alarm notifier

alarm_notifier.py

import boto3
import datetime
import pytz
import os
import logging
import json

cloudwatch_client = boto3.client('cloudwatch')
sns_client = boto3.client('sns')
#Use this to identify alarms for our specific env
environment = os.environ.get("ENV")
minutes_elapsed_to_notify = os.environ.get("WARN_AFTER_MINUTES", default=5)
#arn of SNS topic to send to
sns_arn=os.environ.get("NOTIFY_ARN")

_logger = logging.getLogger(__name__)
log_level = os.getenv('LOG_LEVEL', logging.INFO)
_logger.setLevel(log_level)


def lambda_handler(event, _):
    alarms = cloudwatch_client.describe_alarms(AlarmNamePrefix=f"{environment}-", StateValue="ALARM")
    current_time = datetime.datetime.now(pytz.utc)
    if (len(alarms['MetricAlarms']) > 0):
        _logger.debug(f"Looping through active alarms to see ones older than {minutes_elapsed_to_notify} minutes")
        for record in alarms['MetricAlarms']:
            _logger.debug(f"{record['AlarmName']}: last_update: {record['StateUpdatedTimestamp']}")
            minutes_elapsed = (current_time - record['StateUpdatedTimestamp']).seconds // 60
            if minutes_elapsed > minutes_elapsed_to_notify:
                _logger.info(f"Notifying about alarm {record['AlarmName']}")
                message = {"ContinuedAlarmName" : record['AlarmName'], "AlarmDurationMinutes": minutes_elapsed}
                sns_client.publish(TopicArn=sns_arn, Message=json.dumps(message))