Class: Tupelo::Client::Worker

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

Direct Known Subclasses

Archiver::Worker, PersistentArchiver::Worker

Defined Under Namespace

Classes: Operation, Subspace

Constant Summary collapse

GET_TUPLESPACE = 
"get tuplespace"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(client) ⇒ Worker

Returns a new instance of Worker.



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# File 'lib/tupelo/client/worker.rb', line 68

def initialize client
  @client = client
  @seq = nil
  @arc = nil
  @log = client.log

  @client_id = nil
  @global_tick = nil
  @start_tick = nil
  @local_tick = 0
  @delta = 0

  @cmd_queue = client.make_queue
  @tuplespace = nil
  @message_class = client.message_class
  @blobber = nil

  @read_waiters = []
  @prep_waiters = []
  @trans_waiters = []
  @notify_waiters = []
  @stopping = false
  @subspaces = []
end

Instance Attribute Details

#arc ⇒ Object (readonly)

Returns the value of attribute arc.



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# File 'lib/tupelo/client/worker.rb', line 11

def arc
  @arc
end

#blobber ⇒ Object (readonly)

Returns the value of attribute blobber.



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# File 'lib/tupelo/client/worker.rb', line 22

def blobber
  @blobber
end

#client ⇒ Object (readonly)

Returns the value of attribute client.



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# File 'lib/tupelo/client/worker.rb', line 9

def client
  @client
end

#client_id ⇒ Object (readonly)

Returns the value of attribute client_id.



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# File 'lib/tupelo/client/worker.rb', line 12

def client_id
  @client_id
end

#cmd_queue ⇒ Object (readonly)

Returns the value of attribute cmd_queue.



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# File 'lib/tupelo/client/worker.rb', line 19

def cmd_queue
  @cmd_queue
end

#delta ⇒ Object (readonly)

Returns the value of attribute delta.



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# File 'lib/tupelo/client/worker.rb', line 16

def delta
  @delta
end

#global_tick ⇒ Object (readonly)

Returns the value of attribute global_tick.



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# File 'lib/tupelo/client/worker.rb', line 14

def global_tick
  @global_tick
end

#local_tick ⇒ Object (readonly)

Returns the value of attribute local_tick.



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# File 'lib/tupelo/client/worker.rb', line 13

def local_tick
  @local_tick
end

#message_class ⇒ Object (readonly)

Returns the value of attribute message_class.



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# File 'lib/tupelo/client/worker.rb', line 21

def message_class
  @message_class
end

#msg_reader_thread ⇒ Object (readonly)

Returns the value of attribute msg_reader_thread.



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# File 'lib/tupelo/client/worker.rb', line 17

def msg_reader_thread
  @msg_reader_thread
end

#notify_waiters ⇒ Object (readonly)

Returns the value of attribute notify_waiters.



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# File 'lib/tupelo/client/worker.rb', line 26

def notify_waiters
  @notify_waiters
end

#prep_waiters ⇒ Object (readonly)

Returns the value of attribute prep_waiters.



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# File 'lib/tupelo/client/worker.rb', line 24

def prep_waiters
  @prep_waiters
end

#read_waiters ⇒ Object (readonly)

Returns the value of attribute read_waiters.



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# File 'lib/tupelo/client/worker.rb', line 23

def read_waiters
  @read_waiters
end

#seq ⇒ Object (readonly)

Returns the value of attribute seq.



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# File 'lib/tupelo/client/worker.rb', line 10

def seq
  @seq
end

#start_tick ⇒ Object (readonly)

Returns the value of attribute start_tick.



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# File 'lib/tupelo/client/worker.rb', line 15

def start_tick
  @start_tick
end

#subspaces ⇒ Object (readonly)

Returns the value of attribute subspaces.



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# File 'lib/tupelo/client/worker.rb', line 27

def subspaces
  @subspaces
end

#trans_waiters ⇒ Object (readonly)

Returns the value of attribute trans_waiters.



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# File 'lib/tupelo/client/worker.rb', line 25

def trans_waiters
  @trans_waiters
end

#tuplespace ⇒ Object (readonly)

Returns the value of attribute tuplespace.



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# File 'lib/tupelo/client/worker.rb', line 20

def tuplespace
  @tuplespace
end

#worker_thread ⇒ Object (readonly)

Returns the value of attribute worker_thread.



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# File 'lib/tupelo/client/worker.rb', line 18

def worker_thread
  @worker_thread
end

Instance Method Details

#<<(cmd) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 162

def << cmd
  cmd_queue << cmd
end

#at(time, &action) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 155

def at time, &action
  @atdo ||= AtDo.new
  @atdo.at time do
    cmd_queue << action
  end
end

#collect_tags(tuple) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 537

def collect_tags tuple
  subspaces.select {|subspace| subspace === tuple}.map(&:tag)
end

#handle_client_request(req) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 451

def handle_client_request req
  log.debug {"client requested #{req.inspect}"}

  case req
  when message_class
    raise "only seq can send messages"

  when Waiter
    handle_waiter req

  when Matcher
    handle_matcher req

  when Unwaiter
    handle_unwaiter req

  when Transaction
    handle_transaction req

  when NotifyWaiter
    notify_waiters.delete req or notify_waiters.push req

  when Proc
    req.call

  else
    raise "unknown request from client: #{req}"
  end
rescue => ex
  log.error "error while handling #{req.inspect}: #{ex}"
  ## Raise an error in the waiter? Need to generalize the mechanism in
  ## Transaction.
end

#handle_matcher(matcher) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 521

def handle_matcher matcher
  if matcher.all
    tuplespace.each {|tuple| matcher.gloms tuple}
      ## maybe should have tuplespace.find_all_matches_for ...
      ## in case there is an optimization
    matcher.fails
  else
    tuple = tuplespace.find_match_for matcher.template
    if tuple
      matcher.peek tuple
    else
      matcher.fails
    end
  end
end

#handle_message(msg) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 285

def handle_message msg
  log.debug {"seq sent #{msg.inspect}"}

  if msg.control?
    client.handle_ack msg
    op_type, tags = msg.control_op
    case op_type
    when Funl::SUBSCRIBE_ALL
      update_to_tick tick: msg.global_tick, all: true
    when Funl::SUBSCRIBE
      update_to_tick tick: msg.global_tick,
        tags: (client.subscribed_tags | tags)
    when Funl::UNSUBSCRIBE_ALL
      update_to_tick tick: msg.global_tick, all: false
    when Funl::UNSUBSCRIBE
      update_to_tick tick: msg.global_tick,
        tags: (client.subscribed_tags - tags)
    else
      raise "Unimplemented: #{msg.inspect}"
    end
    return
  end

  if !global_tick
    raise "bug: should have subscribed and received ack before data"
  end

  if msg.global_tick < global_tick + 1
    log.debug {"discarding redundant message at #{msg.global_tick}"}
      # due to archiver timing, for example
    return
  end

  @global_tick = msg.global_tick
  @delta = 0

  record_history msg
  op = msg.blob ? Operation.new(*blobber.load(msg.blob)) : Operation::NOOP
    ## op.freeze_deeply
  log.debug {"applying #{op} from client #{msg.client_id}"}

  notify_waiters.each do |waiter|
    waiter << [:attempt, msg.global_tick, msg.client_id, op, msg.tags]
  end

  take_tuples = tuplespace.find_distinct_matches_for(op.takes)
  read_tuples = op.reads.map {|t| tuplespace.find_match_for(t)}
  succeeded = take_tuples.all? && read_tuples.all?

  if client.subscribed_all
    write_tuples = op.writes
  else
    write_tuples = op.writes.select do |tuple|
      subspaces.any? {|subspace| subspace === tuple}
    end
  end
  ## This is duplicated effort: the sender has already done this.
  ## So maybe the result could be transmitted in the msg protocol?

  if succeeded
    log.debug {"inserting #{op.writes}; deleting #{take_tuples}"}
    tuplespace.transaction inserts: write_tuples, deletes: take_tuples,
      tick: @global_tick
  
    op.writes.each do |tuple|
      sniff_meta_tuple tuple
    end

    take_tuples.each do |tuple|
      if is_meta_tuple? tuple
        ## do some error checking
        subspaces.delete_if {|sp| sp.tag == tuple["tag"]}
      end
    end
  end

  notify_waiters.each do |waiter|
    waiter << [
      succeeded ?  :success : :failure,
      msg.global_tick, msg.client_id, op, msg.tags]
  end

  trans = nil
  if msg.client_id == client_id
    trans = trans_waiters.first
    unless trans and trans.local_tick == msg.local_tick
      log.error "transaction #{op} out of order in sequence " +
        trans_waiters.inspect
      ## exit? wait?
    end
    trans_waiters.shift
    log.debug {"operation belongs to this client: #{trans.inspect}"}
  end

  if not take_tuples.empty?
    if succeeded
      take_tuples.each do |tuple|
        prep_waiters.keep_if do |waiter|
          waiter.unprepare tuple
          ## optimization: track number of instances of tuple, to avoid
          ## false positive in #unprepare
        end
      end

      log.debug {trans ? "taking #{take_tuples}" :
        "client #{msg.client_id} takes #{take_tuples}"}

    else
      log.debug {
        missing = []
        take_tuples.each_with_index do |tuple, i|
          missing << op.takes[i] unless tuple
        end
        trans ? "failed to take #{missing}" :
        "client #{msg.client_id} failed to take #{missing}"}
    end
  end

  if succeeded
    op.writes.each do |tuple|
      read_waiters.delete_if do |waiter|
        waiter.gloms tuple
      end
    end

    op.pulses.each do |tuple|
      log.debug {"pulsing #{tuple}"}
      read_waiters.delete_if do |waiter|
        waiter.gloms tuple
      end
    end

    op.writes.each do |tuple|
      prep_waiters.keep_if do |waiter|
        waiter.prepare tuple
      end
    end
  end

  if trans
    trans_waiters.delete trans

    if succeeded
      trans.done msg.global_tick, take_tuples # note: tuples not frozen
    else
      trans.fail (op.takes - take_tuples) + (op.reads - read_tuples)
    end
  end
end

#handle_one_request ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 201

def handle_one_request
  case cmd = cmd_queue.pop
  when :stop
    @stopping = true
    if trans_waiters.empty?
      throw :done
    else
      log.info {"stopping; waiting for #{trans_waiters}"}
    end
  when message_class
    handle_message cmd
    if @stopping
      if trans_waiters.empty?
        throw :done
      else
        log.info {"stopping; waiting for #{trans_waiters}"}
      end
    end
  else
    handle_client_request cmd unless @stopping
  end
end

#handle_seq_closed ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 175

def handle_seq_closed
  ## what to do here in general?
  ## for each waiter, push :stop into queue ?
end

#handle_transaction(t) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 485

def handle_transaction t
  case
  when t.open?
    t.prepare
    prep_waiters << t unless prep_waiters.include? t
  when t.closed?
    t.submit
    prep_waiters.delete t
  when t.failed?
  else
    log.warn "not open or closed or failed: #{t.inspect}"
  end
rescue => ex
  log.error "error while handling #{t.inspect}: #{ex}"
  t.error ex
end

#handle_unwaiter(unwaiter) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 502

def handle_unwaiter unwaiter
  waiter = unwaiter.waiter
  read_waiters.delete waiter or prep_waiters.delete waiter
end

#handle_waiter(waiter) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 507

def handle_waiter waiter
  if waiter.once
    tuple = tuplespace.find_match_for waiter.template
    if tuple
      waiter.peek tuple
    else
      read_waiters << waiter
    end
  else
    tuplespace.each {|tuple| waiter.gloms tuple}
    read_waiters << waiter
  end
end

#in_thread? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tupelo/client/worker.rb', line 129

def in_thread?
  Thread.current == worker_thread
end

#is_meta_tuple?(tuple) ⇒ Boolean

Returns true if tuple is subspace metadata.

Returns:

  • (Boolean) 


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# File 'lib/tupelo/client/worker.rb', line 436

def is_meta_tuple? tuple
  tuple.kind_of? Hash and tuple.key? TUPELO_META_KEY and
    tuple[TUPELO_META_KEY] == "subspace"
end

#log(*args) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 93

def log *args
  if args.empty?
    @log
  else
    @log.unknown *args
  end
end

#make_template(obj) ⇒ Object

Used by api to protect worker’s copy from client changes. Also, for serialization types that don’t represent symbols, this converts a template so that it works correctly regardless. So keyword args are very natural: read(k1: val, k2: val)



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# File 'lib/tupelo/client/worker.rb', line 624

def make_template obj
  return obj unless obj.respond_to? :to_ary or obj.respond_to? :to_hash
  spec = Marshal.load(Marshal.dump(obj))
  rot_for(spec).optimize!
end

#observe_started_client ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 133

def observe_started_client
  @client_id = client.client_id
  @blobber = client.blobber
  @seq = client.seq
  @arc = client.arc
  @start_tick = client.start_tick
end

#pot_for(spec) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 634

def pot_for spec
  PortableObjectTemplate.new(spec, proc {|k| blobber.load(blobber.dump(k))})
end

#read_messages_from_seq ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 180

def read_messages_from_seq
  seq.each do |msg|
    self << msg
  end
end

#record_history(msg) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 449

def record_history msg; end

#rot_for(spec) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 630

def rot_for spec
  RubyObjectTemplate.new(spec, proc {|k| blobber.load(blobber.dump(k))})
end

#run_msg_reader_thread ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 166

def run_msg_reader_thread
  read_messages_from_seq
  log.warn "connection to seq closed"
  handle_seq_closed
rescue => ex
  log.error ex
  raise
end

#run_request_loop ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 193

def run_request_loop
  catch :done do
    loop do
      handle_one_request
    end
  end
end

#run_worker_thread ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 186

def run_worker_thread
  run_request_loop
rescue => ex
  log.error ex
  raise
end

#send_transaction(transaction) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 541

def send_transaction transaction
  msg = message_class.new
  msg.client_id = client_id
  msg.local_tick = local_tick + 1
  msg.global_tick = global_tick
  msg.delta = delta + 1 # pipelined write/take
  msg.tags = transaction.tags

  writes = transaction.writes
  pulses = transaction.pulses
  takes = transaction.take_tuples_for_remote.compact
  reads = transaction.read_tuples_for_remote.compact
  
  unless msg.tags
    tags = nil
    [takes, reads].compact.flatten(1).each do |tuple|
      if tags
        tuple_tags = collect_tags(tuple)
        unless tuple_tags == tags
          d = (tuple_tags - tags) + (tags - tuple_tags)
          raise TransactionSubspaceError,
            "tuples crossing subspaces: #{d} in #{transaction.inspect}"
        end
      else
        tags = collect_tags(tuple)
      end
    end
    tags ||= []

    write_tags = []
    [writes, pulses].compact.flatten(1).each do |tuple|
      write_tags |= collect_tags(tuple)
    end

    if takes.empty? and reads.empty?
      tags = write_tags
    else
      d = write_tags - tags
      unless d.empty?
        raise TransactionSubspaceError,
          "writes crossing subspaces: #{d} in #{transaction.inspect}"
      end
    end

    will_get_this_msg = client.subscribed_all ||
      tags.any? {|tag| client.subscribed_tags.include? tag} ## optimize

    unless will_get_this_msg
      tags << true # reflect
    end

    if not tags.empty?
      msg.tags = tags
      log.debug {"tagged transaction: #{tags}"}
    end
  end

  begin
    msg.blob = blobber.dump([writes, pulses, takes, reads])
    ## optimization: use bitfields to identify which ops are present
    ## (instead of nils), in one int
  rescue => ex
    raise ex, "cannot serialize #{transaction.inspect}: #{ex}"
  end

  begin
    seq << msg
  rescue => ex
    raise ex, "cannot send request for #{transaction.inspect}: #{ex}"
  end

  @local_tick += 1
  @delta += 1

  trans_waiters << transaction

  return msg.local_tick
end

#sniff_meta_tuple(tuple) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 441

def sniff_meta_tuple tuple
  if is_meta_tuple? tuple
    ## do some error checking
    ## what if subspace already exists?
    subspaces << Subspace.new(tuple, self)
  end
end

#start ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 114

def start
  return if @worker_thread

  log.info "worker starting"
  observe_started_client

  @msg_reader_thread = Thread.new do
    run_msg_reader_thread
  end

  @worker_thread = Thread.new do
    run_worker_thread
  end
end

#stop ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 141

def stop
  cmd_queue << :stop
  worker_thread.join if worker_thread ## join(limit)?
  msg_reader_thread.kill if msg_reader_thread
  @atdo.stop if @atdo
end

#stop! ⇒ Object

stop without any remote handshaking



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# File 'lib/tupelo/client/worker.rb', line 149

def stop!
  @msg_reader_thread.kill if msg_reader_thread
  @worker_thread.kill if worker_thread
  @atdo.stop if @atdo
end

#update_to_tick(tick: nil, tags: nil, all: false) ⇒ Object 



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# File 'lib/tupelo/client/worker.rb', line 224

def update_to_tick tick: nil, tags: nil, all: false
  # At this point we know that the seq messages now accumulating in
  # cmd_queue are tick+1, tick+2, ....
  # (or a subset of this sequence if not subscribed_all).
  # Some of these might get discarded later if archiver is more current.
  log.debug {"update_to_tick #{tick}"}

  unless arc
    if tick > 0
      log.warn "no archiver provided; assuming pubsub mode; " +
        "some client ops (take and local read) will not work"
    end
    @global_tick = tick
    log.info "global_tick = #{global_tick}"
    return
  end

  log.info "requesting tuplespace from arc"
  subscription_delta = {
    request_all: all,
    request_tags: tags,
    subscribed_all: client.subscribed_all,
    subscribed_tags: client.subscribed_tags
  }
  arc << [GET_TUPLESPACE, subscription_delta, tick]

  begin
    tuplespace.clear
      ## In some cases, we can keep some of it, but the current
      ## archiver is not smart enough to send exactly the delta.
      ## Also, might need to abort some current transactions.

    arc_tick = arc.read[0]
    log.info "arc says global_tick = #{arc_tick}"

    done = false
    count = 0
    arc.each do |tuple|
      if tuple.nil?
        done = true
      else
        raise "bad object stream from archiver" if done
        sniff_meta_tuple tuple
        tuplespace.insert tuple
        count += 1
      end
    end
    unless done
      raise "did not get all of tuplespace from archiver" ## roll back?
    end

    log.info "received tuplespace from arc: #{count} tuples"

    @global_tick = arc_tick
    log.info "global_tick = #{global_tick}"
  end

ensure
  arc.close if arc and not arc.closed?
end