constant_sandbox

Constant Sandbox is a cli tool for ruby codebases used to enforce boundaries and modularize Rails applications. Inspired by packwerk but without the rails 6 requirement.

Constant Sandbox can be used to:

• Combine groups of files into packages
• Define package-level constant visibility (i.e. have publicly accessible constants)
• Enforce privacy (inbound) and dependency (outbound) boundaries between packages
• Help existing codebases to become more modular without obstructing development

Prerequisites

No dependencies are required for your ruby codebase. The parser library used support ruby 3.0.

Installation

At this time the only path to install this is using rust's cargo install. I plan on publishing precompiled versions and adding homebrew recipes soon.

Usage

The primary sub-command to use this tool is verify. This looks for box.yml files in your codebase that it treats as entry points for packages. These box.yml allow you to define what constants this folder exports and imports to the rest of your codebase.

To create your first constant sandbox the init command can take a folder and generate values for imports and exports based on your current usage.

constant_sandbox init lib/rubrowser/parser

You can now verify the box that was created by typing:

constant_sandbox verify

The last command available is inspect. This command evaluates your ruby codebase and outputs to stdout all of the connections that exist to the provided folder. Outputing a box configuration that would cover your current usage. This is useful for learning more about the cohesion of your codebase.

Example output:

For more information try --help
../constant_sandbox/target/release/constant_sandbox inspect lib/rubrowser/parser
non exported reference Rubrowser::Parser::Factory found in lib/rubrowser/data.rb on line 26
non imported reference Parser::Builders::Default found in lib/rubrowser/parser/file/builder.rb on line 8
non imported reference Parser::SyntaxError found in lib/rubrowser/parser/file.rb on line 26
non imported reference Parser::Source::Buffer found in lib/rubrowser/parser/file.rb on line 33
non imported reference Encoding::UTF_8 found in lib/rubrowser/parser/file.rb on line 34
non imported reference Parser::CurrentRuby found in lib/rubrowser/parser/file.rb on line 41
non imported reference Parser::AST::Node found in lib/rubrowser/parser/file.rb on line 145
---
imports:
  - "Encoding::UTF_8"
  - "Parser::AST::Node"
  - "Parser::Builders::Default"
  - "Parser::CurrentRuby"
  - "Parser::Source::Buffer"
  - "Parser::SyntaxError"
exports:
  - "Rubrowser::Parser::Factory"