Foodchain

Foodchain is a single-file library to help you document and install your DragonRuby game's dependencies.

Rationale

Installing dependencies in DragonRuby isn't particularly hard — the majority of library code available for the framework is available as single-file libraries that can be downloaded, required, and forgotten. DragonRuby GTK even includes the download_stb_rb function to facilitate downloading these libraries, which is great … for as far as it goes.

On the other extreme you have tools like RubyGems, which are a publishing platform for code that's production ready, a tool for putting that code (and any code that it depends on) into a centralized location, and a runtime library for ensuring that code in that centralized location can be loaded. Built on top of that are tools like Bundler, which manage the specific versions of dependencies required by your application (in a way that's repeatable across machines), and which isolate your appilication from the other centrally installed libraries. The caveat for DragonRuby developers is that these tools do not (and cannot) work with the DragonRuby runtime, and most of the libraries that are published as RubyGems won't work anyway.

Foodchain intends to sit in the gap between those two extremes.

• Fully Decentralized
  • Pull what you want from wherever it lives.
• Git-Aware
  • Pin your dependencies to a particular branch, tag, or commit.
• Documentation
  • Borrow code with the confidence that you'll remember it came from.
• No External Dependencies
  • Everything runs inside the DragonRuby runtime you already have.

Usage

Start by saving foodchain.rb into your game's source tree. DragonRuby even provides a built-in tool for doing this, which you can run from your game's console:

# Downloads to pvande/foodchain/foodchain.rb
$gtk.download_stb_rb "pvande", "foodchain", "foodchain.rb"

# OR

# Downloads to wherever/you/want.rb
url = "https://raw.githubusercontent.com/pvande/foodchain/main/foodchain.rb"
$gtk.download_stb_rb_raw url, "wherever/you/want.rb"

Next, you'll create a dependency manifest — a file that lists the dependencies you want Foodchain to install. Conventionally, we recommend using a file named dependencies.rb, living in the root directory of your game.

Require Foodchain inside your dependency manifest file.

# mygame/dependencies.rb
require "pvande/foodchain/foodchain"

In this file, you'll document your game's dependencies.

When you're ready to install, just run that dependency manifest.

./dragonruby mygame --eval dependencies.rb

What's __END__?

After successfully installing your dependencies, Foodchain will record a few details about the process at the end of your dependency manifest. This isn't cause for alarm: Foodchain will use this to detect when there's an update available for one of your dependencies, and notify you.

Foodchain will never automatically overwrite any of your installed dependencies, so you can run it and rerun it as often as you like. When you're ready to test an update, you can rerun your dependency manifest with the --update flag, and the file(s) will be downloaded fresh.

Configuration

Foodchain dependencies currently come in the following flavors:

github [owner], [repo], [path], ref: [ref?], destination: [destination?]

GitHub dependencies are fetched based on the path within the owner's fork of the named repo.

A specific ref may be specified to follow a particular Git branch, or pin to a particular Git tag or commit. When omitted, this will fetch from the repositories default branch (usually main or master).

Downloaded dependencies will then be saved into the specified destination. When omitted, this will default to vendor/$owner/$repo/$path.

The path indicated can specify either a path to a regular file within the repository, or the path to a directory. In the latter case, all files from that directory in the repository will be downloaded recursively and stored in a directory named destination.

url [url], destination: [destination]

URL dependencies are handled as a simple HTTP fetch — the contents of the remote url are saved into the file named by destination. This is a useful option when a more specific dependency type is not available.

Example Manifest

# mygame/dependencies.rb

require "lib/foodchain"

# Download the version of `pvande/dragonborn/dragonborn.rb` from `main`.
# Creates `vendor/pvande/dragonborn/dragonborn.rb`.
github :pvande, :dragonborn, "dragonborn.rb"

# Download the version of `xenobrain/rubycolors/color.rb` from `bab319b65`.
# Creates `vendor/xenobrain/rubycolors/color.rb`.
github :xenobrain, :rubycolors, "color.rb", ref: "bab319b65"

# Download the version of `mruby/mruby/mrbgems/mruby-set/mrblib/set.rb` from `main`.
# Creates `vendor/set.rb`.
github :mruby, :mruby, "mrbgems/mruby-set/mrblib/set.rb", destination: "vendor/set.rb"

# Download the version of `danhealy/dragonruby-zif/lib` from `main`.
# Creates `vendor/zif`.
github :danhealy, "dragonruby-zif", "lib", destination: "vendor/zif"

# Downloads the URL into `vendor/fang/from_now.rb`.
url "https://gitlab.com/dragon-ruby/fang/-/raw/main/from_now.rb", destination: "vendor/fang/from_now.rb"