So you have a Buck based project and want to use Travis as your CI, first that’s a great choice, secondly Buck is quick. Buck is a build system developed and used by Facebook. It encourages the creation of small, reusable modules consisting of code and resources, and supports a variety of languages on many platforms. In this weeks tutorial I’ll be showing you how to integrate Buck into your Travis CI builds.

Buck up and let’s get building

A few things you’ll want to have, first thing is a file entitled BUCK, I wrote up a little example of how this file should look like:

cxx_binary(
  name = 'montana',
  srcs = [
    'main.cpp',
  ],
  compiler_flags = [
    '-v',
  ],
)

Now let’s edit our file entitled montana.cpp, this is a quick C++ program I’ve made that will reverse sentences using recursion:

#include <iostream>
using namespace std;

void rev_str(char* string)

{
  if (*string == '\0')

    return;

  else

  {
    rev_str(string + 1);

    cout << *string;
  }
}

int main()

{
  char string[] = "Building with Travis CI";

  cout << "Original String: " << string << endl;

  cout << "Reversed String: ";

  rev_str(string);

  return 0;
}

Alright we now have our BUCK file, and our C++ program! Let’s start setting up Travis for Buck.

The setup

So first, let’s pick a dist we want to use, in this case I’ll be using trusty, I’ll be setting my language to cpp this of course is C++, and you’ll see something rather specific, which is we will not be using Homebrew in this .travis.yml file, but Linuxbrew, let’s get started:

language: cpp
sudo: true # Not compulsory, I just do this out of habit still. - Montana 
dist: trusty

addons:
  apt:
    sources:
      - ubuntu-toolchain-r-test
    packages:
      - g++-6
      - gcc-6

before_install:
- sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-6 90
- sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-6 90
- sudo apt-get install -y equivs openjdk-8-jdk
- wget -O buck.deb https://github.com/facebook/buck/releases/download/v2018.08.27.01/buck.2018.08.27.01_all.deb
- sudo dpkg -i buck.deb
- buck --version
- wget -O buckaroo.deb https://github.com/LoopPerfect/buckaroo/releases/download/v1.4.1/buckaroo.deb
- sudo dpkg -i buckaroo.deb
- buckaroo version
- c++ --version
- g++ --version
- gcc --version

script:
- buckaroo install
- buck build :montana
- buck test :montana

Now at this point, you’ve picked your language, dist, and now you’ve fetched Linuxbrew. Let’s now use the script hook in Travis to utilize Buck:

script:
- buckaroo install
- buck build :montana
- buck test :montana

As you can see Travis is going to run buck build and we also are caching the linuxbrew directory. It is all about speed right? So in it’s entirety, your .travis.yml file should look like this:

language: cpp
sudo: true
dist: trusty

addons:
  apt:
    sources:
      - ubuntu-toolchain-r-test
    packages:
      - g++-6
      - gcc-6

before_install:
- sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-6 90
- sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-6 90
- sudo apt-get install -y equivs openjdk-8-jdk
- wget -O buck.deb https://github.com/facebook/buck/releases/download/v2018.08.27.01/buck.2018.08.27.01_all.deb
- sudo dpkg -i buck.deb
- buck --version
- wget -O buckaroo.deb https://github.com/LoopPerfect/buckaroo/releases/download/v1.4.1/buckaroo.deb
- sudo dpkg -i buckaroo.deb
- buckaroo version
- c++ --version
- g++ --version
- gcc --version

After all said and done and you trigger the build, you should see similar results to this:

Buckaroo

You’ll also not want to forget to create a file called Buckaroo.json, this file should look a bit something like this:

{
  "name": "montana",
  "dependencies": {
  }
}

You also need a .buckconfig file, you’ll notice we instructed Travis to grab Buckaroo via these lines:

- wget -O buckaroo.deb https://github.com/LoopPerfect/buckaroo/releases/download/v1.4.1/buckaroo.deb
- sudo dpkg -i buckaroo.deb
- buckaroo version

We are going to use the wget CLI tool to fetch Buckaroo, and then printing the version out for a more verbose look at your Travis CI log. Let’s move onto the .buckconfig file.

You’ll also need to make a file called buckaroo.toml, this is how mine looks:

targets = [ "//:montana" ]

[[dependency]]
package = "github.com/buckaroo-pm/google-googletest"
version = "branch=master"
private = true

As you see, I’ve also attached screenshots from Vim to better explain the process.

Buck config

Let’s create a file called .buckconfig, this is an exact copy of what mine looks like currently, feel free to use it:

[project]
  ignore = .git, .buckd

[parser]
  default_build_file_syntax = SKYLARK

[cxx]
  should_remap_host_platform = true

[cxx#linux-x86_64]
  cxxflags = -std=c++14

[cxx#macosx-x86_64]
  cxxflags = -std=c++14

When it comes to package managers you fetch from, you’ll want to use cURL, on that note you have a choice obviously of using Linuxbrew or Homebrew. In my example I used Linuxbrew, this is just a choice, you can use Homebrew if you wish, you need to make sure you have something called a Brewfile, create a file called Brewfile, and add the following:

tap 'facebook/fb'
brew 'buck'
brew 'xctool'

As you can see my build with Buck was successful with Travis, and there you have it! If you have any questions please feel free to contact me at montana@travis-ci.com, and happy building!

Resources

Here is the source code via my GitHub so you can follow along! Travis CI + Buck GitHub Source Code via Montana Mendy.