text: import os
  import random
  from time import sleep
  
  import pytest
  from tlz import partition_all, first
  from tornado import gen
  
  from dask import delayed
  from distributed import Client, Nanny, wait
  from distributed.comm import CommClosedError
  from distributed.client import wait
  from distributed.metrics import time
  from distributed.utils import sync, ignoring, CancelledError
  from distributed.utils_test import (
      gen_cluster,
      cluster,
      inc,
      div,
      slowinc,
      slowadd,
      captured_logger,
  )
  from distributed.utils_test import loop  # noqa: F401
  
  
  def test_submit_after_failed_worker_sync(loop):
      with cluster(active_rpc_timeout=10, disconnect_timeout=10) as (s, [a, b]):
          with Client(s["address"], loop=loop) as c:
              L = c.map(inc, range(10))
              wait(L)
              a["proc"]().terminate()
              total = c.submit(sum, L)
              assert total.result() == sum(map(inc, range(10)))
  
  
  @gen_cluster(client=True, timeout=60, active_rpc_timeout=10)
  def test_submit_after_failed_worker_async(c, s, a, b):
      n = yield Nanny(s.address, nthreads=2, loop=s.loop)
      while len(s.workers) < 3:
          yield gen.sleep(0.1)
  
      L = c.map(inc, range(10))
      yield wait(L)
  
      s.loop.add_callback(n.kill)
      total = c.submit(sum, L)
      result = yield total
      assert result == sum(map(inc, range(10)))
  
      yield n.close()
  
  
  @gen_cluster(client=True, timeout=60)
  def test_submit_after_failed_worker(c, s, a, b):
      L = c.map(inc, range(10))
      yield wait(L)
      yield a.close()
  
      total = c.submit(sum, L)
      result = yield total
      assert result == sum(map(inc, range(10)))
  
  
  def test_gather_after_failed_worker(loop):
      with cluster(active_rpc_timeout=10, disconnect_timeout=10) as (s, [a, b]):
          with Client(s["address"], loop=loop) as c:
              L = c.map(inc, range(10))
              wait(L)
              a["proc"]().terminate()
              result = c.gather(L)
              assert result == list(map(inc, range(10)))
  
  
  @gen_cluster(
      client=True,
      Worker=Nanny,
      nthreads=[("127.0.0.1", 1)] * 4,
      config={"distributed.comm.timeouts.connect": "1s"},
  )
  def test_gather_then_submit_after_failed_workers(c, s, w, x, y, z):
      L = c.map(inc, range(20))
      yield wait(L)
  
      w.process.process._process.terminate()
      total = c.submit(sum, L)
  
      for i in range(3):
          yield wait(total)
          addr = first(s.tasks[total.key].who_has).address
          for worker in [x, y, z]:
              if worker.worker_address == addr:
                  worker.process.process._process.terminate()
                  break
  
          result = yield c.gather([total])
          assert result == [sum(map(inc, range(20)))]
  
  
  @gen_cluster(Worker=Nanny, timeout=60, client=True)
  def test_failed_worker_without_warning(c, s, a, b):
      L = c.map(inc, range(10))
      yield wait(L)
  
      original_pid = a.pid
      with ignoring(CommClosedError):
          yield c._run(os._exit, 1, workers=[a.worker_address])
      start = time()
      while a.pid == original_pid:
          yield gen.sleep(0.01)
          assert time() - start < 10
  
      yield gen.sleep(0.5)
  
      start = time()
      while len(s.nthreads) < 2:
          yield gen.sleep(0.01)
          assert time() - start < 10
  
      yield wait(L)
  
      L2 = c.map(inc, range(10, 20))
      yield wait(L2)
      assert all(len(keys) > 0 for keys in s.has_what.values())
      nthreads2 = dict(s.nthreads)
  
      yield c.restart()
  
      L = c.map(inc, range(10))
      yield wait(L)
      assert all(len(keys) > 0 for keys in s.has_what.values())
  
      assert not (set(nthreads2) & set(s.nthreads))  # no overlap
  
  
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  def test_restart(c, s, a, b):
      assert s.nthreads == {a.worker_address: 1, b.worker_address: 2}
  
      x = c.submit(inc, 1)
      y = c.submit(inc, x)
      z = c.submit(div, 1, 0)
      yield y
  
      assert set(s.who_has) == {x.key, y.key}
  
      f = yield c.restart()
      assert f is c
  
      assert len(s.workers) == 2
      assert not any(ws.occupancy for ws in s.workers.values())
  
      assert not s.who_has
  
      assert x.cancelled()
      assert y.cancelled()
      assert z.cancelled()
      assert z.key not in s.exceptions
  
      assert not s.who_wants
      assert not any(cs.wants_what for cs in s.clients.values())
  
  
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  def test_restart_cleared(c, s, a, b):
      x = 2 * delayed(1) + 1
      f = c.compute(x)
      yield wait([f])
  
      yield c.restart()
  
      for coll in [s.tasks, s.unrunnable]:
          assert not coll
  
  
  def test_restart_sync_no_center(loop):
      with cluster(nanny=True) as (s, [a, b]):
          with Client(s["address"], loop=loop) as c:
              x = c.submit(inc, 1)
              c.restart()
              assert x.cancelled()
              y = c.submit(inc, 2)
              assert y.result() == 3
              assert len(c.nthreads()) == 2
  
  
  def test_restart_sync(loop):
      with cluster(nanny=True) as (s, [a, b]):
          with Client(s["address"], loop=loop) as c:
              x = c.submit(div, 1, 2)
              x.result()
  
              assert sync(loop, c.scheduler.who_has)
              c.restart()
              assert not sync(loop, c.scheduler.who_has)
              assert x.cancelled()
              assert len(c.nthreads()) == 2
  
              with pytest.raises(CancelledError):
                  x.result()
  
              y = c.submit(div, 1, 3)
              assert y.result() == 1 / 3
  
  
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  def test_restart_fast(c, s, a, b):
      L = c.map(sleep, range(10))
  
      start = time()
      yield c.restart()
      assert time() - start < 10
      assert len(s.nthreads) == 2
  
      assert all(x.status == "cancelled" for x in L)
  
      x = c.submit(inc, 1)
      result = yield x
      assert result == 2
  
  
  def test_worker_doesnt_await_task_completion(loop):
      with cluster(nanny=True, nworkers=1) as (s, [w]):
          with Client(s["address"], loop=loop) as c:
              future = c.submit(sleep, 100)
              sleep(0.1)
              start = time()
              c.restart()
              stop = time()
              assert stop - start < 5
  
  
  def test_restart_fast_sync(loop):
      with cluster(nanny=True) as (s, [a, b]):
          with Client(s["address"], loop=loop) as c:
              L = c.map(sleep, range(10))
  
              start = time()
              c.restart()
              assert time() - start < 10
              assert len(c.nthreads()) == 2
  
              assert all(x.status == "cancelled" for x in L)
  
              x = c.submit(inc, 1)
              assert x.result() == 2
  
  
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  def test_fast_kill(c, s, a, b):
      L = c.map(sleep, range(10))
  
      start = time()
      yield c.restart()
      assert time() - start < 10
  
      assert all(x.status == "cancelled" for x in L)
  
      x = c.submit(inc, 1)
      result = yield x
      assert result == 2
  
  
  @gen_cluster(Worker=Nanny, timeout=60)
  def test_multiple_clients_restart(s, a, b):
      c1 = yield Client(s.address, asynchronous=True)
      c2 = yield Client(s.address, asynchronous=True)
  
      x = c1.submit(inc, 1)
      y = c2.submit(inc, 2)
      xx = yield x
      yy = yield y
      assert xx == 2
      assert yy == 3
  
      yield c1.restart()
  
      assert x.cancelled()
      start = time()
      while not y.cancelled():
          yield gen.sleep(0.01)
          assert time() < start + 5
  
      yield c1.close()
      yield c2.close()
  
  
  @gen_cluster(Worker=Nanny, timeout=60)
  def test_restart_scheduler(s, a, b):
      import gc
  
      gc.collect()
      addrs = (a.worker_address, b.worker_address)
      yield s.restart()
      assert len(s.nthreads) == 2
      addrs2 = (a.worker_address, b.worker_address)
  
      assert addrs != addrs2
  
  
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  def test_forgotten_futures_dont_clean_up_new_futures(c, s, a, b):
      x = c.submit(inc, 1)
      yield c.restart()
      y = c.submit(inc, 1)
      del x
      import gc
  
      gc.collect()
      yield gen.sleep(0.1)
      yield y
  
  
  @gen_cluster(client=True, timeout=60, active_rpc_timeout=10)
  def test_broken_worker_during_computation(c, s, a, b):
      s.allowed_failures = 100
      n = yield Nanny(s.address, nthreads=2, loop=s.loop)
  
      start = time()
      while len(s.nthreads) < 3:
          yield gen.sleep(0.01)
          assert time() < start + 5
  
      N = 256
      expected_result = N * (N + 1) // 2
      i = 0
      L = c.map(inc, range(N), key=["inc-%d-%d" % (i, j) for j in range(N)])
      while len(L) > 1:
          i += 1
          L = c.map(
              slowadd,
              *zip(*partition_all(2, L)),
              key=["add-%d-%d" % (i, j) for j in range(len(L) // 2)]
          )
  
      yield gen.sleep(random.random() / 20)
      with ignoring(CommClosedError):  # comm will be closed abrupty
          yield c._run(os._exit, 1, workers=[n.worker_address])
  
      yield gen.sleep(random.random() / 20)
      while len(s.workers) < 3:
          yield gen.sleep(0.01)
  
      with ignoring(
          CommClosedError, EnvironmentError
      ):  # perhaps new worker can't be contacted yet
          yield c._run(os._exit, 1, workers=[n.worker_address])
  
      [result] = yield c.gather(L)
      assert isinstance(result, int)
      assert result == expected_result
  
      yield n.close()
  
  
  @gen_cluster(client=True, Worker=Nanny, timeout=60)
  def test_restart_during_computation(c, s, a, b):
      xs = [delayed(slowinc)(i, delay=0.01) for i in range(50)]
      ys = [delayed(slowinc)(i, delay=0.01) for i in xs]
      zs = [delayed(slowadd)(x, y, delay=0.01) for x, y in zip(xs, ys)]
      total = delayed(sum)(zs)
      result = c.compute(total)
  
      yield gen.sleep(0.5)
      assert s.rprocessing
      yield c.restart()
      assert not s.rprocessing
  
      assert len(s.nthreads) == 2
      assert not s.tasks
  
  
  @gen_cluster(client=True, timeout=60)
  def test_worker_who_has_clears_after_failed_connection(c, s, a, b):
      n = yield Nanny(s.address, nthreads=2, loop=s.loop)
  
      start = time()
      while len(s.nthreads) < 3:
          yield gen.sleep(0.01)
          assert time() < start + 5
  
      futures = c.map(slowinc, range(20), delay=0.01, key=["f%d" % i for i in range(20)])
      yield wait(futures)
  
      result = yield c.submit(sum, futures, workers=a.address)
      for dep in set(a.dep_state) - set(a.task_state):
          a.release_dep(dep, report=True)
  
      n_worker_address = n.worker_address
      with ignoring(CommClosedError):
          yield c._run(os._exit, 1, workers=[n_worker_address])
  
      while len(s.workers) > 2:
          yield gen.sleep(0.01)
  
      total = c.submit(sum, futures, workers=a.address)
      yield total
  
      assert not a.has_what.get(n_worker_address)
      assert not any(n_worker_address in s for s in a.who_has.values())
  
      yield n.close()
  
  
  @pytest.mark.slow
  @gen_cluster(client=True, timeout=60, Worker=Nanny, nthreads=[("127.0.0.1", 1)])
  def test_restart_timeout_on_long_running_task(c, s, a):
      with captured_logger("distributed.scheduler") as sio:
          future = c.submit(sleep, 3600)
          yield gen.sleep(0.1)
          yield c.restart(timeout=20)
  
      text = sio.getvalue()
      assert "timeout" not in text.lower()
  
  
  @gen_cluster(client=True, scheduler_kwargs={"worker_ttl": "500ms"})
  def test_worker_time_to_live(c, s, a, b):
      assert set(s.workers) == {a.address, b.address}
      a.periodic_callbacks["heartbeat"].stop()
      yield gen.sleep(0.010)
      assert set(s.workers) == {a.address, b.address}
  
      start = time()
      while set(s.workers) == {a.address, b.address}:
          yield gen.sleep(0.050)
          assert time() < start + 2
  
      set(s.workers) == {b.address}
  