packs

packs are a specification for an extensible packaging system to help modularize Ruby applications.

A pack (short for package) is a folder of Ruby code with a package.yml at the root that is intended to represent a well-modularized domain.

This gem provides a development CLI, bin/packs, to make using packs easier.

Configuration

By default, this library will look for packs in the folder packs/*/package.yml (as well as nested packs at packs/*/*/package.yml). To change where packs are located, create a packs.yml file in the root of your project:

pack_paths:
  - "{packs,utilities,deprecated}/*" # packs with multiple roots!
  - "{packs,utilities,deprecated}/*/*" # nested packs!
  - gems/* # gems can be packs too!

Ecosystem

The rest of the rubyatscale ecosystem is intended to help make using packs and improving the boundaries between them more clear.

Here are some example integrations with packs:

packs-specification is a low-dependency gem that allows your production environment to query simple information about packs
packs-rails can be used to integrate packs into your rails application
rubocop-packs contains cops to improve boundaries around packs
packwerk and packwerk-extensions help you describe and constrain your package graph in terms of dependencies between packs and pack public API
code_ownership gives your application the capability to determine the owner of a pack
pack_stats makes it easy to send metrics about pack adoption and modularization to your favorite metrics provider, such as DataDog (which has built-in support).

How is a pack different from a gem?

A ruby gem is the Ruby community solution for packaging and distributing Ruby code. A gem is a great place to start new projects, and a great end state for code that's been extracted from an existing codebase. packs are intended to help gradually modularize an application that has some conceptual boundaries, but is not yet ready to be factored into gems.

Usage

Add the gem to your Gemfile and do a bundle install

gem 'packs-rails'
gem 'packs'

Initialize packwerk

bundle binstub packwerk
bin/packwerk init

Make sure to run bundle binstub packs to generate bin/packs within your application.

CLI Documentation

Describe available commands or one specific command

bin/packs help [COMMAND]

Create pack with name packs/your_pack

bin/packs create packs/your_pack

Add packs/to_pack to packs/from_pack/package.yml list of dependencies

bin/packs add_dependency packs/from_pack packs/to_pack

Use this to add a dependency between packs.

When you use bin/packs add_dependency packs/from_pack packs/to_pack, this command will modify packs/from_pack/package.yml's list of dependencies and add packs/to_pack.

This command will also sort the list and make it unique.

List the top violations of a specific type for packs/your_pack.

bin/packs list_top_violations type [ packs/your_pack ]

Possible types are: dependency, privacy, layer.

Want to see who is depending on you? Not sure how your pack's code is being used in an unstated way? You can use this command to list the top dependency violations.

Want to create interfaces? Not sure how your pack's code is being used? You can use this command to list the top privacy violations.

Want to focus on the big picture first? You can use this command to list the top layer violations.

If no pack name is passed in, this will list out violations across all packs.

Make files or directories public API

bin/packs make_public path/to/file.rb path/to/directory

This moves a file or directory to public API (either the app/public folder or the pack's specified public path).

Make sure there are no spaces between the comma-separated list of paths of directories.

Move files or directories from one pack to another

bin/packs move packs/destination_pack path/to/file.rb path/to/directory

This is used for moving files into a pack (the pack must already exist). Note this works for moving files to packs from the monolith or from other packs

Make sure there are no spaces between the comma-separated list of paths of directories.

Lint `package_todo.yml` files to check for formatting issues

bin/packs lint_package_todo_yml_files

Lint `package.yml` files

bin/packs lint_package_yml_files [ packs/my_pack packs/my_other_pack ]

Run bin/packwerk validate (detects cycles)

bin/packs validate

Run bin/packwerk check

bin/packs check [ packs/my_pack ]

Run bin/packwerk update-todo

bin/packs update

Get info about size and violations for packs

bin/packs get_info [ packs/my_pack packs/my_other_pack ]

Rename a pack

bin/packs rename

Set packs/child_pack as a child of packs/parent_pack

bin/packs move_to_parent packs/child_pack packs/parent_pack

Move packs/foo to the some/directory folder, where some/directory does not contain a package.yml file

bin/packs move_to_folder packs/foo some/directory

Releasing

Releases happen automatically through github actions once a version update is committed to main.

Discussions, Issues, Questions, and More

To keep things organized, here are some recommended homes:

rubyatscale/packs