feat: use builder plugin metadata to set ODB TTL

[emilyzhang]

Which problem is this pull request solving?
We need a way to pass TTL information from an ODB function response to the rest of our systems which interpret and act on the specified TTL.

List other issues or pull requests related to this problem
Relevant issue: https://github.com/netlify/runtime-integrated-apps/issues/127

Describe the solution you've chosen
We are passing TTL information from the function response struct into the builder metadata, which is information that we receive in our downstream services.

Another solution would be passing TTL information through a custom header of some sort, but we decided to use the builder metadata to more tightly couple the TTL information to the ODB feature.

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[ascorbic]

It would be great if we could type BuilderResponse, extending Response. That way we could do it without adding an unused ttl prop to normal funciton reponses, which could get confusing. You could then make that the return type of the funciton returned by wrapHandler.

[eduardoboucas]

It would be great if we could type BuilderResponse, extending Response. That way we could do it without adding an unused ttl prop to normal funciton reponses, which could get confusing. You could then make that the return type of the funciton returned by wrapHandler.

I agree with @ascorbic! That would be a nice way of differentiating the response type of normal functions from ODBs.

[ascorbic]

But otherwise this is great. I reckon we should avoid merging this until it actually works (even if not launched or properly documented), as it's effectively the public API for the feature.

[emilyzhang]

@ascorbic @eduardoboucas do you know if there's any way i can make a "test" release for integration testing? the main issue re: waiting to merge until production is that i can't think of a good way otherwise to test the ODB TTL/SWR behavior in staging/production.

[eduardoboucas]

@emilyzhang you can publish a beta version from this branch using the tag property.

Example:

1. Publish: npm publish --tag=beta
2. Install: npm install @netlify/functions@beta

[emilyzhang]

@eduardoboucas thank you!

[ascorbic]

@emilyzhang I've tried this and the types aren't being enforced in handlers. I think we need a new Builder type, that's like a Handler but returns a BuilderResponse. Happy to pair on this with you tomorrow if you'd like

[emilyzhang]

@ascorbic i'd love to, but i'm unfortunately out for the rest of the week. i can try making changes based on your descriptions today though, and i would also love to pair when i'm back next week! also out of curiosity, how were you able to try/test this to see that the types weren't being enforced? thanks!

[ascorbic]

Nothing fancy! I checked-out your PR, and created a test.ts file that imported it.

import { builder } from './dist/lib/builder'

async function odb() {
  return {
    body: '',
    statusCode: 200,
    ttl: 'this should fail',
  }
}

export const handler = builder(odb)

[ascorbic]

Great stuff! I think I've worked out a way to prohibit ttl in regular handlers. See my separate comment.

[ascorbic]

This looks great, and should be ready to merge. We shouldn't put it in until it's available in all nodes (even if it's not GA). We should probably set it to draft to ensure it doesn't go in yet.

[eduardoboucas]

I left a comment with a couple of questions, but otherwise this looks great!

[emilyzhang]

@ascorbic @eduardoboucas Thanks for your comments!

This could actually use another look because of the auth work (#217) that was merged in earlier today, I had to fix some merge conflicts.

I'll be making another beta release to test that this functionality still works (I've also tested using Matt Kane's local ODB function method described earlier in this PR and that looks good). Thanks!

Update: I've since tested that both auth and ODB changes work as expected with a beta version of the latest changes.

[eduardoboucas]

LGTM!

[ascorbic]

Looking good! We can merge this as soon as support is deployed to all nodes.