Class: Pazuzu::Supervisor

Inherits:
Object
  • Object
show all
Includes:
Utility::Runnable
Defined in:
lib/pazuzu/supervisor.rb

Overview

The supervisor controls the different applications registered with it.

Constant Summary collapse

DEFAULT_SOCKET_PATH = 
'/var/run/pazuzud.socket'

Instance Attribute Summary collapse

Attributes included from Utility::Runnable

#started_at, #stopped_at

Instance Method Summary collapse

Methods included from Utility::Runnable

#run_state, #start!, #stop!, #wait_for_state_change!

Constructor Details

#initialize(options) ⇒ Supervisor

Returns a new instance of Supervisor.



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# File 'lib/pazuzu/supervisor.rb', line 12

def initialize(options)
  options.assert_valid_keys(:config_path)
  @logger = Logger.new($stderr)
  @logger.level = Logger::WARN
  @applications = Utility::RunnablePool.new
  @config_path = options[:config_path]
  Thread.start {
    # Wait for PIDs, otherwise we will get zombies
    loop do
      begin
        Process.waitpid
      rescue Errno::ECHILD
        sleep(1)
      rescue
        # Ignore
      end
    end
  }
  super()
end

Instance Attribute Details

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/pazuzu/supervisor.rb', line 131

def logger
  @logger
end

Instance Method Details

#applications ⇒ Object 



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# File 'lib/pazuzu/supervisor.rb', line 116

def applications
  @applications.children
end

#cgroup_for_instance(instance) ⇒ Object

Returns a Cgroup object given an instance.



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# File 'lib/pazuzu/supervisor.rb', line 121

def cgroup_for_instance(instance)
  path = [
    @cgroup_hieararchy_root,
    instance.worker.application.name,
    instance.worker.name,
    instance.index
  ].join('/')
  Cgroup.new(@cgroups_fs_root_path, path, @cgroup_subsystems)
end

#configure!(configuration) ⇒ Object 



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# File 'lib/pazuzu/supervisor.rb', line 45

def configure!(configuration)
  case configuration['log_path']
    when 'syslog'
      @logger = SyslogLogger('pazuzu')
    when nil
      @logger = Logger.new($stderr)
    else
      @logger = Logger.new(configuration['log_path'])
  end
  @logger.level = Logger::DEBUG

  new_socket_path = configuration['socket_path']
  new_socket_path ||= DEFAULT_SOCKET_PATH
  if @socket_path and new_socket_path != @socket_path
    @logger.warn("Cannot change socket path after start")
  else
    @socket_path = new_socket_path
  end

  @socket_server ||= Control::SocketServer.new(self, @socket_path)

  leftover_applications = @applications.children.dup
  (configuration['applications'] || {}).each do |name, app_config|
    if app_config
      name = name.to_s
      application = @applications.children.select { |a| a.name == name }.first
      if application
        leftover_applications.delete(application)
      else
        @logger.info("Adding application #{name}")
        application = Application.new(self, name)
        @applications.register(application)
      end
      application.configure!(app_config['procfile'], app_config)
    end
  end
  leftover_applications.each do |application|
    @logger.info("Removing application #{name}")
    @applications.unregister(application)
  end

  cgroups_config = configuration['cgroups'] || {}

  new_cgroup_hiearchy_root = cgroups_config['hieararchy_root']
  new_cgroup_hiearchy_root ||= 'pazuzu'
  new_cgroup_hiearchy_root.gsub!(/^\/+/, '')
  new_cgroup_hiearchy_root.gsub!(/\/$/, '')
  if @cgroup_hieararchy_root and new_cgroup_hiearchy_root != @cgroup_hieararchy_root
    @logger.warn("Cannot change cgroups hiearchy root after start")
  else
    @cgroup_hieararchy_root = new_cgroup_hiearchy_root
  end

  new_cgroup_subsystems = [cgroups_config['subsystems']].flatten.compact
  new_cgroup_subsystems ||= %w(memory cpu cpuacct blkio)
  if @cgroup_subsystems and new_cgroup_subsystems != @cgroup_subsystems
    @logger.warn("Cannot change cgroups subsystems after start")
  else
    @cgroup_subsystems = new_cgroup_subsystems
  end

  new_cgroups_fs_root_path = cgroups_config['fs_root']
  new_cgroups_fs_root_path ||= '/sys/fs/cgroup'
  new_cgroups_fs_root_path.gsub!(/\/$/, '')
  if @cgroups_fs_root_path and @cgroups_fs_root_path != new_cgroups_fs_root_path
    @logger.warn("Cannot change cgroups root after start")
  else
    @cgroups_fs_root_path = new_cgroups_fs_root_path
  end
end

#load_configuration! ⇒ Object 



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# File 'lib/pazuzu/supervisor.rb', line 41

def load_configuration!
  configure!(load_config_from_yaml(@config_path))
end

#run! ⇒ Object 



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# File 'lib/pazuzu/supervisor.rb', line 33

def run!
  load_configuration!
  start!
  while [:starting, :running].include?(run_state)
    sleep(1)
  end
end