Gembrew

Generate conventional Homebrew formulae for published Ruby command-line gems.

Install

gem install gembrew

Usage

mkdir homebrew-tap
cd homebrew-tap
gembrew init GEM
gembrew build
gembrew check

init requires an empty directory, with the exception of Git's .git directory. It creates a tap repository containing gembrew.yml, Formula/, and a Docker Compose environment under support/. build reads the configuration and writes the formula.

The configuration filename is always gembrew.yml.

For example, gembrew init example generates:

gem: example
output: Formula/example.rb

test: |-
  system bin/"example", "--version"

Edit gembrew.yml as needed, then generate the formula:

gembrew build

The required settings are gem, output, and exactly one of test or test_from_file. Relative paths are resolved from gembrew.yml.

gem: example
output: Formula/example.rb

# Optional published gem version. The latest stable version is used by default.
version: "1.2.3"

# Optional gem metadata overrides:
desc: Example command-line application
homepage: https://example.com
license: MIT
executable: example

test: |-
  system bin/"example", "--version"

# Use this instead of `test` to load the test body from another file:
# test_from_file: support/test.rb

Gembrew resolves the generic Ruby dependency graph and generates a Homebrew resource for every runtime dependency. Original .gem archives are reused from RubyGems' local cache when available. Downloaded archives are retained in ${XDG_CACHE_HOME:-~/.cache}/gembrew/gems.

Open the generated Homebrew environment with:

gembrew shell

The repository is mounted as a local tap, so formulae can be addressed by gem name inside the shell:

brew style example
brew audit --new --online example
brew install --build-from-source example
brew test example

Run the complete workflow non-interactively in one clean container:

gembrew check

This rebuilds the formula, then runs Homebrew style, online audit, source installation, and the formula test. The generated Compose check service can also be invoked directly.

Contributing / Support

If you experience any issue, have a question or a suggestion, or if you wish to contribute, feel free to open an issue.

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