extensive refactoring around detecting changed local caches; reduces …

…cyclomatic complexity and eliminates unnecessary pipefitting

lib/capistrano/recipes/deploy/strategy/exceptions.reek

@@ -5,10 +5,11 @@ Duplication:
   - command
   - deploy!
   - rsync_host
+  - remove_cache_if_repo_changed
 
 FeatureEnvy:
   exclude:
   - check!
 
 LongMethod: 
-  max_statements: 15
+  max_statements: 10

lib/capistrano/recipes/deploy/strategy/rsync_with_remote_cache.rb

@@ -6,6 +6,13 @@ module Deploy
     module Strategy
       class RsyncWithRemoteCache < Remote
 
+        INFO_COMMANDS = {
+          :subversion => "svn info . | sed -n \'s/URL: //p\'",
+          :git        => "git config remote.origin.url",
+          :mercurial  => "hg showconfig paths.default",
+          :bzr        => "bzr info | grep parent | sed \'s/^.*parent branch: //\'"
+        }
+
         # The deployment method itself, in three major steps: update the local cache, update the remote
         # cache, and copy the remote cache into place.
         def deploy!
@@ -63,45 +70,34 @@ def rsync_host(server)
           end
         end
 
-        # Command to get source from SCM on the local side. If the local_cache directory exists,
-        # we check to see if it's an SCM checkout that matches the currently configured repository.
-        # If it matches, we update it. If it doesn't match (either it's for another repository or
-        # not a checkout at all), we remove the directory and recreate it with a fresh SCM checkout.
-        # If the directory doesn't exist, we create it with a fresh SCM checkout.
+        # Remove the local cache (so it can be recreated) if the repository URL has changed
+        # since the last deployment.
         # TODO: punt in some sensible way if local_cache exists but is a regular file.
-        def command
-          case configuration[:scm]
-          when :subversion
-            info_command = "svn info #{local_cache} | sed -n 's/URL: //p'"
-          when :git
-            info_command = "cd #{local_cache} && git config remote.origin.url"
-          when :mercurial
-            info_command = "cd #{local_cache} && hg showconfig paths.default"
-          when :bzr
-            info_command = "cd #{local_cache} && bzr info | grep parent | sed 's/^.*parent branch: //'"
-          else
-            # an effective no-op
-            info_command = "echo #{configuration[:repository]}"
-          end
-          cache_info = IO.popen(info_command)
-
-          cached_repository = cache_info.gets
-          cache_info.close
-          if cached_repository && cached_repository.chomp != configuration[:repository]
-            logger.trace "repository has changed; removing old local cache"
-            FileUtils.rm_rf local_cache
+        def remove_cache_if_repo_changed
+          if INFO_COMMANDS[configuration[:scm]] && File.directory?(local_cache)
+            info_command = "cd #{local_cache} && #{INFO_COMMANDS[configuration[:scm]]}"
+            cached_repo_url = IO.popen(info_command){|pipe| pipe.readline}.chomp
+            if cached_repo_url != configuration[:repository]
+              logger.trace "repository has changed; removing old local cache"
+              FileUtils.rm_rf(local_cache)
+            end
           end
+        end
 
+        # Command to get source from SCM on the local side. The local cache is either created,
+        # updated, or destroyed and recreated depending on whether it exists and is a cache of
+        # the right repository.
+        def command
+          remove_cache_if_repo_changed
           if File.exists?(local_cache) && File.directory?(local_cache)
             logger.trace "updating local cache to revision #{revision}"
-            cmd = source.sync(revision, local_cache)
+            return source.sync(revision, local_cache)
           else
             logger.trace "creating local cache with revision #{revision}"
             File.delete(local_cache) if File.exists?(local_cache)
             Dir.mkdir(File.dirname(local_cache)) unless File.directory?(File.dirname(local_cache))
-            cmd = source.checkout(revision, local_cache)
+            return source.checkout(revision, local_cache)
           end
-          cmd
         end
       end
     end

test/capistrano_rsync_with_remote_cache_test.rb

@@ -9,25 +9,9 @@ def stub_configuration(hash)
     @rwrc.expects(:configuration).at_least_once.returns(hash)
   end
 
-  def stub_creation_of_new_local_cache
-    File.expects(:exists?).with('.rsync_cache').times(2).returns(false)
-    File.expects(:directory?).with(File.dirname('.rsync_cache')).returns(false)
-    Dir.expects(:mkdir).with(File.dirname('.rsync_cache'))
-    source_stub = stub()
-    source_stub.expects(:checkout)
-    @rwrc.expects(:source).returns(source_stub)
-  end
-
-  def stub_detection_of_changed_local_cache(command, returns)
-    cache_info_stub = stub()
-    cache_info_stub.expects(:gets).returns(returns)
-    cache_info_stub.expects(:close)
-    IO.expects(:popen).with(command).returns(cache_info_stub)
-  end
-
-  def stub_recreation_of_local_cache
-    FileUtils.expects(:rm_rf).with('.rsync_cache')
-    stub_creation_of_new_local_cache
+  def stub_detection_of_changed_local_cache(command, returned)
+    File.expects(:directory?).with('.rsync_cache').returns(true)
+    IO.expects(:popen).with(command).returns(returned)
   end
 
   context 'RsyncWithRemoteCache' do
@@ -128,66 +112,66 @@ def stub_recreation_of_local_cache
       end
     end
 
-    context 'command' do
+    context 'remove_cache_if_repo_changed' do
       should 'purge local cache if it detects subversion info has changed' do
         stub_configuration(:scm => :subversion, :repository => 'repository')
-        stub_detection_of_changed_local_cache("svn info .rsync_cache | sed -n 's/URL: //p'", "URL: url\n")
-        stub_recreation_of_local_cache
-        @rwrc.send(:command)
+        stub_detection_of_changed_local_cache("cd .rsync_cache && svn info . | sed -n 's/URL: //p'", "URL: url\n")
+        FileUtils.expects(:rm_rf).with('.rsync_cache')
+        @rwrc.send(:remove_cache_if_repo_changed)
       end
 
       should 'purge local cache if it detects git info has changed' do
         stub_configuration(:scm => :git, :repository => 'repository')
         stub_detection_of_changed_local_cache("cd .rsync_cache && git config remote.origin.url", "beep\n")
-        stub_recreation_of_local_cache
-        @rwrc.send(:command)
+        FileUtils.expects(:rm_rf).with('.rsync_cache')
+        @rwrc.send(:remove_cache_if_repo_changed)
       end
 
       should 'purge local cache if it detects hg info has changed' do
         stub_configuration(:scm => :mercurial, :repository => 'repository')
         stub_detection_of_changed_local_cache("cd .rsync_cache && hg showconfig paths.default", "beep\n")
-        stub_recreation_of_local_cache
-        @rwrc.send(:command)
+        FileUtils.expects(:rm_rf).with('.rsync_cache')
+        @rwrc.send(:remove_cache_if_repo_changed)
       end
 
       should 'purge local cache if it detects bzr info has changed' do
         stub_configuration(:scm => :bzr, :repository => 'repository')
         stub_detection_of_changed_local_cache("cd .rsync_cache && bzr info | grep parent | sed 's/^.*parent branch: //'", "beep\n")
-        stub_recreation_of_local_cache
-        @rwrc.send(:command)
+        FileUtils.expects(:rm_rf).with('.rsync_cache')
+        @rwrc.send(:remove_cache_if_repo_changed)
       end
 
       should 'not attempt to purge local cache that does not exist' do
         stub_configuration(:scm => :subversion, :repository => 'repository')
-        stub_detection_of_changed_local_cache("svn info .rsync_cache | sed -n 's/URL: //p'", nil)
+        File.expects(:directory?).with('.rsync_cache').returns(false)
         FileUtils.expects(:rm_rf).with('.rsync_cache').never
-        stub_creation_of_new_local_cache
-
-        @rwrc.send(:command)
+        @rwrc.send(:remove_cache_if_repo_changed)
       end
 
       should 'not attempt to purge local cache if the scm is not supported by this gem' do
         stub_configuration(:scm => :cvs, :repository => 'repository')
-        stub_detection_of_changed_local_cache("echo repository", "repository\n")
         FileUtils.expects(:rm_rf).with('.rsync_cache').never
-        stub_creation_of_new_local_cache
-
-        @rwrc.send(:command)
+        @rwrc.send(:remove_cache_if_repo_changed)
       end
+    end
 
+    context 'command' do
       should 'update local cache if it exists' do
         File.expects(:exists?).with('.rsync_cache').returns(true)
         File.expects(:directory?).with('.rsync_cache').returns(true)
         source_stub = stub()
         source_stub.expects(:sync)
         @rwrc.expects(:source).returns(source_stub)
-
         @rwrc.send(:command)
       end
 
       should 'create local cache if it does not exist' do
-        stub_creation_of_new_local_cache
-
+        File.expects(:exists?).with('.rsync_cache').times(2).returns(false)
+        File.expects(:directory?).with(File.dirname('.rsync_cache')).returns(false)
+        Dir.expects(:mkdir).with(File.dirname('.rsync_cache'))
+        source_stub = stub()
+        source_stub.expects(:checkout)
+        @rwrc.expects(:source).returns(source_stub)
         @rwrc.send(:command)
       end
     end