Error The script will never generate a response on Cloudflare Worker when using mesh

[abby-ran]

### Issue workflow progress

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• 1. The issue provides a reproduction available on
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Make sure to fork this template and run yarn generate in the terminal.

Please make sure Mesh package versions under package.json matches yours.

• 2. A failing test has been provided
• 3. A local solution has been provided
• 4. A pull request is pending review

---

Describe the bug

We have a POC of a graphql gateway using the mesh library on a Cloudflare worker.
When running performance testing we notices a lot of these errors: The script will never generate a response.
On research of this error we think this is due to meshInstance$ being a global variable and several requests trying to access it at the same time, and they fail with a failed Promise error. I see this error in the console log:
A hanging Promise was canceled. This happens when the worker runtime is waiting for a Promise from JavaScript to resolve, but has detected that the Promise cannot possibly ever resolve because all code and events related to the Promise's I/O context have already finished.
Our worker code is very simple, this is the index.ts:

import { createBuiltMeshHTTPHandler } from '../.mesh';
self.addEventListener('fetch', createBuiltMeshHTTPHandler());

with a few online API graphql endpoints in our yaml file

To Reproduce Steps to reproduce the behavior:

Create a new mesh gateway and with that index.ts and load to a Cloudflare worker using wrangler.

Expected behavior

Being able to run a load test without having these unresolved Promise errors

Environment:
"wrangler": "2.8.0",
"@graphql-mesh/cli": "^0.82.10",
"@graphql-mesh/graphql": "^0.33.8",
"@graphql-mesh/runtime": "^0.46.5",
"@graphql-mesh/transform-resolvers-composition": "^0.13.5",
"graphql": "^16.6.0",
"http-status-codes": "^2.2.0",
"envelop": "^1.4.0"

• OS:
• @graphql-mesh/...:
• NodeJS:
  v18.13.0

Additional context

This is very similar to this issue but no solution was offered

[tv42]

I'd assume this is https://zuplo.com/blog/the-script-will-never-generate-a-response-on-cloudflare-workers/

I haven't yet sorted what hoops to jump through to avoid this. Seems really hard to write e.g. in-memory caching with this limitation.

[abby-ran]

We found that the node compatibility was causing this, once we removed it we haven't seen any errors. We moved to using plugins instead of transforms in the yaml file for our mesh gateway, so we didn't need the node compatibility anymore!

[ardatan]

Awesome! So we can close this issue then!

[abby-ran]

Yes this is solved for us, thanks :)

[ardatan]

Do you think we should mention that in our docs?

[abby-ran]

That would be great.
There seems to be an issue with that node compatibility, it would be great to have a note in the docs that this causes errors when running the mesh on a CF worker

[ardatan]

Would you contribute to our docs with a PR because I think the words from your perspective would be better :)

[abby-ran]

yeah sure :) which doc\file should I add this too?

[ardatan]

Maybe here? What do you think?
https://github.com/Urigo/graphql-mesh/blob/master/website/src/pages/docs/getting-started/deploy-mesh-gateway.mdx#deploy-mesh-on-cloudflare-workers