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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#
# Impala tests for Hive Metastore, covering the expected propagation
# of metadata from Hive to Impala or Impala to Hive. Each test
# modifies the metadata via Hive and checks that the modification
# succeeded by querying Impala, or vice versa.

import logging
import requests
import time
import json

LOG = logging.getLogger('event_processor_utils')
LOG.setLevel(level=logging.DEBUG)
class EventProcessorUtils(object):

  DEFAULT_CATALOG_URL = "http://localhost:25020"

  @staticmethod
  def wait_for_event_processing(test_suite, timeout=10):
      """Waits till the event processor has synced to the latest event id from metastore
         or the timeout value in seconds whichever is earlier"""
      success = False
      assert timeout > 0
      assert test_suite.hive_client is not None
      current_event_id = EventProcessorUtils.get_current_notification_id(
        test_suite.hive_client)
      LOG.info("Waiting until events processor syncs to event id:" + str(current_event_id))
      end_time = time.time() + timeout
      while time.time() < end_time:
        last_synced_id = EventProcessorUtils.get_last_synced_event_id()
        if last_synced_id >= current_event_id:
          LOG.debug(
            "Metric last-synced-event-id has reached the desired value:" + str(
              last_synced_id))
          success = True
          break
        time.sleep(0.1)
      if not success:
        raise Exception(
          "Event processor did not sync till last known event id {0} \
          within {1} seconds".format(current_event_id, timeout))
      # Wait until the impalad catalog versions agree with the catalogd's version.
      catalogd_version = test_suite.cluster.catalogd.service.get_catalog_version()
      for impalad in test_suite.cluster.impalads:
        impalad.service.wait_for_metric_value("catalog.curr-version", catalogd_version)
      return success

  @staticmethod
  def get_event_processor_metrics():
     """Scrapes the catalog's /events webpage and return a dictionary with the event
     processor metrics."""
     response = requests.get("%s/events?json" % EventProcessorUtils.DEFAULT_CATALOG_URL)
     assert response.status_code == requests.codes.ok
     varz_json = json.loads(response.text)
     metrics = varz_json["event_processor_metrics"].strip().splitlines()

     # Helper to strip a pair of elements
     def strip_pair(p):
       return (p[0].strip(), p[1].strip())

     pairs = [strip_pair(kv.split(':')) for kv in metrics if kv]
     return dict(pairs)

  @staticmethod
  def get_event_processor_metric(metric_key, default_val=None):
    """Returns the event processor metric from the /events catalog debug page"""
    metrics = EventProcessorUtils.get_event_processor_metrics()
    if metric_key not in metrics:
      return default_val
    return metrics[metric_key]

  @staticmethod
  def get_last_synced_event_id():
    """Returns the last_synced_event_id."""
    metrics = EventProcessorUtils.get_event_processor_metrics()
    assert 'last-synced-event-id' in metrics.keys()
    return int(metrics['last-synced-event-id'])

  @staticmethod
  def get_event_processor_status():
    """
    Returns the current status of the EventsProcessor
    """
    metrics = EventProcessorUtils.get_event_processor_metrics()
    assert 'status' in metrics.keys()
    return metrics['status']

  @staticmethod
  def get_current_notification_id(hive_client):
    """Returns the current notification from metastore"""
    assert hive_client is not None
    return int(hive_client.get_current_notificationEventId().eventId)