Class for handling MassTransit errors and sending faults to NewRelic.

NewRelicReceiveObserver.cs

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using MassTransit;
using NewRelic.Api.Agent;

/// <summary>
/// <see cref="IReceiveObserver"/> implementation that sends faults to NewRelic.
/// </summary>
public class NewRelicReceiveObserver : IReceiveObserver
{
    public Task PreReceive(ReceiveContext context) => Task.CompletedTask;

    public Task PostReceive(ReceiveContext context) => Task.CompletedTask;

    public Task PostConsume<T>(ConsumeContext<T> context, TimeSpan duration, string consumerType)
        where T : class
        => Task.CompletedTask;

    public Task ConsumeFault<T>(ConsumeContext<T> context, TimeSpan duration, string consumerType, Exception exception)
        where T : class
        => SendErrorToNewRelic(exception, nameof(ConsumeFault), consumerType);

    public Task ReceiveFault(ReceiveContext context, Exception exception)
        => SendErrorToNewRelic(exception, nameof(ReceiveFault));

    private static Task SendErrorToNewRelic(Exception exception, string faultType, string consumerType = null)
    {
        var newRelicParams = new Dictionary<string, string>
        {
            ["source"] = "MassTransit",
            ["faultType"] = faultType
        };

        if (consumerType != null)
        {
            newRelicParams.Add("consumerType", consumerType);
        }

        NewRelic.NoticeError(exception, newRelicParams);
        return Task.CompletedTask;
    }
}