Making blue green deployment work for dependent ECS services

Question

I have two ECS services. UI(http://<LB>/SS_UI/) and API(http://<LB>/webservice/). UI calls API and it's config file will have references to the API e.g.

public static springURL = "http://<LB>/webservice/"

The documentation for blue green deployment for ECS(https://cicd-pipeline-cdk-eks-bluegreen.workshop.aws/en/ecsbg/serviceupd.html) suggests creating two listener on the load balancer and two target groups

<LB>:80 -> Original set with live traffic
<LB>:8080 -> Replacement set for testing

This works if I want to test changes to individual projects. I commit to API. Old version of API is on port 80. New version is on port 8080. After testing http://<LB>:8080/webservice/ the switchover can happen after pre-defined time(pic)

But it doesn't work if I want to test from the UI because UI references the old version of API on port 80

If I commit changes to the UI project by referencing http://<LB>:8080/webservice/, even though I can test from UI at http://<LB>:8080/SS_UI/, I cannot allow the replacement set for UI to become the original set because API on port 8080 will eventually get deleted. How can I ensure that as soon as replacement set for API at port 8080 moves to port 80, the UI also starts referencing API of port 80?

Answer 1

I don't think CodeDeploy is designed to include these type of use cases (also because the ramifications and options of allowing that flexibility are pretty much infinite). CodeDeploy is designed to manage B/G deployments for a single micro-service and not for a complex app like you are describing (sure your app isn't very complex but where do you stop supporting complex configurations?). In the context of CodeDeploy these would be two separate B/G deployments (and you'd need to test the back end service via API).

The only alternative I can think of to make this work is to create an additional (hidden/secured?) path in your front-end (e.g. /SS_UI-8080 or perhaps passing a parameter to the /SS_UI path?) that allows you to modify (in your code) the port to use to connect to the back end service via the LB.