Stratara.Outbox.RabbitMQ 4.0.1

Prefix Reserved
There is a newer version of this package available.
See the version list below for details.
dotnet add package Stratara.Outbox.RabbitMQ --version 4.0.1
                    
NuGet\Install-Package Stratara.Outbox.RabbitMQ -Version 4.0.1
                    
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package.
<PackageReference Include="Stratara.Outbox.RabbitMQ" Version="4.0.1" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="Stratara.Outbox.RabbitMQ" Version="4.0.1" />
                    
Directory.Packages.props
<PackageReference Include="Stratara.Outbox.RabbitMQ" />
                    
Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package.
paket add Stratara.Outbox.RabbitMQ --version 4.0.1
                    
#r "nuget: Stratara.Outbox.RabbitMQ, 4.0.1"
                    
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package.
#:package Stratara.Outbox.RabbitMQ@4.0.1
                    
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package.
#addin nuget:?package=Stratara.Outbox.RabbitMQ&version=4.0.1
                    
Install as a Cake Addin
#tool nuget:?package=Stratara.Outbox.RabbitMQ&version=4.0.1
                    
Install as a Cake Tool

Stratara.Outbox.RabbitMQ

Derived. The behaviour described here is specified under openspec/specs/. Those specifications are the source; this page explains and illustrates them.

License: MIT.

Outbox-pattern command + event dispatch for the Stratara event-sourced stack with a RabbitMQ message-bus implementation. Contains the write-side dispatchers, the outbox-retry worker, the read-side mediator command worker, the RabbitMQ bus, and the Redis-backed ProjectionReplayState that coordinates dispatch skip during projection replay. Azure Service Bus ships separately as Stratara.Outbox.AzureServiceBus.

What's in the box

Folder Contents
Outbox/ OutboxOptions, CommandOutboxDispatcher (write-side ICommand fan-out via IMessageBus, falls back to outbox table on bus failure), EventBundleOutboxDispatcher (same for EventBundle), OutboxWorker (hosted service that retries unpublished outbox rows on a polling interval), NullOutboxLock + RedisOutboxLock (IOutboxLock implementations — default no-op for single-instance deployments, Redis-leased distributed lock for multi-replica setups)
Messaging/ RabbitMqBusIMessageBus over RabbitMQ. Azure Service Bus ships as the sibling Stratara.Outbox.AzureServiceBus package.
Mediator/ MediatorCommandWorker (hosted service that subscribes to the command topic and dispatches into the in-process IMediator)
Projections/ ProjectionReplayState (Redis-backed concrete IProjectionReplayState; dispatchers skip publishing while replay is active), ProjectionReplayOptions (how long the replay marking survives without renewal)
DependencyInjection/ AddOutboxDispatcher(), AddOutboxWorker(IConfiguration), AddRedisOutboxLock() (opt-in distributed lock), AddProjectionReplayState(), AddMediatorWorker(), AddMessaging()
Diagnostics/Extensions/ LoggerOutboxExtensions, LoggerMessagingExtensions (source-generated logger surfaces)

Quick start

// In your API host:
builder.AddMessaging();                          // IMessageBus + MessagingOptions binding
builder.Services
    .AddOutboxDispatcher()                       // CommandOutboxDispatcher + EventBundleOutboxDispatcher + ProjectionReplayState
    .AddOutboxWorker(builder.Configuration);     // OutboxWorker hosted service (only if this host owns retries)

// In your command worker:
builder.Services
    .AddMediatorWorker();                        // MediatorCommandWorker hosted service

The dispatchers consult IProjectionReplayState.IsReplayActive before each publish and skip dispatch (writing to the outbox table only) while a replay is in progress. They also record the outbox.published counter for what the broker accepted — the worker counts nothing, because only the dispatcher knows what went out.

The replay marking and its progress counters are held on the lease configured by ProjectionReplayOptions.LeaseSeconds (default 300), which the replay renews every time it reports progress. A replay whose host is killed stops renewing it and the marking lapses on its own, instead of suppressing publication indefinitely. AddProjectionReplayState() registers the options with their defaults; override with services.Configure<ProjectionReplayOptions>(...). Set it longer than the slowest stretch between two progress reports — too short lets the marking lapse while the replay is still running.

A drain cycle takes one batch of each kind and ends. Rows the broker would not accept stay in the table for the next interval; a cycle never re-reads what it just failed to publish, so an unreachable broker or a suppressed drain cannot turn a cycle into a loop over the same rows.

Multi-instance outbox workers

AddOutboxWorker registers NullOutboxLock as the default IOutboxLock — a no-op that preserves the single-instance assumption. For multi-replica deployments call AddRedisOutboxLock() afterwards; it replaces the no-op with a Redis-leased lock (SET stratara:outbox:lock NX EX) so only one replica drains at a time:

builder.AddCaching();                              // registers IConnectionMultiplexer
builder.Services
    .AddOutboxDispatcher()
    .AddOutboxWorker(builder.Configuration)
    .AddRedisOutboxLock();                         // multi-replica safe

The lease defaults to 60 s (OutboxOptions.LockLeaseSeconds). Tune it so it exceeds the worst-case drain duration; otherwise the lock can expire mid-cycle and a peer may start a concurrent drain. Outbox semantics are still at-least-once, so a duplicate publish is recoverable provided handlers stay idempotent.

Dependencies

  • Stratara.Abstractions — for ICommand, IEvent, IMessageBus, ICommandOutboxDispatcher, IEventBundleOutboxDispatcher, IProjectionReplayState, IMessagingIdentifier, IWriteUnitOfWork (used at runtime via the outbox repository).
  • Stratara.Contracts — for EventBundle + CommandEnvelope messages.
  • Stratara.MediatorMediatorCommandWorker dispatches into the in-process IMediator.
  • Stratara.Sessions — dispatcher hydrates CommandEnvelope from the current session context.
  • Stratara.Shared — for messaging primitives, resilience pipeline names, mapping helpers, and the diagnostics base.
  • RabbitMQ.Client, StackExchange.Redis (replay-state + optional outbox-lock).
  • Microsoft.Extensions.Hosting.Abstractions + Microsoft.Extensions.Options.ConfigurationExtensions — for hosted services + options binding.

The outbox dispatcher persists rows through IWriteUnitOfWork.CreateOutboxRepository — that interface lives in Stratara.Abstractions, but the concrete implementation comes from Stratara.EventSourcing.EntityFrameworkCore. Reference that package alongside this one to get a working stack.

Product Compatible and additional computed target framework versions.
.NET net10.0 is compatible.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (2)

Showing the top 2 NuGet packages that depend on Stratara.Outbox.RabbitMQ:

Package Downloads
Stratara.Infrastructure

Infrastructure glue for the Stratara framework — authorization decorators, configuration providers, and DI composition helpers that wire Mediator, Outbox, Identity, and EF Core into a hosted app.

Stratara.EventSourcing.WorkerDefaults

Worker-host wiring composites for the Stratara event-sourced stack. IHostApplicationBuilder extensions (AddBackendServices, AddCommandWorkerServices, AddHeavyCommandWorkerServices, AddEventProjectionWorkerServices, AddEventStreamHashWorkerServices, AddSagaWorkerServices, AddOutboxWorkerServices) bundle the per-concern DI calls so each worker host opts in with one line.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
4.0.3 82 9/3/2026
4.0.2 394 9/3/2026
4.0.1 156 9/2/2026
4.0.0 160 8/31/2026
4.0.0-preview.1 68 8/31/2026
3.4.0 153 8/28/2026
3.3.0 119 8/25/2026
3.2.3 133 8/22/2026
3.2.2 139 8/14/2026
3.2.1 147 8/2/2026
3.2.0 140 7/18/2026
3.1.7 154 7/1/2026
3.1.6 569 6/22/2026
3.1.5 151 6/22/2026
3.1.4 152 6/15/2026
3.1.3 153 6/10/2026
3.1.2 170 6/5/2026
3.1.1 228 6/1/2026
3.1.0 151 5/30/2026
3.0.23 141 5/28/2026

### Added

- **Bundles about one aggregate are now applied one at a time within a process, a handler can say
 "not yet", and the workers' parallelism is configurable.** The projection worker and the saga
 worker open one consumer per processor on a shared queue, so two bundles published milliseconds
 apart — the fact that creates an entity and the first fact about it — landed on two consumers and
 ran at the same time, and whichever finished first won. A projection that then found no row for
 the follow-up could only warn and acknowledge a fact it never applied, or throw and have the
 bundle discarded; either way the read model lost the fact until a replay. The command worker has
 never had this problem, because it takes a per-aggregate lock before it runs a command.

 Both workers now take the same lock, keyed on the streams the bundle's events belong to. Bundles
 about different aggregates still run in parallel; bundles about one aggregate queue behind each
 other. The guarantee is per process — two replicas consuming the same subscription do not
 serialise against each other — and the delivery guarantee now says so explicitly.

 The lock serialises but does not order, so the residual case gets a second chance:
 `PrecedingFactMissingException(streamId, eventTypeName)` in `Stratara.Abstractions` is the one
 exception the workers retry — five attempts from 100 ms doubling, about three seconds in all,
 under the new named policy `ResilienceNames.PrecedingFact`, with every aggregate lock released
 between attempts so the creating fact can land in the gap. Once the retries are exhausted the
 bundle fails as any unhandled failure does, and the warning logged on each attempt
 (`104_010` for projections, `110_005` for sagas) names the stream and the event type. Any other
 exception fails the bundle on the first attempt, as before.

 `Projections:DegreeOfParallelism` and `Sagas:DegreeOfParallelism` set the number of consumers each
 worker opens; a value that is not a positive number means the processor count, and `1` gives a
 worker that applies every bundle in the order the transport delivers it.

 A consumer that changes nothing gets the serialisation and the default parallelism it had. A
 consumer that implements `IMessageBus` itself is unaffected: the retry runs inside the worker
 before the transport sees an outcome. `BucketLockPool`, previously internal to the mediator, is
 now public in `Stratara.Abstractions` so that every worker takes the same lock from the same
 place; the mediator's own copy is gone.

### Changed

- **A published version now announces itself in the repository.** The release workflow gained a
 third job that creates the GitHub release entry for the tag once the packages have reached
 nuget.org, with the changelog section for that version as its notes — the same section the
 packages already carry as their release notes. A prerelease tag is marked as one, so it does not
 displace the current stable version. Until now the release list was maintained by hand and had
 fallen behind: 4.0.0 was on nuget.org while the repository still presented 3.4.0 as current.
 Nothing about what publishes, when, or on whose approval has changed.