README.md

robot rumble - logic backend

https://robotrumble.org

Robot Rumble is a game where you code robots to battle other users' bots in an arena. This is the logic backend, which is primarily written in Rust (using wasm-bindgen in the browser and tokio + wasmer otherwise).

A detailed writeup of our architecture/infrastructure can be found here.

Directory structure

• logic/: This contains the pure game logic of robot rumble. It mainly operates on the RobotRunner trait, which has a single method that takes in the state of the board and outputs a list of actions for each unit under its control.
• lang-runners/: wasm modules that implement our runner "ABI"/"protocol", for running user code in a sandboxed WebAssembly environment. Each runner receives JSON-serialized ProgramInput structs in stdin, and should print JSON-serialized ProgramResults to stdout (types defined in logic/).
  • lang-runners/javascript: implements the robot rumble API/environment for JavaScript, running JS code in the quickjs interpreter.
  • lang-runners/python: the same as above, but running Python in RustPython.
  • lang-runners/lang-common.*: "shared" functionality used for implementing lang-runners.
• env-runners/: libraries or binaries that wrap the logic crate in order to run in environments like AWS lambda or the browser. Notably absent is the rumblebot CLI, which lives in its own repo at robot-rumble/cli.
  • env-runners/browser/: a wasm-bindgen wasm module that runs robots as web workers, in conjunction with the portions of the garage that are written in JS.
  • env-runners/lambda: an AWS lambda function that runs a battle between two robots and outputs the results to SQS for our backend server to process.
  • env-runners/lambda-cache: a tool to precompile the lang-runners to native code for running on lambda.
  • env-runners/native: a crate providing a RobotRunner that runs in tokio, with robots running as (blocking) tokio tasks. This is used by the cli and the lambda runner.