Flow: ultra light-weight eventsourcing, state management and projection library

v1.1.3 2019-01-27 08:01 UTC


Flow is a light-weight eventsourcing, state and projection framework.


  • Events are just multi-dimensional arrays. No custom object-model to learn or conform to
  • Projectors are simple to write, and operate on array data
  • Simple state management included, with a base class for state-based projectors
  • Extensive use of Interfaces, so EventStores, Projectors and State Stores can all be easily swapped out and optimized
  • In-memory and database-backed event and state stores
  • Designed to be used as a library in event-based applications


The example/ directory contains a simple example with events, projectors, etc.

You can run it by executing:

php example/example.php

It will output the states of relevant entities as JSON on stdout.

Database initialization

The example can also be executed with database backed event and state stores. Initialize your database using:

./vendor/bin/dbtk-schema-loader schema:load example/schema.xml mysql://user:password@localhost/flow --apply

Database configuration

The example script loads it's database configuration from the environment variable FLOW_EXAMPLE_DSN. The easiest way to set it is to copy .env.dist to .env, and update the configuration based on your database settings.

If a .env exists, it's configuration is automatically loaded into the environment

If FLOW_EXAMPLE_DSN is not defined, in-memory (array) based event- and state stores will be used. These are much faster, but don't support persistence, and will not scale as well as database backed stores.


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