Stratara.Projections
4.4.2
Prefix Reserved
dotnet add package Stratara.Projections --version 4.4.2
NuGet\Install-Package Stratara.Projections -Version 4.4.2
<PackageReference Include="Stratara.Projections" Version="4.4.2" />
<PackageVersion Include="Stratara.Projections" Version="4.4.2" />
<PackageReference Include="Stratara.Projections" />
paket add Stratara.Projections --version 4.4.2
#r "nuget: Stratara.Projections, 4.4.2"
#:package Stratara.Projections@4.4.2
#addin nuget:?package=Stratara.Projections&version=4.4.2
#tool nuget:?package=Stratara.Projections&version=4.4.2
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— forEventBundle+IEvent<T>.Stratara.Domain— for the framework'sTenantaggregate (only consumed byTenantProjection).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 | Versions 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. |
-
net10.0
- JetBrains.Annotations (>= 2026.2.0)
- Microsoft.Extensions.Hosting.Abstractions (>= 10.0.11)
- Microsoft.Extensions.Options.ConfigurationExtensions (>= 10.0.11)
- Stratara.Contracts (>= 4.4.2)
- Stratara.Domain (>= 4.4.2)
- Stratara.Shared (>= 4.4.2)
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 |
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.