fix(aws-cdk-lib): temporary Cloud Assemblies are not cleaned up (#36043)

The CDK framework creates a temporary directory in `/tmp` for every unit test, and never cleans those up.

In this PR, register all temporary assembly directories created by doing `new Stack()` or `new App()` without an `outdir`, and delete them when the Node process exits.

This will only affect unit tests: if the `outdir` property is set explicitly, or the CDK App is being synthesized by the CLI (and `$CDK_OUTDIR` is set), the assembly directory will not be cleaned. For users: if you set `outdir` you are reponsible for cleaning up the directory. If you don't set `outdir`, it will be automatically removed at some point.

This will benefit both `aws-cdk` development itself, as well as users writing unit tests against CDK.

Relates to #802.

Also in this PR: cleanup of other temporary directories we create during tests. These will only benefit development on `aws-cdk` itself.

----

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

Author: rix0rrr

packages/@aws-cdk-testing/framework-integ/test/aws-s3-deployment/test/integ.bucket-deployment-big-response.ts

@@ -31,6 +31,10 @@ class TestBucketDeployment extends cdk.Stack {
     const sources = [];
     for (let i = 0; i < numFiles; i++) {
       const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'tmpcdk'));
+      process.on('exit', () => {
+        fs.rmSync(tempDir, { force: true, recursive: true });
+      });
+
       fs.mkdirSync(tempDir, { recursive: true });
       const fileName = `${i+1}.txt`;
       const filePath = path.join(tempDir, fileName);

packages/@aws-cdk-testing/framework-integ/test/aws-s3-deployment/test/integ.bucket-deployment-large-file.ts

@@ -30,6 +30,9 @@ const bucket = new Bucket(stack, 'Bucket', {
 
 // Create a temporary directory for our large files
 const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-large-files-'));
+process.on('exit', () => {
+  fs.rmSync(tempDir, { force: true, recursive: true });
+});
 
 // Generate a large JSON file (10MB) programmatically
 const largeJsonFilePath = path.join(tempDir, 'large-file.json');

packages/@aws-cdk/custom-resource-handlers/test/core/nodejs-entrypoint-handler.test.ts

@@ -179,6 +179,9 @@ async function invokeHandler(req: AWSLambda.CloudFormationCustomResourceEvent, u
 
   // stage entry point and user handler.
   const workdir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-custom-resource-provider-handler-test-'));
+  process.on('exit', () => {
+    fs.rmSync(workdir, { recursive: true, force: true });
+  });
   entrypoint.external.userHandlerIndex = path.join(workdir, 'index.js');
   fs.writeFileSync(entrypoint.external.userHandlerIndex, `exports.handler = ${userHandler.toString()};`);
 

packages/@aws-cdk/custom-resource-handlers/test/custom-resources-framework/callable-expr.test.ts

@@ -14,6 +14,10 @@ describe('callable expression', () => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-test'));
   });
 
+  afterEach(() => {
+    fs.removeSync(tmpDir);
+  });
+
   test('callable expression toString return expression name', () => {
     // GIVEN
     const expressionName = 'determineRuntime';

packages/@aws-cdk/custom-resource-handlers/test/custom-resources-framework/framework.test.ts

@@ -14,6 +14,10 @@ describe('framework', () => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-test'));
   });
 
+  afterEach(() => {
+    fs.removeSync(tmpDir);
+  });
+
   test('can codegen cdk function', () => {
     // GIVEN
     const module = new HandlerFrameworkModule('cdk-testing/test-provider');

packages/@aws-cdk/custom-resource-handlers/test/custom-resources-framework/module-importer.test.ts

@@ -12,6 +12,10 @@ describe('module importer', () => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-test'));
   });
 
+  afterEach(() => {
+    fs.removeSync(tmpDir);
+  });
+
   test('aliased import', () => {
     // GIVEN
     const module = new HandlerFrameworkModule('cdk-testing');

packages/@aws-cdk/custom-resource-handlers/test/nodejs-entrypoint.test.ts

@@ -179,6 +179,9 @@ async function invokeHandler(req: AWSLambda.CloudFormationCustomResourceEvent, u
 
   // stage entry point and user handler.
   const workdir = fs.mkdtempSync(path.join(os.tmpdir(), 'cdk-custom-resource-provider-handler-test-'));
+  process.on('exit', () => {
+    fs.rmSync(workdir, { recursive: true, force: true });
+  });
   entrypoint.external.userHandlerIndex = path.join(workdir, 'index.js');
   fs.writeFileSync(entrypoint.external.userHandlerIndex, `exports.handler = ${userHandler.toString()};`);
 

packages/@aws-cdk/integ-tests-alpha/test/manifest-synthesizer.test.ts

@@ -18,6 +18,7 @@ beforeEach(() => {
 });
 
 afterEach(() => {
+  fs.rmSync(tmpDir, { force: true, recursive: true });
   jest.restoreAllMocks();
 });
 

packages/aws-cdk-lib/aws-s3-deployment/lib/source.ts

@@ -193,17 +193,22 @@ export class Source {
     return {
       bind: (scope: Construct, context?: DeploymentSourceContext) => {
         const workdir = FileSystem.mkdtemp('s3-deployment');
-        const outputPath = join(workdir, objectKey);
-        const rendered = renderData(data);
-        fs.mkdirSync(dirname(outputPath), { recursive: true });
-        fs.writeFileSync(outputPath, rendered.text);
-        const asset = this.asset(workdir).bind(scope, context);
-        return {
-          bucket: asset.bucket,
-          zipObjectKey: asset.zipObjectKey,
-          markers: rendered.markers,
-          markersConfig: markersConfig,
-        };
+        try {
+          const outputPath = join(workdir, objectKey);
+          const rendered = renderData(data);
+          fs.mkdirSync(dirname(outputPath), { recursive: true });
+          fs.writeFileSync(outputPath, rendered.text);
+          const asset = this.asset(workdir).bind(scope, context);
+          return {
+            bucket: asset.bucket,
+            zipObjectKey: asset.zipObjectKey,
+            markers: rendered.markers,
+            markersConfig: markersConfig,
+          };
+        } finally {
+          // Calling `this.asset()` has copied files to the assembly, so we can delete the temporary directory.
+          FileSystem.rmrf(workdir);
+        }
       },
     };
   }

packages/aws-cdk-lib/core/lib/fs/index.ts

@@ -69,5 +69,12 @@ export class FileSystem {
     return fs.mkdtempSync(path.join(FileSystem.tmpdir, prefix));
   }
 
+  /**
+   * Deletes a directory
+   */
+  public static rmrf(dirname: string) {
+    fs.rmSync(dirname, { force: true, recursive: true });
+  }
+
   private static _tmpdir?: string;
 }