Update AWS Cloudwatch Retention Policy on Log Groups

update_log-retention_policy.sh

#!/bin/bash

# This script takes the number of days to retain AWS Cloudwatch logs as an argument
# and updates all AWS Cloudwatch logs policy to the desired retention length

if [ $# -eq 0 ]
  then
    echo "Please specify the number of days to retain AWS Cloudwatch Logs"
    echo "Usage: update-log-retention-policy 90"
    echo "Done"
    echo ""
    return 0
fi

days=$1

echo "Number of days to retain logs set to $days"

#create json file
echo "Getting log groups from AWS..."
aws logs describe-log-groups > logGroups.json

#find logs with retention less than $days (ignore null, that means already are indefinite)
echo "Filtering logs based on desired retention..."
logs=$(cat logGroups.json | jq '.[] | map({logGroupName: .logGroupName, retention: .retentionInDays })' | jq -cr --argjson DAYS "$days" '.[] | select((.retention != null) and .retention < $DAYS)')

if [ -z "$logs" ]
  then
    echo "No logs found with retention < $days"
    echo "Done"
    echo ""
    return 0
fi

echo "Updating retention policy..."

#update the retention policy
echo $logs | jq -r '.logGroupName' | while read log; do echo "Updating retention policy for log group: $log"; aws logs put-retention-policy --log-group-name $log --retention-in-days $days; done

rm logGroups.json

echo "Done"
echo ""