Bazel, Google’s Open Source Build System

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One of the most important, yet unsung, applications in a software developer’s life is the Make utility, or its equivalent. Make first appeared in 1977 and has been with us ever since. There are a very large number of build utilities, some based on Make, others completely different. The principle remains the same. The build system has a set of rules that tell it how to build an application from source files, usually fetched from a version control system. The Make utility reads the rules, then runs the compilers and linkers to do the build. The really good ones will run tests, as well.

Google has been using their own system, called Blaze, and open-sourced part of it as the anagrammatically named Bazel — recently released at alpha status. In this article I’ll give a general overview of Bazel.

So what’s different about Bazel? It aims to do two things: build quickly and correctly. It uses a massive shared code repository where all software is built from source. Speed is achieved using both caching and parallelism. Blaze solves a slightly different problem from Bazel as it is designed for Google’s internal systems. Any Google engineer can build any Google product from source on any machine by invoking a Blaze command. 

Read more at The New Stack