feat: minimum tweak to use bundling for building

- This work is done according to the comment:
  rnag#10 (comment)

Author: kikuomax

lib/bundling.ts

@@ -6,16 +6,24 @@ import {
     Code,
     Runtime,
 } from 'aws-cdk-lib/aws-lambda';
-import { dirname } from 'path';
+import * as fs from 'fs';
+import * as path from 'path';
+import { build } from './build';
 
 /**
  * Options for bundling
  */
 export interface BundlingProps extends DockerRunOptions {
     /**
-     * CDK output (staging) directory for the lambda function
+     * Path to the directory that contains the project to be built; i.e., the
+     * directory containing `Cargo.toml`.
      */
-    readonly handlerDir: string;
+    readonly entry: string;
+
+    /**
+     * Executable name.
+     */
+    readonly bin?: string;
 
     /**
      * The runtime of the lambda function
@@ -26,6 +34,11 @@ export interface BundlingProps extends DockerRunOptions {
      * The system architecture of the lambda function
      */
     readonly architecture: Architecture;
+
+    /**
+     * Target of `cargo build`.
+     */
+    readonly target: string;
 }
 
 /**
@@ -35,7 +48,7 @@ export class Bundling implements cdk.BundlingOptions {
     public static bundle(options: BundlingProps): AssetCode {
         const bundling = new Bundling(options);
 
-        return Code.fromAsset(dirname(options.handlerDir), {
+        return Code.fromAsset(options.entry, {
             assetHashType: cdk.AssetHashType.OUTPUT,
             bundling: {
                 image: bundling.image,
@@ -54,9 +67,22 @@ export class Bundling implements cdk.BundlingOptions {
         this.image = cdk.DockerImage.fromRegistry('dummy'); // Do not build if we don't need to
 
         this.local = {
-            tryBundle(outputDir: string) {
-                // TODO
-                console.log(`BUNDLING...: ${outputDir}`);
+            tryBundle(outDir: string) {
+                console.log(`BUNDLING...: ${outDir}`);
+                build({
+                    entry: props.entry,
+                    bin: props.bin,
+                    target: props.target,
+                    outDir,
+                });
+                // moves <bin>/bootstrap → ./bootstrap
+                // and cleans up the empty folder
+                const binDir = path.join(outDir, props.bin!);
+                fs.renameSync(
+                  path.join(binDir, 'bootstrap'),
+                  path.join(outDir, 'bootstrap')
+                );
+                fs.rmdirSync(binDir);
 
                 return true;
             },

lib/function.ts

@@ -3,8 +3,8 @@ import { Construct } from 'constructs';
 import { join } from 'path';
 import { performance } from 'perf_hooks';
 import { Settings } from '.';
-import { BaseBuildProps, build } from './build';
-// import { Bundling } from './bundling';
+import { BaseBuildProps } from './build';
+import { Bundling } from './bundling';
 import {
     Code,
     Function,
@@ -99,27 +99,6 @@ export class RustFunction extends Function {
                 'T'
             );
 
-        // Build with `cargo-lambda`
-        if (shouldBuild && !Settings.SKIP_BUILD) {
-            let start = performance.now();
-
-            build({
-                ...props,
-                entry,
-                bin: binName,
-                target: target,
-                outDir: buildDir,
-            });
-
-            logTime(start, `🎯  Cross-compile \`${executable}\``);
-        }
-        // Else, skip the build (or bundle) step.
-        //
-        // At a minimum, we need to ensure the output directory
-        // exists -- otherwise, CDK complains that it can't
-        // locate the asset.
-        else ensureDirExists(handlerDir);
-
         let lambdaEnv = props.environment;
         // Sets up logging if needed.
         //   Ref: https://rust-lang-nursery.github.io/rust-cookbook/development_tools/debugging/config_log.html
@@ -136,12 +115,13 @@ export class RustFunction extends Function {
             ...props,
             runtime: Settings.RUNTIME,
             architecture: arch,
-            code: Code.fromAsset(handlerDir),
-            // code: Bundling.bundle({
-            //     handlerDir,
-            //     runtime: Settings.RUNTIME,
-            //     architecture: arch,
-            // }),
+            code: Bundling.bundle({
+                entry,
+                bin: binName,
+                runtime: Settings.RUNTIME,
+                architecture: arch,
+                target,
+            }),
             handler: handler,
             environment: lambdaEnv,
         });