mscorlib: Error: Cannot find module 'crypto' after using Webpack on an application

Question

I've got a project which utilizes the openpgpjs library as a dependency, and I'm WebPacking up this whole application for deployment on an Azure Functions to resolve cold start issues.

The Azure functions work fine when running locally in a non-Webpacked format, but as soon as I WebPack up the files I keep getting the error at runtime:

"mscorlib: Error: Cannot find module 'crypto'"

The code which is triggering this error appears to be from Openpgpjs's util.js.

This whole file is here: https://github.com/openpgpjs/openpgpjs/blob/master/src/util.js

The offending code snipper is below:

/**
   * Get native Node.js crypto api. The default configuration is to use
   * the api when available. But it can also be deactivated with config.use_native
   * @return {Object}   The crypto module or 'undefined'
   */
  getNodeCrypto: function() {
    if (!this.detectNode() || !config.use_native) {
      return;
    }

    return require('crypto');
  },

For the life of me, I can't figure out why this is happening and I can't get the error to go away.

I'm using my own script pack-git to do the Webpacking, etc. However, I get the same behavior if I use Azure's function pack. (Which didn't exist when I started writing the code for master-pack.

As a result I think this has something to do with the way the library is playing with WebPack, but I'm not sure where to begin in figuring it out/troubleshooting.

Does anyone have any ideas on what is going wrong, or at least ideas to help me further isolate the problem?

------------------- EDIT ---------------------

I've created a simple project that reproduces the issue when run through Funcpack, which is using Webpack.

Reproduction Steps:

1. Install funcpack, and azure-functions-cli globally:

   npm install -g funcpack azure-functions-cli

2. Clone the following repo:

   git clone https://github.com/securityvoid/funcpack-bug.git

3. Run an npm install while in the folder you cloned into:

   npm install

4. Start the Azure Function with azure-functions-cli from within the base of the cloned repository.

   func run aaaa

5. Navigate to the following URL and validate you get a blank page back, which shows its working:

   http://localhost:7071/Test

6. Stop the azure-functions-cli by closing the window.

7. Run funcpack in the base of the directory:

   funcpack

8. Repeat steps 4-5

NOTE: This time you get an error about the module crypto not being found.