AWS CloudWatch Log Group Retention

Amazon CloudWatch Logs is used as centralized place to monitor, store, and access all our log files from different AWS services

CloudWatch organises logs in a log group and when a new log group is created, it’s retention period is set to Never expire by default, which means logs will be retained forever.

Here is a sample python script that helps with changing the retention days to 60.

import boto3
# set the number of retention days 
retention_days = 60
# list the regions you are interested to run this script on
regions=['us-east-1']

for region in regions:
    client = boto3.client('logs',region)
    response = client.describe_log_groups(
    )
    nextToken=response.get('nextToken',None)
    retention = response['logGroups']
    while (nextToken is not None):
        response = client.describe_log_groups(
            nextToken=nextToken
        )
        nextToken = response.get('nextToken', None)
        retention = retention + response['logGroups']
    for group in retention:
        if 'retentionInDays' in group.keys():
            print(group['logGroupName'], group['retentionInDays'],region)
        else:
            print("Retention Not found for ",group['logGroupName'],region)
            setretention = client.put_retention_policy(
                logGroupName=group['logGroupName'],
                retentionInDays=retention_days
                )
            print(setretention)

Once this script is run problem is solved for existing log groups but it would be nice to automate it using cloud watch events to run a python code using lambda in that way all the log groups created going forward will have retention value set.