Add project files.

src/modules/Elsa.MassTransit.RabbitMq/Elsa.MassTransit.RabbitMq.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <Description>
+            Provides integration of RabbitMQ with MassTransit's integration of Elsa.
+        </Description>
+        <PackageTags>elsa module service-bus masstransit rabbitmq</PackageTags>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\Elsa.Hosting.Management\Elsa.Hosting.Management.csproj" />
+      <ProjectReference Include="..\Elsa.MassTransit\Elsa.MassTransit.csproj" />
+    </ItemGroup>
+    
+    <ItemGroup>
+        <PackageReference Include="MassTransit.RabbitMQ" />
+    </ItemGroup>
+
+</Project>

src/modules/Elsa.MassTransit.RabbitMq/Extensions/ModuleExtensions.cs

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+using Elsa.Features.Services;
+using Elsa.MassTransit.Features;
+using Elsa.MassTransit.RabbitMq.Features;
+
+// ReSharper disable once CheckNamespace
+namespace Elsa.Extensions;
+
+/// <summary>
+/// Provides extensions to <see cref="IModule"/> that enables and configures MassTransit and the RabbitMQ transport.
+/// </summary>
+public static class ModuleExtensions
+{
+    /// <summary>
+    /// Enable and configure the RabbitMQ transport for MassTransit.
+    /// </summary>
+    public static MassTransitFeature UseRabbitMq(this MassTransitFeature feature, string connectionString)
+    {
+        feature.Module.Configure((Action<RabbitMqServiceBusFeature>)Configure);
+        return feature;
+
+        void Configure(RabbitMqServiceBusFeature bus)
+        {
+            bus.ConnectionString = connectionString;
+        }
+    }
+
+    /// <summary>
+    /// Enable and configure the RabbitMQ transport for MassTransit.
+    /// </summary>
+    public static MassTransitFeature UseRabbitMq(this MassTransitFeature feature, Action<RabbitMqServiceBusFeature> configure)
+    {
+        feature.Module.Configure(configure);
+        return feature;
+    }
+
+    /// <summary>
+    /// Enable and configure the RabbitMQ transport for MassTransit.
+    /// </summary>
+    public static MassTransitFeature UseRabbitMq(this MassTransitFeature feature, string connectionString, Action<RabbitMqServiceBusFeature> configure)
+    {
+        feature.Module.Configure<RabbitMqServiceBusFeature>(rabbitMqFeature =>
+        {
+            rabbitMqFeature.ConnectionString = connectionString;
+            configure(rabbitMqFeature);
+        });
+        return feature;
+    }
+}

src/modules/Elsa.MassTransit.RabbitMq/Features/RabbitMqServiceBusFeature.cs

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+using Elsa.Common;
+using Elsa.Extensions;
+using Elsa.Features.Abstractions;
+using Elsa.Features.Attributes;
+using Elsa.Features.Services;
+using Elsa.Hosting.Management.Contracts;
+using Elsa.Hosting.Management.Features;
+using Elsa.MassTransit.Extensions;
+using Elsa.MassTransit.Features;
+using Elsa.MassTransit.Options;
+using MassTransit;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace Elsa.MassTransit.RabbitMq.Features;
+
+/// <summary>
+/// Configures MassTransit to use the RabbitMQ transport.
+/// </summary>
+[DependsOn(typeof(MassTransitFeature))]
+[DependsOn(typeof(ClusteringFeature))]
+public class RabbitMqServiceBusFeature : FeatureBase
+{
+    /// <inheritdoc />
+    public RabbitMqServiceBusFeature(IModule module) : base(module)
+    {
+    }
+
+    /// <summary>
+    /// A RabbitMQ connection string.
+    /// </summary>
+    public string? ConnectionString { get; set; }
+
+    /// <summary>
+    /// Configures the RabbitMQ transport options.
+    /// </summary>
+    public Action<RabbitMqTransportOptions>? TransportOptions { get; set; }
+
+    /// <summary>
+    /// Configures the RabbitMQ bus.
+    /// </summary>
+    /// <remarks>This method is being marked as obsolete in favor of the ConfigureTransportBus which will provide additional access to the <see cref="IBusRegistrationContext"/></remarks>
+    [Obsolete("Use ConfigureTransportBus instead which provides a reference to IBusRegistrationContext.")]
+    public Action<IRabbitMqBusFactoryConfigurator>? ConfigureServiceBus { get; set; }
+
+    /// <summary>
+    /// Configures the RabbitMQ bus within MassTransit for additional transport level components or features.
+    /// This action provides access to the <see cref="IBusRegistrationContext"/> and <see cref="IRabbitMqBusFactoryConfigurator"/>.
+    /// </summary>
+    /// <remarks>
+    /// Use this action to configure advanced settings and features for the RabbitMQ bus, such as middleware 
+    /// or additional endpoints. This action will run in addition to the Elsa required configuration.
+    /// </remarks>
+    public Action<IBusRegistrationContext, IRabbitMqBusFactoryConfigurator> ConfigureTransportBus { get; set; }
+
+    /// <inheritdoc />
+    public override void Configure()
+    {
+        Module.Configure<MassTransitFeature>(massTransitFeature =>
+        {
+            massTransitFeature.BusConfigurator = configure =>
+            {
+                var temporaryConsumers = massTransitFeature.GetConsumers()
+                    .Where(c => c.IsTemporary)
+                    .ToList();
+
+                // Consumers need to be added before the UsingRabbitMq statement to prevent exceptions.
+                foreach (var consumer in temporaryConsumers)
+                    configure.AddConsumer(consumer.ConsumerType).ExcludeFromConfigureEndpoints();
+
+                configure.UsingRabbitMq((context, configurator) =>
+                {
+                    var options = context.GetRequiredService<IOptions<MassTransitOptions>>().Value;
+                    var instanceNameProvider = context.GetRequiredService<IApplicationInstanceNameProvider>();
+
+                    if (!string.IsNullOrEmpty(ConnectionString))
+                        configurator.Host(ConnectionString);
+
+                    if (options.PrefetchCount is not null)
+                        configurator.PrefetchCount = options.PrefetchCount.Value;
+                    configurator.ConcurrentMessageLimit = options.ConcurrentMessageLimit;
+
+                    ConfigureServiceBus?.Invoke(configurator);
+                    ConfigureTransportBus?.Invoke(context, configurator);
+
+                    foreach (var consumer in temporaryConsumers)
+                    {
+                        configurator.ReceiveEndpoint($"{instanceNameProvider.GetName()}-{consumer.Name}",
+                            endpointConfigurator =>
+                            {
+                                endpointConfigurator.QueueExpiration = options.TemporaryQueueTtl ?? TimeSpan.FromHours(1);
+                                endpointConfigurator.ConcurrentMessageLimit = options.ConcurrentMessageLimit;
+                                endpointConfigurator.Durable = false;
+                                endpointConfigurator.AutoDelete = true;
+                                endpointConfigurator.ConfigureConsumer(context, consumer.ConsumerType);
+                            });
+                    }
+
+                    if (!massTransitFeature.DisableConsumers)
+                    {
+                        if (Module.HasFeature<MassTransitWorkflowDispatcherFeature>())
+                            configurator.SetupWorkflowDispatcherEndpoints(context);
+                    }
+
+                    configurator.ConfigureEndpoints(context, new KebabCaseEndpointNameFormatter("Elsa", false));
+                    
+                    configurator.ConfigureJsonSerializerOptions(serializerOptions =>
+                    {
+                        var serializer = context.GetRequiredService<IJsonSerializer>();
+                        serializer.ApplyOptions(serializerOptions);
+                        return serializerOptions;
+                    });
+                    
+                    configurator.ConfigureTenantMiddleware(context);
+                });
+            };
+        });
+    }
+
+    /// <inheritdoc />
+    public override void Apply()
+    {
+        if (TransportOptions != null) Services.Configure(TransportOptions);
+    }
+}

src/modules/Elsa.MassTransit.RabbitMq/FodyWeavers.xml

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+<Weavers xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="FodyWeavers.xsd">
+  <ConfigureAwait />
+</Weavers>