feature() add async_hooks module (async storage) [BLOCKED]

[kamilmysliwiec]

PR Checklist

Please check if your PR fulfills the following requirements:

• [x] The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• [x] Tests for the changes have been added (for bug fixes / features)
• [ ] Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: N/A

What is the new behavior?

AsyncHooksModule which uses async_hooks module capabilities (share async state, for example, between HTTP requests). Blocked due to memory leaks - async_hooks is still in experimental stage.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[coveralls]

Pull Request Test Coverage Report for Build 1344

• 32 of 56 (57.14%) changed or added relevant lines in 7 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.6%) to 92.516%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/common/hooks/async-hooks-middleware.ts	3	5	60.0%
packages/common/hooks/async-hooks-helper.ts	3	6	50.0%
packages/common/hooks/async-hooks-storage.ts	6	11	54.55%
packages/common/hooks/async-context.ts	13	27	48.15%
<!--	Total:	32	56

Totals
Change from base Build 1336:	-0.6%
Covered Lines:	3118
Relevant Lines:	3288

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 1346

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.002%) to 93.068%

---

Totals
Change from base Build 1336:	0.002%
Covered Lines:	3087
Relevant Lines:	3233

---

💛 - Coveralls

[elderapo]

It's been 2 years, async_hooks are still experimental but maybe we could get this feature behind the experimental flag?

[apricote]

We adopted the code from this PR in @narando/nest-xray to implement async storage. So far we have not encountered any bugs.

https://github.com/narando/nest-xray/tree/master/lib/async-hooks

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Instead of using async_hooks directly, we should explore using AsyncLocalStorage to provide this functionality. It was released in Node.js 14 and is part of the experimental async_hooks module.

[gelito]

Why not try to reactivate it? Two years later the technology has been improved.

[gms1]

Instead of using async_hooks directly, we should explore using AsyncLocalStorage to provide this functionality. It was released in Node.js 14 and is part of the experimental async_hooks module.

it has even been back ported to Node.js 12 ( the latest EOL release :-) )

[Papooch]

I was also looking for this functionality, so I spent some time researching and testing and the result is this package: https://github.com/Papooch/nestjs-cls It would be great if Nest provided some 'request hooks' so we could wrap the execution context of the whole request somehow instead of relying on a middleware or an 'enhancer' (though I don't know if that's even possible)

[mwebb33]

Any updates? This issue is basically 3 years old, and it seems like the node AsyncLocalStorage API has matured quite a bit in that time. I think it would make a huge impact on NestJS- specifically as a mechanism to pass req/ctx while avoiding the performance penalty of request scoped providers.

[kamilmysliwiec]

specifically as a mechanism to pass req/ctx while avoiding the performance penalty of request scoped providers.

I wouldn't be so sure that using AsyncLocalStorage atm would be better (performance-wise) than properly designed request-scoped providers.

Any updates? This issue is basically 3 years old

According to the official Node.js docs, async_hooks are still experimental https://nodejs.org/api/async_hooks.html and this PR won't get merged till that changes.

[kamilmysliwiec]

async_hooks are still experimental but if anyone wants to use this feature now, check out this library https://github.com/Papooch/nestjs-cls