Class: Spring::Application

Inherits:
Object
  • Object
show all
Defined in:
lib/spring/application.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(manager, original_env, spring_env = Env.new) ⇒ Application


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# File 'lib/spring/application.rb', line 9

def initialize(manager, original_env, spring_env = Env.new)
  @manager      = manager
  @original_env = original_env
  @spring_env   = spring_env
  @mutex        = Mutex.new
  @waiting      = Set.new
  @preloaded    = false
  @state        = :initialized
  @interrupt    = IO.pipe
end

Instance Attribute Details

#managerObject (readonly)

Returns the value of attribute manager


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# File 'lib/spring/application.rb', line 7

def manager
  @manager
end

#original_envObject (readonly)

Returns the value of attribute original_env


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# File 'lib/spring/application.rb', line 7

def original_env
  @original_env
end

#spring_envObject (readonly)

Returns the value of attribute spring_env


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# File 'lib/spring/application.rb', line 7

def spring_env
  @spring_env
end

#watcherObject (readonly)

Returns the value of attribute watcher


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# File 'lib/spring/application.rb', line 7

def watcher
  @watcher
end

Instance Method Details

#app_envObject


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# File 'lib/spring/application.rb', line 31

def app_env
  ENV['RAILS_ENV']
end

#app_nameObject


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# File 'lib/spring/application.rb', line 35

def app_name
  spring_env.app_name
end

#connect_databaseObject


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# File 'lib/spring/application.rb', line 290

def connect_database
  ActiveRecord::Base.establish_connection if active_record_configured?
end

#disconnect_databaseObject


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# File 'lib/spring/application.rb', line 286

def disconnect_database
  ActiveRecord::Base.remove_connection if active_record_configured?
end

#eager_preloadObject


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# File 'lib/spring/application.rb', line 131

def eager_preload
  with_pty { preload }
end

#exitObject


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# File 'lib/spring/application.rb', line 253

def exit
  state :exiting
  manager.shutdown(:RDWR)
  exit_if_finished
  sleep
end

#exit_if_finishedObject


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# File 'lib/spring/application.rb', line 260

def exit_if_finished
  @mutex.synchronize {
    Kernel.exit if exiting? && @waiting.empty?
  }
end

#exiting?Boolean


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# File 'lib/spring/application.rb', line 51

def exiting?
  @state == :exiting
end

#initialized?Boolean


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# File 'lib/spring/application.rb', line 63

def initialized?
  @state == :initialized
end

#invoke_after_fork_callbacksObject


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# File 'lib/spring/application.rb', line 275

def invoke_after_fork_callbacks
  Spring.after_fork_callbacks.each do |callback|
    callback.call
  end
end

#loaded_application_featuresObject


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# File 'lib/spring/application.rb', line 281

def loaded_application_features
  root = Spring.application_root_path.to_s
  $LOADED_FEATURES.select { |f| f.start_with?(root) }
end

#log(message) ⇒ Object


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# File 'lib/spring/application.rb', line 39

def log(message)
  spring_env.log "[application:#{app_env}] #{message}"
end

#preloadObject


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# File 'lib/spring/application.rb', line 83

def preload
  log "preloading app"

  begin
    require "spring/commands"
  ensure
    start_watcher
  end

  require Spring.application_root_path.join("config", "application")

  unless Rails.respond_to?(:gem_version) && Rails.gem_version >= Gem::Version.new('4.2.0')
    raise "Spring only supports Rails >= 4.2.0"
  end

  # config/environments/test.rb will have config.cache_classes = true. However
  # we want it to be false so that we can reload files. This is a hack to
  # override the effect of config.cache_classes = true. We can then actually
  # set config.cache_classes = false after loading the environment.
  Rails::Application.initializer :initialize_dependency_mechanism, group: :all do
    ActiveSupport::Dependencies.mechanism = :load
  end

  require Spring.application_root_path.join("config", "environment")

  @original_cache_classes = Rails.application.config.cache_classes
  Rails.application.config.cache_classes = false

  disconnect_database

  @preloaded = :success
rescue Exception => e
  @preloaded = :failure
  watcher.add e.backtrace.map { |line| line[/^(.*)\:\d+/, 1] }
  raise e unless initialized?
ensure
  watcher.add loaded_application_features
  watcher.add Spring.gemfile, "#{Spring.gemfile}.lock"

  if defined?(Rails) && Rails.application
    watcher.add Rails.application.paths["config/initializers"]
    watcher.add Rails.application.paths["config/database"]
    if secrets_path = Rails.application.paths["config/secrets"]
      watcher.add secrets_path
    end
  end
end

#preload_failed?Boolean


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# File 'lib/spring/application.rb', line 47

def preload_failed?
  @preloaded == :failure
end

#preloaded?Boolean


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# File 'lib/spring/application.rb', line 43

def preloaded?
  @preloaded
end

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# File 'lib/spring/application.rb', line 313

def print_exception(stream, error)
  first, rest = error.backtrace.first, error.backtrace.drop(1)
  stream.puts("#{first}: #{error} (#{error.class})")
  rest.each { |line| stream.puts("\tfrom #{line}") }
end

#reset_streamsObject


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# File 'lib/spring/application.rb', line 332

def reset_streams
  [STDOUT, STDERR].each { |stream| stream.reopen(spring_env.log_file) }
  STDIN.reopen("/dev/null")
end

#runObject


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# File 'lib/spring/application.rb', line 135

def run
  state :running
  manager.puts

  loop do
    IO.select [manager, @interrupt.first]

    if terminating? || watcher_stale? || preload_failed?
      exit
    else
      serve manager.recv_io(UNIXSocket)
    end
  end
end

#serve(client) ⇒ Object


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# File 'lib/spring/application.rb', line 150

def serve(client)
  log "got client"
  manager.puts

  _stdout, stderr, _stdin = streams = 3.times.map { client.recv_io }
  [STDOUT, STDERR, STDIN].zip(streams).each { |a, b| a.reopen(b) }

  preload unless preloaded?

  args, env = JSON.load(client.read(client.gets.to_i)).values_at("args", "env")
  command   = Spring.command(args.shift)

  connect_database
  setup command

  if Rails.application.reloaders.any?(&:updated?)
    # Rails 5.1 forward-compat. AD::R is deprecated to AS::R in Rails 5.
    if defined? ActiveSupport::Reloader
      Rails.application.reloader.reload!
    else
      ActionDispatch::Reloader.cleanup!
      ActionDispatch::Reloader.prepare!
    end
  end

  pid = fork {
    Process.setsid
    IGNORE_SIGNALS.each { |sig| trap(sig, "DEFAULT") }
    trap("TERM", "DEFAULT")

    unless Spring.quiet
      STDERR.puts "Running via Spring preloader in process #{Process.pid}"

      if Rails.env.production?
        STDERR.puts "WARNING: Spring is running in production. To fix "         \
                    "this make sure the spring gem is only present "            \
                    "in `development` and `test` groups in your Gemfile "       \
                    "and make sure you always use "                             \
                    "`bundle install --without development test` in production"
      end
    end

    ARGV.replace(args)
    $0 = command.exec_name

    # Delete all env vars which are unchanged from before Spring started
    original_env.each { |k, v| ENV.delete k if ENV[k] == v }

    # Load in the current env vars, except those which *were* changed when Spring started
    env.each { |k, v| ENV[k] ||= v }

    # requiring is faster, so if config.cache_classes was true in
    # the environment's config file, then we can respect that from
    # here on as we no longer need constant reloading.
    if @original_cache_classes
      ActiveSupport::Dependencies.mechanism = :require
      Rails.application.config.cache_classes = true
    end

    connect_database
    srand

    invoke_after_fork_callbacks
    shush_backtraces

    command.call
  }

  disconnect_database

  log "forked #{pid}"
  manager.puts pid

  wait pid, streams, client
rescue Exception => e
  log "exception: #{e}"
  manager.puts unless pid

  if streams && !e.is_a?(SystemExit)
    print_exception(stderr, e)
    streams.each(&:close)
  end

  client.puts(1) if pid
  client.close
ensure
  # Redirect STDOUT and STDERR to prevent from keeping the original FDs
  # (i.e. to prevent `spring rake -T | grep db` from hanging forever),
  # even when exception is raised before forking (i.e. preloading).
  reset_streams
end

#setup(command) ⇒ Object

The command might need to require some files in the main process so that they are cached. For example a test command wants to load the helper file once and have it cached.


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# File 'lib/spring/application.rb', line 269

def setup(command)
  if command.setup
    watcher.add loaded_application_features # loaded features may have changed
  end
end

#shush_backtracesObject

This feels very naughty


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# File 'lib/spring/application.rb', line 295

def shush_backtraces
  Kernel.module_eval do
    old_raise = Kernel.method(:raise)
    remove_method :raise
    define_method :raise do |*args|
      begin
        old_raise.call(*args)
      ensure
        if $!
          lib = File.expand_path("..", __FILE__)
          $!.backtrace.reject! { |line| line.start_with?(lib) }
        end
      end
    end
    private :raise
  end
end

#start_watcherObject


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# File 'lib/spring/application.rb', line 67

def start_watcher
  @watcher = Spring.watcher

  @watcher.on_stale do
    state! :watcher_stale
  end

  if @watcher.respond_to? :on_debug
    @watcher.on_debug do |message|
      spring_env.log "[watcher:#{app_env}] #{message}"
    end
  end

  @watcher.start
end

#state(val) ⇒ Object


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# File 'lib/spring/application.rb', line 20

def state(val)
  return if exiting?
  log "#{@state} -> #{val}"
  @state = val
end

#state!(val) ⇒ Object


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# File 'lib/spring/application.rb', line 26

def state!(val)
  state val
  @interrupt.last.write "."
end

#terminateObject


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# File 'lib/spring/application.rb', line 242

def terminate
  if exiting?
    # Ensure that we do not ignore subsequent termination attempts
    log "forced exit"
    @waiting.each { |pid| Process.kill("TERM", pid) }
    Kernel.exit
  else
    state! :terminating
  end
end

#terminating?Boolean


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# File 'lib/spring/application.rb', line 55

def terminating?
  @state == :terminating
end

#wait(pid, streams, client) ⇒ Object


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# File 'lib/spring/application.rb', line 337

def wait(pid, streams, client)
  @mutex.synchronize { @waiting << pid }

  # Wait in a separate thread so we can run multiple commands at once
  Spring.failsafe_thread {
    begin
      _, status = Process.wait2 pid
      log "#{pid} exited with #{status.exitstatus}"

      streams.each(&:close)
      client.puts(status.exitstatus)
      client.close
    ensure
      @mutex.synchronize { @waiting.delete pid }
      exit_if_finished
    end
  }

  Spring.failsafe_thread {
    while signal = client.gets.chomp
      begin
        Process.kill(signal, -Process.getpgid(pid))
        client.puts(0)
      rescue Errno::ESRCH
        client.puts(1)
      end
    end
  }
end

#watcher_stale?Boolean


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# File 'lib/spring/application.rb', line 59

def watcher_stale?
  @state == :watcher_stale
end

#with_ptyObject


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# File 'lib/spring/application.rb', line 319

def with_pty
  PTY.open do |master, slave|
    [STDOUT, STDERR, STDIN].each { |s| s.reopen slave }
    reader_thread = Spring.failsafe_thread { master.read }
    begin
      yield
    ensure
      reader_thread.kill
      reset_streams
    end
  end
end