This repository is an illustration of how to use Bazel with Travis-CI.

How it works

There's a couple of tricks in here to make things work.

Basically, .travis.yml lists a couple of apt packages that need to be installed to compile Bazel, and in before_install it clones the latest version of Bazel and compiles it.

To do so it provides its own bazelrc file, which limits the RAM allocated to Bazel. It also adds more verbosity to the build process. Note that this bazelrc is not used to compile your code: it's used during the self-hosting process of Bazel.

How do I use this?

You will need:

• Everything that's in .travis.yml. Note that you can just merge that into your existing .travis.yml just fine - it doesn't specify any exclusive option, except that it requires Linux (either container-based or legacy).
• The .bazelrc.
• Everything under tools/, that includes the sha256 fingerprint for Bazel's installer.
• A (possibly empty) WORKSPACE file. See below.
• Your own script section in the .travis.yml config file.

Where to put the WORKSPACE file

If you don't know what a WORKSPACE file is, please refer to the relevant Bazel documentation.

In this example, I chose to put WORKSPACE at the root of the repository. This has the advantage that I can follow the convention of having my code in /src/ at the root of the repository and have that be //src/ for Bazel.

Be careful about using //.... This will include paths that are in Bazel's base workspace, including build utilities for many languages and environments (Rust, D, Android, etc.). This may make Bazel pull large blobs from the network.

Using Bazel in your Travis config

The bazel binary is in ~/bin/. You can do stuff like:

script:
  - bin/bazel test //src/...

but see the caveat in the "Where to put the WORKSPACE file" section above if you plan to use //....