarder

The Metrics Forwarder for TAS is a service that allows apps to emit metrics to the Loggregator system and consume those metrics from the Loggregator Firehose.

You can interact with the service through the Cloud Foundry Command Line Interface (cf CLI), TAS Apps Manager, and an HTTP API. See the documentation for details on how to use the service in your application.

Metrics Forwarder for TAS enables users to do the following:

• Configure apps to emit custom metrics to Loggregator system.
• Read custom metrics from the Loggregator Firehose using a Firehose consumer of their choice, including community and third-party nozzles.

There are many third-party products you can choose from, including PCF Metrics.

Configure Settings

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

Key	Description	Default
endpoint	the uri used to POST metrics	null
accessToken	the authentication token needed to access the endpoint	null
rateMilli	delay in milliseconds between metrics POSTs	60000
validateCertificates	validate SSL certificates received from exporter service	true
timeoutSeconds	timeout used in seconds for each POST request	3
applicationId	cloud foundry application ID the POST applies to	null
instanceId	cloud foundry application instance ID the POST applies to	null
instanceIndex	cloud foundry application instance index the POST applies to	null
micrometerMetricWriter	emit metrics using Spring Boot 2.x format	false

Note: The endpoint, accessToken,applicationId, instanceId and instanceIndex settings above will be automatically picked up from the Metrics Forwarder service binding found for your application.

ASP.NET Core App

There are three steps needed to use the Metrics Forwarder for TAS service:

1. Create and bind a forwarder service to your application. Follow the steps in the Metrics Forwarder for PCF documentation.
2. Add the exporter to the service container. Use the AddMetricsForwarderExporter() extension method from EndpointServiceCollectionExtensions.
3. Start the exporter background thread. Use the UseMetricsExporter() extension method from EndpointApplicationBuilderExtensions.

public class Startup
{
    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }
    public void ConfigureServices(IServiceCollection services)
    {
        // Add Metrics collection
        services.AddMetricsActuator(Configuration);

        // Export metrics to Cloud Foundry forwarder
        services.AddMetricsForwarderExporter(Configuration);
        ...
    }
    public void Configure(IApplicationBuilder app)
    {
        app.UseStaticFiles();

        // Expose Metrics endpoint
        app.UseMetricsActuator();

        app.UseMvc();

        // Start up metrics exporter
        app.UseMetricsExporter();
    }
}

ASP.NET 4.x App

There are two steps needed to use the Metrics Forwarder for TAS service:

1. Create and bind a forwarder service to your application. Follow the steps in the Metrics Forwarder for PCF documentation.
2. Configure and start the exporter background thread.

public class ManagementConfig
{
    public static IMetricsExporter MetricsExporter { get; set; }

    public static void UseCloudFoundryMetricsExporter(IConfiguration configuration, ILoggerFactory loggerFactory = null)
    {
        var options = new CloudFoundryForwarderOptions(configuration);
        MetricsExporter = new CloudFoundryForwarderExporter(
            options,
            OpenCensusStats.Instance,
            loggerFactory != null ? loggerFactory.CreateLogger<CloudFoundryForwarderExporter>() : null);
    }
    public static void Start()
    {
        DiagnosticsManager.Instance.Start();
        if (MetricsExporter != null)
        {
            MetricsExporter.Start();
        }
    }
    public static void Stop()
    {
        DiagnosticsManager.Instance.Stop();
        if (MetricsExporter != null)
        {
            MetricsExporter.Stop();
        }
    }
}