Building a Rust Project

What This Guide Covers #

For Language versions and other build-environment specific information visit our reference pages:

• Precise
• Trusty
• Xenial
• Bionic
• Focal
• Jammy
• macOS
• Windows
• FreeBSD

The rest of this guide covers configuring Rust projects in Travis CI. If you’re new to Travis CI please read our Tutorial and build configuration guides first.

Choosing a Rust version #

By default, we download and install the latest stable Rust release at the start of the build (thanks to rustup). The minimal profile is used and includes the following language tools: cargo, rustc, and rustup.

If you want additional language tools like rustfmt or clippy, please install them in before_install.

To test against specific Rust releases:

language: rust
rust:
  - 1.0.0
  - 1.1.0

Travis CI also supports all three Rust release channels: stable, beta, and nightly.

The Rust team appreciates testing against the beta and nightly channels, even if you are only targeting stable. A full configuration looks like this:

language: rust
rust:
  - stable
  - beta
  - nightly
jobs:
  allow_failures:
    - rust: nightly
  fast_finish: true

This will run your tests against all three channels, but any breakage in nightly will not fail the rest of build.

Dependency Management #

Travis CI uses Cargo to install your dependencies:

cargo build --verbose

You can cache your dependencies so they are only recompiled if they or the compiler were upgraded:

cache: cargo

This adds the following directories to the cache:

• $TRAVIS_HOME/.cache/sccache
• $TRAVIS_HOME/.cargo/
• $TRAVIS_HOME/.rustup/
• target

In addition, it adds the following command to the before_cache phase of the job in order to reduce cache size:

rm -rf "$TRAVIS_HOME/.cargo/registry/src"

This means that, if you override the before_cache step for another reason, you should add the step above in order to reduce the cache size:

before_cache:
  - rm -rf "$TRAVIS_HOME/.cargo/registry/src"
  ⋮ # rest of your existing "before_cache"

Default Build Script #

Travis CI uses Cargo to run your build, the default commands are:

cargo test --verbose

You can always configure different commands if you need to. For example, if your project is a workspace, you should pass --workspace to the build commands to build and test all of the member crates:

language: rust
script:
  - cargo build --verbose --workspace
  - cargo test --verbose --workspace

Environment variables #

The Rust version that is specified in the .travis.yml is available during the build in the TRAVIS_RUST_VERSION environment variable.

Build Config Reference #

You can find more information on the build config format for Rust in our Travis CI Build Config Reference.