Prometheus Metrics

MassTransit.Prometheus

MassTransit supports Prometheus metric capture, which provides useful observability into the bus, endpoints, consumers, and messages.

The prometheus-net library is used as the Prometheus client since it is mentioned on the Prometheus client list.

Configuration

To configure the bus to capture metrics, add the UsePrometheusMetrics() method to your bus configuration.

public void ConfigureServices(IServiceCollection services)
{
    // this registration is simplified
    services.AddMassTransit(x =>
    {

        x.AddBus(context => Bus.Factory.CreateUsingRabbitMq(cfg =>
        {
            cfg.UsePrometheusMetrics(serviceName: "order_service");
        }));
    });
}

Publishing Metrics

Metrics must be available on an HTTP endpoint, by default it is /metrics. Add the ASP.NET Core integration package to get this endpoint out-of-the-box.

TIP

To publish metrics so that they can be scraped by Prometheus, an ASP.NET Core Generic Host is recommended, with the Kestrel HTTP server configured.

dotnet add package prometheus-net.AspNetCore

And then, add the metric server to the application builder.

public void Configure(IApplicationBuilder app)
{
    app.UseMetricServer();
}

For more details, see the Prometheus-Net Documentation.

Metrics Captured

The metrics captured by MassTransit are listed below.

Name	Description
mt_receive_total	Total number of messages received
mt_receive_fault_total	Total number of messages receive faults
mt_receive_duration_seconds	Elapsed time spent receiving messages, in seconds
mt_receive_in_progress	Number of messages being received
mt_consume_total	Total number of messages consumed
mt_consume_fault_total	Total number of message consume faults
mt_consume_retry_total	Total number of message consume retries
mt_consume_duration_seconds	Elapsed time spent consuming a message, in seconds
mt_delivery_duration_seconds	Elapsed time between when the message was sent and when it was consumed, in seconds.
mt_publish_total	Total number of messages published
mt_publish_fault_total	Total number of message publish faults
mt_send_total	Total number of messages sent
mt_send_fault_total	Total number of message send faults
mt_bus	Number of bus instances
mt_endpoint	Number of receive endpoint instances
mt_consumer_in_progress	Number of consumers in progress
mt_handler_in_progress	Number of handlers in progress
mt_saga_in_progress	Number of sagas in progress
mt_activity_execute_in_progress	Number of activity executions in progress
mt_activity_compensate_in_progress	Number of activity compensations in progress
mt_activity_execute_total	Total number of activities executed
mt_activity_execute_fault_total	Total number of activity executions faults
mt_activity_execute_duration_seconds	Elapsed time spent executing an activity, in seconds
mt_activity_compensate_total	Total number of activities compensated
mt_activity_compensate_failure_total	Total number of activity compensation failures
mt_activity_compensate_duration_seconds	Elapsed time spent compensating an activity, in seconds

Labels

For the metrics above, labels are specified where appropriate.

Name	Description
service_name	The service name specified at bus configuration
endpoint_address	The endpoint address
message_type	The message type for the metric
consumer_type	The consumer, saga, or activity type for the metric
activity_name	The activity name
argument_type	The activity execute argument type
log_type	The activity compensate log type
exception_type	The exception type for a fault metric