(@aws-cdk/aws-lambda-nodejs): "error: Could not resolve" while bundling without Docker

[sbassin]

I'm trying to bundle my Lambda using NodejsFunction but am failing. If I set forceDockerBundling to true (default is false), bundling (during cdk synth) is successful.

Reproduction Steps

    this.lambdaFunction = new lambdaNodeJs.NodejsFunction(this, 'MyLambda', {
      functionName: 'my-function',
      runtime: lambda.Runtime.NODEJS_12_X,
      memorySize: 256,
      depsLockFilePath: '../lambda',
      entry: '../lambda/build/index.js',
      handler: 'main',
      bundling: {
        externalModules: ['graphql'], // I found out this might be a problem due to an error I saw when forceDockerBundling was set to true
      },
      environment: {
        MY_FLAG: 'true',
      },
    });

For what it's worth, my project is structured like:

├─ my-project
├── cdk
├── lambda

What did you expect to happen?

I expected the Lambda and (hopefully) its dependencies would be packaged using esbuild.

What actually happened?

$ cdk synth
Bundling asset FooStack/FooLambda/MyLambda/Code/Stage...
 > error: Could not resolve "../lambda/build/index.js"

1 error

Environment

• CDK CLI Version : 1.78.0
• Framework Version: 1.78.0
• Node.js Version: 12.20.0
• OS : macOS 10.15.7
• Language (Version): TypeScript 3.9.7

Other

I've tried setting the entry to a file that doesn't exist, and I get a different error altogether. So I'm pretty sure that the file is being found, but some other problem is happening.

# cdk synth
Cannot find entry file at ../lambda/build/foo.js

---

This is 🐛 Bug Report

[jogold]

Can you show the content of the file at ../lambda/build/index.js?

Also can you share the full stack trace of the error?

[sbassin]

@jogold, the ../lambda/build/index.js is the result of a tsc build. Now that I think of it, when I was trying to bundle with Docker, I noticed a number of warnings about how dd-trace imports are set up. I didn't address them since they're just warnings, but now I'm curious… 🤔

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const datadog_lambda_js_1 = require("datadog-lambda-js");
const dd_trace_1 = __importDefault(require("dd-trace"));
const processIncomingEvent_1 = __importDefault(require("./processIncomingEvent"));
dd_trace_1.default.init();
exports.main = datadog_lambda_js_1.datadog(processIncomingEvent_1.default);
//# sourceMappingURL=data:application/json;base64,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

Here's the stack trace I get when running cdk synth -v:

Error: Subprocess exited with error 1
    at ChildProcess.<anonymous> (/Users/sbassin/.nvm/versions/node/v12.20.0/lib/node_modules/cdk/node_modules/aws-cdk/lib/api/cxapp/exec.ts:122:23)
    at ChildProcess.emit (events.js:314:20)
    at ChildProcess.EventEmitter.emit (domain.js:483:12)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:276:12)

[jogold]

What happens if you point your entry to the .ts file?

Can you please share the full console output of the error from Bundling... and also with the Could not resolve part?

[sbassin]

Pointing to the .ts file gives me the same error:

$ cdk synth
Bundling asset FooStack/FooLambda/MyLambda/Code/Stage...
 > error: Could not resolve "../lambda/src/index.ts"

1 error
Failed to bundle asset FooStack/FooLambda/MyLambda/Code/Stage, bundle output is located at /Users/sbassin/Development/my-project/cdk/cdk.out/bundling-temp-d9c47ce4518849903f729fa37b1175435ea4dc7ce04d627c791c0fb3fb76f676-error: Error: bash exited with status 1
Subprocess exited with error 1
Error: Subprocess exited with error 1
    at ChildProcess.<anonymous> (/Users/sbassin/.nvm/versions/node/v12.20.0/lib/node_modules/cdk/node_modules/aws-cdk/lib/api/cxapp/exec.ts:122:23)
    at ChildProcess.emit (events.js:314:20)
    at ChildProcess.EventEmitter.emit (domain.js:483:12)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:276:12)

Is that what you're looking for, @jogold?

And there's nothing in the directory indicated as the location of the bundle output.

I appreciate the help!

[jogold]

depsLockFilePath should point to your lockfile (not the directory containing it), can you test this?

If this doesn't work, it would help if you could share a full repro.

[jogold]

Can you also test with absolute paths?

[sbassin]

I changed to:

      depsLockFilePath: '../lambda/package-lock.json',

but got the same error.

I just saw your edit about absolute paths and tried that. I haven't confirmed if I can deploy a working Lambda that way, but I did get cdk synth to complete successfully! That'll be a difficult long-term solution, but I understand this is an experimental feature you're working on. Thanks! 🎉

Please let me know if there's anything else you'd like me to try on my end. If you want a full repository, I'll have a bit of sanitizing to do.

[jogold]

Can you just confirm which of the paths must be absolute? Is it depsLockFilePath only?

[jogold]

Also note that the idea of the NodejsFunction is that you don't have to split your project between CDK and Lambda. Everything can live together and have a common package.json file. And you can point to a TS file.

[sbassin]

Looks like only depsLockFilePath is requiring the absolute path. entry doesn't seem to require that.

For what it's worth, I was actually able to run cdk synth while providing the absolute path to the folder containing package-lock.json. I didn't have to include /package-lock.json.

I'm curious what the project organization would look like if I don't split the project. Possibly this?

├─ my-project
├── src
├─── cdk
├─── lambda1
├─── lambda2

One concern I'd have about merging them would be if I want different versions of Node.js or TypeScript in the Lambda from what CDK itself supports. I'm pretty new to JS/TS and CDK, so I'm not sure if that's a valid concern, though.

[jogold]

I'm curious what the project organization would look like if I don't split the project.

I recommend the approach described in https://github.com/aws/aws-cdk/blob/v1.78.0/packages/@aws-cdk/aws-lambda-nodejs/README.md#nodejs-function where your handler lives next to the file where the NodejsFunction is defined.

If everything lives together you can share utils and types between your infra code and Lambda code.

(also you don't have to specify depsLockFilePath in this case, there's only one lock file at the root of your repo and it will be detected)

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[sbassin]

Thanks for the help and the fix, @jogold! 🙇‍♂️