Switch ImageOptim pre-commit hook to use executable

The `image_optim` gem now has a friendly CLI we can use instead of
integrating with the Ruby API directly. It is better to use the CLI
since it allows us to further decouple ourselves from the tool.

Change-Id: Icb4df4cc29016f0b79561eaa3ceb8abc0c8135fb
Reviewed-on: http://gerrit.causes.com/47233
Tested-by: jenkins <jenkins@brigade.com>
Reviewed-by: Shane da Silva <shane.dasilva@brigade.com>

Author: sds

CHANGELOG.md

@@ -7,6 +7,7 @@
   a list of paths a hook should load with `Kernel.require` before running
 * Disable `ShellCheck` pre-commit hook by default
 * Fix `CssLint` pre-commit hook to ignore blank lines in `csslint` output
+* Switch `ImageOptim` hook to use executable instead of Ruby API
 
 ## 0.23.0
 

config/default.yml

@@ -163,7 +163,7 @@ PreCommit:
 
   ImageOptim:
     description: 'Checking for optimizable images'
-    required_library: 'image_optim'
+    required_executable: 'image_optim'
     install_command: 'gem install image_optim'
     include:
       - '**/*.gif'

lib/overcommit/hook/pre_commit/image_optim.rb

@@ -2,34 +2,23 @@ module Overcommit::Hook::PreCommit
   # Checks for images that can be optimized with `image_optim`.
   class ImageOptim < Base
     def run
-      optimized_images =
-        begin
-          optimize_images(applicable_files)
-        rescue ::ImageOptim::BinResolver::BinNotFound => e
-          return :fail, "#{e.message}. The image_optim gem is dependendent on this binary."
-        end
+      result = execute(command + applicable_files)
+      return [:fail, result.stdout + result.stderr] unless result.success?
 
-      if optimized_images.any?
-        return :fail,
-          "The following images are optimizable:\n#{optimized_images.join("\n")}" \
-          "\n\nOptimize them by running:\n" \
-          "  image_optim --skip-missing-workers #{optimized_images.join(' ')}"
-      end
+      optimized_files = extract_optimized_files(result.stdout)
+      return :pass if optimized_files.empty?
 
-      :pass
+      output = "The following images are optimizable:\n#{optimized_files.join("\n")}"
+      output += "\n\nOptimize them by running `#{command.join(' ')} #{optimized_files.join(' ')}`"
+      [:fail, output]
     end
 
     private
 
-    def optimize_images(image_paths)
-      image_optim = ::ImageOptim.new(skip_missing_workers: true)
-
-      optimized_images =
-        image_optim.optimize_images(image_paths) do |path, optimized|
-          path if optimized
-        end
-
-      optimized_images.compact
+    def extract_optimized_files(output)
+      output.split("\n").
+             select { |line| line =~ /^\d+/ }.
+             map    { |line| line.split(/\s+/).last }
     end
   end
 end

overcommit.gemspec

@@ -28,7 +28,6 @@ Gem::Specification.new do |s|
 
   s.add_dependency             'childprocess', '~> 0.5.0'
 
-  s.add_development_dependency 'image_optim', '~> 0.20.0'
   s.add_development_dependency 'rspec', '~> 3.0'
   s.add_development_dependency 'travis', '~> 1.7'
   s.add_development_dependency 'w3c_validators', '~> 1.2'

spec/overcommit/hook/pre_commit/image_optim_spec.rb

@@ -1,5 +1,4 @@
 require 'spec_helper'
-require 'image_optim'
 
 describe Overcommit::Hook::PreCommit::ImageOptim do
   let(:config)  { Overcommit::ConfigurationLoader.default_configuration }
@@ -10,27 +9,47 @@
     subject.stub(:applicable_files).and_return(%w[file1.jpg file2.png])
   end
 
-  context 'when a dependency of image_optim is not installed' do
+  context 'when image_optim exits successfully' do
+    let(:result) { double('result') }
+
     before do
-      subject.stub(:optimize_images).and_raise(::ImageOptim::BinResolver::BinNotFound)
+      result.stub(:success?).and_return(true)
+      subject.stub(:execute).and_return(result)
     end
 
-    it { should fail_hook }
-  end
+    context 'and images were optimized' do
+      before do
+        result.stub(:stdout).and_return([
+          '32.30%   1.2K  file1.jpg',
+          'Total: 32.30%   1.2K',
+        ].join("\n"))
+      end
 
-  context 'when an image was optimized' do
-    before do
-      subject.stub(:optimize_images).and_return(['file1.jpg'])
+      it { should fail_hook }
     end
 
-    it { should fail_hook }
+    context 'and no images were optimized' do
+      before do
+        result.stub(:stdout).and_return([
+          '------         app/assets/images/favicons/favicon-96x96.png',
+          'Total: ------',
+        ].join("\n"))
+      end
+
+      it { should pass }
+    end
   end
 
-  context 'when no images were optimized' do
+  context 'when image_optim exits unsuccessfully' do
+    let(:result) { double('result') }
+
     before do
-      subject.stub(:optimize_images).and_return([])
+      result.stub(:success?).and_return(false)
+      result.stub(:stdout).and_return('An error occurred')
+      result.stub(:stderr).and_return('')
+      subject.stub(:execute).and_return(result)
     end
 
-    it { should pass }
+    it { should fail_hook }
   end
 end