Buck VS Litho (By Facebook)

Hyper-large tech companies managing hyper-large monorepos using Bazel (google), buck (Facebook), please (thought machine), pants (Twitter, Foursquare & Square) enjoy them but also have a lot of resources devoted to running and maintaining it.

We use Buck company wide. Our packaging / deployment system, for example, expects to be given a Buck target to build, not a pre-built binary - I can’t just build my app with dotnet and upload it. While it is possible for a Buck target to be a simple bash command (i.e dotnet publish), doing so makes the target “opaque” - Buck wouldn’t have any knowledge of my app’s build graph so I’d lose many of the benefits it gives us (incremental cached builds etc.)

Oh excellent, then better (and more portable!) tools are available:

http://pants.build

https://ninja-build.org

https://buck.build

and, if you hate yourself: https://bazel.build

I’m feeling sorry for everyone affected.

Let’s hope that this isn’t going to impact Buck [0] too much. It’s one of the best things Facebook has ever made.

[0]: https://github.com/facebook/buck/tree/dev

Pioneered by tech giants like Google and Meta with tools like Bazel and Buck, monorepos are seeing widespread adoption across companies of all sizes and industries.

Buck has a http_file() that you can use this way, and it has first-class support for Java.

That's a good bridge into saying that we don't use pretty much any standard tooling. Our build system is Buck, we use Mercurial instead of Git, and the IDE of choice seems to be Visual Studio (although Android Studio is supported, with some custom plugins required).

Didn't know it was python based. Their github repo shows 90% of the code is java, only 2% is python. Regardless, C++ build systems should be written by people who are familiar with C++ and the specific problems they need to solve. That means the build system should be written in C++ or C and not in java, lua, or python. I certainly do not want to install python just to build my C++ programs in a CI environment, it just increases my build complexity and attack surface

The landing page of https://buck.build/ explains some of the most basic stuff. This Meta Engineering blog post summarizes some of the deeper optimizations possible through buck: https://engineering.fb.com/2017/11/09/android/rethinking-android-app-compilation-with-buck/

Waiting for Litho to be the new UI development standard https://fblitho.com/

IIRC fb is using this custom list view https://fblitho.com/

Litho by Facebook

Just a little correction, none of facebook or instagram mobile app use react native. On android, facebook, messenger, and instagram use litho library (which facebook team has also developed)

It seems unlikely that FB would give up on Litho, which is extremely performance focused, to use react native instead. Not for their bread & butter flagship news feed anyway https://fblitho.com/

I've seen some old conference talks from their team about https://fblitho.com/. I believe that what they use or at least used.

Facebook's internal android repository is still mostly Java, but there is a large push to switch to Kotlin, and Kotlin's internal support has grown dramatically over the last couple of years. Coroutines have recently been allowed (although I'm personally not a fan of that decision). Flow/Compose are not necessary as we have internal tools that do similar things (looking at you, Litho).