Module: God

Defined in:
lib/god.rb,
lib/god/task.rb,
lib/god/watch.rb,
lib/god/driver.rb,
lib/god/errors.rb,
lib/god/logger.rb,
lib/god/metric.rb,
lib/god/socket.rb,
lib/god/cli/run.rb,
lib/god/contact.rb,
lib/god/process.rb,
lib/god/trigger.rb,
lib/god/behavior.rb,
lib/god/registry.rb,
lib/god/timeline.rb,
lib/god/condition.rb,
lib/god/cli/command.rb,
lib/god/cli/version.rb,
lib/god/configurable.rb,
lib/god/event_handler.rb,
lib/god/simple_logger.rb,
lib/god/contacts/email.rb,
lib/god/contacts/prowl.rb,
lib/god/contacts/scout.rb,
lib/god/contacts/sensu.rb,
lib/god/contacts/slack.rb,
lib/god/system/process.rb,
lib/god/contacts/jabber.rb,
lib/god/contacts/statsd.rb,
lib/god/conditions/tries.rb,
lib/god/contacts/hipchat.rb,
lib/god/contacts/twitter.rb,
lib/god/contacts/webhook.rb,
lib/god/conditions/always.rb,
lib/god/conditions/lambda.rb,
lib/god/contacts/airbrake.rb,
lib/god/contacts/campfire.rb,
lib/god/conditions/complex.rb,
lib/god/conditions/flapping.rb,
lib/god/conditions/cpu_usage.rb,
lib/god/conditions/disk_usage.rb,
lib/god/conditions/file_mtime.rb,
lib/god/system/portable_poller.rb,
lib/god/conditions/file_touched.rb,
lib/god/conditions/memory_usage.rb,
lib/god/behaviors/clean_pid_file.rb,
lib/god/conditions/process_exits.rb,
lib/god/system/slash_proc_poller.rb,
lib/god/conditions/process_running.rb,
lib/god/behaviors/clean_unix_socket.rb,
lib/god/conditions/degrading_lambda.rb,
lib/god/conditions/socket_responding.rb,
lib/god/event_handlers/dummy_handler.rb,
lib/god/conditions/http_response_code.rb,
lib/god/event_handlers/kqueue_handler.rb,
lib/god/behaviors/notify_when_flapping.rb,
lib/god/event_handlers/netlink_handler.rb

Defined Under Namespace

Modules: Behaviors, CLI, Conditions, Configurable, Contacts, System Classes: AbstractMethodNotOverriddenError, Behavior, Condition, Contact, Driver, DriverEvent, DriverEventQueue, DriverOperation, DummyHandler, EventCondition, EventHandler, EventRegistrationFailedError, InvalidCommandError, KQueueHandler, Logger, Metric, NetlinkHandler, NoSuchBehaviorError, NoSuchConditionError, NoSuchContactError, NoSuchWatchError, PollCondition, Process, Registry, SimpleLogger, Socket, Task, TimedEvent, Timeline, Trigger, TriggerCondition, Watch

Constant Summary collapse

VERSION = 
'0.13.7'
LOG_BUFFER_SIZE_DEFAULT = 
100
PID_FILE_DIRECTORY_DEFAULTS = 
['/var/run/god', '~/.god/pids']
DRB_PORT_DEFAULT = 
17165
DRB_ALLOW_DEFAULT = 
['127.0.0.1']
LOG_LEVEL_DEFAULT = 
:info
TERMINATE_TIMEOUT_DEFAULT = 
10
STOP_TIMEOUT_DEFAULT = 
10
STOP_SIGNAL_DEFAULT = 
'TERM'

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.contact_groups ⇒ Object

Returns the value of attribute contact_groups


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# File 'lib/god.rb', line 210

def contact_groups
  @contact_groups
end

.contacts ⇒ Object

Returns the value of attribute contacts


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# File 'lib/god.rb', line 210

def contacts
  @contacts
end

.groups ⇒ Object

Returns the value of attribute groups


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# File 'lib/god.rb', line 210

def groups
  @groups
end

.inited ⇒ Object

Returns the value of attribute inited


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# File 'lib/god.rb', line 210

def inited
  @inited
end

.main ⇒ Object

Returns the value of attribute main


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# File 'lib/god.rb', line 210

def main
  @main
end

.pending_watch_states ⇒ Object

Returns the value of attribute pending_watch_states


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# File 'lib/god.rb', line 210

def pending_watch_states
  @pending_watch_states
end

.pending_watches ⇒ Object

Returns the value of attribute pending_watches


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# File 'lib/god.rb', line 210

def pending_watches
  @pending_watches
end

.running ⇒ Object

Returns the value of attribute running


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# File 'lib/god.rb', line 210

def running
  @running
end

.server ⇒ Object

Returns the value of attribute server


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# File 'lib/god.rb', line 210

def server
  @server
end

.watches ⇒ Object

Returns the value of attribute watches


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# File 'lib/god.rb', line 210

def watches
  @watches
end

Class Method Details

.at_exit ⇒ Object

To be called on program exit to start god.

Returns nothing.


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# File 'lib/god.rb', line 738

def self.at_exit
  self.start
  self.join
end

.contact(kind) {|c| ... } ⇒ Object

Yields:

  • (c) 

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# File 'lib/god.rb', line 373

def self.contact(kind)
  # Ensure internal init has run.
  self.internal_init

  # Verify contact has been loaded.
  if CONTACT_LOAD_SUCCESS[kind] == false
    applog(nil, :error, "A required dependency for the #{kind} contact is unavailable.")
    applog(nil, :error, "Run the following commands to install the dependencies:")
    CONTACT_DEPS[kind].each do |d|
      applog(nil, :error, "  [sudo] gem install #{d}")
    end
    abort
  end

  # Create the contact.
  begin
    c = Contact.generate(kind)
  rescue NoSuchContactError => e
    abort e.message
  end

  # Send to block so config can set attributes.
  yield(c) if block_given?

  # Call prepare on the contact.
  c.prepare

  # Remove existing contacts of same name.
  existing_contact = self.contacts[c.name]
  if self.running && existing_contact
    self.uncontact(existing_contact)
  end

  # Warn and noop if the contact has been defined before.
  if self.contacts[c.name] || self.contact_groups[c.name]
    applog(nil, :warn, "Contact name '#{c.name}' already used for a Contact or Contact Group")
    return
  end

  # Abort if the Contact is invalid, the Contact will have printed out its
  # own error messages by now.
  unless Contact.valid?(c) && c.valid?
    abort "Exiting on invalid contact"
  end

  # Add to list of contacts.
  self.contacts[c.name] = c

  # Add to contact group if specified.
  if c.group
    # Ensure group name hasn't been used for a contact already.
    if self.contacts[c.group]
      abort "Contact Group name '#{c.group}' already used for a Contact"
    end

    self.contact_groups[c.group] ||= []
    self.contact_groups[c.group] << c
  end
end

.control(name, command) ⇒ Object 


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# File 'lib/god.rb', line 459

def self.control(name, command)
  # Get the list of items.
  items = self.watches_by_name(name)

  jobs = []

  # Do the command.
  case command
    when "start", "monitor"
      items.each { |w| jobs << Thread.new { w.monitor if w.state != :up } }
    when "restart"
      items.each { |w| jobs << Thread.new { w.move(:restart) } }
    when "stop"
      items.each { |w| jobs << Thread.new { w.action(:stop); w.unmonitor if w.state != :unmonitored } }
    when "unmonitor"
      items.each { |w| jobs << Thread.new { w.unmonitor if w.state != :unmonitored } }
    when "remove"
      items.each { |w| self.unwatch(w) }
    else
      raise InvalidCommandError.new
  end

  jobs.each { |j| j.join }

  items.map { |x| x.name }
end

.internal_init ⇒ Object 


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# File 'lib/god.rb', line 238

def self.internal_init
  # Only do this once.
  return if self.inited

  # Variable init.
  self.watches = {}
  self.groups = {}
  self.pending_watches = []
  self.pending_watch_states = {}
  self.contacts = {}
  self.contact_groups = {}

  # Set defaults.
  self.log_buffer_size ||= LOG_BUFFER_SIZE_DEFAULT
  self.port ||= DRB_PORT_DEFAULT
  self.allow ||= DRB_ALLOW_DEFAULT
  self.log_level ||= LOG_LEVEL_DEFAULT
  self.terminate_timeout ||= TERMINATE_TIMEOUT_DEFAULT

  # Additional setup.
  self.setup

  # Log level.
  log_level_map = {:debug => Logger::DEBUG,
                   :info => Logger::INFO,
                   :warn => Logger::WARN,
                   :error => Logger::ERROR,
                   :fatal => Logger::FATAL}
  LOG.level = log_level_map[self.log_level]

  # Init has been executed.
  self.inited = true

  # Not yet running.
  self.running = false
end

.join ⇒ Object

Prevent god from exiting.

Returns nothing.


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# File 'lib/god.rb', line 726

def self.join
  self.main.join if self.main
end

.load(glob) ⇒ Object

Load the given file(s) according to the given glob.

glob - The glob-enabled String path to load.

Returns nothing.


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# File 'lib/god.rb', line 644

def self.load(glob)
  Dir[glob].each do |f|
    Kernel.load f
  end
end

.pattern_match(pattern, list) ⇒ Object

Match a shortened pattern against a list of String candidates. The pattern is expanded into a regular expression by inserting .* between each character.

pattern - The String containing the abbreviation. list - The Array of Strings to match against.

Examples

list = %w{ foo bar bars }
pattern = 'br'
God.pattern_match(list, pattern)
# => ['bar', 'bars']

Returns the Array of matching name Strings.


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# File 'lib/god.rb', line 760

def self.pattern_match(pattern, list)
  regex = pattern.split('').join('.*')

  list.select do |item|
    item =~ Regexp.new(regex)
  end.sort_by { |x| x.size }
end

.registry ⇒ Object 


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# File 'lib/god/registry.rb', line 2

def self.registry
  @registry ||= Registry.new
end

.running_load(code, filename, action = nil) ⇒ Object 


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# File 'lib/god.rb', line 583

def self.running_load(code, filename, action = nil)
  errors = ""
  loaded_watches = []
  unloaded_watches = []
  jobs = []

  begin
    LOG.start_capture

    Gem.clear_paths
    eval(code, root_binding, filename)
    self.pending_watches.each do |w|
      if previous_state = self.pending_watch_states[w.name]
        w.monitor unless previous_state == :unmonitored
      else
        w.monitor if w.autostart?
      end
    end
    loaded_watches = self.pending_watches.map { |w| w.name }
    self.pending_watches.clear
    self.pending_watch_states.clear

    self.watches.each do |name, watch|
      next if loaded_watches.include?(name)

      case action
      when 'stop'
        jobs << Thread.new(watch) { |w| w.action(:stop); self.unwatch(w) }
        unloaded_watches << name
      when 'remove'
        jobs << Thread.new(watch) { |w| self.unwatch(w) }
        unloaded_watches << name
      when 'leave', '', nil
        # Do nothing
      else
        raise InvalidCommandError, "Unknown action: #{action}"
      end
    end

    # Make sure we quit capturing when we're done.
    LOG.finish_capture
  rescue Exception => e
    # Don't ever let running_load take down god.
    errors << LOG.finish_capture

    unless e.instance_of?(SystemExit)
      errors << e.message << "\n"
      errors << e.backtrace.join("\n")
    end
  end

  jobs.each { |t| t.join }

  [loaded_watches, errors, unloaded_watches]
end

.running_log(watch_name, since) ⇒ Object 


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# File 'lib/god.rb', line 556

def self.running_log(watch_name, since)
  matches = pattern_match(watch_name, self.watches.keys)

  unless matches.first
    raise NoSuchWatchError.new
  end

  LOG.watch_log_since(matches.first, since)
end

.setup ⇒ Object

Setup pid file directory and log system.

Returns nothing.


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# File 'lib/god.rb', line 653

def self.setup
  if self.pid_file_directory
    # Pid file dir was specified, ensure it is created and writable.
    unless File.exist?(self.pid_file_directory)
      begin
        FileUtils.mkdir_p(self.pid_file_directory)
      rescue Errno::EACCES => e
        abort "Failed to create pid file directory: #{e.message}"
      end
    end

    unless File.writable?(self.pid_file_directory)
      abort "The pid file directory (#{self.pid_file_directory}) is not writable by #{Etc.getlogin}"
    end
  else
    # No pid file dir specified, try defaults.
    PID_FILE_DIRECTORY_DEFAULTS.each do |idir|
      dir = File.expand_path(idir)
      begin
        FileUtils.mkdir_p(dir)
        if File.writable?(dir)
          self.pid_file_directory = dir
          break
        end
      rescue Errno::EACCES => e
      end
    end

    unless self.pid_file_directory
      dirs = PID_FILE_DIRECTORY_DEFAULTS.map { |x| File.expand_path(x) }
      abort "No pid file directory exists, could be created, or is writable at any of #{dirs.join(', ')}"
    end
  end

  if God::Logger.syslog
    LOG.info("Syslog enabled.")
  else
    LOG.info("Syslog disabled.")
  end

  applog(nil, :info, "Using pid file directory: #{self.pid_file_directory}")
end

.signal(name, signal) ⇒ Object 


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# File 'lib/god.rb', line 541

def self.signal(name, signal)
  items = watches_by_name(name)
  jobs = []
  items.each { |w| jobs << Thread.new { w.signal(signal) } }
  jobs.each { |j| j.join }
  items.map { |x| x.name }
end

.start ⇒ Object

Initialize and startup the machinery that makes god work.

Returns nothing.


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# File 'lib/god.rb', line 699

def self.start
  self.internal_init

  # Instantiate server.
  self.server = Socket.new(self.port, self.socket_user, self.socket_group, self.socket_perms)

  # Start monitoring any watches set to autostart.
  self.watches.values.each { |w| w.monitor if w.autostart? }

  # Clear pending watches.
  self.pending_watches.clear

  # Mark as running.
  self.running = true

  # Don't exit.
  self.main =
  Thread.new do
    loop do
      sleep 60
    end
  end
end

.status ⇒ Object 


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# File 'lib/god.rb', line 527

def self.status
  info = {}
  self.watches.map do |name, w|
    info[name] = {:state => w.state, :group => w.group}
  end
  info
end

.stop_all ⇒ Object 


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# File 'lib/god.rb', line 490

def self.stop_all
  self.watches.sort.each do |name, w|
    Thread.new do
      w.action(:stop)
      w.unmonitor if w.state != :unmonitored
    end
  end

  terminate_timeout.times do
    return true unless self.watches.map { |name, w| w.alive? }.any?
    sleep 1
  end

  return false
end

.task(klass = Task) {|t| ... } ⇒ Object

Yields:

  • (t) 

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# File 'lib/god.rb', line 289

def self.task(klass = Task)
  # Ensure internal init has run.
  self.internal_init

  t = klass.new
  yield(t)

  # Do the post-configuration.
  t.prepare

  # If running, completely remove the watch (if necessary) to prepare for
  # the reload
  existing_watch = self.watches[t.name]
  if self.running && existing_watch
    self.pending_watch_states[existing_watch.name] = existing_watch.state
    self.unwatch(existing_watch)
  end

  # Ensure the new watch has a unique name.
  if self.watches[t.name] || self.groups[t.name]
    abort "Task name '#{t.name}' already used for a Task or Group"
  end

  # Ensure watch is internally valid.
  t.valid? || abort("Task '#{t.name}' is not valid (see above)")

  # Add to list of watches.
  self.watches[t.name] = t

  # Add to pending watches.
  self.pending_watches << t

  # Add to group if specified.
  if t.group
    # Ensure group name hasn't been used for a watch already.
    if self.watches[t.group]
      abort "Group name '#{t.group}' already used for a Task"
    end

    self.groups[t.group] ||= []
    self.groups[t.group] << t
  end

  # Register watch.
  t.register!

  # Log.
  if self.running && existing_watch
    applog(t, :info, "#{t.name} Reloaded config")
  elsif self.running
    applog(t, :info, "#{t.name} Loaded config")
  end
end

.terminate ⇒ Object 


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# File 'lib/god.rb', line 512

def self.terminate
  FileUtils.rm_f(self.pid) if self.pid
  self.server.stop if self.server
  exit!(0)
end

.uncontact(contact) ⇒ Object 


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# File 'lib/god.rb', line 438

def self.uncontact(contact)
  self.contacts.delete(contact.name)
  if contact.group
    self.contact_groups[contact.group].delete(contact)
  end
end

.unwatch(watch) ⇒ Object 


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# File 'lib/god.rb', line 348

def self.unwatch(watch)
  # Unmonitor.
  watch.unmonitor unless watch.state == :unmonitored

  # Unregister.
  watch.unregister!

  # Remove from watches.
  self.watches.delete(watch.name)

  # Remove from groups.
  if watch.group
    self.groups[watch.group].delete(watch)
  end

  applog(watch, :info, "#{watch.name} unwatched")
end

.version ⇒ Object

Returns the version String.


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# File 'lib/god.rb', line 731

def self.version
  God::VERSION
end

.watch(&block) ⇒ Object 


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# File 'lib/god.rb', line 280

def self.watch(&block)
  self.task(Watch, &block)
end

.watches_by_name(name) ⇒ Object 


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# File 'lib/god.rb', line 445

def self.watches_by_name(name)
  case name 
    when "", nil then self.watches.values.dup
    else Array(self.watches[name] || self.groups[name]).dup
  end
end