Chef Cookstyle - Chef Infra Cookbook and InSpec profile linting with autocorrection

• Umbrella Project: Chef Infra
• Project State: Active
• Issues Response Time Maximum: 14 days
• Pull Request Response Time Maximum: 14 days

Cookstyle is a code linting tool that helps you to write better Chef Infra cookbooks and InSpec profiles by detecting and automatically correcting style, syntax, logic, and security mistakes in your code.

Cookstyle is powered by the RuboCop linting engine. RuboCop ships with over three-hundred rules, or cops, designed to detect common Ruby coding mistakes and enforce a common coding style. We've customized Cookstyle with a subset of those cops that we believe are perfectly tailored for cookbook development. We also ship 259 Chef Infra specific cops that catch common cookbook coding mistakes, cleanup portions of code that are no longer necessary, and detect deprecations that prevent cookbooks from running on the latest releases of Chef Infra Client.

For complete usage documentation along with documentation for all the included cops see https://docs.chef.io/workstation/cookstyle/

How does Cookstyle differ from RuboCop?

Cookbook and profile development differs from that of traditional Ruby software development, so we have tailored the list of built-in cops in RuboCop for cookbook development. For the most part, this means disabling cops deemed not useful for cookbook development. Occasionally, we've changed the configuration of a rule to enforce a different behavior altogether. We've also extended the base RuboCop package with a set of our own Chef Infra-specific cops. These cops are only found in Cookstyle and will help you to write more reliable and future-proof cookbooks.

See the current set of cops in Cops Documentation

RuboCop is an incredibly active project with new cops being introduced monthly. The new cops cause existing codebases to fail CI tests and force authors to constantly update their code. With Cookstyle, we update the RuboCop engine for bug and performance fixes, but we only change the set of cops that will fail tests once a year during Chef Infra's April major release. All new cops are introduced at RuboCop's "refactor" alert level, meaning they will alert to the screen as you run Cookstyle, but they won't fail a build. This stability means you are free to upgrade releases of Cookstyle without being forced to update your infrastructure code.

Cookstyle is the replacement for Foodcritic. For more information on why we decided to replace Foodcritic see our blog post Goodbye Foodcritic

Cookstyle is included in Chef Workstation. If you choose not to use the Chef Workstation package, you can still install Cookstyle manually using the instructions below.

Add this line to your application's Gemfile:

gem 'cookstyle'

And then execute:

bundle

Or install it yourself as:

gem install cookstyle

Use this tool just as you would RuboCop, but invoke the cookstyle binary instead, which patches RuboCop to load cops from the cookstyle gem. For example:

cookstyle -D --format offenses

In a Rakefile, the setup is similar, except you need to require the cookstyle library first:

require 'cookstyle'
require 'rubocop/rake_task'
RuboCop::RakeTask.new(:cookstyle) do |task|
  task.options << '--display-cop-names'
end

Run RuboCop as normal, and simply add a -r cookstyle option when running:

rubocop -r cookstyle -D --format offenses

You can use one of two methods. The simplest is to add the -r cookstyle option to the :cli option in your Guardfile:

guard :rubocop, cli: "-r cookstyle" do
  watch(%r{.+\.rb$})
  watch(%r{(?:.+/)?\.rubocop\.yml$}) { |m| File.dirname(m[0]) }
end

Alternatively you could pass the path to Cookstyle's configuration by using the Cookstyle.config method:

require "cookstyle"

guard :rubocop, cli: "--config #{Cookstyle.config}" do
  watch(%r{.+\.rb$})
  watch(%r{(?:.+/)?\.rubocop\.yml$}) { |m| File.dirname(m[0]) }
end

As with RuboCop, any custom settings can still be placed in a .rubocop.yml file in the root of your project.

Many of the cops included in Cookstyle will autocorrect Chef Infra cookbook code in ways that will require fairly recent releases of Chef Infra Client in order to run those cookbooks. For example the Chef/Modernize/UnnecessaryDependsChef14 cop will remove cookbook dependencies from your metadata.rb which are no longer necessary with Chef Infra Client 14+. This cop would be problematic if you ran it against your cookbooks, and had yet to upgrade your fleet of systems to Chef Infra Client 14+. For this reason you may want to configure Cookstyle to skip cops that would be destructive on older version of Chef Infra Client by setting.

Cookstyle now includes a new top-level configuration option TargetChefVersion. This new configuration option works similarly to RuboCop's TargetRubyVersion config option and allows you to specify a Chef Infra version that you want to target in your Cookstyle analysis. By setting the target version you disable incompatible cops and autocorrect from running. This allows you to gradually update your target version to allow stepped upgrades of Chef Infra Client such as 12.something -> 12.latest -> 13.latest -> 14.latest -> 15.latest.

Example .rubocop.yml config specifying a TargetChefVersion of 14.0:

AllCops:
  TargetChefVersion: 14.0

We'd love to have your help in developing Cookstyle. See our Contributing Guide for more information on contributing to Chef projects. There's also a Developer Guide for Cookstyle that outlines how the configs work and how you can upgrade the RuboCop engine.

Copyright 2016-2021, Chef Software, Inc.

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