EventSourcing.NetCore

Extended distributed processes examples with Choreography and Process Manager in addition to the already existing Saga example.

See details in PR https://github.com/oskardudycz/EventSourcing.NetCore/pull/206.

Full sample: https://github.com/oskardudycz/EventSourcing.NetCore/tree/main/Sample/HotelManagement

Video with explanation:

Added link to talk CQRS is simpler than you think with C#11 and .NET 7!

Watch it below:

Added example showing step-by-step how to migrate from CRUD-based application into CQRS.

See more in: https://github.com/oskardudycz/EventSourcing.NetCore/tree/main/Sample/CRUDToCQRS.

You can watch:

and read:

• 📝 Let's build event store in one hour!

Check the full self-paced kit a and do it on your ownt: https://github.com/oskardudycz/EventSourcing.NetCore/tree/main/Workshops/BuildYourOwnEventStore

Simplified the repositories usage. Previously they were all in one, plus optimistic concurrency handling from the HTTP request ETag had too many classes. Now they were dropped and replaced with repositories decorators.

Added also repositories registration helpers that are capable of building the onion around the base repository with Optimistic Concurrency scope and Telemetry data.

What's Changed

• Refactored Append Scopes into Repository Decorators by @oskardudycz in https://github.com/oskardudycz/EventSourcing.NetCore/pull/191
• Added wrapper for Marten repository instead of the internal logic for tracing by @oskardudycz in https://github.com/oskardudycz/EventSourcing.NetCore/pull/192

Full Changelog: https://github.com/oskardudycz/EventSourcing.NetCore/compare/v17.0.0...v18.0.0

Added example of distributed processes management using Group Guests Checkout as an example.
It was modelled and explained in detail in the Implementing Distributed Processes Webinar:

It shows how to:

• orchestrate and coordinate business workflow spanning across multiple aggregates using Saga pattern,
• handle distributed processing both for asynchronous commands scheduling and events publishing,
• getting at-least-once delivery guarantee,
• implementing command store and outbox pattern on top of Marten and EventStoreDB,
• unit testing aggregates and Saga with a little help from Ogooreck,
• testing asynchronous code,

Read more in:

• Saga and Process Manager - distributed processes in practice
• Event-driven distributed processes by example.

See more in PR: https://github.com/oskardudycz/EventSourcing.NetCore/pull/167.

What's Changed

• Brought back test reporter in https://github.com/oskardudycz/EventSourcing.NetCore/pull/189

Full Changelog: https://github.com/oskardudycz/EventSourcing.NetCore/compare/v16.2.0...v16.3.0

What's Changed

• Configured static analysis and applied ConfigureAwait(false) to Core classes by @oskardudycz in https://github.com/oskardudycz/EventSourcing.NetCore/pull/188
• Fix for CustomerIncidentsSummaryGrouper Issue in Helpdesk sample by @stavris8894 in https://github.com/oskardudycz/EventSourcing.NetCore/pull/173
• Fixed typo in the composite key example. by @oskardudycz in https://github.com/oskardudycz/EventSourcing.NetCore/pull/187

New Contributors

• @stavris8894 made their first contribution in https://github.com/oskardudycz/EventSourcing.NetCore/pull/173

Full Changelog: https://github.com/oskardudycz/EventSourcing.NetCore/compare/v16.1.0...v16.2.0

What's Changed

• Replaced Event Bus with Event Store in projection tests to make them more explicit and self-explanatory in https://github.com/oskardudycz/EventSourcing.NetCore/pull/186

Full Changelog: https://github.com/oskardudycz/EventSourcing.NetCore/compare/v16.0.0...v16.1.0

Introduced Open Telemetry tracing together with context propagation:

• CQRS processing,
• Marten,
• EventStoreDB,
• Kafka.

Removed MediatR as:

• I'd like to have more customisation around Open Telemetry instrumentation,
• Retries,
• I haven't used either pipelines or behaviours,
• it was more limiting than helping (especially with its enforcement of marker interfaces).

Removed previous manual instrumentation around correlation and causation ids.

TODO:

• https://github.com/oskardudycz/EventSourcing.NetCore/issues/184,
• https://github.com/oskardudycz/EventSourcing.NetCore/issues/185.

See details in https://github.com/oskardudycz/EventSourcing.NetCore/pull/181.

• Simplest CQRS and Event Sourcing flow using Minimal API,
• Cutting the number of layers and boilerplate complex code to the bare minimum,
• Using all Marten helpers like WriteToAggregate and AggregateStream to simplify the processing,
• Examples of all the typical Marten's projections,
• Example of how and where to use C# Records, Nullable Reference Types, etc,
• No Aggregates. Commands are handled in the domain service as pure functions.

See more in https://github.com/oskardudycz/EventSourcing.NetCore/pull/161.

1. Migrated all API tests to Ogooreck.
2. Removed all startup classes and used a single Program file and WebApplicationFactory for tests.
3. Aligned tests, and removed obsolete helpers.
4. Fixed issue with doubled registration of event handlers because of open-generic EventListener registration (replaced with IEventBus decorator).

Read more about Ogooreck in my blog post: Ogooreck, a sneaky testing library in BDD style.

See details in PR: https://github.com/oskardudycz/EventSourcing.NetCore/pull/136.

1. Aligned also Marten projections naming to latest convention:

• AggregateProjection to SingleStreamAggregation,
• ViewProjection to MultiStreamAggregation

2. Used convention-based version assignment on stream aggregation and single-stream projections.

Fixed Kafka integration

• added the initialiser to docker-compose to set the Kafka topics upfront.
• fixed EventEnvelope creation to use a generic one. Changed the non-generic from record to interface to make sure that it won't be used.
• made sure that EventBus takes only EventEnvelope.
• created EventEnvelope in the external publishing.
• used handler in KafkaConsumer to deserialise contracts with private constructors,
• changed KafkaConsumer setting to commit offset manually.
• enforced EventEnvelope on in-memory bus.
• added EventEnvelopeExtensions for Kafka message deserialisation and aligned with EventStoreDB subscription to all to ignore messages that are not able to deserialise

See more in PR: https://github.com/oskardudycz/EventSourcing.NetCore/pull/150

Do you know that you can use .NET MinimalAPI methods not only in Program.cs?
Yes, you can! It lets you slice your architecture and put endpoints definitions separately, near the respectful business logic. This matches great with CQRS.

See more in the PR: https://github.com/oskardudycz/EventSourcing.NetCore/pull/144

• CQRS flow using Minimal API,
• example how to inject handlers in MediatR'like style to decouple API from handling,
• example of how and where to use C# Records, Nullable Reference Types, etc,
• No Event Sourcing! Using Entity Framework to show that CQRS is not bounded to Event Sourcing or any type of storage,
• No Aggregates! CQRS does not need DDD. Business logic can be handled by handlers.
• 📝 Read more CQRS is simpler than you think with .NET 6 and C# 10

See more in

• code https://github.com/oskardudycz/EventSourcing.NetCore/tree/main/Sample/Warehouse.MinimalAPI
• PR https://github.com/oskardudycz/EventSourcing.NetCore/pull/92.

Refactored and added solutions projections exercises

Refactored projections tests to focus on single-stream projections first, then expand on multi-stream projections. Mixing them in the same exercise brings too many concepts immediately. I decided to refactor the current one to show details and list projections for the single stream and include multi-stream projections as the follow-up exercises. They will come in one of the following pull requests.

See the new version of the exercises:

• projections,
• projections with idempotency handling,
• projections with eventual consistency handling.

Related Pull Requests: #139 , #140

Added link to "CQRS is simpler than you think with C#9 and NET 5!" webinar

Watch it 👇

Added link to "How to deal with privacy and GDPR in Event-Sourced systems" talk.
Watch it 👇

Upgraded also packages to the most recent versions.

Added link to "Let's build the worst Event Sourcing system!" talk I gave at EventSourcing Live 2021 conference.
Watch it 👇