text: import asyncio
  import os
  import random
  from contextlib import suppress
  from time import sleep
  from unittest import mock
  
  import pytest
  from tlz import first, partition_all
  
  from dask import delayed
  
  from distributed import Client, Nanny, wait
  from distributed.comm import CommClosedError
  from distributed.compatibility import MACOS
  from distributed.metrics import time
  from distributed.scheduler import COMPILED
  from distributed.utils import CancelledError, sync
  from distributed.utils_test import (
      captured_logger,
      cluster,
      div,
      gen_cluster,
      inc,
      slowadd,
      slowinc,
  )
  from distributed.worker_state_machine import TaskState
  
  pytestmark = pytest.mark.ci1
  
  
  @pytest.mark.slow()
  def test_submit_after_failed_worker_sync(loop):
      with cluster() 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)))
  
  
  @pytest.mark.slow()
  @gen_cluster(client=True, timeout=60, active_rpc_timeout=10)
  async def test_submit_after_failed_worker_async(c, s, a, b):
      n = await Nanny(s.address, nthreads=2, loop=s.loop)
      while len(s.workers) < 3:
          await asyncio.sleep(0.1)
  
      L = c.map(inc, range(10))
      await wait(L)
  
      s.loop.add_callback(n.kill)
      total = c.submit(sum, L)
      result = await total
      assert result == sum(map(inc, range(10)))
  
      await n.close()
  
  
  @gen_cluster(client=True, timeout=60)
  async def test_submit_after_failed_worker(c, s, a, b):
      L = c.map(inc, range(10))
      await wait(L)
      await a.close()
  
      total = c.submit(sum, L)
      result = await total
      assert result == sum(map(inc, range(10)))
  
  
  @pytest.mark.slow
  def test_gather_after_failed_worker(loop):
      with cluster() 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)))
  
  
  @pytest.mark.slow
  @gen_cluster(client=True, Worker=Nanny, nthreads=[("127.0.0.1", 1)] * 4, timeout=60)
  async def test_gather_then_submit_after_failed_workers(c, s, w, x, y, z):
      L = c.map(inc, range(20))
      await wait(L)
  
      w.process.process._process.terminate()
      total = c.submit(sum, L)
  
      for _ in range(3):
          await 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 = await c.gather([total])
          assert result == [sum(map(inc, range(20)))]
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  async 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)
      await y
  
      assert set(s.who_has) == {x.key, y.key}
  
      f = await 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())
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  async def test_restart_cleared(c, s, a, b):
      x = 2 * delayed(1) + 1
      f = c.compute(x)
      await wait([f])
  
      await c.restart()
  
      for coll in [s.tasks, s.unrunnable]:
          assert not coll
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  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
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  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
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  async def test_restart_fast(c, s, a, b):
      L = c.map(sleep, range(10))
  
      start = time()
      await 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 = await x
      assert result == 2
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  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
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  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
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  async def test_fast_kill(c, s, a, b):
      L = c.map(sleep, range(10))
  
      start = time()
      await c.restart()
      assert time() - start < 10
  
      assert all(x.status == "cancelled" for x in L)
  
      x = c.submit(inc, 1)
      result = await x
      assert result == 2
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  @gen_cluster(Worker=Nanny, timeout=60)
  async def test_multiple_clients_restart(s, a, b):
      c1 = await Client(s.address, asynchronous=True)
      c2 = await Client(s.address, asynchronous=True)
  
      x = c1.submit(inc, 1)
      y = c2.submit(inc, 2)
      xx = await x
      yy = await y
      assert xx == 2
      assert yy == 3
  
      await c1.restart()
  
      assert x.cancelled()
      start = time()
      while not y.cancelled():
          await asyncio.sleep(0.01)
          assert time() < start + 5
  
      await c1.close()
      await c2.close()
  
  
  @gen_cluster(Worker=Nanny, timeout=60)
  async def test_restart_scheduler(s, a, b):
      assert len(s.nthreads) == 2
      pids = (a.pid, b.pid)
      assert pids[0]
      assert pids[1]
  
      await s.restart()
  
      assert len(s.nthreads) == 2
      pids2 = (a.pid, b.pid)
      assert pids2[0]
      assert pids2[1]
      assert pids != pids2
  
  
  @gen_cluster(Worker=Nanny, client=True, timeout=60)
  async def test_forgotten_futures_dont_clean_up_new_futures(c, s, a, b):
      x = c.submit(inc, 1)
      await c.restart()
      y = c.submit(inc, 1)
      del x
      import gc
  
      gc.collect()
      await asyncio.sleep(0.1)
      await y
  
  
  @pytest.mark.slow
  @pytest.mark.flaky(condition=MACOS, reruns=10, reruns_delay=5)
  @gen_cluster(client=True, timeout=60, active_rpc_timeout=10)
  async def test_broken_worker_during_computation(c, s, a, b):
      s.allowed_failures = 100
      n = await Nanny(s.address, nthreads=2, loop=s.loop)
  
      start = time()
      while len(s.nthreads) < 3:
          await asyncio.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)],
          )
  
      await asyncio.sleep(random.random() / 20)
      with suppress(CommClosedError):  # comm will be closed abrupty
          await c._run(os._exit, 1, workers=[n.worker_address])
  
      await asyncio.sleep(random.random() / 20)
      while len(s.workers) < 3:
          await asyncio.sleep(0.01)
  
      with suppress(
          CommClosedError, EnvironmentError
      ):  # perhaps new worker can't be contacted yet
          await c._run(os._exit, 1, workers=[n.worker_address])
  
      [result] = await c.gather(L)
      assert isinstance(result, int)
      assert result == expected_result
  
      await n.close()
  
  
  @pytest.mark.skipif(COMPILED, reason="Fails with cythonized scheduler")
  @gen_cluster(client=True, Worker=Nanny, timeout=60)
  async 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)
  
      await asyncio.sleep(0.5)
      assert s.rprocessing
      await c.restart()
      assert not s.rprocessing
  
      assert len(s.nthreads) == 2
      assert not s.tasks
  
  
  class SlowTransmitData:
      def __init__(self, data, delay=0.1):
          self.delay = delay
          self.data = data
  
      def __reduce__(self):
          import time
  
          time.sleep(self.delay)
          return (SlowTransmitData, (self.delay,))
  
      def __sizeof__(self) -> int:
          # Ensure this is offloaded to avoid blocking loop
          import dask
          from dask.utils import parse_bytes
  
          return parse_bytes(dask.config.get("distributed.comm.offload")) + 1
  
  
  @gen_cluster(client=True)
  async def test_worker_who_has_clears_after_failed_connection(c, s, a, b):
      """This test is very sensitive to cluster state consistency. Timeouts often
      indicate subtle deadlocks. Be mindful when marking flaky/repeat/etc."""
      n = await Nanny(s.address, nthreads=2, loop=s.loop)
  
      while len(s.nthreads) < 3:
          await asyncio.sleep(0.01)
  
      def slow_ser(x, delay):
          return SlowTransmitData(x, delay=delay)
  
      n_worker_address = n.worker_address
      futures = c.map(
          slow_ser,
          range(20),
          delay=0.1,
          key=["f%d" % i for i in range(20)],
          workers=[n_worker_address],
          allow_other_workers=True,
      )
  
      def sink(*args):
          pass
  
      await wait(futures)
      result_fut = c.submit(sink, futures, workers=a.address)
  
      with suppress(CommClosedError):
          await c._run(os._exit, 1, workers=[n_worker_address])
  
      while len(s.workers) > 2:
          await asyncio.sleep(0.01)
  
      await result_fut
  
      assert not a.has_what.get(n_worker_address)
      assert not any(n_worker_address in s for ts in a.tasks.values() for s in ts.who_has)
  
      await n.close()
  
  
  @gen_cluster(
      client=True,
      nthreads=[("127.0.0.1", 1), ("127.0.0.1", 2), ("127.0.0.1", 3)],
  )
  async def test_worker_same_host_replicas_missing(c, s, a, b, x):
      # See GH4784
      def mock_address_host(addr):
          # act as if A and X are on the same host
          nonlocal a, b, x
          if addr in [a.address, x.address]:
              return "A"
          else:
              return "B"
  
      with mock.patch("distributed.worker.get_address_host", mock_address_host):
          futures = c.map(
              slowinc,
              range(20),
              delay=0.1,
              key=["f%d" % i for i in range(20)],
              workers=[a.address],
              allow_other_workers=True,
          )
          await wait(futures)
  
          # replicate data to avoid the scheduler retriggering the computation
          # retriggering cleans up the state nicely but doesn't reflect real world
          # scenarios where there may be replicas on the cluster, e.g. they are
          # replicated as a dependency somewhere else
          await c.replicate(futures, n=2, workers=[a.address, b.address])
  
          def sink(*args):
              pass
  
          # Since A and X are mocked to be co-located, X will consistently pick A
          # to fetch data from. It will never succeed since we're removing data
          # artificially, without notifying the scheduler.
          # This can only succeed if B handles the missing data properly by
          # removing A from the known sources of keys
          a.handle_free_keys(keys=["f1"], stimulus_id="Am I evil?")  # Yes, I am!
          result_fut = c.submit(sink, futures, workers=x.address)
  
          await result_fut
  
  
  @pytest.mark.slow
  @gen_cluster(client=True, timeout=60, Worker=Nanny, nthreads=[("127.0.0.1", 1)])
  async def test_restart_timeout_on_long_running_task(c, s, a):
      with captured_logger("distributed.scheduler") as sio:
          future = c.submit(sleep, 3600)
          await asyncio.sleep(0.1)
          await c.restart()
  
      text = sio.getvalue()
      assert "timeout" not in text.lower()
  
  
  @pytest.mark.slow
  @gen_cluster(client=True, scheduler_kwargs={"worker_ttl": "500ms"})
  async def test_worker_time_to_live(c, s, a, b):
      from distributed.scheduler import heartbeat_interval
  
      # worker removal is also controlled by 10 * heartbeat
      assert set(s.workers) == {a.address, b.address}
      interval = 10 * heartbeat_interval(len(s.workers)) + 0.5
  
      a.periodic_callbacks["heartbeat"].stop()
      await asyncio.sleep(0.010)
      assert set(s.workers) == {a.address, b.address}
  
      start = time()
      while set(s.workers) == {a.address, b.address}:
          await asyncio.sleep(interval)
          assert time() < start + interval + 0.1
  
      set(s.workers) == {b.address}
  
  
  @gen_cluster()
  async def test_forget_data_not_supposed_to_have(s, a, b):
      """If a dependency fetch finishes on a worker after the scheduler already released
      everything, the worker might be stuck with a redundant replica which is never
      cleaned up.
      """
      # FIXME: Replace with "blackbox test" which shows an actual example where
      #        this situation is provoked if this is even possible.
      ts = TaskState("key", state="flight")
      a.tasks["key"] = ts
      recommendations = {ts: ("memory", 123)}
      a.transitions(recommendations, stimulus_id="test")
  
      assert a.data
      while a.data:
          await asyncio.sleep(0.001)
  
  
  @gen_cluster(
      client=True,
      nthreads=[("127.0.0.1", 1) for _ in range(3)],
      config={"distributed.comm.timeouts.connect": "1s"},
      Worker=Nanny,
  )
  async def test_failing_worker_with_additional_replicas_on_cluster(c, s, *workers):
      """
      If a worker detects a missing dependency, the scheduler is notified. If no
      other replica is available, the dependency is rescheduled. A reschedule
      typically causes a lot of state to be reset. However, if another replica is
      available, we'll need to ensure that the worker can detect outdated state
      and correct its state.
      """
  
      def slow_transfer(x, delay=0.1):
          return SlowTransmitData(x, delay=delay)
  
      def dummy(*args, **kwargs):
          return
  
      import psutil
  
      proc = psutil.Process(workers[1].pid)
      f1 = c.submit(
          slow_transfer,
          1,
          key="f1",
          workers=[workers[0].worker_address],
      )
      # We'll schedule tasks on two workers, s.t. f1 is replicated. We will
      # suspend one of the workers and kill the origin worker of f1 such that a
      # comm failure causes the worker to handle a missing dependency. It will ask
      # the schedule such that it knows that a replica is available on f2 and
      # reschedules the fetch
      f2 = c.submit(dummy, f1, pure=False, key="f2", workers=[workers[1].worker_address])
      f3 = c.submit(dummy, f1, pure=False, key="f3", workers=[workers[2].worker_address])
  
      await wait(f1)
      proc.suspend()
  
      await wait(f3)
      await workers[0].close()
  
      proc.resume()
      await c.gather([f1, f2, f3])
  