bisrael / sluggerator

Helps remove build artifacts from your Heroku slug

Sluggerator

Sluggerator™ helps remove build artifacts from your Heroku slug before it's compressed.

Why?

Heroku's .slugignore file is useful for pruning out files from YOUR git repo from the generated slug. But unfortunately, it doesn't do anything for file generated during the build process.

For example, the wkhtmltopdf-binary ruby gem installs almost a dozen 17MB binary files, most of which are unnecessary on any given platform. Heroku's .slugignore can't handle this situation because the gem is installed during the build process, not in git ahead of time.

Dependencies / Language Support

Sluggerator is language- and framework-independent and is written in pure bash using very basic utilities.

Compatibility

Sluggerator is known to work on the heroku-18, heroku-20 and heroku-22 stacks on Heroku.

Basic Usage

heroku buildpacks:add https://github.com/bisrael/sluggerator.git

Note!

This should probably be the last buildpack in your list.

The above command will add it as such, but if adding other buildpacks later, make sure to use the -i flag to put your other buildpacks before this one.

Modes of Operation

There are two primary modes that Sluggerator operates in:

1. Sluggerator file mode
2. .slugignore file mode

Sluggerator can also help you report on various file sizes with a Sluggerator.report-only file

Sluggerator file mode

Add a Sluggerator file to the root of your app's repo.

The format is similar to other .ignore-type files, any globbing supported by Ubuntu's ls command on your build container is supported.

Example Sluggerator file:

This removes a bunch of extraneous binaries from the wkhtmltopdf-binary gem that are not needed on the Heroku runtime:

vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_archlinux_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_centos_6_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_centos_6_i386.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_centos_7_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_centos_7_i386.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_centos_8_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_debian_10_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_debian_10_i386.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_debian_9_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_debian_9_i386.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_macos_cocoa.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_ubuntu_16.04_amd64.gz
vendor/bundle/ruby/2.6.0/gems/wkhtmltopdf-binary-0.12.6.5/bin/wkhtmltopdf_ubuntu_16.04_i386.gz

You can version and future-proof this like so:

vendor/bundle/ruby/*/gems/wkhtmltopdf-binary-*/bin/wkhtmltopdf_archlinux*
vendor/bundle/ruby/*/gems/wkhtmltopdf-binary-*/bin/wkhtmltopdf_centos*
vendor/bundle/ruby/*/gems/wkhtmltopdf-binary-*/bin/wkhtmltopdf_debian*
vendor/bundle/ruby/*/gems/wkhtmltopdf-binary-*/bin/wkhtmltopdf_macos*
vendor/bundle/ruby/*/gems/wkhtmltopdf-binary-*/bin/wkhtmltopdf_ubuntu*i386*
vendor/bundle/ruby/*/gems/wkhtmltopdf-binary-*/bin/wkhtmltopdf_ubuntu_16*

.slugignore file mode

This mode operates basically exactly as above, but instead reads the heroku-supported .slugignore file.

The same rules apply here, but allow you to put all of your ignore

Other Features

Sluggerator.report-only file

After Sluggerator removes files from your heroku slug, you can optionally have it report on file-sizing in various directories.

You can do this by creating a Sluggerator.report-only file in your app root.

# This causes an output of large gemfiles at the end of the build:
vendor/bundle/ruby/*/gems/*
vendor/bundle/ruby/*/gems/**/*

Syntax supported here is any file globbing that the du utility on your Ubuntu/Heroku stack supports.

Currently, Sluggerator only reports files >= 10 Megabytes

Development

See: https://devcenter.heroku.com/articles/buildpack-api