Merge pull request #2094 from guardian/aa/riff-raff-yaml-stack-deps

feat(riff-raff.yaml): Support cross stack dependencies

.changeset/chatty-rabbits-cry.md

@@ -0,0 +1,19 @@
+---
+"@guardian/cdk": minor
+---
+
+feat(riff-raff.yaml): Support cross stack dependencies
+
+Currently the `riff-raff.yaml` generator is not able to create dependencies between `cloud-formation` deployments. This means each `cloud-formation` deployment could happen at the same time.
+
+This does not work in the scenario where we have:
+- Stack A containing a bucket
+- Stack B CODE containing an app that uses A's bucket
+- Stack B PROD containing an app that uses A's bucket
+
+That is, we can't guarantee Stack A is deployed first.
+
+In this change we add support for the scenario where we have a shared resources stack.
+The generated `riff-raff.yaml` file will describe that Stack B CODE, and Stack B PROD depend on Stack A.
+
+It uses the AWS CDK mechanism https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.Stack.html#addwbrdependencytarget-reason.

src/riff-raff-yaml-file/index.test.ts

@@ -1185,4 +1185,74 @@ describe("The RiffRaffYamlFile class", () => {
       "
     `);
   });
+
+  it("Should support cloudformation stacks that depend on other cloudformation stacks", () => {
+    const app = new App({ outdir: "/tmp/cdk.out" });
+
+    class SharedResourceStack extends GuStack {}
+    class ApplicationStack extends GuStack {}
+
+    const sharedResources = new SharedResourceStack(app, "Shared-INFRA", {
+      env: {
+        region: "eu-west-1",
+      },
+      stack: "deploy",
+      stage: "INFRA",
+    });
+
+    const codeStack = new ApplicationStack(app, "App-CODE", {
+      env: {
+        region: "eu-west-1",
+      },
+      stack: "deploy",
+      stage: "CODE",
+    });
+
+    const prodStack = new ApplicationStack(app, "App-PROD", {
+      env: {
+        region: "eu-west-1",
+      },
+      stack: "deploy",
+      stage: "PROD",
+    });
+
+    codeStack.addDependency(sharedResources);
+    prodStack.addDependency(sharedResources);
+
+    const actual = new RiffRaffYamlFile(app).toYAML();
+
+    expect(actual).toMatchInlineSnapshot(`
+    "allowedStages:
+      - INFRA
+      - CODE
+      - PROD
+    deployments:
+      cfn-eu-west-1-deploy-shared-resource-stack:
+        type: cloud-formation
+        regions:
+          - eu-west-1
+        stacks:
+          - deploy
+        app: shared-resource-stack
+        contentDirectory: /tmp/cdk.out
+        parameters:
+          templateStagePaths:
+            INFRA: Shared-INFRA.template.json
+      cfn-eu-west-1-deploy-application-stack:
+        type: cloud-formation
+        regions:
+          - eu-west-1
+        stacks:
+          - deploy
+        app: application-stack
+        contentDirectory: /tmp/cdk.out
+        parameters:
+          templateStagePaths:
+            CODE: App-CODE.template.json
+            PROD: App-PROD.template.json
+        dependencies:
+          - cfn-eu-west-1-deploy-shared-resource-stack
+    "
+    `);
+  });
 });

src/riff-raff-yaml-file/index.ts

@@ -196,6 +196,10 @@ export class RiffRaffYamlFile {
     return cdkStack.node.findAll().filter((_) => _ instanceof GuAutoScalingGroup) as GuAutoScalingGroup[];
   }
 
+  private getGuStackDependencies(cdkStack: GuStack): GuStack[] {
+    return cdkStack.dependencies.filter((_) => _ instanceof GuStack) as GuStack[];
+  }
+
   // eslint-disable-next-line custom-rules/valid-constructors -- this needs to sit above GuStack on the cdk tree
   constructor(app: App) {
     this.allCdkStacks = app.node.findAll().filter((_) => _ instanceof GuStack) as GuStack[];
@@ -235,7 +239,11 @@ export class RiffRaffYamlFile {
           ].flat();
           artifactUploads.forEach(({ name, props }) => deployments.set(name, props));
 
-          const cfnDeployment = cloudFormationDeployment(stacks, artifactUploads, this.outdir);
+          const parentStacks: RiffRaffDeployment[] = this.getGuStackDependencies(stack).map((x) =>
+            cloudFormationDeployment([x], [], this.outdir),
+          );
+
+          const cfnDeployment = cloudFormationDeployment(stacks, [...artifactUploads, ...parentStacks], this.outdir);
           deployments.set(cfnDeployment.name, cfnDeployment.props);
 
           const lambdasWithoutAnAlias = lambdas.filter((lambda) => lambda.alias === undefined);