Event Sourcing in Python

This project is a comprehensive Python library for implementing event sourcing, a design pattern where all changes to application state are stored as a sequence of events. This library provides a solid foundation for building event-sourced applications in Python, with a focus on reliability, performance, and developer experience. This project is hosted on GitHub.

Contents

• Installation
  • Pip install
  • Install options
  • Project template
  • Developers
• Support
  • Community support
  • Training workshops
  • Professional support
• Introduction
  • Event sourcing in 15 minutes
  • Synopsis
  • Features
  • Design overview
  • Buy the book
  • What is an event?
  • What is event sourcing?
  • Why event sourcing?
  • Enterprise application architecture
    • Interfaces
    • Applications
    • Domain models
    • Persistence
  • This library
  • Register issues
• Tutorial
  • Tutorial - Part 1 - Getting started
    • Python classes
    • Event-sourced aggregates
    • Event-sourced applications
    • Writing tests
    • Project structure
    • Exercise
    • Next steps
  • Tutorial - Part 2 - Aggregates
    • Aggregates in more detail
    • “Created” events
    • Subsequent events
    • Explicitly defined event classes
    • Decorating private methods
    • Exercises
    • Next steps
  • Tutorial - Part 3 - Applications
    • Applications in more detail
    • Repository
    • Event store
    • Mapper
    • Recorder
    • Command methods
    • Query methods
    • Notification log
    • Database configuration
    • Development environment
    • SQLite environment
    • PostgreSQL environment
    • Exercises
    • Next steps
  • Tutorial - Part 4 - Projections
    • Views
    • View test case
    • View interface
    • In-memory view
    • PostgreSQL view
    • Projections
    • Example projection
    • Runners
    • Counting events in memory
    • Counting events in PostgreSQL
    • Exercises
    • Next steps
  • Tutorial - Part 5 - Systems
    • Process applications
    • Defining an event-driven system
    • Running an event-driven system
    • Single-threaded runner
    • Multi-threaded runner
    • SQLite environment
    • PostgreSQL environment
    • Exercises
    • Next steps
• Modules
  • domain — Domain models
    • Aggregates in DDD
    • Event-sourced aggregates
    • Declarative syntax
    • Timestamp timezones
    • Initial version number
    • Topic strings
    • Registering topics
    • Explicit topics
    • Versioning
    • Snapshots
    • Notes
    • Code reference
  • application — Applications
    • Domain-driven design
    • Application objects
    • Simple example
    • Repository
    • Notification log
    • Mappers, transcoders and transcodings
    • Saving multiple aggregates
    • Event-sourced log
    • Application configuration
    • Configuring aggregate caching
    • Configuring persistence
    • Configuring compression
    • Configuring encryption
    • Snapshotting
    • Code reference
  • persistence — Persistence
    • Requirements
    • Overview
    • Stored event
    • Transcoder
    • Transcodings
    • Mapper
    • Compression
    • Encryption
    • Compression and encryption
    • Notification
    • Tracking
    • Recorders
    • Persistence modules
    • Event store
    • Infrastructure factory
    • Code reference
  • projection — Projections
    • Application subscriptions
    • Projection
    • Projection runner
    • Event-sourced projection
    • Event-sourced projection runner
    • Code reference
  • system — Event-driven systems
    • System of applications
    • Single-threaded runner
    • Multi-threaded runner
    • Code reference
  • interface — Interface
    • Classes
• Examples
  • Example aggregates
    • Aggregate 1 - Declarative syntax
    • Aggregate 2 - Explicit event classes
    • Aggregate 3 - Explicit trigger and apply
    • Aggregate 4 - Custom base classes
    • Aggregate 5 - Immutable aggregate
    • Aggregate 6 - Functional style
    • Aggregate 7 - Pydantic and orjson
    • Aggregate 8 - Pydantic with declarative syntax
    • Aggregate 9 - msgspec structs
    • Aggregate 10 - msgspec with declarative syntax
    • Aggregate 11 - String IDs
  • Example applications
    • Application 1 - Bank accounts
    • Application 2 - Cargo shipping
    • Application 3 - Content management
    • Application 4 - Searchable timestamps
    • Application 5 - Searchable content
    • Application 6 - Shopping cart
    • Application 7 - Vertical slices
  • Example projections
    • Projections 1 - Full text search
  • Example systems
    • System 1 - Content management system
• Release notes
  • Version 9.x
    • Version 9.4.6 (released 15 May 2025)
    • Version 9.4.5 (released 14 May 2025)
    • Version 9.4.4 (released 9 May 2025)
    • Version 9.4.3 (released 8 May 2025)
    • Version 9.4.2 (released 7 May 2025)
    • Version 9.4.1 (released 6 May 2025)
    • Version 9.4.0 (released 6 May 2025)
    • Version 9.3.5 (released 8 November 2024)
    • Version 9.3.4 (released 7 November 2024)
    • Version 9.3.3 (released 7 November 2024)
    • Version 9.3.2 (released 22 August 2024)
    • Version 9.3.1 (released 22 August 2024)
    • Version 9.3.0 (released 20 August 2024)
    • Version 9.2.22 (released 20 Jan 2024)
    • Version 9.2.21 (released 13 Oct 2023)
    • Version 9.2.20 (released 19 May 2023)
    • Version 9.2.19 (released 19 April 2023)
    • Version 9.2.18 (released 22 March 2023)
    • Version 9.2.17 (released 10 January 2023)
    • Version 9.2.16 (released 11 June 2022)
    • Version 9.2.15 (released 6 June 2022)
    • Version 9.2.14 (released 24 May 2022)
    • Version 9.2.13 (released 14 May 2022)
    • Version 9.2.12 (released 9 May 2022)
    • Version 9.2.11 (released 4 May 2022)
    • Version 9.2.10 (released 27 April 2022)
    • Version 9.2.9 (released 23 April 2022)
    • Version 9.2.8 (released 21 April 2022)
    • Version 9.2.7 (released 21 April 2022)
    • Version 9.2.6 (released 20 April 2022)
    • Version 9.2.5 (released 16 April 2022)
    • Version 9.2.4 (released 7 April 2022)
    • Version 9.2.3 (released 3 March 2022)
    • Version 9.2.2 (released 17 February 2022)
    • Version 9.2.1 (released 15 February 2022)
    • Version 9.2.0 (released 1 February 2022)
    • Version 9.1.9 (released 5 December 2021)
    • Version 9.1.8 (released 30 November 2021)
    • Version 9.1.7 (released 19 November 2021)
    • Version 9.1.6 (released 18 November 2021)
    • Version 9.1.5 (released 17 November 2021)
    • Version 9.1.4 (released 20 October 2021)
    • Version 9.1.3 (released 8 October 2021)
    • Version 9.1.2 (released 1 October 2021)
    • Version 9.1.1 (released 20 August 2021)
    • Version 9.1.0 (released 18 August 2021)
    • Version 9.0.3 (released 17 May 2021)
    • Version 9.0.2 (released 16 April 2021)
    • Version 9.0.1 (released 29 March 2021)
    • Version 9.0.0 (released 13 March 2021)
  • Version 8.x
    • Version 8.3.0 (released 9 January 2021)
    • Version 8.2.5 (released 22 Dec 2020)
    • Version 8.2.4 (released 12 Nov 2020)
    • Version 8.2.3 (released 19 May 2020)
    • Version 8.2.2 (released 16 May 2020)
    • Version 8.2.1 (released 11 March 2020)
    • Version 8.2.0 (released 10 March 2020)
    • Version 8.1.0 (released 11 January 2020)
    • Version 8.0.0 (released 7 December 2019)
  • Version 7.x
    • Version 7.2.4 (released 9 Oct 2019)
    • Version 7.2.3 (released 9 Oct 2019)
    • Version 7.2.2 (released 6 Oct 2019)
    • Version 7.2.1 (released 6 Oct 2019)
    • Version 7.2.0 (released 1 Oct 2019)
    • Version 7.1.6 (released 2 Aug 2019)
    • Version 7.1.5 (released 26 Jul 2019)
    • Version 7.1.4 (released 10 Jul 2019)
    • Version 7.1.3 (released 4 Jul 2019)
    • Version 7.1.2 (released 26 Jun 2019)
    • Version 7.1.1 (released 21 Jun 2019)
    • Version 7.1.0 (released 11 Jun 2019)
    • Version 7.0.0 (released 21 Feb 2019)
  • Version 6.x
    • Version 6.2.0 (released 15 Jul 2018)
    • Version 6.2.0 (released 26 Jun 2018)
    • Version 6.1.0 (released 14 Jun 2018)
    • Version 6.0.0 (released 23 Apr 2018)
  • Version 5.x
    • Version 5.1.1 (released 4 Apr 2018)
    • Version 5.1.0 (released 16 Feb 2018)
    • Version 5.0.0 (released 24 Jan 2018)
  • Version 4.x
    • Version 4.0.0 (released 11 Dec 2017)
  • Version 3.x
    • Version 3.1.0 (released 23 Nov 2017)
    • Version 3.0.0 (released 25 May 2017)
  • Version 2.x
    • Version 2.1.1 (released 30 Mar 2017)
    • Version 2.1.0 (released 27 Mar 2017)
    • Version 2.0.0 (released 27 Mar 2017)
  • Version 1.x
    • Version 1.2.1 (released 23 Oct 2016)
    • Version 1.2.0 (released 23 Oct 2016)
    • Version 1.1.0 (released 19 Oct 2016)
    • Version 1.0.10 (released 5 Oct 2016)
    • Version 1.0.9 (released 17 Aug 2016)
    • Version 1.0.8 (released 30 Jul 2016)
    • Version 1.0.7 (released 13 Jul 2016)
    • Version 1.0.6 (released 7 Jul 2016)
    • Version 1.0.5 (released 1 Jul 2016)
    • Version 1.0.4 (released 30 Jun 2016)
    • Version 1.0.3 (released 30 Jun 2016)
    • Version 1.0.2 (released 8 Jun 2016)
    • Version 1.0.1 (released 7 Jun 2016)
  • Version 0.x
    • Version 0.9.4 (released 11 Feb 2016)
    • Version 0.9.3 (released 1 Dec 2015)
    • Version 0.9.2 (released 1 Dec 2015)
    • Version 0.9.1 (released 10 Nov 2015)
    • Version 0.9.0 (released 14 Sep 2015)
    • Version 0.8.4 (released 14 Sep 2015)
    • Version 0.8.3 (released 5 Sep 2015)
    • Version 0.8.2 (released 5 Sep 2015)
    • Version 0.8.1 (released 4 Sep 2015)
    • Version 0.8.0 (released 29 Aug 2015)
    • Version 0.7.0 (released 29 Aug 2015)
    • Version 0.6.0 (released 28 Aug 2015)
    • Version 0.5.0 (released 28 Aug 2015)
    • Version 0.4.0 (released 28 Aug 2015)
    • Version 0.3.0 (released 28 Aug 2015)
    • Version 0.2.0 (released 27 Aug 2015)
    • Version 0.1.0 (released 27 Aug 2015)

Modules Reference

• Index

• Module Index