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What is Buck2?

Welcome to Buck2! If you're new here, this page will give you a brief overview of what Buck2 is and the key reasons you might consider using it.

What is Buck2?​

Buck2 is a build system developed and used by Meta. Think of a build system as a tool that automates the process of creating executable binary from source code. This includes compiling code, linking libraries, and packaging everything together.

Here are a few key things to know about Buck2:

  • Supports Many Languages: Buck2 can build projects written in a variety of programming languages, including C++, Rust, Python, Go, OCaml, Erlang, and more.
  • Designed for Large Monorepos
  • Open Source: You can find its source code and contribute at https://github.com/facebook/buck2.
  • Fast: 2x as fast as Buck1 🚀
  • Correctness: Buck enforces hermeticity to ensure builds are correct by default.
  • Extensible: Allows developers to easily extend and customize their build process. Buck2 runs on various operating systems including Windows, Linux, and macOS, and can build for these platforms as well as for Android, iOS, and others.

Why Use Buck2? Key Advantages​

  • Performance:

    • Faster Parallel Builds: Buck2 is architected to build different parts of your project simultaneously (in parallel) whenever possible, significantly speeding up the overall build process.
    • Low Incremental Build Time: After you make a small change to your code, Buck2 is very efficient at only rebuilding what's necessary. This leads to faster iterations when you're developing and testing.

  • Determinism and Reproducibility:

    • Hermetic Builds: Buck2 aims for "hermetic" builds. This means that builds are self-contained and don't depend on external factors or pre-installed tools on your machine that aren't explicitly declared. This ensures that if you build the same code, you get the same result, every time, regardless of where or when it's built.

  • Transparency:

    • Dependency Comprehension: Buck2 has a clear way of defining and understanding the dependencies between different parts of your code. You can use queries to explore and understand these relationships, which is invaluable in large projects.

  • Correctness at Scale: By ensuring builds are reproducible and dependencies are explicit, Buck2 helps maintain correctness even as your codebase grows and becomes more complex.

  • Language Extensibility: Buck2's rule system is designed to be extensible, allowing support for new languages and tools to be added.

  • Remote Execution and Caching: Buck2 supports distributing build actions across multiple machines (remote execution) and caching build results. This can dramatically speed up builds, especially for lage teams and projects, as work done by one developer can benefit others.

In essence, Buck2 is designed to make the build process faster, more reliable, and more understandable, especially for large and complex software projects. For a more in-depth look at these advantages, you can visit Why Use Buck2?.