Continuous Integration (CI)

The Wasmtime and Cranelift projects heavily rely on Continuous Integration (CI) to ensure everything keeps working and keep the final end state of the code at consistently high quality. The CI setup for this repository is relatively involved and extensive, and so it's worth covering here how it's organized and what's expected of contributors.

All CI currently happens on GitHub Actions and is configured in the .github directory of the repository.

PRs and CI

Currently the full CI test suite runs on every Pull Request. All PRs need to have that lovely green checkmark before being candidates for being merged. If a test is failing you'll want to check out the logs on CI and fix it before the PR can be merged.

PR authors are expected to fix CI failures in their PR, unless the CI failure is systemic and unrelated to the PR. In that case other maintainers should be alerted to ensure that the problem can be addressed.

Tests run on CI

While this may not be fully exhaustive, the general idea of all the checks we run on CI looks like this:

  • Code formatting - we run cargo fmt -- --check on CI to ensure that all code in the repository is formatted with rustfmt. All PRs are expected to be formatted with the latest stable version of rustfmt.

  • Book documentation tests - code snippets (Rust ones at least) in the book documentation (the docs folder) are tested on CI to ensure they are working.

  • Crate tests - the moral equivalent of cargo test --all and cargo test --all --release is executed on CI. This means that all workspace crates have their entire test suite run, documentation tests and all, in both debug and release mode. Additionally we execute all crate tests on macOS, Windows, and Linux, to ensure that everything works on all the platforms.

  • Fuzz regression tests - we take a random sampling of the fuzz corpus and run it through the fuzzers. This is mostly intended to be a pretty quick regression test and testing the fuzzers still build, most of our fuzzing happens on oss-fuzz.

While we do run more tests here and there, this is the general shape of what you can be expected to get tested on CI for all commits and all PRs. You can of course always feel free to expand our CI coverage by editing the CI files themselves, we always like to run more tests!

Artifacts produced on CI

Our CI system is also responsible for producing all binary releases and documentation of Wasmtime and Cranelift. Currently this consists of:

  • Tarballs of the wasmtime CLI - produced for macOS, Windows, and Linux we try to make these "binary compatible" wherever possible, for example producing the Linux build in a really old CentOS container to have a very low glibc requirement.

  • Tarballs of the Python extension - also produced on the main three platforms these wheels are compiled on each commit.

  • Book and API documentation - the book is rendered with mdbook and we also build all documentation with cargo doc.

Artifacts are produced for every single commit and every single PR. You should be able to find a downloadable version of all artifacts produced on the "runs" page in GitHub Actions. For example here's an example job, and if you're looking at a specific builder you can see the artifacts link in the top right. Note that artifacts don't become available until the whole run finishes.

Commits merged into the main branch will rerun CI and will also produce artifacts as usual. On the main branch, however, documentation is pushed to the gh-pages branch as well, and binaries are pushed to the dev release on GitHub. Finally, tagged commits get a whole dedicated release to them too.