Complete Guide to setup VS Code for Ruby on Rails (Debugger, Linter, Completion, Formatting)

This article explain how configure Visual Studio Code debugger and language server for your Ruby or Ruby on Rails project. After setup you will be able to debug and navigate through Ruby code like an in RubyMine but for free :).

Motivation

When I tried to configure Ruby debugger for the first time, I read many articles and tutorials but don't found how get things done when Ruby installed through asdf / rbenv or another version manager. Problems with relative paths, terminal environments, conflicts with existed ruby and gems versions.
Lets try to fix that and build isolated environment for our project.

Requirements

VS Code with plugins #1, #2

Ruby installed through rbenv or asdf, Bundler.

Project setup

Dependencies

Add to your Gemfile:

group :development, :test do
  gem "ruby-debug-ide", require: false
  gem "debase", require: false
  gem 'solargraph', require: false
end

and run

$ bundle install

Ruby version

Create .ruby-version file in root of project if it not already exists.

$ echo "3.0.2" > .ruby-version

Binstubs

Generate bintubs for gems which will be very useful later:

$ bundle binstubs bundler ruby-debug-ide solargraph

Binstub for test library (rspec for example):

$ bundle binstubs rspec-core

After all in bin folder you will see 4 new files: rdebug-ide, gdb_wrapper, bundle, rspec, which will be used in VS Code configuration files.

Launch and Settings

Copy to .vscode/launch.json

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Start rails server",
      "type": "Ruby",
      "request": "launch",
      "cwd": "${workspaceRoot}",
      "program": "${workspaceRoot}/bin/rails",
      "useBundler": true,
      "pathToBundler": "${workspaceRoot}/bin/bundle",
      "showDebuggerOutput": true,
      "pathToRDebugIDE": "/${workspaceRoot}/bin/rdebug-ide",
      "args": ["s"]
    },
    {
      "name": "Run tests",
      "type": "Ruby",
      "request": "launch",
      "cwd": "${workspaceRoot}",
      "program": "${workspaceRoot}/bin/rspec",
      "useBundler": true,
      "pathToBundler": "${workspaceRoot}/bin/bundle",
      "showDebuggerOutput": true,
      "pathToRDebugIDE": "/${workspaceRoot}/bin/rdebug-ide",
      "args": []
    }
  ]
}

Copy to settings.json

{
    "solargraph.commandPath": "bin/solargraph",
    "solargraph.formatting": true,
    "editor.formatOnSave": true,
    "solargraph.diagnostics": true,
}

Result

We configure debugger,language server for completion, linting & formatting. Our config depends only on project binstubs, works as expected, and don't conflicts with other environments, because all stuff stores in project folder.
In the future, the config can be easily transferred to another project.

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