aws-cdk remove resource from stack that used in another stack

Question

Try to understand a strange behavior of CDK:

I have 2 stacks

StackA -> define resource outA

StackB -> define resource outB - its depend on resource outA

the first 'CDK deploy' is run without any problem.

Now I change StackA by deleting 'outA' resource and create a new resource call 'outAnew' and update StackB to use this new value

at this time I can't deploy any Stack! if I try to deploy StackA got error:

Export outA cannot be deleted as it is in use by StackB and StackC

and if try to deploy StackB it first tries to deploy StackA because of the dependency.

any Idea?

Example code:

StackA:

export class CdkDependenciesStackA extends cdk.Stack {
// public out_a: cdk.CfnOutput;
public out_a_new: cdk.CfnOutput;
constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
super(scope, id, props);
// this.out_a = new cdk.CfnOutput(this, "out_a", {
//   value: "outA",
//   exportName: "outA",
// });
this.out_a_new = new cdk.CfnOutput(this, "out_a_new", {
  value: "outAnew",
  exportName: "outAnew",
});

} 
}

StackB:

export class CdkDependenciesStackB extends cdk.Stack {
    public out_b: cdk.CfnOutput;
    constructor(
      scope: cdk.Construct,
      id: string,
      outputValue: cdk.CfnOutput,
      props?: cdk.StackProps
    ) {
      super(scope, id, props);
      this.out_b = new cdk.CfnOutput(this, "out_b", {
        value: `outB_${outputValue.importValue}`,
        exportName: "outB",
       });
    }
  }

App:

const app = new cdk.App();
const stack_a = new stacks.CdkDependenciesStackA(
  app,
  "CdkDependenciesStack",
  {}
   );

 const stack_b =new stacks.CdkDependenciesStackB(
   app,
   "CdkDependenciesStackB",
   stack_a.out_a_new,
   {}
  );
 stack_b.addDependency(stack_a)

Answer 1

This seems to be common problem across CDK userbase. The solution that helped me is described at https://aws-blog.de/2020/09/deployment-issues-with-cross-stack-dependencies-and-the-cdk.html. I also created my own blog post about it, going into greater details - https://medium.com/life-at-apollo-division/resolve-aws-cdk-stack-dependency-conflicts-c6a3dee0c28d.

Since the stack that is exporting values is deployed first, you still need to keep that original export so that

• Exporting stack can be deployed to export new value
• Importing stack can be deployed to import new value and stop importing old value

After that you can stop exporting the old value.