Using file access for Vercel deployment

Problem

When using libraries that need file access, there is no supported way to do this with Vercel + Redwood. Typically the use case here is templating libraries that initialize with a template directory of files, which the serverless functions need access to.

Attempts to make this work

Using the following vercel config option - https://vercel.com/knowledge/how-can-i-use-files-in-serverless-functions. By including the following vercel.json config

{
    "functions": {
        "api/src/functions/*.js": {
             "includeFiles": "api/src/templates/**"
        }
     }
}

However, you get an error. I’ve tried many different patterns but they all seem to fail with the following message

Error: The pattern "api/src/functions/*.js" defined in functionsdoesn't match any Serverless Functions inside theapi directory. Learn More: https://vercel.link/unmatched-function-pattern

The following repo can be used to reproduce the issue - https://github.com/viperfx/redwood-fs-vercel-bug

Vercel’s response

After getting in touch with Vercel, and providing them with a repo to reproduce the issue, eventually, I got a reply from an engineer.

Checking this issue with one of our engineers, Vercel can’t support “includeFiles” with Redwood at the moment. The way Redwood is configured is that it will bundle the dependencies together and all required files at build-time. Requiring a file at runtime will not work unless the file is also bundled in the function at the build-phase.

Checking the Redwood documentation and code-base, it appears you can’t run this code either on AWS Lambda or Netlify, as it is a framework limitation.

References

Known workaround for Netlify - https://community.redwoodjs.com/t/how-can-i-read-and-bundle-a-non-js-or-ts-file-from-my-netlify-function/1021/11

[krinoid]

I’ve tried using the zip workaround on Vercel but it doesn’t work due to the zip not being available during build:

I can imagine that one can create a node script to do this during build, but I’m exploring other potential solutions/workarounds for my case.

[dthyresson]

I’ve chatted with @viperfx is Discord at it was I who referred him to the

Known workaround for Netlify - https://community.redwoodjs.com/t/how-can-i-read-and-bundle-a-non-js-or-ts-file-from-my-netlify-function/1021/11

that will inject the included file into the function zip created by Netlify’s zip-it-and-ship it build process.

zip -ur ${FUNCTIONS_DIST}/graphql.zip ./email/src/templates

It literally adds a file into the archive.

As Vercel notes:

Requiring a file at runtime will not work unless the file is also bundled in the function at the build-phase.

And that’s what that workaround does in the build plugin … and what would have to be solved in a general way during any deploy.

But, right now I don’t have a solution in mind.