Rake tasks for deploying a web app via rsync, and comparing local / remote file changes

deploy.rake

## -- Rake Tasks -- ##
desc "Deploy website via rsync (e.g. rake deploy [path=...] [options=<extra rsync options>])"
task :deploy do

  # Run commands
  puts "## Deploying website via Rsync"
  puts "-----------\nCommand: #{rsync_command '--dry-run'}\n-----------"
  system(rsync_command '--dry-run')

  # Prompt for continuance
  puts
  proceed = get_stdin "The above actions will be taken. Continue? (This cannot be undone) [No]: "

  # The real deal
  if "y yes".split.include? proceed.downcase
    ok_failed system(rsync_command)
    if CONFIG["restart_apache"]
      restart_apache, ssh_port, ssh_host = CONFIG.values_at "restart_apache", "ssh_port", "ssh_host"
      puts
      puts "## Restarting Apache server"
      ok_failed system("ssh #{"-p "+ssh_port.to_s unless ssh_port == nil} #{ssh_host} '#{restart_apache}'")
    end
  else
    puts "Deployment cancelled by user."
  end
end

namespace :remote do
  desc "Connect to the remote console"
  task :console do
    puts "## Initializing remote console"
    puts "----------\nCommand: #{ssh_command}\n----------"
    system(ssh_command)
  end

  desc "Show differences between local and remote files"
  task :diff do
    document_root, site_dir = CONFIG.values_at "document_root", "site_dir"

    # Get the local path
    local_path  = ENV['path'] ? ENV['path'] : site_dir
    if File.exists?(local_path)
      local_path = File.expand_path(local_path)
      local_path = local_path + '/' if File.directory?(local_path)
    end

    # Build the remote path
    remote_path = "#{document_root}/#{local_path.sub(File.expand_path(site_dir), '')}".gsub(/\/+/, '/')

    # Files get compared straight-up
    if File.file?(local_path)
      system(%Q:bash -c 'diff -Naur "#{local_path}" <(#{ssh_command "cat #{remote_path}"})':)

    # Directories process each file
    else
      changes = `#{rsync_command '--dry-run'}`
      num_changes = changes.lines.count

      proceed = get_stdin "#{changes.lines.count} file(s) will be compared. Continue? [No]: " if num_changes > 10

      if proceed == nil or "y yes".split.include? proceed.downcase
        changes.each_line do |line|
          action, file = line.chomp.split(' ', 2)

          system %Q:bash -c 'diff -Naur "#{local_path + file}" <(#{ssh_command "cat #{remote_path + file}"})':
        end
      end
    end
  end
end

## -- Utility functions -- ##
def ssh_command(command=nil)
  ssh_port, ssh_host = CONFIG.values_at "ssh_port", "ssh_host"
  "ssh #{"-p "+ssh_port.to_s unless ssh_port == nil} #{ssh_host} #{%Q'"#{command}"' unless command == nil}"
end

def rsync_command(options=nil)
  document_root, rsync_delete, site_dir, ssh_port, ssh_host =
    CONFIG.values_at "document_root", "rsync_delete", "site_dir", "ssh_port", "ssh_host"

  # Get the local path
  local_path  = ENV['path'] ? ENV['path'] : site_dir
  if File.exists?(local_path)
    local_path = File.expand_path(local_path)
    local_path = local_path + '/' if File.directory?(local_path)
  end

  # Build the remote path
  remote_path = "#{document_root}/#{local_path.sub(File.expand_path(site_dir), '')}".gsub(/\/+/, '/')

  # Exclude file
  exclude = ""
  if File.exists?('./deploy-exclude')
    exclude="--exclude-from '#{File.expand_path('./deploy-exclude')}'"
  end

  # Build rsync options
  rsync_options  =
    "--archive --no-group --no-owner --no-perms --no-times --update " +
    "--human-readable --compress --checksum " +
    "--itemize-changes #{exclude} " +
    "#{"--rsh='ssh -p #{ssh_port}' " unless ssh_port == nil}" +
    "#{"--delete " unless rsync_delete == "no"}" +
    "#{options} #{ENV['options']} " +
    "#{local_path} #{ssh_host}:#{remote_path}"

  return "rsync #{rsync_options}"
end

Rakefile

# Include all rake files in the tasks directory
Dir.glob('tasks/*.rake').each { |r| import r }

# Read configuration from tasks/config.yaml
require 'yaml'
CONFIG = YAML.load_file('tasks/config.yaml')[ENV['env'] || 'development']

# Default utility functions available in all tasks
def ok_failed(condition)
  if (condition)
    puts "OK"
  else
    puts "FAILED"
  end
end

def get_stdin(message)
  print message
  STDIN.gets.chomp
end

def ask(message, valid_options)
  if valid_options
    answer = get_stdin("#{message} #{valid_options.to_s.gsub(/"/, '').gsub(/, /,'/')} ") while !valid_options.include?(answer)
  else
    answer = get_stdin(message)
  end
  answer
end

Borrowed some from the Octopress.org Rakefile