SwitchTower: incorporate deployment generator for simple Rails integration

git-svn-id: http://svn.rubyonrails.org/rails/tools/switchtower@2084 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

lib/switchtower/cli.rb

@@ -32,12 +32,17 @@ module SwitchTower
     end
 
     attr_reader :options
+    attr_reader :args
 
-    def initialize
+    def initialize(args = ARGV)
+      @args = args
       @options = { :verbose => 0, :recipes => [], :actions => [], :vars => {} }
 
       OptionParser.new do |opts|
-        opts.banner = "Usage: #{$0} [options]"
+        opts.banner = "Usage: #{$0} [options] [args]"
+
+        opts.separator ""
+        opts.separator "Recipe Options -----------------------"
         opts.separator ""
 
         opts.on("-a", "--action ACTION",
@@ -50,14 +55,6 @@ module SwitchTower
           "(Default: prompt for password)"
         ) { |value| @options[:password] = value }
 
-        opts.on("-P", "--[no-]pretend",
-          "Run the task(s), but don't actually connect to or",
-          "execute anything on the servers. (For various reasons",
-          "this will not necessarily be an accurate depiction",
-          "of the work that will actually be performed.",
-          "Default: don't pretend.)"
-        ) { |value| @options[:pretend] = value }
-
         opts.on("-r", "--recipe RECIPE",
           "A recipe file to load. Multiple recipes may",
           "be specified, and are loaded in the given order."
@@ -71,17 +68,39 @@ module SwitchTower
           @options[:vars][name.to_sym] = value
         end
 
+        opts.separator ""
+        opts.separator "Framework Integration Options --------"
+        opts.separator ""
+
+        opts.on("-A", "--apply-to [DIRECTORY]",
+          "Create a minimal set of scripts and recipes to use",
+          "switchtower with the application at the given",
+          "directory. (Currently only works with Rails apps.)"
+        ) { |value| @options[:apply_to] = value }
+
+        opts.separator ""
+        opts.separator "Miscellaneous Options ----------------"
+        opts.separator ""
+
+        opts.on("-h", "--help", "Display this help message") do
+          puts opts
+          exit
+        end
+
+        opts.on("-P", "--[no-]pretend",
+          "Run the task(s), but don't actually connect to or",
+          "execute anything on the servers. (For various reasons",
+          "this will not necessarily be an accurate depiction",
+          "of the work that will actually be performed.",
+          "Default: don't pretend.)"
+        ) { |value| @options[:pretend] = value }
+
         opts.on("-v", "--verbose",
           "Specify the verbosity of the output.",
           "May be given multiple times. (Default: silent)"
         ) { @options[:verbose] += 1 }
 
-        opts.separator ""
-        opts.on_tail("-h", "--help", "Display this help message") do
-          puts opts
-          exit
-        end
-        opts.on_tail("-V", "--version",
+        opts.on("-V", "--version",
           "Display the version info for this utility"
         ) do
           require 'switchtower/version'
@@ -89,11 +108,25 @@ module SwitchTower
           exit
         end
 
-        opts.parse!
+        opts.separator ""
+        opts.separator <<DETAIL.split(/\n/)
+You can use the --apply-to switch to generate a minimal set of switchtower
+scripts and recipes for an application. Just specify the path to the application
+as the argument to --apply-to, and then specify the name of your application,
+like this:
+
+  switchtower --apply-to ~/projects/myapp MyApplication
+
+You'll wind up with a sample deployment recipe in config/deploy.rb, some new
+rake tasks in config/tasks, and a switchtower script in your script directory.
+
+(Currently, --apply-to only works with Rails applications.)
+DETAIL
+
+        opts.parse!(args)
       end
 
-      abort "You must specify at least one recipe" if @options[:recipes].empty?
-      abort "You must specify at least one action" if @options[:actions].empty?
+      check_options!
 
       unless @options.has_key?(:password)
         @options[:password] = Proc.new do
@@ -113,18 +146,55 @@ module SwitchTower
     end
 
     def execute!
-      config = SwitchTower::Configuration.new
-      config.logger.level = options[:verbose]
-      config.set :password, options[:password]
-      config.set :pretend, options[:pretend]
-
-      config.load "standard" # load the standard recipe definition
-
-      options[:recipes].each { |recipe| config.load(recipe) }
-      options[:vars].each { |name, value| config.set(name, value) }
-
-      actor = config.actor
-      options[:actions].each { |action| actor.send action }
+      if !@options[:recipes].empty?
+        execute_recipes!
+      elsif @options[:apply_to]
+        execute_apply_to!
+      end
     end
+
+    private
+
+      def execute_recipes!
+        config = SwitchTower::Configuration.new
+        config.logger.level = options[:verbose]
+        config.set :password, options[:password]
+        config.set :pretend, options[:pretend]
+
+        config.load "standard" # load the standard recipe definition
+
+        options[:recipes].each { |recipe| config.load(recipe) }
+        options[:vars].each { |name, value| config.set(name, value) }
+
+        actor = config.actor
+        options[:actions].each { |action| actor.send action }
+      end
+
+      def execute_apply_to!
+        require 'switchtower/generators/rails/loader'
+        Generators::RailsLoader.load! @options
+      end
+
+      APPLY_TO_OPTIONS = [:apply_to]
+      RECIPE_OPTIONS   = [:password]
+
+      def check_options!
+        apply_to_given = !(@options.keys & APPLY_TO_OPTIONS).empty?
+        recipe_given   = !(@options.keys & RECIPE_OPTIONS).empty? ||
+                         !@options[:recipes].empty? ||
+                         !@options[:actions].empty?
+
+        if apply_to_given && recipe_given
+          abort "You cannot specify both recipe options and framework integration options."
+        elsif !apply_to_given
+          abort "You must specify at least one recipe" if @options[:recipes].empty?
+          abort "You must specify at least one action" if @options[:actions].empty?
+        else
+          @options[:application] = args.shift
+          @options[:recipe_file] = args.shift
+
+          abort "You must specify the name of the application" if @options[:application].nil?
+        end
+      end
   end
 end

lib/switchtower/generators/rails/deployment/deployment_generator.rb

@@ -0,0 +1,26 @@
+class DeploymentGenerator < Rails::Generator::NamedBase
+  attr_reader :recipe_file
+
+  def initialize(runtime_args, runtime_options = {})
+    super
+    @recipe_file = @args.shift || "deploy"
+  end
+
+  def manifest
+    record do |m|
+      m.directory "script"
+      m.file "switchtower", File.join("script", "switchtower")
+      m.directory "config/tasks"
+      m.template "deploy.rb", File.join("config", "#{recipe_file}.rb")
+      m.template "switchtower.rake", File.join("config", "tasks", "switchtower.rake")
+    end
+  end
+
+  protected
+
+    # Override with your own usage banner.
+    def banner
+      "Usage: #{$0} deployment ApplicationName [recipe-name]\n" +
+      "  (recipe-name defaults to \"deploy\")"
+    end
+end

lib/switchtower/generators/rails/deployment/templates/deploy.rb

@@ -0,0 +1,116 @@
+# This defines a deployment "recipe" that you can feed to switchtower
+# (http://manuals.rubyonrails.com/read/book/17). It allows you to automate
+# (among other things) the deployment of your application.
+
+# =============================================================================
+# REQUIRED VARIABLES
+# =============================================================================
+# You must always specify the application and repository for every recipe. The
+# repository must be the URL of the repository you want this recipe to
+# correspond to. The deploy_to path must be the path on each machine that will
+# form the root of the application path.
+
+set :application, "<%= singular_name %>"
+set :repository, "http://svn.yourhost.com/#{application}/trunk"
+
+# =============================================================================
+# ROLES
+# =============================================================================
+# You can define any number of roles, each of which contains any number of
+# machines. Roles might include such things as :web, or :app, or :db, defining
+# what the purpose of each machine is. You can also specify options that can
+# be used to single out a specific subset of boxes in a particular role, like
+# :primary => true.
+
+role :web, "www01.example.com", "www02.example.com"
+role :app, "app01.example.com", "app02.example.com", "app03.example.com"
+role :db,  "db01.example.com", :primary => true
+role :db,  "db02.example.com", "db03.example.com"
+
+# =============================================================================
+# OPTIONAL VARIABLES
+# =============================================================================
+# set :deploy_to, "/path/to/app" # defaults to "/u/apps/#{application}"
+# set :user, "flippy"            # defaults to the currently logged in user
+# set :scm, :darcs               # defaults to :subversion
+# set :svn, "/path/to/svn"       # defaults to searching the PATH
+# set :darcs, "/path/to/darcs"   # defaults to searching the PATH
+# set :cvs, "/path/to/cvs"       # defaults to searching the PATH
+# set :gateway, "gate.host.com"  # default to no gateway
+
+# =============================================================================
+# TASKS
+# =============================================================================
+# Define tasks that run on all (or only some) of the machines. You can specify
+# a role (or set of roles) that each task should be executed on. You can also
+# narrow the set of servers to a subset of a role by specifying options, which
+# must match the options given for the servers to select (like :primary => true)
+
+desc <<DESC
+An imaginary backup task. (Execute the 'show_tasks' task to display all
+available tasks.)
+DESC
+task :backup, :roles => :db, :only => { :primary => true } do
+  # the on_rollback handler is only executed if this task is executed within
+  # a transaction (see below), AND it or a subsequent task fails.
+  on_rollback { delete "/tmp/dump.sql" }
+
+  run "mysqldump -u theuser -p thedatabase > /tmp/dump.sql" do |ch, stream, out|
+    ch.send_data "thepassword\n" if out =~ /^Enter password:/
+  end
+end
+
+# Tasks may take advantage of several different helper methods to interact
+# with the remote server(s). These are:
+#
+# * run(command, options={}, &block): execute the given command on all servers
+#   associated with the current task, in parallel. The block, if given, should
+#   accept three parameters: the communication channel, a symbol identifying the
+#   type of stream (:err or :out), and the data. The block is invoked for all
+#   output from the command, allowing you to inspect output and act
+#   accordingly.
+# * sudo(command, options={}, &block): same as run, but it executes the command
+#   via sudo.
+# * delete(path, options={}): deletes the given file or directory from all
+#   associated servers. If :recursive => true is given in the options, the
+#   delete uses "rm -rf" instead of "rm -f".
+# * put(buffer, path, options={}): creates or overwrites a file at "path" on
+#   all associated servers, populating it with the contents of "buffer". You
+#   can specify :mode as an integer value, which will be used to set the mode
+#   on the file.
+# * render(template, options={}) or render(options={}): renders the given
+#   template and returns a string. Alternatively, if the :template key is given,
+#   it will be treated as the contents of the template to render. Any other keys
+#   are treated as local variables, which are made available to the (ERb)
+#   template.
+
+desc "Demonstrates the various helper methods available to recipes."
+task :helper_demo do
+  # "setup" is a standard task which sets up the directory structure on the
+  # remote servers. It is a good idea to run the "setup" task at least once
+  # at the beginning of your app's lifetime (it is non-destructive).
+  setup
+
+  buffer = render("maintenance.rhtml", :deadline => ENV['UNTIL'])
+  put buffer, "#{shared_path}/system/maintenance.html", :mode => 0644
+  sudo "killall -USR1 dispatch.fcgi"
+  run "#{release_path}/script/spin"
+  delete "#{shared_path}/system/maintenance.html"
+end
+
+# You can use "transaction" to indicate that if any of the tasks within it fail,
+# all should be rolled back (for each task that specifies an on_rollback
+# handler).
+
+desc "A task demonstrating the use of transactions."
+task :long_deploy do
+  transaction do
+    update_code
+    disable_web
+    symlink
+    migrate
+  end
+
+  restart
+  enable_web
+end

lib/switchtower/generators/rails/deployment/templates/switchtower

@@ -0,0 +1,12 @@
+#!/usr/local/bin/ruby
+
+VENDOR = File.dirname(__FILE__) + "/../vendor"
+$:.unshift "#{VENDOR}/switchtower/lib"
+
+begin
+  require 'rubygems'
+rescue LoadError
+end
+
+require 'switchtower/cli'
+SwitchTower::CLI.execute!

lib/switchtower/generators/rails/deployment/templates/switchtower.rake

@@ -0,0 +1,28 @@
+# =============================================================================
+# A set of rake tasks for invoking the SwitchTower automation utility.
+# =============================================================================
+
+desc "Push the latest revision into production using the release manager"
+task :deploy do
+  system "script/switchtower -vvvv -r config/<%= recipe_file %> -a deploy"
+end
+
+desc "Rollback to the release before the current release in production"
+task :rollback do
+  system "script/switchtower -vvvv -r config/<%= recipe_file %> -a rollback"
+end
+
+desc "Enumerate all available deployment tasks"
+task :show_deploy_tasks do
+  system "script/switchtower -r config/<%= recipe_file %> -a show_tasks"
+end
+
+desc "Execute a specific action using the release manager"
+task :remote_exec do
+  unless ENV['ACTION']
+    raise "Please specify an action (or comma separated list of actions) via the ACTION environment variable"
+  end
+
+  actions = ENV['ACTION'].split(",").map { |a| "-a #{a}" }.join(" ")
+  system "script/switchtower -vvvv -r config/<%= recipe_file %> #{actions}"
+end

lib/switchtower/generators/rails/loader.rb

@@ -0,0 +1,20 @@
+module SwitchTower
+  module Generators
+    class RailsLoader
+      def self.load!(options)
+        require "#{options[:apply_to]}/config/environment"
+        require "rails_generator"
+        require "rails_generator/scripts/generate"
+
+        Rails::Generator::Base.sources << Rails::Generator::PathSource.new(
+          :switchtower, File.dirname(__FILE__))
+
+        args = ["deployment"]
+        args << options[:application] || "Application"
+        args << options[:recipe_file] || "deploy"
+
+        Rails::Generator::Scripts::Generate.new.run(args)
+      end
+    end
+  end
+end

lib/switchtower/version.rb

@@ -1,7 +1,7 @@
 module SwitchTower
   module Version #:nodoc:
     MAJOR = 0
-    MINOR = 8
+    MINOR = 9
     TINY  = 0
 
     STRING = [MAJOR, MINOR, TINY].join(".")