Spike aggregation: TypeError: '<' not supported between instances of 'NoneType' and 'int'

[vaddenz]

1. Exception Log:

ERROR:elastalert:Traceback (most recent call last):
  File "elastalert2/elastalert/elastalert.py", line 1260, in handle_rule_execution
    num_matches = self.run_rule(rule, endtime, rule.get('initial_starttime'))
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "elastalert2/elastalert/elastalert.py", line 883, in run_rule
    if not self.run_query(rule, tmp_endtime, endtime):
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "elastalert2/elastalert/elastalert.py", line 637, in run_query
    rule_inst.add_aggregation_data(data)
  File "elastalert2/elastalert/ruletypes.py", line 1202, in add_aggregation_data
    self.unwrap_term_buckets(timestamp, payload_data['bucket_aggs'])
  File "elastalert2/elastalert/ruletypes.py", line 1236, in unwrap_term_buckets
    self.handle_event(event, agg_value, qk_str)
  File "elastalert2/elastalert/ruletypes.py", line 500, in handle_event
    if self.find_matches(ref, cur):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "elastalert2/elastalert/ruletypes.py", line 528, in find_matches
    ref < self.rules.get('threshold_ref', 0)):
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: '<' not supported between instances of 'NoneType' and 'int'

2. Reproduction

Start elastalert with the following index pattern & rule config, when first time frame is reached, the exception above occurs.

2.1 ElasticSearch Index Pattern

{
  "metrics": {
    "name": "request.timer",
    "value": {
      "timer": {
        "histogram": {
          "p95": 796
        }
      }
    },
    "labels": {
      "appId": "<appId>"
    }
  },
  "@timestamp": "2024-02-28T02:10:30.179346Z"
}

2.2 Rule Configuration

name: 'Request Timer Alert'
description: '3 Minute Request Timer Alert'
type: 'spike_aggregation'
is_enabled: true
timeframe:
  minutes: 3
buffer_time:
  minutes: 3
search_extra_index: true

# Spike
index: '<index>-*'
metric_agg_key: 'metrics.value.timer.histogram.p95'
metric_agg_type: 'avg'
spike_height: 1.1
spike_type: 'up'
query_key: 'metrics.labels.appId.keyword'
alert_on_new_data: true
filter:
  - term:
      'metrics.name.keyword': 'request.timer'

# ElasticSearch cluster config
es_host: '<host>'

# Alert configs
alert:
  - 'post2'
http_post2_url: '<url>'
http_post2_all_values: true

3. Investigation

The exception is caused by ruletypes.py/SpikeRule.find_matches(ref, cur), in which ref & cur may be None but not validated.
Therefore this exception can be fixed as follow:

class SpikeRule(RuleType):
    ...
    def find_matches(self, ref, cur):
        if ref is None or cur is None:
            return False
        ...

[github-actions[bot]]

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