Stratara.Projections
4.3.1
Prefix Reserved
See the version list below for details.
dotnet add package Stratara.Projections --version 4.3.1
NuGet\Install-Package Stratara.Projections -Version 4.3.1
<PackageReference Include="Stratara.Projections" Version="4.3.1" />
<PackageVersion Include="Stratara.Projections" Version="4.3.1" />
<PackageReference Include="Stratara.Projections" />
paket add Stratara.Projections --version 4.3.1
#r "nuget: Stratara.Projections, 4.3.1"
#:package Stratara.Projections@4.3.1
#addin nuget:?package=Stratara.Projections&version=4.3.1
#tool nuget:?package=Stratara.Projections&version=4.3.1
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— 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 (>= 4.3.1)
- Stratara.Domain (>= 4.3.1)
- Stratara.Shared (>= 4.3.1)
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 |
|---|---|---|
| 4.4.4 | 0 | 10/10/2026 |
| 4.4.3 | 0 | 10/10/2026 |
| 4.4.2 | 328 | 10/2/2026 |
| 4.4.1 | 415 | 9/29/2026 |
| 4.4.0 | 173 | 9/27/2026 |
| 4.3.1 | 179 | 9/25/2026 |
| 4.3.0 | 340 | 9/23/2026 |
| 4.2.0 | 219 | 9/18/2026 |
| 4.1.1 | 141 | 9/16/2026 |
| 4.1.0 | 147 | 9/16/2026 |
| 4.0.4 | 964 | 9/14/2026 |
| 4.0.3 | 200 | 9/3/2026 |
| 4.0.2 | 636 | 9/3/2026 |
| 4.0.1 | 349 | 9/2/2026 |
| 4.0.0 | 186 | 8/31/2026 |
| 4.0.0-preview.1 | 83 | 8/31/2026 |
| 3.4.0 | 175 | 8/28/2026 |
| 3.3.0 | 145 | 8/25/2026 |
| 3.2.3 | 166 | 8/22/2026 |
| 3.2.2 | 166 | 8/14/2026 |
A correctness release. A projection replay could apply a stream's later fact before its first and
then fail on every attempt, leaving the read models it had emptied empty; the two backfills that
prepare existing history for the Orleans execution model's commit-order readers took the same wrong
order. Beyond that, the setting store no longer needs declared settings, and a setting or permission
vocabulary can be declared in parts.
**Upgrading:**
- **If you replay projections, upgrade.** A store in which one save appended several versions of a
stream can hold sequence numbers that run against those versions, and a replay over it could not
complete. No entry is rewritten and no migration is needed.
- **If you implement `IEventStreamRepository` yourself,** override
`GetManyAfterSequenceInStreamOrderAsync` to give your replay the same guarantee; the default keeps
sequence order.
- **If you backfilled a store for a commit-order reader before this release,** the Orleans migration
guide gives the query that tells whether that history holds a stream out of version order, and how
to repair it.
- **A host that declared an empty `SettingCatalog` as a workaround can drop it.** A host that
registers a catalog through a factory and then calls `AddSettingCatalog` or `AddPermissionCatalog`
now fails at registration instead of replacing that catalog.
- No schema change.
### Added
- **`IEventStreamRepository.GetManyAfterSequenceInStreamOrderAsync`**: a range of the store in the order a
replay applies it — each stream's entries in version order, the streams interleaved as their sequence numbers
interleave them, and the range extended until it no longer ends between two versions of one stream. The default
implementation returns `GetManyAfterSequenceAsync`, sequence order, so a repository of your own compiles and
behaves as before; override the member to give your replay the guarantee.
### Fixed
- **A projection replay applies each stream in version order.** A save does not number its entries in version
order — EF Core chooses the statement order and the identity column numbers the rows as they arrive — and the
replay walked the store by sequence number, so it met a stream's later fact before its first. A projection that
reports a missing preceding fact then failed the batch on every attempt, and because a replay empties the read
models first, each attempt left the read side empty. On a store where many saves wrote several versions of one
stream, no replay could complete. The replay now reads through the new repository member; a batch can hold more
entries than `Projections:BatchSize`. No entry is rewritten and no migration is needed.
- **Both commit-order backfills keep each stream in version order.** `CommitTransactionIdBackfill` could end a
batch between two versions of one stream, stamping the later one with the earlier transaction.
`PartitionCounterBackfill` handed out positions in sequence order, so every save it positioned that the store
had numbered against its versions was read inverted by the portable reader. Both now extend a batch until it no
longer ends inside a stream, and the portable backfill positions each stream's entries in version order.
History backfilled with an earlier version is not revisited, because checkpoints stand on its commit records and
positions; the Orleans migration guide gives the query that tells whether a store holds such a stream.
- **The setting store works without declared settings.** `AddSettingStore<TContext>()` and
`AddSettingStoreFromContextFactory<TContext>()` resolved the `SettingCatalog` inside a factory, so a
host that registered the store and `AddStrataraErasure()` but declared no settings built, passed
`ValidateOnBuild` and every start-up check, and failed on its first erasure with *No service for type
`SettingCatalog` has been registered*. The store now registers an empty catalog when none is declared:
the store works, erasure included, and reading any setting through `ISettingProvider` fails as
undeclared. The example on `AddStrataraErasure` was exactly that composition. A host that declared an
empty catalog as a workaround can drop it.
- **A second `AddSettingCatalog` or `AddPermissionCatalog` call no longer replaces the first.** Each
call registered a new catalog and the last one won, so a host declaring its vocabulary per module kept
only the last module's — the others' settings failed as undeclared and their permissions were denied
without a word. Every call now adds to the one registered catalog, in whichever order it runs relative
to the setting store. A setting name declared in two parts throws as a duplicate; a redeclared
permission has no effect and grants to one role accumulate. A catalog registered as a factory cannot be
added to, and the next call now throws `InvalidOperationException` saying so instead of replacing it.