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async_hooks: add sync enterWith to ALS · nodejs/node@4d5981b

3 files changed

lines changed

Original file line numberDiff line numberDiff line change

@@ -950,6 +950,48 @@ If this method is called outside of an asynchronous context initialized by

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calling `asyncLocalStorage.run` or `asyncLocalStorage.runAndReturn`, it will

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return `undefined`.

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### `asyncLocalStorage.enterWith(store)`

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<!-- YAML

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added: REPLACEME

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-->

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* `store` {any}

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Calling `asyncLocalStorage.enterWith(store)` will transition into the context

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for the remainder of the current synchronous execution and will persist

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through any following asynchronous calls.

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Example:

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```js

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const store = { id: 1 };

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asyncLocalStorage.enterWith(store);

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asyncLocalStorage.getStore(); // Returns the store object

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someAsyncOperation(() => {

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asyncLocalStorage.getStore(); // Returns the same object

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});

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```

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This transition will continue for the _entire_ synchronous execution.

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This means that if, for example, the context is entered within an event

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handler subsequent event handlers will also run within that context unless

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specifically bound to another context with an `AsyncResource`.

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```js

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const store = { id: 1 };

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emitter.on('my-event', () => {

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asyncLocalStorage.enterWith(store);

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});

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emitter.on('my-event', () => {

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asyncLocalStorage.getStore(); // Returns the same object

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});

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asyncLocalStorage.getStore(); // Returns undefined

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emitter.emit('my-event');

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asyncLocalStorage.getStore(); // Returns the same object

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```

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### `asyncLocalStorage.run(store, callback[, ...args])`

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<!-- YAML

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added: v13.10.0

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@@ -245,7 +245,7 @@ class AsyncLocalStorage {

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}

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}

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_enter(store) {

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enterWith(store) {

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if (!this.enabled) {

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this.enabled = true;

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storageList.push(this);

@@ -258,7 +258,7 @@ class AsyncLocalStorage {

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runSyncAndReturn(store, callback, ...args) {

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const resource = executionAsyncResource();

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const outerStore = resource[this.kResourceStore];

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this._enter(store);

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this.enterWith(store);

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try {

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return callback(...args);

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} finally {

@@ -288,7 +288,7 @@ class AsyncLocalStorage {

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run(store, callback, ...args) {

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const resource = executionAsyncResource();

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const outerStore = resource[this.kResourceStore];

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this._enter(store);

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this.enterWith(store);

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process.nextTick(callback, ...args);

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resource[this.kResourceStore] = outerStore;

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}

Original file line numberDiff line numberDiff line change

@@ -0,0 +1,20 @@

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'use strict';

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require('../common');

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const assert = require('assert');

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const { AsyncLocalStorage } = require('async_hooks');

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const asyncLocalStorage = new AsyncLocalStorage();

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setImmediate(() => {

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const store = { foo: 'bar' };

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asyncLocalStorage.enterWith(store);

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assert.strictEqual(asyncLocalStorage.getStore(), store);

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setTimeout(() => {

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assert.strictEqual(asyncLocalStorage.getStore(), store);

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}, 10);

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});

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setTimeout(() => {

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assert.strictEqual(asyncLocalStorage.getStore(), undefined);

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}, 10);