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 Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ WorkerLoop

Optional argument :duration (in seconds) for how long the worker loop runs or :limit (integer) for max number of iterations

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# File 'lib/new_relic/agent/worker_loop.rb', line 17

def initialize(opts = {})
  @should_run = true
  @next_invocation_time = Process.clock_gettime(Process::CLOCK_REALTIME)
  @period = 60.0
  @duration = opts[:duration]
  @limit = opts[:limit]
  @iterations = 0
  @propagate_errors = opts.fetch(:propagate_errors, false)
  @deadline = nil
end

Instance Attribute Details

#iterations ⇒ Object (readonly) 


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# File 'lib/new_relic/agent/worker_loop.rb', line 13

def iterations
  @iterations
end

#period ⇒ Object 


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# File 'lib/new_relic/agent/worker_loop.rb', line 12

def period
  @period
end

#propagate_errors ⇒ Object 


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# File 'lib/new_relic/agent/worker_loop.rb', line 12

def propagate_errors
  @propagate_errors
end

Instance Method Details

#keep_running? ⇒ Boolean

a simple accessor for @should_run

Returns:

  • (Boolean)
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# File 'lib/new_relic/agent/worker_loop.rb', line 62

def keep_running?
  @should_run && under_duration? && under_limit?
end

#run(period = nil, &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. This will run the task immediately.

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# File 'lib/new_relic/agent/worker_loop.rb', line 43

def run(period = nil, &block)
  setup(period, block)
  while keep_running?
    sleep_time = schedule_next_invocation
    sleep(sleep_time) if sleep_time > 0
    run_task if keep_running?
    @iterations += 1
  end
end

#run_task ⇒ Object

Executes the block given to the worker loop, and handles errors.

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# File 'lib/new_relic/agent/worker_loop.rb', line 80

def run_task
  if @propagate_errors
    @task.call
  else
    begin
      @task.call
    rescue NewRelic::Agent::ForceRestartException, NewRelic::Agent::ForceDisconnectException
      # blow out the loop
      raise
    rescue => e
      # Don't blow out the stack for anything that hasn't already propagated
      ::NewRelic::Agent.logger.error('Error running task in agent worker loop:', e)
    end
  end
end

#schedule_next_invocation ⇒ Object

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# File 'lib/new_relic/agent/worker_loop.rb', line 53

def schedule_next_invocation
  now = Process.clock_gettime(Process::CLOCK_REALTIME)
  while @next_invocation_time <= now && @period > 0
    @next_invocation_time += @period
  end
  @next_invocation_time - Process.clock_gettime(Process::CLOCK_REALTIME)
end

#setup(period, task) ⇒ Object

Reset state that is changed by running the worker loop

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# File 'lib/new_relic/agent/worker_loop.rb', line 29

def setup(period, task)
  @task = task
  @period = period if period
  @should_run = true
  @iterations = 0

  now = Process.clock_gettime(Process::CLOCK_REALTIME)
  @deadline = now + @duration if @duration
  @next_invocation_time = (now + @period)
end

#stop ⇒ Object

Sets @should_run to false. Returns false

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# File 'lib/new_relic/agent/worker_loop.rb', line 75

def stop
  @should_run = false
end

#under_duration? ⇒ Boolean

Returns:

  • (Boolean)
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# File 'lib/new_relic/agent/worker_loop.rb', line 66

def under_duration?
  !@deadline || Process.clock_gettime(Process::CLOCK_REALTIME) < @deadline
end

#under_limit? ⇒ Boolean

Returns:

  • (Boolean)
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# File 'lib/new_relic/agent/worker_loop.rb', line 70

def under_limit?
  @limit.nil? || @iterations < @limit
end