Builds

Shuttle builds run on AWS CodeBuild, where we compile your Rust app and place it in a Shuttle runtime Debian-based Docker image.

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Builder image

The Rust builder image is based on cargo-chef to utilize Docker-layer caching of the build dependencies.

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Rust toolchain

The Rust version in the image is regularly updated to the latest stable stable-x86_64-unknown-linux-gnu toolchain.

By default, the wasm32-unknown-unknown target is installed, which enables compiling WASM frontends.

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External tools

Apart from what is already found in the Debian-based cargo-chef image [1] [2], these apt packages are also installed:

• clang
• cmake
• llvm-dev
• libclang-dev
• mold
• protobuf-compiler

Additionally, these tools are installed:

• cargo-binstall (latest)
• trunk (0.19.2)

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Customize build process

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Feature flags

Use the “shuttle” feature flag for custom behavior when building on Shuttle.

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Environment variables

The SHUTTLE=true env var is set in the builder image.

If you have build flags or env variables that need to be set during compilation, you can add them in .cargo/config.toml (docs) and include it in your deployment. Below are some examples.

[build]
rustflags = ["--foo", "bar"]

[env]
MY_ENV_VAR = "Shuttle to the moon! 🚀🚀🚀"

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Runtime image

The runtime image that your built executable is placed in is a bookworm-slim (Debian 12) with ca-certificates and curl installed.

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(EXPERIMENTAL) Hook scripts

There are three optional bash scripts that can be used to run custom commands during the build. Create them at the root of your project.

• shuttle_prebuild.sh: Runs before cargo build. Can be used to install custom build dependencies.
• shuttle_postbuild.sh: Runs after cargo build.
• shuttle_setup_container.sh: Runs in the runtime image before build artifacts are copied into it. Can be used to install custom runtime dependencies.

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Example: Install a custom Rust toolchain

In this example, we install and switch to the nighlty toolchain.

rustup install nightly --profile minimal
rustup default nightly

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Example: Install a build dependency

apt update
apt install -y libopus-dev

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Example: Build a WASM frontend

cd frontend
trunk build --release

Note: To use the built static assets at runtime, use build.assets.

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Example: Install a runtime dependency

apt update
apt install -y ffmpeg