Add ability to choose rules applied, refs #4.

The DSL now accepts a tags array to define the set of tags available to choose
whether or not to apply the rule. This is lifted straight from Cucumber tag
expressions.

Gemfile.lock

@@ -3,12 +3,13 @@ PATH
   specs:
     foodcritic (0.4.0)
       chef (~> 0.10.4)
+      gherkin (~> 2.7.1)
       nokogiri (~> 1.5.0)
 
 GEM
   remote: http://rubygems.org/
   specs:
-    aruba (0.4.8)
+    aruba (0.4.9)
       childprocess (>= 0.2.3)
       cucumber (>= 1.1.1)
       ffi (= 1.0.11)
@@ -33,16 +34,16 @@ GEM
       uuidtools
     childprocess (0.2.3)
       ffi (~> 1.0.6)
-    cucumber (1.1.3)
+    cucumber (1.1.4)
       builder (>= 2.1.2)
       diff-lcs (>= 1.1.2)
-      gherkin (~> 2.6.7)
+      gherkin (~> 2.7.1)
       json (>= 1.4.6)
       term-ansicolor (>= 1.0.6)
     diff-lcs (1.1.3)
     erubis (2.7.0)
     ffi (1.0.11)
-    gherkin (2.6.9)
+    gherkin (2.7.1)
       json (>= 1.4.6)
     guard (0.8.8)
       thor (~> 0.14.6)

bin/foodcritic

@@ -1,8 +1,19 @@
 #!/usr/bin/env ruby
 require 'foodcritic'
+require 'optparse'
+
+options = {}
+options[:tags] = []
+parser = OptionParser.new do |opts|
+  opts.banner = 'foodcritic [cookbook_path]'
+  opts.on("-t", "--tags TAGS", "Only check against rules with the specified tags.") {|t|options[:tags] << t}
+end
+parser.parse!
+
 unless ARGV.length == 1 and Dir.exists?(ARGV[0])
-  STDERR.puts 'foodcritic [cookbook_path]'
+  puts parser.help
   exit 1
 end
-review = FoodCritic::Linter.new.check(ARGV[0])
-puts review unless review.warnings.empty?
+
+review = FoodCritic::Linter.new.check(ARGV[0], options)
+puts review unless review.warnings.empty?

features/command_line_help.feature

@@ -0,0 +1,25 @@
+Feature: Command line help
+
+  In order to be able to learn about the options available for checking my cookbooks
+  As a developer
+  I want to be able to interactively get help on the options from the command line
+
+  Scenario: No arguments
+    Given I have installed the lint tool
+     When I run it on the command line with no arguments
+     Then the simple usage text should be displayed along with a non-zero exit code
+
+  Scenario: Too many arguments
+    Given I have installed the lint tool
+     When I run it on the command line with too many arguments
+     Then the simple usage text should be displayed along with a non-zero exit code
+
+  Scenario: Non-existent cookbook directory
+    Given I have installed the lint tool
+     When I run it on the command line specifying a cookbook that does not exist
+     Then the simple usage text should be displayed along with a non-zero exit code
+
+  Scenario: Command help
+    Given I have installed the lint tool
+     When I run it on the command line with the help option
+     Then the simple usage text should be displayed along with a zero exit code

features/step_definitions/command_line_steps.rb

@@ -0,0 +1,29 @@
+Given /^I have installed the lint tool$/ do
+
+end
+
+When /^I run it on the command line with no arguments$/ do
+  run_simple('foodcritic', false)
+end
+
+When /^I run it on the command line with too many arguments$/ do
+  run_simple('foodcritic example example', false)
+end
+
+When /^I run it on the command line specifying a cookbook that does not exist$/ do
+  run_simple('foodcritic no-such-cookbook', false)
+end
+
+When /^I run it on the command line with the help option$/ do
+  run_simple('foodcritic --help', false)
+end
+
+Then /^the simple usage text should be displayed along with a (non-)?zero exit code$/ do |non_zero|
+  assert_partial_output 'foodcritic [cookbook_path]', all_output
+  assert_matching_output('( )+-t, --tags TAGS( )+Only check against rules with the specified tags.', all_output)
+  if non_zero.nil?
+    assert_exit_status 0
+  else
+    assert_not_exit_status 0
+  end
+end

foodcritic.gemspec

@@ -11,6 +11,7 @@ Gem::Specification.new do |s|
   s.license = 'MIT'
   s.executables << 'foodcritic'
   s.add_dependency('chef', '~> 0.10.4')
+  s.add_dependency('gherkin', '~> 2.7.1')
   s.add_dependency('nokogiri', '~> 1.5.0')
   s.files = Dir['lib/**/*.rb']
   s.required_ruby_version = '>= 1.9.3'

lib/foodcritic/domain.rb

@@ -38,14 +38,15 @@ def to_s
 
   # A rule to be matched against.
   class Rule
-    attr_accessor :code, :name, :description, :recipe
+    attr_accessor :code, :name, :description, :recipe, :tags
 
     # Create a new rule
     #
     # @param [String] code The short unique identifier for this rule, e.g. 'FC001'
     # @param [String] name The short descriptive name of this rule presented to the end user.
     def initialize(code, name)
       @code, @name = code, name
+      @tags = [code]
     end
   end
 

lib/foodcritic/dsl.rb

@@ -19,6 +19,13 @@ def rule(code, name, &block)
       yield self
     end
 
+    # Add tags to the rule which can be used to filter the rules to be applied.
+    #
+    # @param [Array] tags The tags associated with this rule.
+    def tags(tags)
+      rules.last.tags += tags
+    end
+
     # Set the rule description
     #
     # @param [String] description Set the rule description.

lib/foodcritic/linter.rb

@@ -1,4 +1,5 @@
 require 'ripper'
+require 'gherkin/tag_expression'
 
 module FoodCritic
 
@@ -15,14 +16,19 @@ def initialize
     # Review the cookbooks at the provided path, identifying potential improvements.
     #
     # @param [String] cookbook_path The file path to an individual cookbook directory
+    # @param [Hash] options Options to apply to the linting
+    # @option options [Array] tags The tags to filter rules based on
     # @return [FoodCritic::Review] A review of your cookbooks, with any warnings issued.
-    def check(cookbook_path)
+    def check(cookbook_path, options)
       warnings = []
+      tag_expr = Gherkin::TagExpression.new(options[:tags])
       files_to_process(cookbook_path).each do |file|
         ast = read_file(file)
         @rules.each do |rule|
-          matches = rule.recipe.yield(ast, file)
-          matches.each{|match| warnings << Warning.new(rule, {:filename => file}.merge(match))} unless matches.nil?
+          if tag_expr.eval(rule.tags)
+            matches = rule.recipe.yield(ast, file)
+            matches.each{|match| warnings << Warning.new(rule, {:filename => file}.merge(match))} unless matches.nil?
+          end
         end
       end
       Review.new(warnings)

lib/foodcritic/rules.rb

@@ -1,4 +1,5 @@
 rule "FC002", "Avoid string interpolation where not required" do
+  tags %w{style}
   description "When setting a resource value avoid string interpolation where not required."
   recipe do |ast|
     ast.xpath(%q{//string_literal[count(descendant::string_embexpr) = 1 and
@@ -7,13 +8,15 @@
 end
 
 rule "FC003", "Check whether you are running with chef server before using server-specific features" do
+  tags %w{portability solo}
   description "Ideally your cookbooks should be usable without requiring chef server."
   recipe do |ast|
     checks_for_chef_solo?(ast) ? [] : searches(ast).map{|s| match(s)}
   end
 end
 
 rule "FC004", "Use a service resource to start and stop services" do
+  tags %w{style}
   description "Avoid use of execute to control services - use the service resource instead."
   recipe do |ast|
     find_resources(ast, 'execute').find_all do |cmd|
@@ -24,6 +27,7 @@
 end
 
 rule "FC005", "Avoid repetition of resource declarations" do
+  tags %w{style}
   description "Where you have a lot of resources that vary in only a single attribute wrap them in a loop for brevity."
   recipe do |ast|
     matches = []
@@ -39,6 +43,7 @@
 end
 
 rule "FC006", "Mode should be quoted or fully specified when setting file permissions" do
+  tags %w{correctness}
   description "Not quoting mode when setting permissions can lead to incorrect permissions being set."
   recipe do |ast|
     ast.xpath(%q{//ident[@value='mode']/parent::command/descendant::int[string-length(@value) < 4]/
@@ -47,6 +52,7 @@
 end
 
 rule "FC007", "Ensure recipe dependencies are reflected in cookbook metadata" do
+  tags %w{correctness metadata}
   description "You are including a recipe that is not in the current cookbook and not defined as a dependency in your cookbook metadata."
   recipe do |ast,filename|
     metadata_path = Pathname.new(File.join(File.dirname(filename), '..', 'metadata.rb')).cleanpath
@@ -60,6 +66,7 @@
 end
 
 rule "FC008", "Generated cookbook metadata needs updating" do
+  tags %w{style metadata}
   description "The cookbook metadata for this cookbook is boilerplate output from knife generate cookbook and needs updating with the real details of your cookbook."
   recipe do |ast,filename|
     metadata_path = Pathname.new(File.join(File.dirname(filename), '..', 'metadata.rb')).cleanpath
@@ -74,6 +81,7 @@
 end
 
 rule "FC009", "Resource attribute not recognised" do
+  tags %w{correctness}
   description "You appear to be using an unrecognised attribute on a standard Chef resource. Please check for typos."
   recipe do |ast|
     matches = []
@@ -93,6 +101,7 @@
 end
 
 rule "FC010", "Invalid search syntax" do
+  tags %w{correctness search}
   description "The search expression in the recipe could not be parsed. Please check your syntax."
   recipe do |ast|
     # This only works for literal search strings