Skip to content

[v12.x backport] async_hooks: add AsyncLocalStorage #32318

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
puzpuzpuz wants to merge 15 commits into from
Closed

[v12.x backport] async_hooks: add AsyncLocalStorage #32318

Changes from 1 commit
Commits
Show all changes
15 commits
Select commit Hold shift + click to select a range
8752332
async_hooks: add executionAsyncResource
mcollina May 4, 2018
1f61d3c
async_hooks: executionAsyncResource matches in hooks
Flarna Feb 16, 2020
adc1afb
src: move InternalCallbackScope to StartExecution
codebytere Feb 25, 2020
288663c
src: pass resource object along with InternalMakeCallback
addaleax Mar 3, 2020
0807da3
async_hooks: introduce async-context API
vdeturckheim Mar 1, 2019
bedb27e
async_hooks: add store arg in AsyncLocalStorage
puzpuzpuz Feb 24, 2020
be305fe
test: improve disable AsyncLocalStorage test
puzpuzpuz Feb 28, 2020
ecc5935
test: add GC test for disabled AsyncLocalStorage
puzpuzpuz Feb 26, 2020
5036117
async_hooks: fix ctx loss after nested ALS calls
puzpuzpuz Mar 4, 2020
e9b3918
async_hooks: add sync enterWith to ALS
Qard Feb 25, 2020
2e04161
test: add new scenario for async-local storage
HarshithaKP Mar 4, 2020
45ad080
benchmark: fix error on server close in AsyncLocalStorage benchmark
puzpuzpuz Mar 26, 2020
4cd19bc
async_hooks: prevent sync methods of async storage exiting outer context
Qard Feb 25, 2020
c6f7f55
async_hooks: merge run and exit methods
puzpuzpuz Mar 14, 2020
fce0272
doc: improve AsyncLocalStorage sample
puzpuzpuz Apr 10, 2020
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Prev Previous commit
doc: improve AsyncLocalStorage sample 
PR-URL: #32757
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
  • Loading branch information
@puzpuzpuz
puzpuzpuz committed Apr 14, 2020
commit fce02724b1bc908b70cbd1c0c89e5f3e760079a9
49 changes: 24 additions & 25 deletions doc/api/async_hooks.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -869,41 +869,40 @@ chains. It allows storing data throughout the lifetime of a web request
or any other asynchronous duration. It is similar to thread-local storage
in other languages.

The following example builds a logger that will always know the current HTTP
request and uses it to display enhanced logs without needing to explicitly
provide the current HTTP request to it.
The following example uses `AsyncLocalStorage` to build a simple logger
that assigns IDs to incoming HTTP requests and includes them in messages
logged within each request.

```js
const { AsyncLocalStorage } = require('async_hooks');
const http = require('http');
const { AsyncLocalStorage } = require('async_hooks');

const kReq = 'CURRENT_REQUEST';
const asyncLocalStorage = new AsyncLocalStorage();

function log(...args) {
const store = asyncLocalStorage.getStore();
// Make sure the store exists and it contains a request.
if (store && store.has(kReq)) {
const req = store.get(kReq);
// Prints `GET /items ERR could not do something
console.log(req.method, req.url, ...args);
} else {
console.log(...args);
}
function logWithId(msg) {
const id = asyncLocalStorage.getStore();
console.log(`${id !== undefined ? id : '-'}:`, msg);
}

http.createServer((request, response) => {
asyncLocalStorage.run(new Map(), () => {
const store = asyncLocalStorage.getStore();
store.set(kReq, request);
someAsyncOperation((err, result) => {
if (err) {
log('ERR', err.message);
}
let idSeq = 0;
http.createServer((req, res) => {
asyncLocalStorage.run(idSeq++, () => {
logWithId('start');
// Imagine any chain of async operations here
setImmediate(() => {
logWithId('finish');
res.end();
});
});
})
.listen(8080);
}).listen(8080);

http.get('http://localhost:8080');
http.get('http://localhost:8080');
// Prints:
// 0: start
// 1: start
// 0: finish
// 1: finish
```

When having multiple instances of `AsyncLocalStorage`, they are independent
Expand Down