EventFlow

$ dotnet add package EventFlow

EventFlow is a basic CQRS+ES framework designed to be easy to use.

Have a look at our getting started guide, the do’s and don’ts and the FAQ.

Alternatively, join our Discord server to engage with the community. Its hopefully getting a reboot to kickstart the upcoming release of v1.

Features

• Easy to use: Designed with sensible defaults and implementations that make it easy to create an example application
• Highly configurable and extendable: EventFlow uses interfaces for every part of its core, making it easy to replace or extend existing features with custom implementation
• No use of threads or background workers
• MIT licensed Easy to understand and use license for enterprise

Versions

Development of version 1.0 has started and is mainly braking changes regarding changes related to replacing EventFlow types with that of Microsoft extension abstractions, mainly IServiceProvider and ILogger<>.

The following list key characteristics of each version as well as its related branches (not properly configured yet).

• 1.x

  Represents the next iteration of EventFlow that aligns EventFlow with the standard packages for .NET. Releases here will only support .NET Standard, .NET Core and .NET versions 6+ going forward.

  • Released
  • Still development
  • Not all projects migrated yet

  Read the migration guide to view the full list of breaking changes as well as recommendations on how to migrate.

  Documentation

  Version 1.x documentation has been pulled into this repository in order to have the code and documentation closer together and have the documentation updated in the same pull-requests as any code changes. The compiled version of the documentation is available at https://geteventflow.net/.

  NuGet package status

  • 🟢 ported
  • 💚 newly added to 1.0
  • 🟠 not yet ported to 1.0
  • 💀 for packages that are removed as part of 1.0 (see the migration guide for details)

  Projects

  • 🟢 EventFlow
  • 🟠 EventFlow.AspNetCore
  • 💀 EventFlow.Autofac
  • 💀 EventFlow.DependencyInjection
  • 🟠 EventFlow.Elasticsearch
  • 🟢 EventFlow.EntityFramework
  • 🟠 EventFlow.EventStores.EventStore
  • 🟢 EventFlow.Hangfire
  • 🟢 EventFlow.MongoDB
  • 🟢 EventFlow.MsSql
  • 💀 EventFlow.Owin
  • 🟢 EventFlow.PostgreSql
  • 🟠 EventFlow.Redis
  • 🟢 EventFlow.RabbitMQ
  • 🟢 EventFlow.Sql
  • 🟢 EventFlow.SQLite
  • 🟢 EventFlow.TestHelpers

  Branches

  • develop-v1: Development branch, pull requests should be done here
  • release-v1: Release branch, merge commits are done to this branch from develop-v1 to create releases. Typically each commit represents a release

• 0.x (legacy)

  The current stable version of EventFlow and has been the version of EventFlow for almost six years. 0.x versions have .NET Framework support and limited support to the Microsoft extension packages through extra NuGet packages.

  Feature and bug fix releases will still be done while there's interest in the community.

  Branches

  • develop-v0: Development branch, pull requests should be done here
  • release-v0: Release branch, merge commits are done to this branch from develop-v0 to create releases. Typically each commit represents a release

  Documentation

  Version 0.x documentation is (although a bit outdated) is live at https://docs.geteventflow.net/.

Talks directly related to EventFlow

• GOTO Aarhus 2022 by rasmus Practical event sourcing using EventFlow

Examples

• Complete: Shows a complete example on how to use EventFlow with in-memory event store and read models in a relatively few lines of code
• Shipping: To get a more complete example of how EventFlow could be used, have a look at the shipping example found here in the code base. The example is based on the shipping example from the book "Domain-Driven Design - Tackling Complexity in the Heart of Software" by Eric Evans. Its in-progress, but should provide inspiration on how to use EventFlow on a larger scale. If you have ideas and/or comments, create a pull request or an issue

External Examples

List of examples create by different community members. Note that many of these examples will be using EventFlow 0.x.

Create a pull request to get your exampled linked from here.

• Racetimes: Shows some features of EventFlow that are not covered in the complete example. It features entities, a read model for an entity, delete on read models, specifications and snapshots.

  • Racetimes for Azure Functions: Extends the above example to support the HTTP access via Azure Functions

  • Racetimes for Azure Functions and Event Grid: Further extends the Azure Functions Example to publish to Event Grid, following the RabbitMQ pattern

• .NET Core: A Web API running .NET Core 2.2 using the event flow. It uses the pre-defined command/entities/events from the complete example. There are endpoints to create a new example event, getting a data model and to replay all data models.

• ElasticSearch/.NET Core: It is configured with EventFlow, ElasticSearch, EventStore, and RabbitMq. See "withRabbitMq" branch for #384.

• Vehicle Tracking: A Microservice on .NET Core 2.2 with docker based, you can up the service with docker-compose, this project using various tools to up the services aka. Linux Docker based on .NET Core, RabbitMq, EntityFramework with SQL Server and using EventFlow following CQRS-ES architecture and all microservice can access through ApiGateway which using Ocelot

• RestAirline: A classic DDD with CQRS-ES, Hypermedia API project based on EventFlow. It's targeted to ASP.NET Core 2.2 and can be deployed to docker and k8s.

• Full Example: A console application on .NET Core 2.2. You can up the services using docker-compose file. Docker-compose file include EventStore, RabbitMq, MongoDb, and PostgreSQL. It include following EventFlow concepts:

  • Aggregates
  • Command bus and commands
  • Synchronous subscriber
  • Event store (GES)
  • In-memory read model.
  • Snapshots (MongoDb)
  • Sagas
  • Event publising (In-memory, RabbitMq)
  • Metadata
  • Command bus decorator, custom value object, custom execution result, ...

Overview

Here is a list of the EventFlow concepts. Use the links to navigate to the documentation.

• Aggregates: Domains object that guarantees the consistency of changes being made within each aggregate
• Command bus and commands: Entry point for all command/operation execution.
• Event store: Storage of the event stream for aggregates. Currently there is support for these storage types.
  • In-memory - only for test
  • Files - only for test
  • Microsoft SQL Server
  • Entity Framework Core
  • SQLite
  • PostgreSQL
  • EventStore - home page
• Subscribers: Listeners that act on specific domain events. Useful if an specific action needs to be triggered after a domain event has been committed.
• Read models: Denormalized representation of aggregate events optimized for reading fast. Currently there is support for these read model storage types. For the SQL storage types the queries are being generated automatically with quoted columns and table names.
  • Elasticsearch
  • In-memory - only for test
  • Microsoft SQL Server
  • Entity Framework Core
  • SQLite
  • PostgreSQL
• Snapshots: Instead of reading the entire event stream every single time, a snapshot can be created every so often that contains the aggregate state. EventFlow supports upgrading existing snapshots, which is useful for long-lived aggregates. Snapshots in EventFlow are opt-in and EventFlow has support for
  • In-memory - only for test
  • Microsoft SQL Server
  • Entity Framework Core
  • SQLite
  • PostgreSQL
• Sagas: Also known as process managers, coordinates and routes messages between bounded contexts and aggregates
• Queries: Value objects that represent a query without specifying how its executed, that is let to a query handler
• Jobs: Perform scheduled tasks at a later time, e.g. publish a command. EventFlow pro