ALS is deprecated and archived, Better to use AsyncLocalStorage class fom the async_hook std module

[ankitsny]

https://github.com/vicanso/async-local-storage is archived.

Working Example with the native AsyncLocalStorage:

// ctx.ts
import { AsyncLocalStorage } from "async_hooks";

const asyncLocalStorage = new AsyncLocalStorage<Map<string, unknown>>();

export const setInCtx = <T = unknown>(key: string, value: T): void => {
  asyncLocalStorage.getStore()?.set(key, value);
}

export const getFromCtx = <T = unknown>(key: string): T | undefined => asyncLocalStorage.getStore()?.get(key) as T;

export const initReqContext = (req: any, _res: any, next: any) => {
  asyncLocalStorage.run(new Map(), () => {
    const store = asyncLocalStorage.getStore();
    if (store){
      store.set("key",  "value");
    }
    next();
  });
}

// server.ts / index.ts 

import { initReqContext } from './ctx';

// this only works with preHandler hooks
server.addHook("preHandler", initReqContext)

you can start using get and set function to access the store

[kibertoad]

Check out the underlying library that we use, it already uses ALS when supported by used Node version.

[Uzlopak]

As far as I can see if is part of node 14. So i agree, we can replace this dependency with the built in.

Can you provide a PR?

[ankitsny]

This is not an issue, but I struggled to integrate the AsyncLocalStorage with fastify so I am sharing the solution here.
I noticed it only work with the preHandler hook.

[kibertoad]

This plugin works with any lifecycle phase, and does not use the library that you mentioned.
@Uzlopak what's the minimum Node requirement for fastify 4?

[Uzlopak]

node 14 is the minimum requirement.

[kibertoad]

I will create a PR then

[voxpelli]

I think there's a mix up between @kibertoad's asynchronous-local-storage module which is used here and the archived async-local-storage module.

The asynchronous-local-storage module uses the AsyncLocalStorage from node:async_hooks when that's enabled, else downgrades to cls-hooked.

It's probably time to drop cls-hooked in asynchronous-local-storage, but that's a separate issue for that repository I think, its only an issue for this project if that would make asynchronous-local-storage so small that it would make more sense to include it directly within this module.

[kibertoad]

Yeah, I was planning to do that for quite a while. PR would be welcome

[voxpelli]

Yeah, I was planning to do that for quite a while. PR would be welcome

@kibertoad PR for which of the two?

1. Removing cls-hooked from asynchronous-local-storage
2. Moving the node:async_hooks based part of asynchronous-local-storage into this module, removing asynchronous-local-storage as a separate dependency

[kibertoad]

The second one.

[mcollina]

While bumping Fastify major is hard, bumping an individual package is easy. There are good reasons to bump this package major version and drop Node.js v14.

[voxpelli]

I'm making a PR