We are delighted to announce the 0.2.0 release of Bazel. This release marks major improvements in support for external repositories, Skylark and testing, in particular how external repositories and Skylark can work together.

Improvements from our roadmap

Skylark rules can now be loaded from remote repositories

Skylark rules can now be loaded from a remote repository. For example, to use the Scala rules, add the following to your WORKSPACE file:

git_repository(
    name = "io_bazel_rules_scala",
    remote = "https://github.com/bazelbuild/rules_scala.git",
    tag = "0.0.1",
)
load("@io_bazel_rules_scala//scala:scala.bzl", "scala_repositories")
scala_repositories()

This will download all of the tools the rules need to build Scala programs.

Then load and use normally from your BUILD files:

load("@io_bazel_rules_scala//scala:scala.bzl", "scala_library")
scala_library(...)

We will gradually move the existing rules to their own repositories, announcing changes on the mailing list.

Go build and test support

There is now Go language support, see the documentation for details.

Open sourcing tests

We also open sourced over a hundred tests and laid the foundation for open sourcing more. We will continue to open source more tests (both to increase Bazel's stability and to make contributing easier), but this marks a dramatic increase in test coverage.

Other major changes since 0.1.0

• The --package_path definition in .bazelrc is no longer required, nor is the base_workspace/ directory.
• JUnit test runner for Java tests - Use the --nolegacy_bazel_java_test flag (soon to be the default) to get XML output for easy integration into CI systems and easier debugging with --java_debug.
• Skylark macros can now be loaded and used in the WORKSPACE file.
• Remote repository filesystem changes are tracked.
• Debian packages and a Homebrew recipe.

For changes since 0.1.5 (the minor version before 0.2.0), see the release notes for changes.

Future plans

Looking ahead to 0.3.0:

• Windows support is coming! (See the Windows label to follow the progress there).
• Remote caching and execution is in progress (see Alpha Lam's work).
• XCode integration and generic IDE support.
• Ulf has been working on sandboxing for OS X, which will hopefully be available soon.
• More work on parallelization. We currently have experimental support (which can be enabled with the --experimental_interleave_loading_and_analysis flag) which improves clean build time (~30% faster loading and analysis), especially for builds using a lot of select() expressions.

Finally...

A big thank you to our community for your continued support. Particular shout-outs to the following contributors:

• Brian Silverman - for tons of important bug fixes and answering lots of user questions.
• Alpha Lam - for writing up design docs and implementing remote caching/execution.
• P. Oscar Boykin - for putting tons of time and effort into the Scala rules, as well as being a tireless supporter on Twitter.

Thank you all, keep the discussion and bug reports coming!