Class: Workhorse::Worker

Inherits:
Object
  • Object
show all
Defined in:
lib/workhorse/worker.rb

Constant Summary collapse

LOG_LEVELS = 
%i[fatal error warn info debug].freeze
SHUTDOWN_SIGNALS = 
%w[TERM INT].freeze

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(queues: [], pool_size: nil, polling_interval: 5, auto_terminate: true, quiet: true, logger: nil) ⇒ Worker

Instantiates a new worker. The worker is not automatically started.

Parameters:

  • queues (Array) (defaults to: []) —

    The queues you want this worker to process. If an empty array is given, any queues will be processed. Queues need to be specified as a symbol. To also process jobs without a queue, supply ‘nil` within the array.

  • pool_size (Integer) (defaults to: nil) —

    The number of jobs that will be processed simultaneously. If this parameter is not given, it will be set to the number of given queues + 1.

  • polling_interval (Integer) (defaults to: 5) —

    Interval in seconds the database will be polled for new jobs. Set this as high as possible to avoid unnecessary database load Set this as high as possible to avoid unnecessary database load.

  • auto_terminate (Boolean) (defaults to: true) —

    Whether to automatically shut down the worker properly on INT and TERM signals.

  • quiet (Boolean) (defaults to: true) —

    If this is set to ‘false`, the worker will also log to STDOUT.

  • logger (Logger) (defaults to: nil) —

    An optional logger the worker will append to. This can be any instance of ruby’s ‘Logger` but is commonly set to `Rails.logger`.



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# File 'lib/workhorse/worker.rb', line 41

def initialize(queues: [], pool_size: nil, polling_interval: 5, auto_terminate: true, quiet: true, logger: nil)
  @queues = queues
  @pool_size = pool_size || queues.size + 1
  @polling_interval = polling_interval
  @auto_terminate = auto_terminate
  @state = :initialized
  @quiet = quiet

  @mutex = Mutex.new
  @pool = Pool.new(@pool_size)
  @poller = Workhorse::Poller.new(self)
  @logger = logger

  fail 'Polling interval must be an integer.' unless @polling_interval.is_a?(Integer)
end

Instance Attribute Details

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/workhorse/worker.rb', line 11

def logger
  @logger
end

#mutex ⇒ Object (readonly)

Returns the value of attribute mutex.



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# File 'lib/workhorse/worker.rb', line 10

def mutex
  @mutex
end

#polling_interval ⇒ Object (readonly)

Returns the value of attribute polling_interval.



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# File 'lib/workhorse/worker.rb', line 9

def polling_interval
  @polling_interval
end

#pool_size ⇒ Object (readonly)

Returns the value of attribute pool_size.



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# File 'lib/workhorse/worker.rb', line 8

def pool_size
  @pool_size
end

#queues ⇒ Object (readonly)

Returns the value of attribute queues.



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# File 'lib/workhorse/worker.rb', line 6

def queues
  @queues
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/workhorse/worker.rb', line 7

def state
  @state
end

Class Method Details

.start_and_wait(*args) ⇒ Object

Instantiates and starts a new worker with the given arguments and then waits for its completion (i.e. an interrupt).



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# File 'lib/workhorse/worker.rb', line 15

def self.start_and_wait(*args)
  worker = new(*args)
  worker.start
  worker.wait
end

Instance Method Details

#assert_state!(state) ⇒ Object 



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# File 'lib/workhorse/worker.rb', line 83

def assert_state!(state)
  fail "Expected worker to be in state #{state} but current state is #{self.state}." unless self.state == state
end

#id ⇒ Object 



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# File 'lib/workhorse/worker.rb', line 65

def id
  @id ||= "#{Socket.gethostname}.#{Process.pid}.#{SecureRandom.hex(3)}"
end

#idle ⇒ Object 



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# File 'lib/workhorse/worker.rb', line 112

def idle
  @pool.idle
end

#log(text, level = :info) ⇒ Object 



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# File 'lib/workhorse/worker.rb', line 57

def log(text, level = :info)
  text = "[Job worker #{id}] #{text}"
  puts text unless @quiet
  return unless logger
  fail "Log level #{level} is not available. Available are #{LOG_LEVELS.inspect}." unless LOG_LEVELS.include?(level)
  logger.send(level, text.strip)
end

#perform(db_job) ⇒ Object 



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# File 'lib/workhorse/worker.rb', line 116

def perform(db_job)
  mutex.synchronize do
    assert_state! :running
    log "Posting job #{db_job.id} to thread pool"

    @pool.post do
      begin
        Workhorse::Performer.new(db_job, self).perform
      rescue => e
        log %(#{e.message}\n#{e.backtrace.join("\n")}), :error
      end
    end
  end
end

#shutdown ⇒ Object

Shuts down worker and DB poller. Jobs currently beeing processed are properly finished before this method returns. Subsequent calls to this method are ignored.



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# File 'lib/workhorse/worker.rb', line 90

def shutdown
  mutex.synchronize do
    return if @state == :shutdown
    assert_state! :running
    log 'Shutting down'
    @state = :shutdown

    @poller.shutdown
    @pool.shutdown
    log 'Shut down'
  end
end

#start ⇒ Object

Starts the worker. This call is not blocking - call #wait for this purpose.



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# File 'lib/workhorse/worker.rb', line 71

def start
  mutex.synchronize do
    assert_state! :initialized
    log 'Starting up'
    @state = :running
    @poller.start
    log 'Started up'

    trap_termination if @auto_terminate
  end
end

#wait ⇒ Object

Waits until the worker is shut down. This only happens if shutdown gets called - either by another thread or by enabling ‘auto_terminate` and receiving a respective signal. Use this method to let worker run undefinitely.



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# File 'lib/workhorse/worker.rb', line 107

def wait
  assert_state! :running
  @poller.wait
end