Customizable AsyncResource.type and create-resource

[imjuni]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

• pass AsyncResource factory
• pass AsyncResource.type

index.js

fastify.addHook(hook, (req, res, done) => {
    const defaultStoreValues = hasDefaultStoreValuesFactory
      ? opts.defaultStoreValues(req)
      : opts.defaultStoreValues

    asyncLocalStorage.run({ ...defaultStoreValues }, () => {
      const asyncResource =
        opts.createResource != null
          ? opts.createResource(req, requestContext)
          : new AsyncResource(
              opts.resourceType != null ? opts.resourceType : 'fastify-request-context',
            )
      req[asyncResourceSymbol] = asyncResource
      asyncResource.runInAsyncScope(done, req.raw)
    })
  })

Motivation

When using TypeORM or Prisma, logging can be customized: there is a way to use the triggerId of the AsyncContext to find the AsyncResource in order to pass the request.id to the logger. This would require either changing the type of the AsyncResource, or a factory that allows developers to create AsyncResources in whatever form the developers want.

Example

// async_hooks.createHook
watcher
      .setupInitHook()
      .setupBeforeHook()
      .setupAfterHook()
      .setupDestroyHook()
      .setupPromiseResolveHook()
      .start()
      .on(
        'INIT',
        ({
          asyncId,
          type,
          resource,
          triggerAsyncId,
        }: {
          asyncId: number;
          type: string;
          triggerAsyncId: number;
          executionAsyncId: number;
          resource: object;
        }) => {
          idMap.set(asyncId, triggerAsyncId);

          // customized AsyncResource.type
          if (type === 'fastify-request-context' || type === 'tid-async-resource') {
            resourceMap.set(asyncId, resource);
          }
        },
      )
      
// getStore
getStore<T = AsyncResource>(asyncId: number) {
    let resource: object | undefined = resourceMap.get(asyncId);

    if (resource != null) {
      return resource as T;
    }

    let id = idMap.get(asyncId);
    let sentinel = 0;

    while (id != null && sentinel < 1000) {
      resource = resourceMap.get(id);

      if (resource != null) {
        return resource as T;
      }

      id = idMap.get(id);
      sentinel += 1;
    }

    return undefined;
  }

[kibertoad]

Would you be open to send a PR for this? Please remember to include tests and documentation!

[imjuni]

I added this feature by #173, but the test fails. This feature is expected to enhance issue #153 as well.