S3Version.rb

require 'capistrano/recipes/deploy/strategy/copy'
require 'fileutils'
require 'tempfile'  # Dir.tmpdir
require 'json'

module Capistrano
  module Deploy
    module Strategy

      # This class implements the strategy for deploying versioned, static assets
      # to the Amazon S3 service. 
      #
      # Each deployed asset is renamed according to its blob SHA, so:
      # foo.png => foo.0b676ed16.png
      #
      # You must specify an S3 bucket to which files will be pushed:
      #
      #    set :deploy_s3_bucket, "My_S3_Bukkit"
      #
      # You may also specify command-line options to s3cmd:
      #
      #    set :deploy_s3_options, "--dryrun"
      #
      # 
      class S3Version < Copy
        # Obtains a copy of the source code locally (via the #command method),
        # and individually places each changed asset into the S3 bucket with
        # a versioned file name.
        def deploy!
          
          # get list of deployed assets on S3, and add them to copy_exclude
          s3_ls = `s3cmd #{s3cmd_opts} --recursive ls #{bucket_name}`
          # todo...
          
          if copy_cache
            if File.exists?(copy_cache)
              logger.debug "refreshing local cache to revision #{revision} at #{copy_cache}"
              system(source.sync(revision, copy_cache))
            else
              logger.debug "preparing local cache at #{copy_cache}"
              system(source.checkout(revision, copy_cache))
            end

            # Check the return code of last system command and rollback if not 0
            unless $? == 0
              raise Capistrano::Error, "shell command failed with return code #{$?}"
            end

            logger.debug "copying cache to deployment staging area #{destination}"
            Dir.chdir(copy_cache) do
              FileUtils.mkdir_p(destination)
              queue = Dir.glob("*", File::FNM_DOTMATCH)
              while queue.any?
                item = queue.shift
                name = File.basename(item)

                next if name == "." || name == ".."
                next if copy_exclude.any? { |pattern| File.fnmatch(pattern, item) }

                if File.symlink?(item)
                  FileUtils.ln_s(File.readlink(File.join(copy_cache, item)), File.join(destination, item))
                elsif File.directory?(item)
                  queue += Dir.glob("#{item}/*", File::FNM_DOTMATCH)
                  FileUtils.mkdir(File.join(destination, item))
                else
                  FileUtils.ln(File.join(copy_cache, item), File.join(destination, item))
                end
              end
            end
          else
            logger.debug "getting (via #{copy_strategy}) revision #{revision} to #{destination}"
            system(command)

            if copy_exclude.any?
              logger.debug "processing exclusions..."
              if copy_exclude.any?
                copy_exclude.each do |pattern| 
                  delete_list = Dir.glob(File.join(destination, pattern), File::FNM_DOTMATCH)
                  # avoid the /.. trap that deletes the parent directories
                  delete_list.delete_if { |dir| dir =~ /\/\.\.$/ }
                  FileUtils.rm_rf(delete_list.compact)
                end
              end
            end
          end

          # get list of assets before we go making new files
          asset_list = Dir.glob(File.join(destination, "*"), File::FNM_DOTMATCH)
          
          File.open(File.join(destination, "REVISION"), "w") { |f| f.puts(revision) }
          
          # process the asset list and upload + build manifest    
          manifest = {}        
          while asset_list.any?
            item = asset_list.shift
            ext = File.extname(item)
            name = File.basename(item, ext)

            next if name.match(/^\./)
            
            if File.symlink?(item)
              raise "Arg I don't know what to do with symlinks yet"
            elsif File.directory?(item)
              asset_list += Dir.glob("#{item}/*", File::FNM_DOTMATCH)
            else
              # get a short-sha
              Dir.chdir(destination) do
                if `#{source.scm("ls-tree HEAD #{item}")}` =~ /[0-9]*\sblob\s([A-Fa-f0-9]*)/ then
                  sha = $1[0..7]
                  
                  # put the asset to S3
                  system("s3cmd #{s3cmd_opts} put #{bucket_name}:#{name}.#{sha}#{ext} #{item}")
              
                  # add to manifest
                  manifest["#{name}#{ext}"] = ("#{name}.#{sha}#{ext}")
                else
                  logger.important "Could not find #{item} in repository, will not be part of deploy."
                end
              end
            end
          end
          
          # put the manifest to S3
          manifest_file = File.join(destination, "#{revision[0..8]}.json")
          File.open(manifest_file, "w") { |f| f.puts(manifest.to_json) }
          system("s3cmd #{s3cmd_opts} put #{bucket_name}:#{name} #{manifest_file}")
          
          # upload to EC2
          upload(manifest_file, manifest_file)
        ensure
          FileUtils.rm_rf destination rescue nil
        end
        
      private
        
        def bucket_name
          configuration[:deploy_s3_bucket]
        end

        def s3cmd_opts
          configuration[:deploy_s3_options]
        end
      end

    end
  end
end

set :strategy, Capistrano::Deploy::Strategy::S3Version.new(self)
set :copy_strategy, :checkout

set :deploy_s3_bucket, "FacepunchBuckkit"
set :deploy_s3_options, "--dryrun"