Simplifying Event Sourcing in Golang

Event sourcing can be complex, but this golang library simplifies its implementation in Go. With tools for aggregate management, and event storage, it helps you build scalable applications aligned with Domain-Driven Design.

Jasseem Allybokus

Founder & CEO · Jan 22, 2025

Event sourcing and CQRS (Command Query Responsibility Segregation) are powerful architectural patterns for building scalable and maintainable systems. However, implementing them can be complex, especially when you’re striving to follow best practices like Domain-Driven Design (DDD). That’s where thefabric-io/eventsourcing comes in.

In this post, I’ll walk you through how this open-source library simplifies event sourcing in Go, its core features, and how you can get started.

Why Event Sourcing?

Event sourcing is more than just a storage pattern. Instead of persisting the current state of an object, it captures all state changes as a sequence of events. This approach provides several advantages:

• Scalability: Events are immutable, making them easier to scale.
• Auditability: The full history of changes is stored.
• Flexibility: Replay events to reconstruct the state or debug issues.

Combined with CQRS, you can separate the responsibility of writing (commands) and reading (queries), leading to clean and focused code.

Introducing thefabric-io/eventsourcing

This library is designed to make event sourcing easier to implement in Go while staying true to DDD principles. It provides the building blocks for defining aggregates, managing events, and maintaining projections.

Key Features

• Aggregate Management: Simplifies handling aggregate lifecycles.
• Event Storage: Built-in logic for persisting and replaying events.
• CQRS Integration: Supports separating reads and writes.
• Extensibility: Adaptable to various domains and storage backends.

Getting Started

To see the library in action, you can explore the example repository: thefabric-io/eventsourcing.example. It includes a detailed implementation showcasing the library’s capabilities.

Installation

First, install the library using:

go get github.com/thefabric-io/eventsourcing

Example Overview

The example repository provides a comprehensive guide to using the library. You’ll find a setup for managing aggregates, emitting events, and processing them. It demonstrates practices for structuring your project, handling events, and building projections.

You can clone and run the example with the following commands:

git clone https://github.com/thefabric-io/eventsourcing.example.git
cd eventsourcing.example
go run main.go

This example illustrates how to:

• Define aggregates and their behaviors.
• Persist and replay events.
• Query projections for read-side operations.

Refer to the thefabric-io/eventsourcing.example repository for detailed explanations and context.

Real-World Use Cases

Imagine a CRM system where users can create and update customer inquiries. Each change is captured as an event, allowing:

• Reconstruction of the inquiry’s history for debugging.
• Seamless integration of projections for analytics dashboards.
• Event-driven triggers for sending notifications.

With thefabric-io/eventsourcing, these workflows become intuitive and maintainable.

Get Involved

Check out the GitHub repositories:

• Library: thefabric-io/eventsourcing
• Example: thefabric-io/eventsourcing.example

Feel free to:

• Star the repos if you find them useful.
• Report issues or request features.
• Contribute by submitting pull requests.

Conclusion

Event sourcing doesn’t have to be complicated. With thefabric-io/eventsourcing, you can focus on building robust, scalable applications without getting bogged down in boilerplate.

I hope this library helps you on your journey to mastering event sourcing in Go. If you have any questions or feedback, feel free to reach out or open an issue on GitHub. Let’s build better software together!