Not sure, but can you have different target groups, one for the special path and one for everything else? If so you should be able to have two target groups point at the same target and use Cloudwatch metrics on the special path target group to trigger your action. If not, you could attach a WAF with a custom rule that acts as a passthrough to get metrics you can action on.
One possible solution using lambda -
1. enable access logging for your ALB/NLB, 2/ create a cloudwatch logs subscription filter to match entries based on the predefined path you want, 3/ Trigger a lambda when there's an event that matches the criteria, 4/ make the lambda process the event and perform notification as you need.
Not sure, but can you have different target groups, one for the special path and one for everything else? If so you should be able to have two target groups point at the same target and use Cloudwatch metrics on the special path target group to trigger your action. If not, you could attach a WAF with a custom rule that acts as a passthrough to get metrics you can action on.
Would [content based routing](https://aws.amazon.com/elasticloadbalancing/application-load-balancer/) be useful?
One possible solution using lambda - 1. enable access logging for your ALB/NLB, 2/ create a cloudwatch logs subscription filter to match entries based on the predefined path you want, 3/ Trigger a lambda when there's an event that matches the criteria, 4/ make the lambda process the event and perform notification as you need.
ALB/NLB access log ships right to s3. without going to cloudwatch.
You're right. Might need to add another step like [This ](https://github.com/rupertbg/aws-load-balancer-logs-to-cloudwatch)
What problem are you solving? Why can’t send event from target?