Travis CI Homebrew custom bottle script

This script is to help with the scenario where you are compiling for OSX with Travis and you need to install software with Homebrew, but the default options in the brew's bottle won't work for you.

In this situation, you could compile the software from scratch, but this takes a long time on every push and wastes valuable Travis resources.

Instead, you can use this script to create a Homebrew Bottle (precompiled version) of the software you need, then you can simply install the bottle in your OSX build and there's no need to compile anything.

If you have a Mac you could do all this locally, but this script is for those without access to OSX. It uses Travis CI itself to compile the dependency once and upload it as a Github release, where it is easily available for other builds to use.

This script is currently set to brew and bottle boost with the --c++11 parameter, as the official boost bottle has been compiled without C++11 support.

Using this code

To make use of this script:

1. Fork this repository on Github.

2. In your Travis CI profile, use the button to resync to your Github account.

3. Find the newly forked repo in the Travis CI list and enable it.

4. Make a backup of .travis.yml.

5. Run travis setup releases --force. Use your own Github credentials to generate a new OAuth token, so Travis can create Github releases for the repository.

6. Put the new encrypted OAuth token into the .travis.yml backup.

7. Overwrite .travis.yml with the updated backup and delete the backup.

8. Update .travis.yml to compile the bottle you need.

9. Commit the change and set a tag, e.g. git tag boost-1.60-cxx11

10. Push the change to Github, making sure to push the tag also (git push origin master --tags).

11. Watch Travis CI build the brew, bottle it, then upload it as a Github release.

Using the bottle

To use the bottle generated by this process, add the following to the .travis.yml for the project that needs to use the bottle.

before_install:
  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then wget 'https://github.com/<link-to-release>'; fi
  - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then brew install *.bottle.tar.gz; fi