There is a moment that catches a lot of people out who are new to AWS CDK. You deploy a service, the deploy succeeds, and then you realize the service cannot fully configure itself because it did not know its own endpoint until after it was running.
This is not a CDK bug. It is a genuine chicken-and-egg problem, and once you understand it, the solution is straightforward-ish.
The problem
Some resources only exist after CloudFormation has provisioned them: ALB endpoints, service URLs, and auto-assigned DNS names. These values are not known at the cdk synth time. They are outputs that come back after the stack deploys.
If your application needs to know its own public URL (e.g., to build redirect links), well then, you are in a kerfuffle. You cannot pass a value into the stack that the stack itself has not produced yet. CloudFormation is not psychic, so unfortunately neither is CDK (I hear AI is working on this, though).
