Merge pull request #281 from ndbroadbent/assets_rollback_and_expiry

Added support for rolling back assets, and removing expired assets

lib/capistrano/configuration/actions/invocation.rb

@@ -160,7 +160,7 @@ def run(cmd, options={}, &block)
         # or #invoke_command.
         def run_tree(tree, options={}) #:nodoc:
           if tree.branches.empty? && tree.fallback
-            logger.debug "executing #{tree.fallback}"
+            logger.debug "executing #{tree.fallback}" unless options[:silent]
           elsif tree.branches.any?
             logger.debug "executing multiple commands in parallel"
             tree.each do |branch|

lib/capistrano/recipes/deploy/assets.rb

@@ -3,11 +3,15 @@
 _cset :asset_env, "RAILS_GROUPS=assets"
 _cset :assets_prefix, "assets"
 _cset :assets_role, [:web]
+_cset :expire_assets_after, (3600 * 24 * 7)
 
 _cset :normalize_asset_timestamps, false
 
-before 'deploy:finalize_update', 'deploy:assets:symlink'
-after 'deploy:update_code', 'deploy:assets:precompile'
+before 'deploy:finalize_update',   'deploy:assets:symlink'
+after  'deploy:update_code',       'deploy:assets:precompile'
+before 'deploy:assets:precompile', 'deploy:assets:update_asset_mtimes'
+after  'deploy:cleanup',           'deploy:assets:clean_expired'
+after  'deploy:rollback:revision', 'deploy:assets:rollback'
 
 namespace :deploy do
   namespace :assets do
@@ -20,7 +24,7 @@
       :assets_prefix variable to match.
     DESC
     task :symlink, :roles => assets_role, :except => { :no_release => true } do
-      run <<-CMD
+      run <<-CMD.compact
         rm -rf #{latest_release}/public/#{assets_prefix} &&
         mkdir -p #{latest_release}/public &&
         mkdir -p #{shared_path}/assets &&
@@ -39,7 +43,29 @@
         set :asset_env, "RAILS_GROUPS=assets"
     DESC
     task :precompile, :roles => assets_role, :except => { :no_release => true } do
-      run "cd #{latest_release} && #{rake} RAILS_ENV=#{rails_env} #{asset_env} assets:precompile"
+      run <<-CMD.compact
+        cd -- #{latest_release.shellescape} &&
+        #{rake} RAILS_ENV=#{rails_env.shellescape} #{asset_env.shellescape} assets:precompile &&
+        cp -- #{shared_path.shellescape}/assets/manifest.yml #{current_release.shellescape}/assets_manifest.yml
+      CMD
+    end
+
+    desc <<-DESC
+      [internal] Updates the mtimes for assets that are required by the current release.
+      This task runs before assets:precompile.
+    DESC
+    task :update_asset_mtimes, :roles => assets_role, :except => { :no_release => true } do
+      # Fetch assets/manifest.yml contents.
+      manifest_path = "#{shared_path}/assets/manifest.yml"
+      manifest_yml = capture("[ -e #{manifest_path.shellescape} ] && cat #{manifest_path.shellescape} || echo").strip
+
+      if manifest_yml != ""
+        manifest = YAML.load(manifest_yml)
+        current_assets = manifest.to_a.flatten.map {|a| [a, "#{a}.gz"] }.flatten
+        logger.info "Updating mtimes for ~#{current_assets.count} assets..."
+        command = "touch -cm -- " << current_assets.map {|a| "#{shared_path}/assets/#{a}".shellescape }.join(' ')
+        run command, :silent => true
+      end
     end
 
     desc <<-DESC
@@ -56,5 +82,76 @@
     task :clean, :roles => assets_role, :except => { :no_release => true } do
       run "cd #{latest_release} && #{rake} RAILS_ENV=#{rails_env} #{asset_env} assets:clean"
     end
+
+    desc <<-DESC
+      Clean up any assets that haven't been deployed for more than :expire_assets_after seconds.
+      Default time to keep old assets is one week. Set the :expire_assets_after variable
+      to change the assets expiry time. Assets will only be deleted if they are not required by
+      an existing release.
+    DESC
+    task :clean_expired, :roles => assets_role, :except => { :no_release => true } do
+      # Fetch all assets_manifest.yml contents.
+      manifests_output = capture <<-CMD.compact
+        for manifest in #{releases_path.shellescape}/*/assets_manifest.yml; do
+          cat -- "$manifest" 2> /dev/null && printf ':::' || true;
+        done
+      CMD
+      manifests = manifests_output.split(':::')
+
+      if manifests.empty?
+        logger.info "No manifests in #{releases_path}/*/assets_manifest.yml"
+      else
+        logger.info "Fetched #{manifests.count} manifests from #{releases_path}/*/assets_manifest.yml"
+        current_assets = Set.new
+        manifests.each do |yaml|
+          manifest = YAML.load(yaml)
+          current_assets += manifest.to_a.flatten.flat_map do |file|
+            [file, "#{file}.gz"]
+          end
+        end
+        current_assets += %w(manifest.yml sources_manifest.yml)
+
+        # Write the list of required assets to server.
+        # Files must be sorted in dictionary order using Linux sort
+        logger.info "Writing required assets to #{deploy_to}/REQUIRED_ASSETS..."
+        escaped_assets = current_assets.to_a.join("\\n").gsub("\"", "\\\"")
+        run "printf -- \"#{escaped_assets}\" | sort > #{deploy_to.shellescape}/REQUIRED_ASSETS", :silent => true
+
+        # Finds all files older than X minutes, then removes them if they are not referenced
+        # in REQUIRED_ASSETS.
+        expire_after_mins = (expire_assets_after.to_f / 60.0).to_i
+        logger.info "Removing assets that haven't been deployed for #{expire_after_mins} minutes..."
+        run <<-CMD.compact
+          cd -- #{shared_path.shellescape}/assets/ &&
+          for f in $(
+            find * -mmin +#{expire_after_mins.to_s.shellescape} -type f | sort |
+            comm -23 -- - #{deploy_to.shellescape}/REQUIRED_ASSETS
+          ); do
+            echo "Removing unneeded asset: $f";
+            rm -f -- "$f";
+          done;
+          rm -f -- #{deploy_to.shellescape}/REQUIRED_ASSETS
+        CMD
+      end
+    end
+
+    desc <<-DESC
+      Rolls back assets to the previous release by symlinking the release's manifest
+      to shared/assets/manifest.yml, and finally recompiling or regenerating nondigest assets.
+    DESC
+    task :rollback, :roles => assets_role, :except => { :no_release => true } do
+      previous_manifest = "#{previous_release}/assets_manifest.yml"
+      if capture("[ -e #{previous_manifest.shellescape} ] && echo true || echo false").strip != 'true'
+        puts "#{previous_manifest} is missing! Cannot roll back assets. " <<
+             "Please run deploy:assets:precompile to update your assets when the rollback is finished."
+        return false
+      else
+        run <<-CMD.compact
+          cd -- #{previous_release.shellescape} &&
+          cp -f -- #{previous_manifest.shellescape} #{shared_path.shellescape}/assets/manifest.yml &&
+          #{rake} RAILS_ENV=#{rails_env.shellescape} #{asset_env.shellescape} assets:precompile:nondigest
+        CMD
+      end
+    end
   end
 end