Class: Juggler::Runner

Inherits:
Object
  • Object
show all
Defined in:
lib/juggler/runner.rb

Overview

Stopping: This is rather complex. The point of the __STOP__ malarkey it to unblock a blocking reserve so that delete and release commands can be actioned on the currently running jobs before shutdown. Also a Juggler.shutdown_grace_timeout period is availble for jobs to complete before the eventmachine is stopped

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(method, concurrency, strategy) ⇒ Runner

Returns a new instance of Runner.



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# File 'lib/juggler/runner.rb', line 50

def initialize(method, concurrency, strategy)
  @strategy = strategy
  @concurrency = concurrency
  @queue = method.to_s
  
  @running = []
  @reserved = false
end

Class Method Details

.start(runner) ⇒ Object 



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# File 'lib/juggler/runner.rb', line 10

def start(runner)
  @runners ||= []
  @runners << runner
  
  @signals_setup ||= begin
    %w{INT TERM}.each do |sig|
      Signal.trap(sig) {
        stop_all_runners_with_grace
      }
    end
    true
  end
end

Instance Method Details

#reserve ⇒ Object 



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# File 'lib/juggler/runner.rb', line 69

def reserve
  @reserved = true
  
  reserve_call = connection.reserve
  
  reserve_call.callback do |job|
    @reserved = false

    begin
      params = Marshal.load(job.body)
    rescue => e
      handle_exception(e, "#{to_s}: Exception unmarshaling #{@queue} job")
      connection.delete(job)
      next
    end
    
    if params == "__STOP__"
      connection.delete(job)
      next
    end
    
    job_runner = JobRunner.new(job, params, @strategy)
    
    @running << job_runner

    Juggler.logger.debug {
      "#{to_s}: Excecuting #{@running.size} jobs"
    }

    # We may reserve after job is running (after fetching stats)
    job_runner.bind(:running) {
      reserve_if_necessary
    }

    # Also may reserve when a job is done
    job_runner.bind(:done) {
      @running.delete(job_runner)
      reserve_if_necessary
    }

    job_runner.run
  end
  
  reserve_call.errback do |error|
    @reserved = false
    
    if error == :deadline_soon
      # This doesn't necessarily mean that a job has taken too long, it is 
      # quite likely that the blocking reserve is just stopping jobs from 
      # being deleted
      Juggler.logger.debug "#{to_s}: Reserve terminated (deadline_soon)"

      check_all_reserved_jobs.callback {
        reserve_if_necessary
      }
    elsif error == :disconnected
      Juggler.logger.warn "#{to_s}: Reserve terminated (beanstalkd disconnected)"
    else
      Juggler.logger.error "#{to_s}: Unexpected error: #{error}"
      reserve_if_necessary
    end
  end
end

#reserve_if_necessary ⇒ Object

We potentially need to issue a new reserve call after a job is reserved (if we’re not at the concurrency limit), and after a job completes (unless we’re already reserving)



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# File 'lib/juggler/runner.rb', line 62

def reserve_if_necessary
  if @on && @connection.connected? && !@reserved && @running.size < @concurrency
    Juggler.logger.debug "#{to_s}: Reserving"
    reserve
  end
end

#run ⇒ Object 



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# File 'lib/juggler/runner.rb', line 133

def run
  @on = true
  Runner.start(self)
  # Creates beanstalkd connection - reserve happens on connect
  connection
end

#running? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/juggler/runner.rb', line 149

def running?
  @running.size > 0
end

#stop ⇒ Object 



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# File 'lib/juggler/runner.rb', line 140

def stop
  @on = false

  # See class documentation on stopping
  if @reserved
    Juggler.throw(@queue, "__STOP__")
  end
end

#to_s ⇒ Object 



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# File 'lib/juggler/runner.rb', line 153

def to_s
  "Tube #{@queue}"
end