Class: NewRelic::Agent::WorkerLoop

Inherits:
Object
  • Object
show all
Defined in:
lib/new_relic/agent/worker_loop.rb

Overview

A worker loop executes a set of registered tasks on a single thread.

A task is a proc or block with a specified call period in seconds.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ WorkerLoop

Returns a new instance of WorkerLoop.



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# File 'lib/new_relic/agent/worker_loop.rb', line 9

def initialize
  @log = log
  @should_run = true
end

Instance Method Details

#keep_running ⇒ Object 



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# File 'lib/new_relic/agent/worker_loop.rb', line 40

def keep_running
  @should_run
end

#lock ⇒ Object 



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# File 'lib/new_relic/agent/worker_loop.rb', line 14

def lock
  @@lock ||= Mutex.new
end

#log ⇒ Object 



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# File 'lib/new_relic/agent/worker_loop.rb', line 18

def log
  NewRelic::Control.instance.log
end

#run(period, &block) ⇒ Object

Run infinitely, calling the registered tasks at their specified call periods. The caller is responsible for creating the thread that runs this worker loop



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# File 'lib/new_relic/agent/worker_loop.rb', line 24

def run(period, &block)
  @period = period
  @next_invocation_time = Time.now + @period
  @task = block
  while keep_running do
    now = Time.now
    while now < @next_invocation_time
      # sleep until this next task's scheduled invocation time
      sleep_time = @next_invocation_time - now
      sleep sleep_time if sleep_time > 0
      now = Time.now
    end
    run_task if keep_running
  end
end

#run_task ⇒ Object 



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# File 'lib/new_relic/agent/worker_loop.rb', line 48

def run_task
  lock.synchronize do
    @task.call 
  end
rescue ServerError => e
  log.debug "Server Error: #{e}"
rescue NewRelic::Agent::ForceRestartException, NewRelic::Agent::ForceDisconnectException
  # blow out the loop
  raise
rescue RuntimeError => e
  # This is probably a server error which has been logged in the server along
  # with your account name.  Check and see if the agent listener is in the
  # stack trace and log it quietly if it is.
  message = "Error running task in worker loop, likely a server error (#{e})"
  if e.backtrace.grep(/agent_listener/).empty?
    log.error message
  else
    log.debug message
    log.debug e.backtrace.join("\n")
  end
rescue Timeout::Error, NewRelic::Agent::ServerConnectionException
  # Want to ignore these because they are handled already
rescue ScriptError, StandardError => e 
  log.error "Error running task in Agent Worker Loop '#{e}': #{e.backtrace.first}" 
  log.debug e.backtrace.join("\n")
ensure
  while @next_invocation_time < Time.now
    @next_invocation_time += @period
  end        
end

#stop ⇒ Object 



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# File 'lib/new_relic/agent/worker_loop.rb', line 44

def stop
  @should_run = false
end