Stratara.Projections 4.4.2

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dotnet add package Stratara.Projections --version 4.4.2
                    
NuGet\Install-Package Stratara.Projections -Version 4.4.2
                    
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.Projections" Version="4.4.2" />
                    
For projects that support PackageReference, copy this XML node into the project file to reference the package.
<PackageVersion Include="Stratara.Projections" Version="4.4.2" />
                    
Directory.Packages.props
<PackageReference Include="Stratara.Projections" />
                    
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.Projections --version 4.4.2
                    
#r "nuget: Stratara.Projections, 4.4.2"
                    
#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.Projections@4.4.2
                    
#: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.Projections&version=4.4.2
                    
Install as a Cake Addin
#tool nuget:?package=Stratara.Projections&version=4.4.2
                    
Install as a Cake Tool

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
Abstractions/ IProjection and its refinements: IRebuildableProjection (can be rebuilt alone on the Orleans execution model) and IForgetsDeletedTenants (a fact recorded for a tenant after its deletion is passed over instead of failing the projection; the record is kept by IForgottenTenantStore, which the read store provides)
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
4.4.2 270 10/2/2026
4.4.1 415 9/29/2026
4.4.0 173 9/27/2026
4.3.1 177 9/25/2026
4.3.0 338 9/23/2026
4.2.0 216 9/18/2026
4.1.1 139 9/16/2026
4.1.0 145 9/16/2026
4.0.4 962 9/14/2026
4.0.3 198 9/3/2026
4.0.2 634 9/3/2026
4.0.1 343 9/2/2026
4.0.0 184 8/31/2026
4.0.0-preview.1 81 8/31/2026
3.4.0 173 8/28/2026
3.3.0 143 8/25/2026
3.2.3 164 8/22/2026
3.2.2 164 8/14/2026
3.2.1 175 8/2/2026
3.2.0 165 7/18/2026
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A release about a flag that cost too much. Every host sharing the replay coordination state over Redis
asked Redis, with a blocking round trip on the calling thread, whether a replay was active — and the
Orleans execution model asked on every hot path, eight to ten times per command on a host with three
projections, inside grain turns. On a two-core host that was enough to starve the thread pool and time
the Redis connection out, surfacing as failed catch-ups, lagging read models and failed grain
registrations although no replay ever ran. The answer now comes from memory. No migration is needed;
one optional setting is new.

### Fixed

- **No path waits on Redis to learn whether a replay is active.** The Redis-backed replay state answers
 `IsReplayActive` from a field. A change made in the host itself is seen there at once; a change made
 elsewhere — a replay that began or ended in another host, or a marking that lapsed — is announced over
 a channel beside the replay-request channel and seen within its latency, and every host re-reads the
 marking every `ProjectionReplay:RefreshSeconds` regardless, as the safety net for a lost announcement.
 The Orleans execution model's command dispatcher, bundle dispatcher, store readers and drain, and the
 bus dispatchers, make no Redis call for it any more. Nothing changes for a host without Redis, whose
 state was in process already, nor for a host that registers its own `IProjectionReplayState`.

### Added

- **`ProjectionReplayOptions.RefreshSeconds`** (default 5), read from the `ProjectionReplay` section
 like the lease. It bounds how long a host answers from a replay marking that changed elsewhere where the
 announcement was lost. Refused when the host starts at zero or below, and at or above
 `LeaseSeconds`, with an `OptionsValidationException` naming `ProjectionReplay:RefreshSeconds`.
- **Log events `104_015` to `104_018`.** A host that cannot refresh the replay marking from Redis says
 so once at Warning (`104_015`) and keeps its last answer; `104_016` at Information says it reads the
 marking again. A host that cannot subscribe to the marking's announcements says so once at Warning
 (`104_017`), sees a change on the refresh period only, and `104_018` says it is subscribed again.

### Changed

- **A host that cannot reach Redis keeps its last answer about the replay.** Before, every dispatch and
 every catch-up on such a host failed with the connection's exception. Now they proceed on what the host
 last learned — initially that no replay is active — and the loss is logged once. The replay stays
 correct regardless: on the Orleans execution model the readers are paused by the rebuild and the
 replay themselves, and apply the store from the beginning once more when the replay ends.
- **Rolling upgrade.** A host on a release before this one announces nothing when it starts or ends a
 replay, so a host on this release sees that replay at the refresh period rather than at once. The
 marking, its key and its lease are unchanged, so the two releases share one replay state.