NodejsFunction: External dependecy bundling not working?

[rupe120]

Describe the bug

I install a module and reference it in bundling.externalModules[] and the execution fails with a Module Not Found error

Expected Behavior

Successfully import external module

Current Behavior

With uuid both installed and referenced in bundling.externalModules[], the following error is produced.

{
    "errorType": "Runtime.ImportModuleError",
    "errorMessage": "Error: Cannot find module 'uuid'\nRequire stack:\n- /var/task/index.js\n- /var/runtime/index.mjs",
    "stack": [
        "Runtime.ImportModuleError: Error: Cannot find module 'uuid'",
        "Require stack:",
        "- /var/task/index.js",
        "- /var/runtime/index.mjs",
        "    at _loadUserApp (file:///var/runtime/index.mjs:997:17)",
        "    at async UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:1029:21)",
        "    at async start (file:///var/runtime/index.mjs:1192:23)",
        "    at async file:///var/runtime/index.mjs:1198:1"
    ]
}

Reproduction Steps

Deploy the following app and run the Lambda.

https://github.com/rupe120/cdk-typescript-bundling-dependency-test

Possible Solution

Unknown

Additional Information/Context

No response

CDK CLI Version

2.88.0

Framework Version

No response

Node.js Version

v18.16.1

OS

Windows 11 Enterprise build 22621.1702

Language

Typescript

Language Version

Typescript 5.1.6

Other information

No response

[tmokmss]

You should be able to use nodeModules instead of externalModules to make the package available on runtime environment without bundling it.

[jsec]

externalModules actually does the opposite of what you're expecting. It's a list of modules that esbuild will not bundle with your function, because they're considered external modules that are already available in the runtime (ie. @aws-sdk/*). So in this case, you wouldn't want to add uuid to externalModules, so that it's available to your lambda's runtime.

[peterwoodworth]

Thanks for the help offered, does this help unblock @rupe120?

[rupe120]

Thanks for the help offered, does this help unblock @rupe120?

I haven't tried it yet but I think this will resolve my issue.

I do feel like the description should be updated to reference the difference between the 2 properties.

[rupe120]

Yes, not listing the desired module in externalModules solved my issue.

[github-actions]

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