Reactive Programming for Bevy

This library provides sophisticated reactive programming for the bevy ECS. In addition to supporting one-shot chains of async operations, it can support reusable workflows with parallel branches, synchronization, races, and cycles. These workflows can be hierarchical, so a workflow can be used as a building block by other workflows.

Why use bevy impulse?

There are several different categories of problems that bevy impulse sets out to solve. If any one of these use-cases is relevant to you, it's worth considering bevy impulse as a solution:

• Coordinating async activities (e.g. filesystem i/o, network i/o, or long-running calculations) with regular bevy systems
• Calling one-shot systems on an ad hoc basis, where the systems require an input value and produce an output value that you need to use
• Defining a procedure to be followed by your application or by an agent or pipeline within your application
• Designing a complex state machine that gradually switches between different modes or behaviors while interacting with the world
• Managing many parallel threads of activities that need to be synchronized or raced against each other

Helpful Links

• Introduction to workflows
• JSON Diagram Format
• Bevy Impulse Docs
• Bevy Engine
• Bevy Cheat Book
• Rust Book
• Install Rust

Compatibility

Bevy Impulse is supported across several releases of Bevy:

bevy	bevy_impulse
0.14	0.2
0.13	0.1
0.12	0.0.x

The main branch currently targets bevy version 0.12 (bevy impulse 0.0.x) so that new developments are still compatible for users of bevy 0.12. New features will be forward-ported as soon as possible. main will move forward to newer versions of bevy when we judge that enough of the ecosystem has finished migrating forward that there is no longer value in supporting old versions. In the future we may come up with a more concrete policy for this, and we are open to input on the matter.

Dependencies

This is a Rust project that often uses the latest language features. We recommend installing rustup and cargo using the installation instructions from the Rust website: https://www.rust-lang.org/tools/install

Ubuntu Dependencies

For Ubuntu specifically you can run these commands to get the dependencies you need:

• To install rustup and cargo

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

• Make sure you have basic compilation tools installed

sudo apt-get install build-essential

Build

Once dependencies are installed you can run the tests:

cargo test

You can find some illustrative examples for building workflows out of diagrams:

• Calculator
• Door manager that uses zenoh and protobuf
• Mock navigation system using ROS

To use bevy_impulse in your own Rust project, you can run

cargo add bevy_impulse