Stratara.Projections 4.0.4

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paket add Stratara.Projections --version 4.0.4
                    
#r "nuget: Stratara.Projections, 4.0.4"
                    
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#:package Stratara.Projections@4.0.4
                    
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#addin nuget:?package=Stratara.Projections&version=4.0.4
                    
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#tool nuget:?package=Stratara.Projections&version=4.0.4
                    
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Stratara.Projections

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

License: MIT.

Projection runtime for the Stratara event-sourced stack. Discovers IProjection implementations in the consumer's application assemblies, dispatches event bundles to them, and applies the resulting change sets atomically via the read-model repository layer.

What's in the box

Folder Contents
Services/ The runtime, all internal: ProjectionManager (event-bundle → matching projection-handlers fan-out), ProjectionHandler (invokes a projection's matching methods), ProjectionMethodInvoker (reflection-cached method-pointer dispatch into consumer projections). You implement IProjection; these drive it
Multitenancy/ TenantProjection — the framework's own opinionated tenant aggregate projection. Skip the registration if your application has its own tenancy model
Diagnostics/Extensions/ Source-generated LoggerProjectionExtensions, LoggerChangeSetExtensions, LoggerUpdateExtensions — typed [LoggerMessage] surfaces under the Stratara.Projection.* / Stratara.ChangeSet.* / Stratara.Update.* event-ID bands

Quick start

// In your EventProjection worker:
builder.Services
    .AddProjectionWorker(builder.Configuration)                       // the runtime + hosted service
    .AddProjectionsFromAssemblyContaining<MyAppProjectionMarker>();   // your IProjection implementations

Then implement IProjection in your application assembly. The projection manager picks them up automatically.

Both calls are needed: AddProjectionsFromAssemblyContaining<T>() only registers your projections — AddProjectionWorker(IConfiguration) registers the manager, the invoker and the hosted service that consumes the event-bundle subscription. Without it nothing drives your projections. Most hosts get both from the AddEventProjectionWorkerServices() composite in Stratara.EventSourcing.WorkerDefaults.

No checkpoint store. Projections are driven push-wise off the event bus; the framework keeps no per-projection checkpoint, so there is no consumer-lag metric and no built-in resume-from-sequence. Replay is coordinated separately (see Stratara.Outbox.RabbitMQ's replay state).

Dependencies

  • Stratara.Contracts — for EventBundle + IEvent<T>.
  • Stratara.Domain — for the framework's Tenant aggregate (only consumed by TenantProjection).
  • Stratara.Shared — for change-tracking primitives, reflection cache, partitioning helpers, diagnostics base.
  • Microsoft.Extensions.Hosting.Abstractions + Microsoft.Extensions.Options.ConfigurationExtensions — for projection-worker checkpointing options.
  • JetBrains.Annotations — for static-analysis attributes on projection-handler conventions.
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 (3)

Showing the top 3 NuGet packages that depend on Stratara.Projections:

Package Downloads
Stratara.EventSourcing.EntityFrameworkCore

EF Core persistence for the Stratara event-sourced stack on PostgreSQL — write-store, read-store, ASP.NET Identity store, shared conventions, value generators, and UnitOfWork primitives. Targets Npgsql; maps pgvector types for a model that uses them, and needs no database extension otherwise.

Stratara.EventSourcing.WorkerDefaults

Worker-host wiring composites for the Stratara event-sourced stack. IHostApplicationBuilder extensions (AddBackendServices, AddCommandWorkerServices, AddHeavyCommandWorkerServices, AddEventProjectionWorkerServices, AddEventStreamHashWorkerServices, AddSagaWorkerServices, AddOutboxWorkerServices, and AddCommandServices, AddEventProjectionServices and AddSagaServices without the bus-fed workers) bundle the per-concern DI calls so each worker host opts in with one line.

Stratara.Orleans

The Orleans execution model for the Stratara event-sourced stack — one activation per aggregate across the cluster, commands recorded before the call returns and resumed after a crash, projections and sagas that read the store in commit order from a checkpoint, singleton work, owner-checked durable timers and heavy work bounded across the cluster.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
4.2.0 67 9/18/2026
4.1.1 106 9/16/2026
4.1.0 110 9/16/2026
4.0.4 696 9/14/2026
4.0.3 192 9/3/2026
4.0.2 627 9/3/2026
4.0.1 250 9/2/2026
4.0.0 178 8/31/2026
4.0.0-preview.1 77 8/31/2026
3.4.0 167 8/28/2026
3.3.0 140 8/25/2026
3.2.3 159 8/22/2026
3.2.2 156 8/14/2026
3.2.1 168 8/2/2026
3.2.0 155 7/18/2026
3.1.7 440 7/1/2026
3.1.6 579 6/22/2026
3.1.5 164 6/22/2026
3.1.4 178 6/15/2026
3.1.3 168 6/10/2026
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Three findings from a proof of concept of an alternative execution model, each fixed on the shipped
path. A message a handler cannot take is now redelivered a bounded number of times and then
dead-lettered on both brokers instead of being dropped on one of them; an opt-in closes the window
in which a committed fact could be lost between the commit and its publication; and a version
collision is a concurrency conflict on every supported database provider, not only on PostgreSQL.
Additive on every published surface, with one operator step on RabbitMQ: the worker queues change
name and type, and the old ones are deleted once drained.

### Added

- `Outbox:DurableBundles` (`OutboxOptions.DurableBundles`, default `false`): an event bundle is
 written to the outbox table in the transaction that commits its events, published after the
 commit, and removed once the bus has accepted it — so a process that ends between the commit and
 the publish no longer loses the bundle for every subscription. `IEventBundleOutboxDispatcher`
 gains `StoresBundlesWithCommit` and `StoreEventBundleAsync`, and `IOutboxRepository` an
 `AddAsync(Guid id, …)` overload, all default-implemented so a consumer's own implementations keep
 compiling and keep bus-first. `AddOutboxDispatcher()` now binds the `Outbox` section when the host
 carries a configuration. Log event `106_108` records a stored copy the bus accepted but the
 framework could not remove. The default path is unchanged; the specification now names its window.

- `IStoreConflictDetector` in `Stratara.Abstractions.EventSourcing`: recognises a database
 provider's refusal of a duplicate stream version, so the event source can surface it as a
 `ConcurrencyException` on that provider. `AddNpgsqlWriteDbContextFactory<T>()` registers the
 PostgreSQL detector and `AddStrataraTestingEventStore<T>()` the SQLite one; detectors accumulate,
 so a host on another provider adds its own without displacing the framework's. A host that
 registers its write context without `AddNpgsqlWriteDbContextFactory<T>()` gets no detector and
 no longer sees a `ConcurrencyException` on a version collision: it switches to that registration,
 or registers an `IStoreConflictDetector` of its own that recognises PostgreSQL's SQL state
 `23505` in the exception chain (the framework's implementations are not public).

- `MessageRetryOptions` (`Stratara.Abstractions.Messaging`, section `MessageRetry`):
 `MaxDeliveryAttempts` (default 3) and `MaxConflictRequeues` (default 100), bound and validated by
 `AddMessaging()` and by both `AddAzureServiceBus*` registrations. `MessageRetryPolicy` is the
 decision both transports apply. Log event `108_110` and counter `messaging.dead_lettered`
 (tags `messaging.topic`, `messaging.subscription`, `reason`) record every dead-lettering; `108_111`
 warns when a Service Bus subscription's `MaxDeliveryCount` is below the bounds.

### Changed

- A save now maps and signs its event bundle before the transaction opens, so a save with no
 session context — or a signer that fails — fails before anything is committed rather than after
 the commit with the events stranded unpublished.
- **RabbitMQ worker subscriptions are quorum queues with a dead-letter queue, under a new name.**
 A message whose handler throws is redelivered up to `MaxDeliveryAttempts` times (a concurrency
 conflict up to `MaxConflictRequeues` times) and then moved to `<subscription>.dead-letter`; it was
 rejected and dropped by the broker before (conflicts were requeued without bound). Because a
 classic queue cannot be redeclared as a quorum queue, the worker queue is now
 `<subscription>.v2`. **Rollout:** deploy — old and new consumers share the exchange and both
 receive every message — then delete the old `<subscription>` queue once it is drained, or it fills
 forever. Needs RabbitMQ 3.8+.
- **Azure Service Bus applies the same bounds.** A handler failure is abandoned for redelivery until
 `MaxDeliveryAttempts` and then dead-lettered with reason `failure` (it was dead-lettered on the
 first failure with the exception type as reason); a conflict is dead-lettered by the framework
 past `MaxConflictRequeues` with reason `conflict` (it was left to the broker's `MaxDeliveryCount`).
 Set the subscription's `MaxDeliveryCount` at least one above the larger bound.
- `AddAzureServiceBus` and `AddAzureServiceBusWithManagedIdentity` also register a
 `ServiceBusAdministrationClient` (try-add) for the advisory limit check.

### Fixed

- The `MediatorCommandWorker` remark said a failing command was dead-lettered; on RabbitMQ it was
 dropped. It is now dead-lettered on both brokers, and the remark and the
 `BusEnvelopeIntegrityMode.Strict` remark say what happens.
- A duplicate stream version on the SQLite test store (`Stratara.Testing.EntityFrameworkCore`) now
 surfaces as `ConcurrencyException`, as it does on PostgreSQL, instead of a bare
 `DbUpdateException`. A test that asserted the old exception type needs the new one.