fix(lambda-python): docker image gets built even when we don't need to bundle assets

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

@@ -34,6 +34,13 @@ export interface BundlingProps extends BundlingOptions {
    * @default Architecture.X86_64
    */
   readonly architecture?: Architecture;
+
+  /**
+   * Whether or not the bundling process should be skipped
+   *
+   * @default - Does not skip bundling
+   */
+  readonly skip?: boolean;
 }
 
 /**
@@ -45,7 +52,7 @@ export class Bundling implements CdkBundlingOptions {
       assetHash: options.assetHash,
       assetHashType: options.assetHashType,
       exclude: DEPENDENCY_EXCLUDES,
-      bundling: new Bundling(options),
+      bundling: options.skip ? undefined : new Bundling(options),
     });
   }
 
@@ -72,7 +79,7 @@ export class Bundling implements CdkBundlingOptions {
 
     this.image = image ?? DockerImage.fromBuild(path.join(__dirname, '../lib'), {
       buildArgs: {
-        ...props.buildArgs ?? {},
+        ...props.buildArgs,
         IMAGE: runtime.bundlingImage.image,
       },
       platform: architecture.dockerPlatform,

packages/@aws-cdk/aws-lambda-python/lib/function.ts

@@ -1,6 +1,7 @@
 import * as fs from 'fs';
 import * as path from 'path';
 import { Function, FunctionOptions, Runtime, RuntimeFamily } from '@aws-cdk/aws-lambda';
+import { Stack } from '@aws-cdk/core';
 import { Bundling } from './bundling';
 import { BundlingOptions } from './types';
 
@@ -79,6 +80,7 @@ export class PythonFunction extends Function {
       code: Bundling.bundle({
         entry,
         runtime,
+        skip: !Stack.of(scope).bundlingRequired,
         ...props.bundling,
       }),
       handler: resolvedHandler,

packages/@aws-cdk/aws-lambda-python/lib/layer.ts

@@ -1,5 +1,6 @@
 import * as path from 'path';
 import * as lambda from '@aws-cdk/aws-lambda';
+import { Stack } from '@aws-cdk/core';
 import { Bundling } from './bundling';
 import { BundlingOptions } from './types';
 
@@ -67,6 +68,7 @@ export class PythonLayerVersion extends lambda.LayerVersion {
         runtime,
         architecture,
         outputPathSuffix: 'python',
+        skip: !Stack.of(scope).bundlingRequired,
         ...props.bundling,
       }),
     });

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

@@ -249,3 +249,25 @@ test('Bundling with custom environment vars`', () => {
     }),
   }));
 });
+
+test('Do not build docker image when skipping bundling', () => {
+  const entry = path.join(__dirname, 'lambda-handler');
+  Bundling.bundle({
+    entry: entry,
+    runtime: Runtime.PYTHON_3_7,
+    skip: true,
+  });
+
+  expect(DockerImage.fromBuild).not.toHaveBeenCalled();
+});
+
+test('Build docker image when bundling is not skipped', () => {
+  const entry = path.join(__dirname, 'lambda-handler');
+  Bundling.bundle({
+    entry: entry,
+    runtime: Runtime.PYTHON_3_7,
+    skip: false,
+  });
+
+  expect(DockerImage.fromBuild).toHaveBeenCalled();
+});

packages/@aws-cdk/aws-lambda-python/test/function.test.ts

@@ -167,3 +167,35 @@ test('Allows use of custom bundling image', () => {
     image,
   }));
 });
+
+test('Skip bundling when stack does not require it', () => {
+  const spy = jest.spyOn(stack, 'bundlingRequired', 'get').mockReturnValue(false);
+  const entry = path.join(__dirname, 'lambda-handler');
+
+  new PythonFunction(stack, 'function', {
+    entry,
+    runtime: Runtime.PYTHON_3_8,
+  });
+
+  expect(Bundling.bundle).toHaveBeenCalledWith(expect.objectContaining({
+    skip: true,
+  }));
+
+  spy.mockRestore();
+});
+
+test('Do not skip bundling when stack requires it', () => {
+  const spy = jest.spyOn(stack, 'bundlingRequired', 'get').mockReturnValue(true);
+  const entry = path.join(__dirname, 'lambda-handler');
+
+  new PythonFunction(stack, 'function', {
+    entry,
+    runtime: Runtime.PYTHON_3_8,
+  });
+
+  expect(Bundling.bundle).toHaveBeenCalledWith(expect.objectContaining({
+    skip: false,
+  }));
+
+  spy.mockRestore();
+});

packages/@aws-cdk/aws-lambda-python/test/layer.test.ts

@@ -63,3 +63,33 @@ test('Allows use of custom bundling image', () => {
     image,
   }));
 });
+
+test('Skip bundling when stack does not require it', () => {
+  const spy = jest.spyOn(stack, 'bundlingRequired', 'get').mockReturnValue(false);
+  const entry = path.join(__dirname, 'lambda-handler-project');
+
+  new PythonLayerVersion(stack, 'layer', {
+    entry,
+  });
+
+  expect(Bundling.bundle).toHaveBeenCalledWith(expect.objectContaining({
+    skip: true,
+  }));
+
+  spy.mockRestore();
+});
+
+test('Do not skip bundling when stack requires it', () => {
+  const spy = jest.spyOn(stack, 'bundlingRequired', 'get').mockReturnValue(true);
+  const entry = path.join(__dirname, 'lambda-handler-project');
+
+  new PythonLayerVersion(stack, 'layer', {
+    entry,
+  });
+
+  expect(Bundling.bundle).toHaveBeenCalledWith(expect.objectContaining({
+    skip: false,
+  }));
+
+  spy.mockRestore();
+});

packages/@aws-cdk/core/lib/asset-staging.ts

@@ -4,7 +4,6 @@ import * as path from 'path';
 import * as cxapi from '@aws-cdk/cx-api';
 import { Construct } from 'constructs';
 import * as fs from 'fs-extra';
-import * as minimatch from 'minimatch';
 import { AssetHashType, AssetOptions, FileAssetPackaging } from './assets';
 import { BundlingOptions, BundlingOutput } from './bundling';
 import { FileSystem, FingerprintOptions } from './fs';
@@ -188,9 +187,7 @@ export class AssetStaging extends CoreConstruct {
     let skip = false;
     if (props.bundling) {
       // Check if we actually have to bundle for this stack
-      const bundlingStacks: string[] = this.node.tryGetContext(cxapi.BUNDLING_STACKS) ?? ['*'];
-      // bundlingStacks is of the form `Stage/Stack`, convert it to `Stage-Stack` before comparing to stack name
-      skip = !bundlingStacks.find(pattern => minimatch(Stack.of(this).stackName, pattern.replace('/', '-')));
+      skip = !Stack.of(this).bundlingRequired;
       const bundling = props.bundling;
       stageThisAsset = () => this.stageByBundling(bundling, skip);
     } else {

packages/@aws-cdk/core/lib/stack.ts

@@ -3,6 +3,7 @@ import * as path from 'path';
 import * as cxschema from '@aws-cdk/cloud-assembly-schema';
 import * as cxapi from '@aws-cdk/cx-api';
 import { IConstruct, Construct, Node } from 'constructs';
+import * as minimatch from 'minimatch';
 import { Annotations } from './annotations';
 import { App } from './app';
 import { Arn, ArnComponents, ArnFormat } from './arn';
@@ -1153,6 +1154,19 @@ export class Stack extends CoreConstruct implements ITaggable {
 
     return makeStackName(ids);
   }
+
+  /**
+   * Indicates whether the stack requires bundling or not
+   */
+  public get bundlingRequired() {
+    const bundlingStacks: string[] = this.node.tryGetContext(cxapi.BUNDLING_STACKS) ?? ['*'];
+
+    // bundlingStacks is of the form `Stage/Stack`, convert it to `Stage-Stack` before comparing to stack name
+    return bundlingStacks.some(pattern => minimatch(
+      this.stackName,
+      pattern.replace('/', '-'),
+    ));
+  }
 }
 
 function merge(template: any, fragment: any): void {

packages/@aws-cdk/core/test/stack.test.ts

@@ -1191,6 +1191,38 @@ describe('stack', () => {
     expect(new Stack(app, 'Stack', { analyticsReporting: true })._versionReportingEnabled).toBeDefined();
 
   });
+
+  test('requires bundling when wildcard is specified in BUNDLING_STACKS', () => {
+    const app = new App();
+    const stack = new Stack(app, 'Stack');
+    stack.node.setContext(cxapi.BUNDLING_STACKS, ['*']);
+    expect(stack.bundlingRequired).toBe(true);
+
+  });
+
+  test('requires bundling when stackName has an exact match in BUNDLING_STACKS', () => {
+    const app = new App();
+    const stack = new Stack(app, 'Stack');
+    stack.node.setContext(cxapi.BUNDLING_STACKS, ['Stack']);
+    expect(stack.bundlingRequired).toBe(true);
+
+  });
+
+  test('does not require bundling when no item from BUILDING_STACKS matches stackName', () => {
+    const app = new App();
+    const stack = new Stack(app, 'Stack');
+    stack.node.setContext(cxapi.BUNDLING_STACKS, ['Stac']);
+    expect(stack.bundlingRequired).toBe(false);
+
+  });
+
+  test('does not require bundling when BUNDLING_STACKS is empty', () => {
+    const app = new App();
+    const stack = new Stack(app, 'Stack');
+    stack.node.setContext(cxapi.BUNDLING_STACKS, []);
+    expect(stack.bundlingRequired).toBe(false);
+
+  });
 });
 
 describe('regionalFact', () => {