implement switching back to prior env on post-commit, should fix #2

Gemfile

@@ -5,7 +5,11 @@ gemspec
 
 gem 'guard'
 gem 'guard-rspec'
+gem 'guard-cucumber'
+
 gem 'mocha'
 gem 'fakefs'
 gem 'rspec', '~> 2.6.0'
 gem 'rake'
+
+gem 'cucumber'

Guardfile

@@ -1,9 +1,18 @@
 # A sample Guardfile
 # More info at https://github.com/guard/guard#readme
 
+group :rspec do
   guard 'rspec', :cli => '-c', :version => 2 do
     watch(%r{^spec/.+_spec\.rb$})
     watch(%r{^lib/(.+)\.rb$})     { |m| "spec/lib/#{m[1]}_spec.rb" }
     watch('spec/spec_helper.rb')  { "spec" }
   end
+end
 
+group :cucumber do
+  guard 'cucumber' do
+    watch(%r{^features/.+\.feature$})
+    watch(%r{^features/support/.+$})          { 'features' }
+    watch(%r{^features/step_definitions/(.+)_steps\.rb$}) { |m| Dir[File.join("**/#{m[1]}.feature")][0] || 'features' }
+  end
+end

Rakefile

@@ -9,5 +9,24 @@ rescue LoadError
   "#$! - no rspec"
 end
 
-task :default => :spec
+begin
+  require 'rspec/core/rake_task'
+
+  RSpec::Core::RakeTask.new(:spec)
+rescue LoadError
+  "#$! - no rspec"
+end
+
+begin
+  require 'cucumber'
+  require 'cucumber/rake/task'
+
+  Cucumber::Rake::Task.new(:cucumber) do |t|
+    t.cucumber_opts = "features --format pretty"
+  end
+rescue LoadError
+  "#$! - no cucumber"
+end
+
+task :default => [ :spec, :cucumber ]
 

bin/penchant

@@ -29,12 +29,20 @@ class PenchantCLI < Thor
   end
 
   method_options :deployment => false
+  method_options :switch_back => false
   desc "gemfile ENV", "Switch the gemfile environment, or rebuild the current environment if not given"
   def gemfile(env = get_current_env)
     if env
+      if options[:switch_back]
+        puts "[penchant] Switching back, fallback: #{env}..."
+
+        Penchant::Gemfile.switch_back!(env)
+      else
         puts "[penchant] Rebunding for #{env} environment#{options[:deployment] ? ", deployment mode" : ''}..."
+
         Penchant::Gemfile.do_full_env_switch!(env, options[:deployment])
       end
+    end
 
     gemfile = Penchant::Gemfile.new
     if !gemfile.has_gemfile?

features/cli.feature

@@ -0,0 +1,18 @@
+Feature: CLI
+  Scenario: Switch back to the original pre-deployment environment
+    Given I have the file "tmp/Gemfile.erb" with the content:
+      """
+      gem 'rake'
+      """
+      And I have the file "tmp/Gemfile" with the content:
+        """
+        # generated by penchant, environment: production, deployment mode (was local)
+        """
+    When I run "bin/penchant gemfile other --switch-back" in the "tmp" directory
+    Then the file "tmp/Gemfile" should have the following content:
+      """
+      # generated by penchant, environment: local
+      gem 'rake'
+      """
+      And the output should include "fallback: other"
+

features/gemfile.feature

@@ -0,0 +1,33 @@
+@fakefs
+Feature: Gemfiles
+  Scenario: When rebuilding for deployment, save the original state
+    Given I have the file "Gemfile.erb" with the content:
+      """
+      this is content
+      """
+      And I have the file "Gemfile" with the content:
+      """
+      # generated by penchant, environment: local
+      """
+    When I rebuild the Gemfile for "production" mode with deployment
+    Then the file "Gemfile" should have the following content:
+      """
+      # generated by penchant, environment: production, deployment mode (was local)
+      this is content
+      """
+
+  Scenario: When unbundling from deployment with an original state, switch to that state
+    Given I have the file "Gemfile.erb" with the content:
+      """
+      this is content
+      """
+      And I have the file "Gemfile" with the content:
+      """
+      # generated by penchant, environment: production, deployment mode (was local)
+      """
+    When I rebuild the Gemfile asking to switch back to the previous state
+    Then the file "Gemfile" should have the following content:
+      """
+      # generated by penchant, environment: local
+      this is content
+      """

features/step_definitions/given/i_have_the_file_with_content.rb

@@ -0,0 +1,5 @@
+Given /^I have the file "([^"]*)" with the content:$/ do |file, string|
+  FileUtils.mkdir_p File.dirname(file)
+
+  File.open(file, 'wb') { |fh| fh.print string }
+end

features/step_definitions/then/the_file_should_have_content.rb

@@ -0,0 +1,3 @@
+Then /^the file "([^"]*)" should have the following content:$/ do |file, string|
+  File.read(file).should == string
+end

features/step_definitions/then/the_output_should_include.rb

@@ -0,0 +1,3 @@
+Then /^the output should include "([^"]*)"$/ do |text|
+  @output.should include(text)
+end

features/step_definitions/when/i_rebuild_the_gemfile_switching_back.rb

@@ -0,0 +1,3 @@
+When /^I rebuild the Gemfile asking to switch back to the previous state$/ do
+  Penchant::Gemfile.switch_back!("remote")
+end

features/step_definitions/when/i_rebuild_the_gemfile_with_deployment.rb

@@ -0,0 +1,3 @@
+When /^I rebuild the Gemfile for "([^"]*)" mode with deployment$/ do |env|
+  Penchant::Gemfile.do_full_env_switch!(env, true)
+end

features/step_definitions/when/i_run_in.rb

@@ -0,0 +1,3 @@
+When /^I run "([^"]*)" in the "([^"]*)" directory$/ do |command, dir|
+  @output = %x{bash -c 'opwd=$PWD; cd #{dir} && $opwd/#{command}'}
+end

features/support/env.rb

@@ -0,0 +1,13 @@
+require 'fakefs/safe'
+require 'penchant'
+
+Before('@fakefs') do
+  FakeFS.activate!
+end
+
+After do
+  FakeFS.deactivate!
+
+  FileUtils.rm_rf 'tmp'
+end
+

lib/penchant/gemfile.rb

@@ -2,21 +2,30 @@ require 'erb'
 
 module Penchant
   class Gemfile
-    attr_reader :path
+    attr_reader :path, :is_deployment
 
-    class << self
+    def self.do_full_env_switch!(env, deployment = false)
-      def do_full_env_switch!(env, deployment = false)
+      return false if !(gemfile = pre_switch(env, deployment))
-        gemfile = Penchant::Gemfile.new
-        gemfile.run_dot_penchant!(env, deployment)
-
-        if !gemfile.has_gemfile_erb?
-          return false
-        end
 
       gemfile.switch_to!(env, deployment)
     end
+
+    def self.switch_back!(fallback_env)
+      return false if !(gemfile = pre_switch(fallback_env))
+
+      gemfile.switch_back!(fallback_env)
     end
 
+    def self.pre_switch(env, deployment = false)
+      gemfile = Penchant::Gemfile.new
+      return false if !gemfile.has_gemfile_erb?
+      gemfile.run_dot_penchant!(env, deployment)
+
+      gemfile
+    end
+
+    def current_env ; @env ; end
+
     def initialize(path = Dir.pwd)
       @path = path
     end
@@ -26,7 +35,7 @@ module Penchant
     end
 
     def has_gemfile?
-      File.file?('Gemfile')
+      File.file?(gemfile_path)
     end
 
     def has_dot_penchant?
@@ -42,33 +51,52 @@ module Penchant
     end
 
     def environment
-      File.readlines(gemfile_path).first.strip[%r{environment: ([^, ]*)}, 1]
+      gemfile_header.strip[%r{environment: ([^, ]*)}, 1]
     end
 
     def deployment?
-      File.readlines(gemfile_path).first['deployment mode'] != nil
+      gemfile_header['deployment mode'] != nil
     end
 
     def switch_to!(gemfile_env = nil, deployment = false)
       @env, @is_deployment = gemfile_env, deployment
-      template = File.read(gemfile_erb_path)
 
-      File.open(gemfile_path, 'wb') do |fh|
+      output = [ header, ERB.new(template).result(binding) ]
-        fh.puts "# generated by penchant, environment: #{@env || "none"}#{@is_deployment ? " , deployment mode" : ""}"
 
-        fh.print ERB.new(template).result(binding)
+      File.open(gemfile_path, 'wb') { |fh| fh.print output.join("\n") }
-      end
     end
 
     def run_dot_penchant!(env, deployment)
       DotPenchant.run(env || environment, deployment) if has_dot_penchant?
     end
 
+    def header
+      header = [ "# generated by penchant, environment: #{current_env}" ]
+
+      if is_deployment
+        header << ", deployment mode (was #{environment})"
+      end
+
+      header.join
+    end
+
+    def prior_environment
+      gemfile_header[%r{\(was (.+)\)}, 1]
+    end
+
+    def switch_back!(fallback_env)
+      switch_to!(prior_environment || fallback_env)
+    end
+
     private
     def file_in_path(file)
       File.join(@path, file)
     end
 
+    def template
+      File.read(gemfile_erb_path)
+    end
+
     def env(check, &block)
       instance_eval(&block) if check.to_s == @env.to_s
     end
@@ -76,6 +104,10 @@ module Penchant
     def no_deployment(&block)
       instance_eval(&block) if !@is_deployment
     end
+
+    def gemfile_header
+      (has_gemfile? and File.readlines(gemfile_path).first) or ""
+    end
   end
 end
 

spec/lib/penchant/gemfile_spec.rb

@@ -146,5 +146,149 @@ ERB
       end
     end
   end
+
+  describe '#switch_to!' do
+    let(:template) { 'template' }
+    let(:gemfile_path) { 'gemfile path' }
+    let(:header) { 'header' }
+
+    let(:gemfile_out) { File.read(gemfile_path) }
+
+    before do
+      gemfile.stubs(:template).returns(template)
+      gemfile.stubs(:gemfile_path).returns(gemfile_path)
+
+      gemfile.expects(:header).returns(header)
+    end
+
+    it 'should write out the new gemfile' do
+      gemfile.switch_to!
+
+      gemfile_out.should include(template)
+      gemfile_out.should include(header)
+    end
+  end
+
+  describe '#header' do
+    subject { gemfile.header }
+
+    let(:env) { 'env' }
+    let(:prior_environment) { 'prior' }
+
+    before do
+      gemfile.stubs(:current_env).returns(env)
+      gemfile.stubs(:environment).returns(prior_environment)
+    end
+
+    context 'not deployment' do
+      before do
+        gemfile.stubs(:is_deployment).returns(false)
+      end
+
+      it { should == "# generated by penchant, environment: #{env}" }
+    end
+
+    context 'deployment' do
+      before do
+        gemfile.stubs(:is_deployment).returns(true)
+      end
+
+      it { should == "# generated by penchant, environment: #{env}, deployment mode (was #{prior_environment})" }
+    end
+  end
+
+  describe '#prior_environment' do
+    subject { gemfile.prior_environment }
+
+    let(:prior) { 'prior' }
+
+    before do
+      gemfile.stubs(:gemfile_header).returns("# header (was #{prior})")
+    end
+
+    it { should == prior }
+  end
+
+  describe '.switch_back!' do
+    let(:gemfile) { stub }
+    let(:fallback_env) { 'env' }
+
+    context 'pre_switch fails' do
+      before do
+        described_class.stubs(:pre_switch).returns(false)
+
+        gemfile.expects(:switch_back!).never
+      end
+
+      it 'should not switch back' do
+        described_class.switch_back!(fallback_env).should be_false
+      end
+    end
+
+    context 'pre_switch succeeds' do
+      before do
+        described_class.stubs(:pre_switch).returns(gemfile)
+
+        gemfile.expects(:switch_back!).with(fallback_env)
+      end
+
+      it 'should switch back' do
+        described_class.switch_back!(fallback_env)
+      end
+    end
+  end
+
+  describe '.pre_switch' do
+    subject { described_class.pre_switch(env, deployment) }
+
+    let(:env) { 'env' }
+    let(:deployment) { 'deployment' }
+
+    context 'no Gemfile.erb' do
+      before do
+        described_class.any_instance.expects(:has_gemfile_erb?).returns(false)
+      end
+
+      it { should be_false }
+    end
+
+    context 'Gemfile.erb' do
+      before do
+        described_class.any_instance.expects(:has_gemfile_erb?).returns(true)
+        described_class.any_instance.expects(:run_dot_penchant!).with(env, deployment)
+      end
+
+      it { should be_a_kind_of(described_class) }
+    end
+  end
+
+  describe '#switch_back!' do
+    let(:fallback_env) { 'fallback' }
+    let(:prior) { 'prior' }
+
+    context 'no prior' do
+      before do
+        gemfile.stubs(:prior_environment).returns(nil)
+
+        gemfile.expects(:switch_to!).with(fallback_env)
+      end
+
+      it 'should proxy through to switch_to!' do
+        gemfile.switch_back!(fallback_env)
+      end
+    end
+
+    context 'prior' do
+      before do
+        gemfile.stubs(:prior_environment).returns(prior)
+
+        gemfile.expects(:switch_to!).with(prior)
+      end
+
+      it 'should proxy through to switch_to!' do
+        gemfile.switch_back!(fallback_env)
+      end
+    end
+  end
 end
 

template/script/hooks/post-commit

@@ -1,4 +1,4 @@
 #!/bin/bash
 
-penchant gemfile remote
+penchant gemfile remote --switch-back