Class: LogStash::Agent

Inherits:
Object
  • Object
show all
Includes:
Util::Loggable
Defined in:
lib/logstash/agent.rb

Constant Summary collapse

STARTED_AT = 
Time.now.freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Util::Loggable

included, #slow_logger

Constructor Details

#initialize(settings = LogStash::SETTINGS, source_loader = nil) ⇒ Agent

initialize method for LogStash::Agent

Parameters:

  • params (Hash) —

    potential parameters are: :name [String] - identifier for the agent :auto_reload [Boolean] - enable reloading of pipelines :reload_interval [Integer] - reload pipelines every X seconds



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# File 'lib/logstash/agent.rb', line 36

def initialize(settings = LogStash::SETTINGS, source_loader = nil)
  @logger = self.class.logger
  @settings = settings
  @auto_reload = setting("config.reload.automatic")
  @ephemeral_id = SecureRandom.uuid

  # Do not use @pipelines directly. Use #with_pipelines which does locking
  @pipelines = {}
  @pipelines_lock = java.util.concurrent.locks.ReentrantLock.new

  @name = setting("node.name")
  @http_host = setting("http.host")
  @http_port = setting("http.port")
  @http_environment = setting("http.environment")
  # Generate / load the persistent uuid
  id

  # This is for backward compatibility in the tests
  if source_loader.nil?
    @source_loader = LogStash::Config::SourceLoader.new
    @source_loader.add_source(LogStash::Config::Source::Local.new(@settings))
  else
    @source_loader = source_loader
  end

  # Normalize time interval to seconds
  @reload_interval = setting("config.reload.interval") / 1_000_000_000.0

  @collect_metric = setting("metric.collect")

  # Create the collectors and configured it with the library
  configure_metrics_collectors

  @state_resolver = LogStash::StateResolver.new(metric)

  @pipeline_reload_metric = metric.namespace([:stats, :pipelines])
  @instance_reload_metric = metric.namespace([:stats, :reloads])
  initialize_agent_metrics

  @dispatcher = LogStash::EventDispatcher.new(self)
  LogStash::PLUGIN_REGISTRY.hooks.register_emitter(self.class, dispatcher)
  dispatcher.fire(:after_initialize)

  @running = Concurrent::AtomicBoolean.new(false)
end

Instance Attribute Details

#dispatcher ⇒ Object (readonly)

Returns the value of attribute dispatcher.



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# File 'lib/logstash/agent.rb', line 28

def dispatcher
  @dispatcher
end

#ephemeral_id ⇒ Object (readonly)

Returns the value of attribute ephemeral_id.



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# File 'lib/logstash/agent.rb', line 28

def ephemeral_id
  @ephemeral_id
end

#logger ⇒ Object

Returns the value of attribute logger.



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# File 'lib/logstash/agent.rb', line 29

def logger
  @logger
end

#metric ⇒ Object (readonly)

Returns the value of attribute metric.



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# File 'lib/logstash/agent.rb', line 28

def metric
  @metric
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/logstash/agent.rb', line 28

def name
  @name
end

#settings ⇒ Object (readonly)

Returns the value of attribute settings.



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# File 'lib/logstash/agent.rb', line 28

def settings
  @settings
end

#webserver ⇒ Object (readonly)

Returns the value of attribute webserver.



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# File 'lib/logstash/agent.rb', line 28

def webserver
  @webserver
end

Instance Method Details

#auto_reload? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/agent.rb', line 124

def auto_reload?
  @auto_reload
end

#converge_state_and_update ⇒ Object 



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# File 'lib/logstash/agent.rb', line 147

def converge_state_and_update
  results = @source_loader.fetch

  unless results.success?
    if auto_reload?
      logger.debug("Could not fetch the configuration to converge, will retry", :message => results.error, :retrying_in => @reload_interval)
      return
    else
      raise "Could not fetch the configuration, message: #{results.error}"
    end
  end

  # We Lock any access on the pipelines, since the actions will modify the
  # content of it.
  converge_result = nil

  # we don't use the variable here, but we want the locking
  with_pipelines do |pipelines|
    pipeline_actions = resolve_actions(results.response)
    converge_result = converge_state(pipeline_actions)
    update_metrics(converge_result)
  end

  report_currently_running_pipelines(converge_result)
  dispatch_events(converge_result)

  converge_result
rescue => e
  logger.error("An exception happened when converging configuration", :exception => e.class, :message => e.message, :backtrace => e.backtrace)
end

#execute ⇒ Object 



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# File 'lib/logstash/agent.rb', line 82

def execute
  @thread = Thread.current # this var is implicitly used by Stud.stop?
  logger.debug("Starting agent")

  start_webserver

  transition_to_running

  converge_state_and_update

  if auto_reload?
    # `sleep_then_run` instead of firing the interval right away
    Stud.interval(@reload_interval, :sleep_then_run => true) do
      # TODO(ph) OK, in reality, we should get out of the loop, but I am
      # worried about the implication of that change so instead when we are stopped
      # we don't converge.
      #
      # Logstash currently expect to be block here, the signal will force a kill on the agent making
      # the agent thread unblock
      #
      # Actually what we really need is one more state:
      #
      # init => running => stopping => stopped
      converge_state_and_update unless stopped?
    end
  else
    return 1 if clean_state?

    while !Stud.stop?
      if clean_state? || running_user_defined_pipelines?
        sleep(0.5)
      else
        break
      end
    end
  end

  return 0
ensure
  transition_to_stopped
end

#get_pipeline(pipeline_id) ⇒ Object 



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# File 'lib/logstash/agent.rb', line 231

def get_pipeline(pipeline_id)
  with_pipelines do |pipelines|
    pipelines[pipeline_id]
  end
end

#id ⇒ Object 



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# File 'lib/logstash/agent.rb', line 193

def id
  return @id if @id

  uuid = nil
  if ::File.exists?(id_path)
    begin
      uuid = ::File.open(id_path) {|f| f.each_line.first.chomp }
    rescue => e
      logger.warn("Could not open persistent UUID file!",
                  :path => id_path,
                  :error => e.message,
                  :class => e.class.name)
    end
  end

  if !uuid
    uuid = SecureRandom.uuid
    logger.info("No persistent UUID file found. Generating new UUID",
                :uuid => uuid,
                :path => id_path)
    begin
      ::File.open(id_path, 'w') {|f| f.write(uuid) }
    rescue => e
      logger.warn("Could not write persistent UUID file! Will use ephemeral UUID",
                  :uuid => uuid,
                  :path => id_path,
                  :error => e.message,
                  :class => e.class.name)
    end
  end

  @id = uuid
end

#id_path ⇒ Object 



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# File 'lib/logstash/agent.rb', line 227

def id_path
  @id_path ||= ::File.join(settings.get("path.data"), "uuid")
end

#pipelines_count ⇒ Object 



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# File 'lib/logstash/agent.rb', line 237

def pipelines_count
  with_pipelines do |pipelines|
    pipelines.size
  end
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/agent.rb', line 128

def running?
  @running.value
end

#running_pipelines? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/agent.rb', line 249

def running_pipelines?
  running_pipelines_count > 0
end

#running_pipelines_count ⇒ Object 



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# File 'lib/logstash/agent.rb', line 253

def running_pipelines_count
  with_running_pipelines do |pipelines|
    pipelines.size
  end
end

#running_user_defined_pipelines? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/agent.rb', line 259

def running_user_defined_pipelines?
  with_running_user_defined_pipelines do |pipelines|
    pipelines.size > 0
  end
end

#shutdown ⇒ Object 



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# File 'lib/logstash/agent.rb', line 185

def shutdown
  stop_collecting_metrics
  stop_webserver
  transition_to_stopped
  converge_result = shutdown_pipelines
  converge_result
end

#stopped? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/logstash/agent.rb', line 132

def stopped?
  !@running.value
end

#uptime ⇒ Fixnum

Calculate the Logstash uptime in milliseconds

Returns:

  • (Fixnum) —

    Uptime in milliseconds



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# File 'lib/logstash/agent.rb', line 181

def uptime
  ((Time.now.to_f - STARTED_AT.to_f) * 1000.0).to_i
end

#with_pipelines ⇒ Object

Safely perform an operation on the pipelines hash Using the correct synchronization



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# File 'lib/logstash/agent.rb', line 138

def with_pipelines
  begin
    @pipelines_lock.lock
    yield @pipelines
  ensure
    @pipelines_lock.unlock
  end
end

#with_running_pipelines ⇒ Object 



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# File 'lib/logstash/agent.rb', line 243

def with_running_pipelines
  with_pipelines do |pipelines|
    yield pipelines.select {|pipeline_id, _| running_pipeline?(pipeline_id) }
  end
end

#with_running_user_defined_pipelines ⇒ Object 



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# File 'lib/logstash/agent.rb', line 265

def with_running_user_defined_pipelines
  with_pipelines do |pipelines|
    found = pipelines.select do |_, pipeline|
      pipeline.running? && !pipeline.system?
    end

    yield found
  end
end