fix(lambda-python): bundle asset files correctly (aws#18335)

Asset files are incorrectly being bundled under the `asset-input` directory instead of the root of the bundle.

To also copy over hidden files (aws#18306 (comment)), I switched from using `-R` to `-a` based on what I found on [SO](https://stackoverflow.com/a/13020113) and the [man page](https://linux.die.net/man/1/cp). (`-a` is equivalent to `-dR`.)

Fixes aws#18301 and @chrispykim's comment: aws#18082 (comment).

----

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

Author: setu4993

Diff for: packages/@aws-cdk/aws-lambda-python/lib/bundling.ts

@@ -87,7 +87,7 @@ export class Bundling implements CdkBundlingOptions {
     if (packaging.dependenciesFile) {
       bundlingCommands.push(`python -m pip install -r ${DependenciesFile.PIP} -t ${options.outputDir}`);
     }
-    bundlingCommands.push(`cp -R ${options.inputDir}/ ${options.outputDir}`);
+    bundlingCommands.push(`cp -rT ${options.inputDir}/ ${options.outputDir}`);
     return bundlingCommands;
   }
 }

Diff for: packages/@aws-cdk/aws-lambda-python/test/bundling.test.ts

@@ -1,3 +1,4 @@
+import * as fs from 'fs';
 import * as path from 'path';
 import { Architecture, Code, Runtime } from '@aws-cdk/aws-lambda';
 import { DockerImage } from '@aws-cdk/core';
@@ -25,7 +26,7 @@ beforeEach(() => {
 
 test('Bundling a function without dependencies', () => {
   const entry = path.join(__dirname, 'lambda-handler-nodeps');
-  Bundling.bundle({
+  const assetCode = Bundling.bundle({
     entry: entry,
     runtime: Runtime.PYTHON_3_7,
     architecture: Architecture.X86_64,
@@ -36,7 +37,7 @@ test('Bundling a function without dependencies', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'cp -R /asset-input/ /asset-output',
+        'cp -rT /asset-input/ /asset-output',
       ],
     }),
   }));
@@ -47,11 +48,14 @@ test('Bundling a function without dependencies', () => {
     }),
     platform: 'linux/amd64',
   }));
+
+  const files = fs.readdirSync(assetCode.path);
+  expect(files).toContain('index.py');
 });
 
 test('Bundling a function with requirements.txt', () => {
   const entry = path.join(__dirname, 'lambda-handler');
-  Bundling.bundle({
+  const assetCode = Bundling.bundle({
     entry: entry,
     runtime: Runtime.PYTHON_3_7,
     architecture: Architecture.X86_64,
@@ -62,10 +66,14 @@ test('Bundling a function with requirements.txt', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'python -m pip install -r requirements.txt -t /asset-output && cp -R /asset-input/ /asset-output',
+        'python -m pip install -r requirements.txt -t /asset-output && cp -rT /asset-input/ /asset-output',
       ],
     }),
   }));
+
+  const files = fs.readdirSync(assetCode.path);
+  expect(files).toContain('index.py');
+  expect(files).toContain('requirements.txt');
 });
 
 test('Bundling Python 2.7 with requirements.txt installed', () => {
@@ -81,7 +89,7 @@ test('Bundling Python 2.7 with requirements.txt installed', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'python -m pip install -r requirements.txt -t /asset-output && cp -R /asset-input/ /asset-output',
+        'python -m pip install -r requirements.txt -t /asset-output && cp -rT /asset-input/ /asset-output',
       ],
     }),
   }));
@@ -101,7 +109,7 @@ test('Bundling a layer with dependencies', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'python -m pip install -r requirements.txt -t /asset-output/python && cp -R /asset-input/ /asset-output/python',
+        'python -m pip install -r requirements.txt -t /asset-output/python && cp -rT /asset-input/ /asset-output/python',
       ],
     }),
   }));
@@ -121,7 +129,7 @@ test('Bundling a python code layer', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'cp -R /asset-input/ /asset-output/python',
+        'cp -rT /asset-input/ /asset-output/python',
       ],
     }),
   }));
@@ -130,7 +138,7 @@ test('Bundling a python code layer', () => {
 test('Bundling a function with pipenv dependencies', () => {
   const entry = path.join(__dirname, 'lambda-handler-pipenv');
 
-  Bundling.bundle({
+  const assetCode = Bundling.bundle({
     entry: path.join(entry, '.'),
     runtime: Runtime.PYTHON_3_9,
     architecture: Architecture.X86_64,
@@ -141,16 +149,23 @@ test('Bundling a function with pipenv dependencies', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'PIPENV_VENV_IN_PROJECT=1 pipenv lock -r > requirements.txt && rm -rf .venv && python -m pip install -r requirements.txt -t /asset-output/python && cp -R /asset-input/ /asset-output/python',
+        'PIPENV_VENV_IN_PROJECT=1 pipenv lock -r > requirements.txt && rm -rf .venv && python -m pip install -r requirements.txt -t /asset-output/python && cp -rT /asset-input/ /asset-output/python',
       ],
     }),
   }));
+
+  const files = fs.readdirSync(assetCode.path);
+  expect(files).toContain('index.py');
+  expect(files).toContain('Pipfile');
+  expect(files).toContain('Pipfile.lock');
+  // Contains hidden files.
+  expect(files).toContain('.gitignore');
 });
 
 test('Bundling a function with poetry dependencies', () => {
   const entry = path.join(__dirname, 'lambda-handler-poetry');
 
-  Bundling.bundle({
+  const assetCode = Bundling.bundle({
     entry: path.join(entry, '.'),
     runtime: Runtime.PYTHON_3_9,
     architecture: Architecture.X86_64,
@@ -161,10 +176,17 @@ test('Bundling a function with poetry dependencies', () => {
     bundling: expect.objectContaining({
       command: [
         'bash', '-c',
-        'poetry export --with-credentials --format requirements.txt --output requirements.txt && python -m pip install -r requirements.txt -t /asset-output/python && cp -R /asset-input/ /asset-output/python',
+        'poetry export --with-credentials --format requirements.txt --output requirements.txt && python -m pip install -r requirements.txt -t /asset-output/python && cp -rT /asset-input/ /asset-output/python',
       ],
     }),
   }));
+
+  const files = fs.readdirSync(assetCode.path);
+  expect(files).toContain('index.py');
+  expect(files).toContain('pyproject.toml');
+  expect(files).toContain('poetry.lock');
+  // Contains hidden files.
+  expect(files).toContain('.gitignore');
 });
 
 test('Bundling a function with custom bundling image', () => {
@@ -184,7 +206,7 @@ test('Bundling a function with custom bundling image', () => {
       image,
       command: [
         'bash', '-c',
-        'python -m pip install -r requirements.txt -t /asset-output/python && cp -R /asset-input/ /asset-output/python',
+        'python -m pip install -r requirements.txt -t /asset-output/python && cp -rT /asset-input/ /asset-output/python',
       ],
     }),
   }));