chore(app-staging-synthesizer): reduce the size of DefaultStagingStack template by 5KB (#26024)

Since `DefaultStagingStack` is a stack that creates staging resources, it is bound to the CloudFormation [limit](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cloudformation-limits.html) of 51KB. This means that there is an upper limit on how many ECR repositories (and in turn, unique images) are allowed in the CDK App. In an effort to increase this limit, this PR does the following:

- Remove path metadata to save ~2KB
- Remove `AWS::CDK::Metadata` construct to save ~3KB
- Insert a dummy `UsingDefaultStagingStack` construct to the stacks that _use_ the `DefaultStagingStack` for analytics purposes.

In all, this should decrease the size of the DefaultStagingStack template by ~5KB, or ~10% of the overall size allowed.

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: kaizencc

packages/@aws-cdk/app-staging-synthesizer-alpha/lib/default-staging-stack.ts

@@ -17,11 +17,27 @@ import {
   StackProps,
 } from 'aws-cdk-lib/core';
 import { StringSpecializer } from 'aws-cdk-lib/core/lib/helpers-internal';
+import * as cxapi from 'aws-cdk-lib/cx-api';
+import { Construct } from 'constructs';
 import { BootstrapRole } from './bootstrap-roles';
 import { FileStagingLocation, IStagingResources, IStagingResourcesFactory, ImageStagingLocation } from './staging-stack';
 
 export const DEPLOY_TIME_PREFIX = 'deploy-time/';
 
+/**
+ * This is a dummy construct meant to signify that a stack is utilizing
+ * the AppStagingSynthesizer. It does not do anything, and is not meant
+ * to be created on its own. This construct will be a part of the
+ * construct tree only and not the Cfn template. The construct tree is
+ * then encoded in the AWS::CDK::Metadata resource of the stack and
+ * injested in our metrics like every other construct.
+ */
+export class UsingAppStagingSynthesizer extends Construct {
+  constructor(scope: Construct, id: string) {
+    super(scope, id);
+  }
+}
+
 /**
  * User configurable options to the DefaultStagingStack.
  */
@@ -128,6 +144,12 @@ export class DefaultStagingStack extends Stack implements IStagingResources {
           throw new Error(`Stack ${stack.stackName} must be part of an App`);
         }
 
+        // Because we do not keep metrics in the DefaultStagingStack, we will inject
+        // a dummy construct into the stack using the DefaultStagingStack instead.
+        if (cxapi.ANALYTICS_REPORTING_ENABLED_CONTEXT) {
+          new UsingAppStagingSynthesizer(stack, `UsingAppStagingSynthesizer/${stack.stackName}`);
+        }
+
         const stackId = `StagingStack-${appId}-${context.environmentString}`;
         return new DefaultStagingStack(app, stackId, {
           ...options,
@@ -199,7 +221,10 @@ export class DefaultStagingStack extends Stack implements IStagingResources {
     super(scope, id, {
       ...props,
       synthesizer: new BootstraplessSynthesizer(),
+      analyticsReporting: false, // removing AWS::CDK::Metadata construct saves ~3KB
     });
+    // removing path metadata saves ~2KB
+    this.node.setContext(cxapi.PATH_METADATA_ENABLE_CONTEXT, false);
 
     this.appId = this.validateAppId(props.appId);
     this.dependencyStack = this;

packages/@aws-cdk/app-staging-synthesizer-alpha/test/app-staging-synthesizer.test.ts

@@ -121,6 +121,12 @@ describe(AppStagingSynthesizer, () => {
     expect(depStack.stackName).toEqual(`StagingStack-${APP_ID}`);
   });
 
+  test('stack has dummy construct for metrics', () => {
+    // WHEN
+    const dummyConstruct = stack.node.tryFindChild(`UsingAppStagingSynthesizer/${stack.stackName}`);
+    expect(dummyConstruct).toBeDefined();
+  });
+
   test('add file asset', () => {
     // WHEN
     const location = stack.synthesizer.addFileAsset({

packages/@aws-cdk/app-staging-synthesizer-alpha/test/integ.synth-default-resources.js.snapshot/cdk.out

@@ -1 +1 @@
-{"version":"31.0.0"}
+{"version":"32.0.0"}

packages/@aws-cdk/app-staging-synthesizer-alpha/test/integ.synth-default-resources.js.snapshot/integ.json

@@ -1,5 +1,5 @@
 {
-  "version": "31.0.0",
+  "version": "32.0.0",
   "testCases": {
     "integ-tests/DefaultTest": {
       "stacks": [

packages/@aws-cdk/app-staging-synthesizer-alpha/test/integ.synth-default-resources.js.snapshot/integtestsDefaultTestDeployAssert44C8D370.assets.json

@@ -1,5 +1,5 @@
 {
-  "version": "31.0.0",
+  "version": "32.0.0",
   "files": {
     "21fbb51d7b23f6a6c262b46a9caee79d744a3ac019fd45422d988b96d44b2a22": {
       "source": {

packages/@aws-cdk/app-staging-synthesizer-alpha/test/integ.synth-default-resources.js.snapshot/manifest.json

@@ -1,5 +1,5 @@
 {
-  "version": "31.0.0",
+  "version": "32.0.0",
   "artifacts": {
     "synthesize-default-resources.assets": {
       "type": "cdk:asset-manifest",
@@ -78,6 +78,15 @@
             "type": "aws:cdk:logicalId",
             "data": "lambdaecr2615DAF68"
           }
+        ],
+        "UsingDefaultStagingStacksynthesizedefaultresources": [
+          {
+            "type": "aws:cdk:logicalId",
+            "data": "UsingDefaultStagingStacksynthesizedefaultresources",
+            "trace": [
+              "!!DESTRUCTIVE_CHANGES: WILL_DESTROY"
+            ]
+          }
         ]
       },
       "displayName": "synthesize-default-resources"

packages/@aws-cdk/app-staging-synthesizer-alpha/test/integ.synth-default-resources.js.snapshot/synthesize-default-resources.assets.json

@@ -1,5 +1,5 @@
 {
-  "version": "31.0.0",
+  "version": "32.0.0",
   "files": {
     "68539effc3f7ad46fff9765606c2a01b7f7965833643ab37e62799f19a37f650": {
       "source": {

packages/@aws-cdk/app-staging-synthesizer-alpha/test/integ.synth-default-resources.js.snapshot/tree.json

@@ -8,6 +8,14 @@
         "id": "synthesize-default-resources",
         "path": "synthesize-default-resources",
         "children": {
+          "UsingAppStagingSynthesizer--synthesize-default-resources": {
+            "id": "UsingAppStagingSynthesizer--synthesize-default-resources",
+            "path": "synthesize-default-resources/UsingAppStagingSynthesizer--synthesize-default-resources",
+            "constructInfo": {
+              "fqn": "@aws-cdk/app-staging-synthesizer-alpha.UsingAppStagingSynthesizer",
+              "version": "0.0.0"
+            }
+          },
           "lambda-s3": {
             "id": "lambda-s3",
             "path": "synthesize-default-resources/lambda-s3",
@@ -1150,7 +1158,7 @@
           }
         },
         "constructInfo": {
-          "fqn": "aws-cdk-lib.Stack",
+          "fqn": "@aws-cdk/app-staging-synthesizer-alpha.DefaultStagingStack",
           "version": "0.0.0"
         }
       },
@@ -1167,7 +1175,7 @@
                 "path": "integ-tests/DefaultTest/Default",
                 "constructInfo": {
                   "fqn": "constructs.Construct",
-                  "version": "10.2.26"
+                  "version": "10.2.52"
                 }
               },
               "DeployAssert": {
@@ -1213,7 +1221,7 @@
         "path": "Tree",
         "constructInfo": {
           "fqn": "constructs.Construct",
-          "version": "10.2.26"
+          "version": "10.2.52"
         }
       }
     },