automerge/README.md

Automerge

Automerge is a library which provides fast implementations of several different CRDTs, a compact compression format for these CRDTs, and a sync protocol for efficiently transmitting those changes over the network. The objective of the project is to support local-first applications in the same way that relational databases support server applications - by providing mechanisms for persistence which allow application developers to avoid thinking about hard distributed computing problems. Automerge aims to be PostgreSQL for your local-first app.

If you're looking for documentation on the JavaScript implementation take a look at https://automerge.org/docs/hello/. There are other implementations in both Rust and C, but they are earlier and don't have documentation yet. You can find them in rust/automerge and rust/automerge-c if you are comfortable reading the code and tests to figure out how to use them.

If you're familiar with CRDTs and interested in the design of Automerge in particular take a look at https://automerge.org/docs/how-it-works/backend/

Finally, if you want to talk to us about this project please join the Slack

Status

This project is formed of a core Rust implementation which is exposed via FFI in javascript+WASM, C, and soon other languages. Alex (@alexjg]) is working full time on maintaining automerge, other members of Ink and Switch are also contributing time and there are several other maintainers. The focus is currently on shipping the new JS package. We expect to be iterating the API and adding new features over the next six months so there will likely be several major version bumps in all packages in that time.

In general we try and respect semver.

JavaScript

A stable release of the javascript package is currently available as @automerge/automerge@2.0.0 where. pre-release verisions of the 2.0.1 are available as 2.0.1-alpha.n. 2.0.1* packages are also available for Deno at https://deno.land/x/automerge

Rust

The rust codebase is currently oriented around producing a performant backend for the Javascript wrapper and as such the API for Rust code is low level and not well documented. We will be returning to this over the next few months but for now you will need to be comfortable reading the tests and asking questions to figure out how to use it. If you are looking to build rust applications which use automerge you may want to look into autosurgeon

Repository Organisation

• ./rust - the rust rust implementation and also the Rust components of platform specific wrappers (e.g. automerge-wasm for the WASM API or automerge-c for the C FFI bindings)
• ./javascript - The javascript library which uses automerge-wasm internally but presents a more idiomatic javascript interface
• ./scripts - scripts which are useful to maintenance of the repository. This includes the scripts which are run in CI.
• ./img - static assets for use in .md files

Building

To build this codebase you will need:

• rust
• node
• yarn
• cmake
• cmocka

You will also need to install the following with cargo install

• wasm-bindgen-cli
• wasm-opt
• cargo-deny

And ensure you have added the wasm32-unknown-unknown target for rust cross-compilation.

The various subprojects (the rust code, the wrapper projects) have their own build instructions, but to run the tests that will be run in CI you can run ./scripts/ci/run.

For macOS

These instructions worked to build locally on macOS 13.1 (arm64) as of Nov 29th 2022.

# clone the repo
git clone https://github.com/automerge/automerge-rs
cd automerge-rs

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

# install homebrew
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# install cmake, node, cmocka
brew install cmake node cmocka

# install yarn
npm install --global yarn

# install javascript dependencies
yarn --cwd ./javascript

# install rust dependencies
cargo install wasm-bindgen-cli wasm-opt cargo-deny

# get nightly rust to produce optimized automerge-c builds
rustup toolchain install nightly
rustup component add rust-src --toolchain nightly

# add wasm target in addition to current architecture
rustup target add wasm32-unknown-unknown

# Run ci script
./scripts/ci/run

If your build fails to find cmocka.h you may need to teach it about homebrew's installation location:

export CPATH=/opt/homebrew/include
export LIBRARY_PATH=/opt/homebrew/lib
./scripts/ci/run

Contributing

Please try and split your changes up into relatively independent commits which change one subsystem at a time and add good commit messages which describe what the change is and why you're making it (err on the side of longer commit messages). git blame should give future maintainers a good idea of why something is the way it is.