fix(awscdk): AWS SDK v2 is not available for node18.x runtime

The Node.js 18.x runtime includes AWS SDK v3. Adapt esbuild
externals to reflect that.

Same as aws/aws-cdk#22989

src/awscdk/lambda-extension.ts

@@ -120,7 +120,7 @@ export class LambdaExtension extends Component {
     const bundle = bundler.addBundle(options.entrypoint, {
       platform: bundlerRuntime.esbuildPlatform,
       target: bundlerRuntime.esbuildTarget,
-      externals: ["aws-sdk"],
+      externals: bundlerRuntime.defaultExternals,
       outfile: `extensions/${name}`,
       // Make the output executable because Lambda expects to run
       // extensions as stand-alone programs alongside the main lambda

src/awscdk/lambda-function.ts

@@ -175,7 +175,7 @@ export class LambdaFunction extends Component {
     const bundle = bundler.addBundle(entrypoint, {
       target: runtime.esbuildTarget,
       platform: runtime.esbuildPlatform,
-      externals: ["aws-sdk"],
+      externals: runtime.defaultExternals,
       ...options.bundlingOptions,
       tsconfigPath: (project as TypeScriptProject)?.tsconfigDev?.fileName,
     });
@@ -283,6 +283,18 @@ export class LambdaFunction extends Component {
   }
 }
 
+/**
+ * Options for the AWS Lambda function runtime
+ */
+export interface LambdaRuntimeOptions {
+  /**
+   * Packages that are considered externals by default when bundling
+   *
+   * @default ['@aws-sdk/*']
+   */
+  readonly defaultExternals?: string[];
+}
+
 /**
  * The runtime for the AWS Lambda function.
  */
@@ -293,31 +305,35 @@ export class LambdaRuntime {
    */
   public static readonly NODEJS_10_X = new LambdaRuntime(
     "nodejs10.x",
-    "node10"
+    "node10",
+    { defaultExternals: ["aws-sdk"] }
   );
 
   /**
    * Node.js 12.x
    */
   public static readonly NODEJS_12_X = new LambdaRuntime(
     "nodejs12.x",
-    "node12"
+    "node12",
+    { defaultExternals: ["aws-sdk"] }
   );
 
   /**
    * Node.js 14.x
    */
   public static readonly NODEJS_14_X = new LambdaRuntime(
     "nodejs14.x",
-    "node14"
+    "node14",
+    { defaultExternals: ["aws-sdk"] }
   );
 
   /**
    * Node.js 16.x
    */
   public static readonly NODEJS_16_X = new LambdaRuntime(
     "nodejs16.x",
-    "node16"
+    "node16",
+    { defaultExternals: ["aws-sdk"] }
   );
 
   /**
@@ -330,6 +346,8 @@ export class LambdaRuntime {
 
   public readonly esbuildPlatform = "node";
 
+  public readonly defaultExternals: string[];
+
   public constructor(
     /**
      * The Node.js runtime to use
@@ -339,6 +357,13 @@ export class LambdaRuntime {
     /**
      * The esbuild setting to use.
      */
-    public readonly esbuildTarget: string
-  ) {}
+    public readonly esbuildTarget: string,
+
+    /**
+     * Options for this runtime.
+     */
+    options?: LambdaRuntimeOptions
+  ) {
+    this.defaultExternals = options?.defaultExternals ?? ["@aws-sdk/*"];
+  }
 }

test/awscdk/lambda-function.test.ts

@@ -131,6 +131,31 @@ test("runtime can be used to customize the lambda runtime and esbuild target", (
   });
 });
 
+test("aws sdk v3 packages are considered external with NODEJS_18_X", () => {
+  const project = new TypeScriptProject({
+    name: "hello",
+    defaultReleaseBranch: "main",
+  });
+
+  new awscdk.LambdaFunction(project, {
+    entrypoint: join("src", "hello.lambda.ts"),
+    runtime: awscdk.LambdaRuntime.NODEJS_18_X,
+    cdkDeps: cdkDepsForProject(project),
+  });
+
+  const snapshot = Testing.synth(project);
+  const tasks = snapshot[".projen/tasks.json"].tasks;
+  expect(tasks["bundle:hello.lambda"]).toEqual({
+    description: "Create a JavaScript bundle from src/hello.lambda.ts",
+    name: "bundle:hello.lambda",
+    steps: [
+      {
+        exec: 'esbuild --bundle src/hello.lambda.ts --target="node18" --platform="node" --outfile="assets/hello.lambda/index.js" --tsconfig="tsconfig.dev.json" --external:@aws-sdk/*',
+      },
+    ],
+  });
+});
+
 test("AWS SDK connection reuse", () => {
   const project = new TypeScriptProject({
     name: "hello",