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, watcher = Spring.watcher) ⇒ Application

Returns a new instance of Application.



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

def initialize(manager, watcher = Spring.watcher)
  @manager    = manager
  @watcher    = watcher
  @setup      = Set.new
  @spring_env = Env.new
  @preloaded  = false
  @mutex      = Mutex.new
  @waiting    = 0
  @exiting    = false

  # Workaround for GC bug in Ruby 2 which causes segfaults if watcher.to_io
  # instances get dereffed.
  @fds = [manager, watcher.to_io]
end

Instance Attribute Details

#manager ⇒ Object (readonly)

Returns the value of attribute manager.



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

def manager
  @manager
end

#spring_env ⇒ Object (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

#watcher ⇒ Object (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

#connect_database ⇒ Object 



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# File 'lib/spring/application.rb', line 190

def connect_database
  ActiveRecord::Base.establish_connection if defined?(ActiveRecord::Base)
end

#disconnect_database ⇒ Object 



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# File 'lib/spring/application.rb', line 186

def disconnect_database
  ActiveRecord::Base.remove_connection if defined?(ActiveRecord::Base)
end

#exiting? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spring/application.rb', line 32

def exiting?
  @exiting
end

#invoke_after_fork_callbacks ⇒ Object 



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# File 'lib/spring/application.rb', line 176

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

#loaded_application_features ⇒ Object 



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# File 'lib/spring/application.rb', line 182

def loaded_application_features
  $LOADED_FEATURES.select { |f| f.start_with?(File.realpath(Rails.root)) }
end

#log(message) ⇒ Object 



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# File 'lib/spring/application.rb', line 24

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

#preload ⇒ Object 



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# File 'lib/spring/application.rb', line 36

def preload
  log "preloading app"

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

  # 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

  # Ensure eager loading does not take place, even though it usually would do
  # in test mode with config.cache_classes = true. Eager loading in this situation
  # just makes the initial run take longer without much gain in subsequent runs,
  # at least in my testing.
  Rails::Application::Finisher.initializers.delete_if { |i| i.name == :eager_load! }

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

  Rails.application.config.cache_classes = false
  disconnect_database

  watcher.add loaded_application_features
  watcher.add Spring.gemfile, "#{Spring.gemfile}.lock"
  watcher.add Rails.application.paths["config/initializers"]

  @preloaded = true
end

#preloaded? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/spring/application.rb', line 28

def preloaded?
  @preloaded
end

#run ⇒ Object 



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

def run
  log "running"
  watcher.start

  loop do
    IO.select(@fds)

    if watcher.stale?
      log "watcher stale; exiting"
      manager.close
      @exiting = true
      try_exit
      sleep
    else
      serve manager.recv_io(UNIXSocket)
    end
  end
end

#serve(client) ⇒ Object 



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# File 'lib/spring/application.rb', line 92

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

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

  preload unless preloaded?

  args    = JSON.load(client.read(client.gets.to_i))
  command = Spring.command(args.shift)

  connect_database
  setup command

  ActionDispatch::Reloader.cleanup!
  ActionDispatch::Reloader.prepare!

  pid = fork {
    Process.setsid
    STDIN.reopen(streams.last)
    IGNORE_SIGNALS.each { |sig| trap(sig, "DEFAULT") }

    connect_database
    ARGV.replace(args)
    srand

    invoke_after_fork_callbacks
    shush_backtraces

    if command.respond_to?(:call)
      command.call
    else
      exec_name = command.exec_name
      gem_name  = command.gem_name if command.respond_to?(:gem_name)

      exec = Gem.bin_path(gem_name || exec_name, exec_name)
      $0 = exec
      load exec
    end
  }

  disconnect_database
  [STDOUT, STDERR].each { |stream| stream.reopen(spring_env.log_file) }

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

  # Wait in a separate thread so we can run multiple commands at once
  Thread.new {
    @mutex.synchronize { @waiting += 1 }

    _, status = Process.wait2 pid
    log "#{pid} exited with #{status.exitstatus}"

    streams.each(&:close)
    client.puts(status.exitstatus)
    client.close

    @mutex.synchronize { @waiting -= 1 }
    try_exit
  }

rescue => e
  log "exception: #{e}"
  streams.each(&:close) if streams
  client.puts(1)
  client.close
  raise
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 166

def setup(command)
  return if @setup.include?(command.class)
  @setup << command.class

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

#shush_backtraces ⇒ Object

This feels very naughty



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# File 'lib/spring/application.rb', line 195

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
  end
end

#try_exit ⇒ Object 



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# File 'lib/spring/application.rb', line 86

def try_exit
  @mutex.synchronize {
    exit if exiting? && @waiting == 0
  }
end