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# Tests for query expiration.

import pytest
from time import sleep

from tests.common.custom_cluster_test_suite import CustomClusterTestSuite

class TestSessionExpiration(CustomClusterTestSuite):
  """Tests query expiration logic"""

  @pytest.mark.execute_serially
  @CustomClusterTestSuite.with_args("--idle_session_timeout=6")
  def test_session_expiration(self, vector):
    impalad = self.cluster.get_any_impalad()
    # setup_class creates an Impala client to <hostname>:21000 after the cluster starts.
    # The client expires at the same time as the client created below. Since we choose the
    # impalad to connect to randomly, the test becomes flaky, as the metric we expect to
    # be incremented by 1 gets incremented by 2 if both clients are connected to the same
    # Impalad.
    self.client.close()
    num_expired = impalad.service.get_metric_value("impala-server.num-sessions-expired")
    client = impalad.service.create_beeswax_client()
    # Sleep for half the expiration time to confirm that the session is not expired early
    # (see IMPALA-838)
    sleep(3)
    assert num_expired == impalad.service.get_metric_value(
      "impala-server.num-sessions-expired")
    # Wait for session expiration. Session timeout was set for 6 seconds, so Impala
    # will poll the session expiry queue every 3 seconds. So, as long as the sleep in
    # ImpalaSever::ExpireSessions() is not late, the session will expire in at most 9
    # seconds. The test has already waited 3 seconds.
    impalad.service.wait_for_metric_value(
      "impala-server.num-sessions-expired", num_expired + 1, 20)