OpenTelemetry

This SDK produces metrics using OpenTelemetry that allow you to view data such as request timings. These metrics also include attributes for the model and store ID, as well as the API called to allow you to build reporting.

When an OpenTelemetry SDK instance is configured, the metrics will be exported and sent to the collector configured as part of your applications configuration. If you are not using OpenTelemetry, the metric functionality is a no-op and the events are never sent.

In cases when metrics events are sent, they will not be viewable outside of infrastructure configured in your application, and are never available to the OpenFGA team or contributors.

Metrics

Supported Metrics

Metric Name	Type	Enabled by Default	Description
fga-client.request.duration	Histogram	Yes	The total request time for FGA requests
fga-client.query.duration	Histogram	Yes	The amount of time the FGA server took to internally process and evaluate the request
fga-client.http_request.duration	Histogram	No	The duration of individual HTTP requests sent by the SDK
fga-client.credentials.request	Counter	Yes	The total number of times a new token was requested when using ClientCredentials
fga-client.request.count	Counter	No	The total number of requests made to the FGA server

Supported attributes

Attribute Name	Type	Enabled by Default	Description
fga-client.response.model_id	string	Yes	The authorization model ID that the FGA server used
fga-client.request.method	string	Yes	The FGA method/action that was performed (e.g. Check, ListObjects, ...) in TitleCase
fga-client.request.store_id	string	Yes	The store ID that was sent as part of the request
fga-client.request.model_id	string	Yes	The authorization model ID that was sent as part of the request, if any
fga-client.request.client_id	string	Yes	The client ID associated with the request, if any
fga-client.request.batch_check_size	int	No	The number of checks in a batch check request
fga-client.user	string	No	The user that is associated with the action of the request for check and list objects
http.request.resend_count	int	Yes	The number of retries attempted (Only sent if the request was retried. Count of 1 means the request was retried once in addition to the original request)
http.response.status_code	int	Yes	The status code of the response
http.request.method	string	No	The HTTP method for the request
http.host	string	Yes	Host identifier of the origin the request was sent to
url.scheme	string	No	HTTP Scheme of the request (http/https)
url.full	string	No	Full URL of the request
user_agent.original	string	Yes	User Agent used in the query

Default Metrics

Not all metrics and attributes are enabled by default.

Some attributes, like fga-client.user have been disabled by default due to their high cardinality, which may result for very high costs when using some SaaS metric collectors. If you expect to have a high cardinality for a specific attribute, you can disable it by updating the TelemetryConfig accordingly.

Configuration

See the OpenTelemetry docs on Customizing the SDK.

using OpenFga.Sdk.Client;
using OpenFga.Sdk.Client.Model;
using OpenFga.Sdk.Model;
using OpenFga.Sdk.Telemetry;
using OpenTelemetry;
using OpenTelemetry.Metrics;
using OpenTelemetry.Resources;
using System.Diagnostics;

namespace Example {
    public class Example {
        public static async Task Main() {
            try {
                // Setup OpenTelemetry Metrics
                using var meterProvider = Sdk.CreateMeterProviderBuilder()
                    .AddHttpClientInstrumentation() // To instrument the default http client
                    .AddMeter(Metrics.Name) // .AddMeter("OpenFga.Sdk") also works
                    .ConfigureResource(resourceBuilder => resourceBuilder.AddService("openfga-dotnet-example"))
                    .AddOtlpExporter() // Required to export to an OTLP compatible endpoint
                    .AddConsoleExporter() // Only needed to export the metrics to the console (e.g. when debugging)
                    .Build();

                // Configure the OpenFGA SDK with default configuration (default metrics and attributes will be enabled)
                var configuration = new ClientConfiguration() {
                    ApiUrl = Environment.GetEnvironmentVariable("FGA_API_URL"),
                    StoreId = Environment.GetEnvironmentVariable("FGA_STORE_ID"),
                    AuthorizationModelId = Environment.GetEnvironmentVariable("FGA_MODEL_ID"),
                    // Credentials = ... // If needed
                };
                var fgaClient = new OpenFgaClient(configuration);

                // Call the SDK normally
                var response = await fgaClient.ReadAuthorizationModels();
            } catch (ApiException e) {
                 Debug.Print("Error: "+ e);
            }
        }
    }
}

Customize metrics

You can can customize the metrics that are enabled and the attributes that are included in the metrics by setting the TelemetryConfig property on the ClientConfiguration object. If you do set the Telemetry property to anything other than null, the default configuration will be overridden.

TelemetryConfig telemetryConfig = new () {
    Metrics = new Dictionary<string, MetricConfig> {
        [TelemetryMeter.TokenExchangeCount] = new () {
            Attributes = new HashSet<string> {
                TelemetryAttribute.HttpScheme,
                TelemetryAttribute.HttpMethod,
                TelemetryAttribute.HttpHost,
                TelemetryAttribute.HttpStatus,
                TelemetryAttribute.HttpUserAgent,
                TelemetryAttribute.RequestMethod,
                TelemetryAttribute.RequestClientId,
                TelemetryAttribute.RequestStoreId,
                TelemetryAttribute.RequestModelId,
                TelemetryAttribute.RequestRetryCount,
                TelemetryAttribute.ResponseModelId
            }
        },
        [TelemetryMeter.RequestDuration] = new () {
            Attributes = new HashSet<string> {
                TelemetryAttribute.HttpStatus,
                TelemetryAttribute.HttpUserAgent,
                TelemetryAttribute.RequestMethod,
                TelemetryAttribute.RequestClientId,
                TelemetryAttribute.RequestStoreId,
                TelemetryAttribute.RequestModelId,
                TelemetryAttribute.RequestRetryCount,
            }
        },
        [TelemetryMeter.QueryDuration] = new () {
            Attributes = new HashSet<string> {
                TelemetryAttribute.HttpStatus,
                TelemetryAttribute.HttpUserAgent,
                TelemetryAttribute.RequestMethod,
                TelemetryAttribute.RequestClientId,
                TelemetryAttribute.RequestStoreId,
                TelemetryAttribute.RequestModelId,
                TelemetryAttribute.RequestRetryCount,
            }
        },
        [TelemetryMeter.HttpRequestDuration] = new () {
            Attributes = new HashSet<string> {
                TelemetryAttribute.HttpStatus,
                TelemetryAttribute.HttpUserAgent,
                TelemetryAttribute.RequestMethod,
                TelemetryAttribute.RequestClientId,
                TelemetryAttribute.RequestStoreId,
                TelemetryAttribute.RequestModelId,
                TelemetryAttribute.RequestRetryCount,
            }
        },
    }
};

var configuration = new ClientConfiguration() {
    ApiUrl = Environment.GetEnvironmentVariable("FGA_API_URL"),
    StoreId = Environment.GetEnvironmentVariable("FGA_STORE_ID"),
    AuthorizationModelId = Environment.GetEnvironmentVariable("FGA_MODEL_ID"),
    // Credentials = ... // If needed
    Telemetry = telemetryConfig
};

More Resources

• OpenTelemetry.Instrumentation.Http for instrumenting the HttpClient.
• If you are using .NET 8+, checkout the built-in metrics.

A number of these metrics are baked into .NET 8+ as well:

Example

There is an example project that provides some guidance on how to configure OpenTelemetry available in the examples directory.