Bazel, the build system that Google open sourced six months ago, has reached the first beta milestone as planned, adding support for several languages and technologies.
Bazel is Google’s internal Blaze system used to build all their projects cumulating hundreds of millions of LOC kept in one huge workspace. Bazel contains everything Blaze has except dependencies on some internal projects and it lacks support for build clusters. Bazel is tuned for performance, reproducibility and extensibility. While it runs only on Linux and Mac OS, Bazel can build software for other platforms too.
Bazel came out of the box with support for building and testing Java, C++ and Objective-C code, but it has a mechanism for including other languages. Now it supports D, Groovy, JavaScript, Python, Rust, Scala and can build projects for Android, Docker, Google App Engine and iOS. Bazel can include dependencies from external sources such as GitHub or Maven, and it can be extended further with custom build rules using the Skylark extension mechanism.
For version 1.0, planned for May 2016, the team intends to add support for Go, native protobuf and Android Studio integration. Also, though initially considered to require too much work, by that time Bazel will run on Windows with full support for building and testing Android applications, testing on Google Cloud Test Lab and others, as detailed in the roadmap.