monitor cloud watch log continuously

watch_cloudwatch.py

import boto3
from boto3.session import Session
import time
from datetime import datetime
import calendar

def get_log_events(log_group):
    """Generate all the log events from a CloudWatch group.
     thanks to https://alexwlchan.net/2017/11/fetching-cloudwatch-logs/
    :param log_group: Name of the CloudWatch log group.

    """
    use_default_profile = False

    if use_default_profile:
        client = boto3.client('logs')
    else:
        profile = 'PROFILE_NAME_HERE'  # must define profile "PROFILE_NAME_HERE" in ~/.aws/credentials
        session = Session(profile_name=profile)
        client = session.client('logs')

    minutes_ago = 60
    utcNowSec = calendar.timegm(datetime.utcnow().timetuple())
    startTime = (utcNowSec - 60 * minutes_ago) * 1000

    kwargs = {
        'logGroupName': log_group,
        'startTime': startTime,
        'limit': 10000,
    }
    while True:
        resp = client.filter_log_events(**kwargs)
        yield resp['events']
        try:
            kwargs['nextToken'] = resp['nextToken']
        except KeyError:
            try:
                if len(resp['events']) > 0:
                    kwargs['startTime'] = resp[u'events'][len(resp['events'])-1]['timestamp'] + 1
                kwargs.pop('nextToken', None)
                time.sleep(5)
            except KeyError:
                break


if __name__ == '__main__':
    for events in get_log_events('LOGGROUP_NAME_HERE'):
        for event in events:
            print(event['message'])