@aws-cdk/aws-lambda-nodejs: esbuildArgs alias must use : instead of =

[abaschen]

Describe the bug

I want to reference libs in my layers with import { somefunc } from '@layer/somelib';.
When setting the alias build argument for esbuild, it throws an error :

const opts = {
            bundling: {
                externalModules: ['@aws-sdk/*', 'aws-lambda', '@layer/*'],
                esbuildArgs: {
                    '--alias': '@layer=',
                },
            },
        };

It will generate a bundling step like this:

esbuild --bundle src/index.js  --outfile=dist/index.js --alias=@layer=
✘ [ERROR] Invalid build flag: "--alias=@layer="

  Use "--alias:@layer=" instead of "--alias=@layer=". Flags that can be re-specified multiple times
  use ":" instead of "=".

By replacing the = with : it solves the issue

Expected Behavior

esbuildArgs key/value needs : when it can be re-specified.

Current Behavior

esbuildArgs['--alias'] is using = which leads to a bundle error.

Full stack:

    at AssetStaging.bundle (node_modules/aws-cdk-lib/core/lib/asset-staging.js:2:603)
    at AssetStaging.stageByBundling (node_modules/aws-cdk-lib/core/lib/asset-staging.js:1:4540)
    at stageThisAsset (node_modules/aws-cdk-lib/core/lib/asset-staging.js:1:1901)
    at Cache.obtain (node_modules/aws-cdk-lib/core/lib/private/cache.js:1:242)
    at new AssetStaging (node_modules/aws-cdk-lib/core/lib/asset-staging.js:1:2296)
    at new Asset (node_modules/aws-cdk-lib/aws-s3-assets/lib/asset.js:1:736)
    at AssetCode.bind (node_modules/aws-cdk-lib/aws-lambda/lib/code.js:1:4628)
    at new Function (node_modules/aws-cdk-lib/aws-lambda/lib/function.js:1:2829)
    at new NodejsFunction (node_modules/aws-cdk-lib/aws-lambda-nodejs/lib/function.js:1:1171)
    at new MyConstruct (stack/MyConstruct .ts:18:9)

Reproduction Steps

CDK:

new NodejsFunction(this, 'test-function', {
            entry: 'src/functions/test/index.ts',
            architecture: Architecture.ARM_64,
            runtime: Runtime.NODEJS_18_X,
            memorySize: 128,
            tracing: Tracing.ACTIVE,
            handler: 'index.handler',
            timeout: Duration.seconds(30),
            retryAttempts: 0,
            logRetention: RetentionDays.ONE_DAY,
            bundling: {
                minify: process.env.NODE_ENV === 'production',
                banner: 'import { createRequire } from \'module\'; const require = createRequire(import.meta.url);',
                mainFields: ['module', 'main'],
                target: 'node18',
                externalModules: ['@aws-sdk/*', 'aws-lambda', '@layer/*'],
                esbuildArgs: {
                    '--alias': '@layer=',
                },
                format: OutputFormat.ESM,
            },
        });

Lambda

// src/functions/test/index.ts
import { ping } from '@layer/echo';

Layer

// dist/layers/echo/index.js
export{console.log as ping};

Possible Solution

esbuildArgs key/value needs : when it can be re-specified; from documentation:

CLI: If you are using the command-line API, it may be helpful to know that the flags come in one of three forms: --foo, --foo=bar, or --foo:bar. The form --foo is used for enabling boolean flags such as --minify, the form --foo=bar is used for flags that have a single value and are only specified once such as --platform=, and the form --foo:bar is used for flags that have multiple values and can be re-specified multiple times such as --external:.

Additional Information/Context

No response

CDK CLI Version

2.76.0 (build 78c411b)

Framework Version

No response

Node.js Version

Node.js v19.8.1

OS

WSL2 Ubuntu

Language

Typescript

Language Version

Typescript (5.0.4)

Other information

No response

[abaschen]

Using this argument instead will solve the issue:

esbuildArgs: {
    '--alias:@layer': 'my/new/path',
},

It will generate the proper --alias:@layer=my/new/path argument

In my case :

  externalModules: ['@aws-sdk/*', 'aws-lambda', '@layer/*', '/opt/nodejs/node_modules/*'],
  esbuildArgs: {
    '--alias:@layer': '/opt/nodejs/node_modules',
  },

[peterwoodworth]

You're right, we don't have any logic for handling this. The code that currently handles this is found here

aws-cdk/packages/aws-cdk-lib/aws-lambda-nodejs/lib/bundling.ts

Lines 396 to 408 in 5bdb012

	function toCliArgs(esbuildArgs: { [key: string]: string | boolean }): string {
	const args = [];
	for (const [key, value] of Object.entries(esbuildArgs)) {
	if (value === true || value === '') {
	args.push(key);
	} else if (value) {
	args.push(`${key}="${value}"`);
	}
	}
	return args.join(' ');
	}

Looking at the documentation, it doesn't appear your workaround would work for all use cases, is that right?

[abaschen]

It's just a workaround and won't work for empty value but besides that seems like an OK'ish effortless solution.

---

to fix it though we would need to go through all of them. but by default we could keep the '=' sign :

   const repeatableArgs = ['alias'];
   for (const [key, value] of Object.entries(esbuildArgs)) { 
     if (value === true || value === '') { 
       args.push(key); 
     } else if (value) { 
       const separator = repeatableArgs.includes(key) ? ':' : '=';
       args.push(`${key}${separator}"${value}"`); 
     } 
   } 

Something like that and fill the repeatableArgs with all the correct keys.

Or get it from the types https://github.com/evanw/esbuild/blob/main/lib/shared/types.ts it seems that any types with Record or string[] would be with ':' ?

[github-actions]

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