feat: add workerIdleMemoryLimit to support worker recycling in the event of node >16.11.0 memory leaks

.circleci/config.yml

@@ -42,7 +42,11 @@ jobs:
           node-version: lts/*
       - node/install-packages: *install
       - run:
-          command: JEST_JASMINE=1 yarn test-ci-partial --shard=$(expr $CIRCLE_NODE_INDEX + 1)/$CIRCLE_NODE_TOTAL && JEST_JASMINE=1 yarn test-leak
+          name: Test
+          command: JEST_JASMINE=1 yarn test-ci-partial --shard=$(expr $CIRCLE_NODE_INDEX + 1)/$CIRCLE_NODE_TOTAL
+      - run:
+          name: Leak test
+          command: JEST_JASMINE=1 yarn test-leak
       - store_test_results:
           path: reports/junit
 

.gitignore

@@ -53,3 +53,6 @@ api-extractor.json
 **/.pnp.*
 
 crowdin-cli.jar
+
+# We don't want these temp files
+packages/jest-worker/src/workers/__tests__/__temp__

CHANGELOG.md

@@ -5,6 +5,7 @@
 - `[jest-config]` [**BREAKING**] Make `snapshotFormat` default to `escapeString: false` and `printBasicPrototype: false` ([#13036](https://github.com/facebook/jest/pull/13036))
 - `[jest-environment-jsdom]` [**BREAKING**] Upgrade to `jsdom@20` ([#13037](https://github.com/facebook/jest/pull/13037))
 - `[pretty-format]` [**BREAKING**] Remove `ConvertAnsi` plugin in favour of `jest-serializer-ansi-escapes` ([#13040](https://github.com/facebook/jest/pull/13040))
+- `[jest-worker]` Adds `workerIdleMemoryLimit` option which is used as a check for worker memory leaks >= Node 16.11.0 and recycles child workers as required. ([#13056](https://github.com/facebook/jest/pull/13056))
 
 ### Fixes
 

docs/Configuration.md

@@ -2254,6 +2254,45 @@ Default: `true`
 
 Whether to use [`watchman`](https://facebook.github.io/watchman/) for file crawling.
 
+### `workerIdleMemoryLimit` \[number|string]
+
+Default: `undefined`
+
+Specifies the memory limit for workers before they are recycled and is primarily a work-around for [this issue](https://github.com/facebook/jest/issues/11956);
+
+After the worker has executed a test the memory usage of it is checked. If it exceeds the value specified the worker is killed and restarted. The limit can be specified in a number of different ways and whatever the result is `Math.floor` is used to turn it into an integer value:
+
+- `<= 1` - The value is assumed to be a percentage of system memory. So 0.5 sets the memory limit of the worker to half of the total system memory
+- `\> 1` - Assumed to be a fixed byte value. Because of the previous rule if you wanted a value of 1 byte (I don't know why) you could use `1.1`.
+- With units
+  - `50%` - As above, a percentage of total system memory
+  - `100KB`, `65MB`, etc - With units to denote a fixed memory limit.
+    - `K` / `KB` - Kilobytes (x1000)
+    - `KiB` - Kibibytes (x1024)
+    - `M` / `MB` - Megabytes
+    - `MiB` - Mebibytes
+    - `G` / `GB` - Gigabytes
+    - `GiB` - Gibibytes
+
+```js tab
+/** @type {import('jest').Config} */
+const config = {
+  workerIdleMemoryLimit: 0.2,
+};
+
+module.exports = config;
+```
+
+```ts tab
+import type {Config} from 'jest';
+
+const config: Config = {
+  workerIdleMemoryLimit: 0.2,
+};
+
+export default config;
+```
+
 ### `//` \[string]
 
 This option allows comments in `package.json`. Include the comment text as the value of this key:

e2e/__tests__/workerForceExit.test.ts

@@ -74,4 +74,4 @@ test('force exits a worker that fails to exit gracefully', async () => {
   expect(pidNumber).not.toBeNaN();
 
   expect(await findProcess('pid', pidNumber)).toHaveLength(0);
-});
+}, 15000);

jest.config.mjs

@@ -66,14 +66,18 @@ export default {
     '/packages/jest-snapshot/src/__tests__/plugins',
     '/packages/jest-snapshot/src/__tests__/fixtures/',
     '/packages/jest-validate/src/__tests__/fixtures/',
+    '/packages/jest-worker/src/workers/__tests__/__fixtures__/',
     '/e2e/__tests__/iterator-to-null-test.ts',
     '/e2e/__tests__/tsIntegration.test.ts', // this test needs types to be build, it runs in a separate CI job through `jest.config.ts.mjs`
   ],
   testTimeout: 70000,
   transform: {
     '\\.[jt]sx?$': require.resolve('babel-jest'),
   },
-  watchPathIgnorePatterns: ['coverage'],
+  watchPathIgnorePatterns: [
+    'coverage',
+    '<rootDir>/packages/jest-worker/src/workers/__tests__/__temp__',
+  ],
   watchPlugins: [
     require.resolve('jest-watch-typeahead/filename'),
     require.resolve('jest-watch-typeahead/testname'),

packages/jest-config/src/__tests__/normalize.test.ts

@@ -2112,3 +2112,15 @@ describe('logs a deprecation warning', () => {
     expect(console.warn).toMatchSnapshot();
   });
 });
+
+it('parses workerIdleMemoryLimit', async () => {
+  const {options} = await normalize(
+    {
+      rootDir: '/root/',
+      workerIdleMemoryLimit: '45MiB',
+    },
+    {} as Config.Argv,
+  );
+
+  expect(options.workerIdleMemoryLimit).toEqual(47185920);
+});

packages/jest-config/src/__tests__/stringToBytes.test.ts

@@ -0,0 +1,127 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import stringToBytes from '../stringToBytes';
+
+describe('numeric input', () => {
+  test('> 1 represents bytes', () => {
+    expect(stringToBytes(50.8)).toEqual(50);
+  });
+
+  test('1.1 should be a 1', () => {
+    expect(stringToBytes(1.1, 54)).toEqual(1);
+  });
+
+  test('< 1 represents a %', () => {
+    expect(stringToBytes(0.3, 51)).toEqual(15);
+  });
+
+  test('should throw when no reference supplied', () => {
+    expect(() => stringToBytes(0.3)).toThrowError();
+  });
+
+  test('should throw on a bad input', () => {
+    expect(() => stringToBytes(-0.3, 51)).toThrowError();
+  });
+});
+
+describe('string input', () => {
+  describe('numeric passthrough', () => {
+    test('> 1 represents bytes', () => {
+      expect(stringToBytes('50.8')).toEqual(50);
+    });
+
+    test('< 1 represents a %', () => {
+      expect(stringToBytes('0.3', 51)).toEqual(15);
+    });
+
+    test('should throw when no reference supplied', () => {
+      expect(() => stringToBytes('0.3')).toThrowError();
+    });
+
+    test('should throw on a bad input', () => {
+      expect(() => stringToBytes('-0.3', 51)).toThrowError();
+    });
+  });
+
+  describe('parsing', () => {
+    test('0% should throw an error', () => {
+      expect(() => stringToBytes('0%', 51)).toThrowError();
+    });
+
+    test('30%', () => {
+      expect(stringToBytes('30%', 51)).toEqual(15);
+    });
+
+    test('80%', () => {
+      expect(stringToBytes('80%', 51)).toEqual(40);
+    });
+
+    test('100%', () => {
+      expect(stringToBytes('100%', 51)).toEqual(51);
+    });
+
+    // The units caps is intentionally janky to test for forgiving string parsing.
+    describe('k', () => {
+      test('30k', () => {
+        expect(stringToBytes('30K')).toEqual(30000);
+      });
+
+      test('30KB', () => {
+        expect(stringToBytes('30kB')).toEqual(30000);
+      });
+
+      test('30KiB', () => {
+        expect(stringToBytes('30kIb')).toEqual(30720);
+      });
+    });
+
+    describe('m', () => {
+      test('30M', () => {
+        expect(stringToBytes('30M')).toEqual(30000000);
+      });
+
+      test('30MB', () => {
+        expect(stringToBytes('30MB')).toEqual(30000000);
+      });
+
+      test('30MiB', () => {
+        expect(stringToBytes('30MiB')).toEqual(31457280);
+      });
+    });
+
+    describe('g', () => {
+      test('30G', () => {
+        expect(stringToBytes('30G')).toEqual(30000000000);
+      });
+
+      test('30GB', () => {
+        expect(stringToBytes('30gB')).toEqual(30000000000);
+      });
+
+      test('30GiB', () => {
+        expect(stringToBytes('30GIB')).toEqual(32212254720);
+      });
+    });
+
+    test('unknown unit', () => {
+      expect(() => stringToBytes('50XX')).toThrowError();
+    });
+  });
+});
+
+test('nesting', () => {
+  expect(stringToBytes(stringToBytes(stringToBytes('30%', 51)))).toEqual(15);
+});
+
+test('null', () => {
+  expect(stringToBytes(null)).toEqual(null);
+});
+
+test('undefined', () => {
+  expect(stringToBytes(undefined)).toEqual(undefined);
+});

packages/jest-config/src/normalize.ts

@@ -6,6 +6,7 @@
  */
 
 import {createHash} from 'crypto';
+import {totalmem} from 'os';
 import * as path from 'path';
 import chalk = require('chalk');
 import merge = require('deepmerge');
@@ -36,6 +37,7 @@ import {DEFAULT_JS_PATTERN} from './constants';
 import getMaxWorkers from './getMaxWorkers';
 import {parseShardPair} from './parseShardPair';
 import setFromArgv from './setFromArgv';
+import stringToBytes from './stringToBytes';
 import {
   BULLET,
   DOCUMENTATION_NOTE,
@@ -969,6 +971,9 @@ export default async function normalize(
       case 'watchman':
         value = oldOptions[key];
         break;
+      case 'workerIdleMemoryLimit':
+        value = stringToBytes(oldOptions[key], totalmem());
+        break;
       case 'watchPlugins':
         value = (oldOptions[key] || []).map(watchPlugin => {
           if (typeof watchPlugin === 'string') {

packages/jest-config/src/stringToBytes.ts

@@ -0,0 +1,90 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+function stringToBytes(
+  input: undefined,
+  percentageReference?: number,
+): undefined;
+function stringToBytes(input: null, percentageReference?: number): null;
+function stringToBytes(
+  input: string | number,
+  percentageReference?: number,
+): number;
+
+/**
+ * Converts a string representing an amount of memory to bytes.
+ *
+ * @param input The value to convert to bytes.
+ * @param percentageReference The reference value to use when a '%' value is supplied.
+ */
+function stringToBytes(
+  input: string | number | null | undefined,
+  percentageReference?: number,
+): number | null | undefined {
+  if (input === null || input === undefined) {
+    return input;
+  }
+
+  if (typeof input === 'string') {
+    if (isNaN(Number.parseFloat(input.slice(-1)))) {
+      // eslint-disable-next-line prefer-const
+      let [, numericString, trailingChars] =
+        input.match(/(.*?)([^0-9.-]+)$/i) || [];
+
+      if (trailingChars && numericString) {
+        const numericValue = Number.parseFloat(numericString);
+        trailingChars = trailingChars.toLowerCase();
+
+        switch (trailingChars) {
+          case '%':
+            input = numericValue / 100;
+            break;
+          case 'kb':
+          case 'k':
+            return numericValue * 1000;
+          case 'kib':
+            return numericValue * 1024;
+          case 'mb':
+          case 'm':
+            return numericValue * 1000 * 1000;
+          case 'mib':
+            return numericValue * 1024 * 1024;
+          case 'gb':
+          case 'g':
+            return numericValue * 1000 * 1000 * 1000;
+          case 'gib':
+            return numericValue * 1024 * 1024 * 1024;
+        }
+      }
+
+      // It ends in some kind of char so we need to do some parsing
+    } else {
+      input = Number.parseFloat(input);
+    }
+  }
+
+  if (typeof input === 'number') {
+    if (input <= 1 && input > 0) {
+      if (percentageReference) {
+        return Math.floor(input * percentageReference);
+      } else {
+        throw new Error(
+          'For a percentage based memory limit a percentageReference must be supplied',
+        );
+      }
+    } else if (input > 1) {
+      return Math.floor(input);
+    } else {
+      throw new Error('Unexpected numerical input');
+    }
+  }
+
+  throw new Error('Unexpected input');
+}
+
+// https://github.com/import-js/eslint-plugin-import/issues/1590
+export default stringToBytes;

packages/jest-runner/src/index.ts

@@ -107,6 +107,12 @@ export default class TestRunner extends EmittingTestRunner {
     const worker = new Worker(require.resolve('./testWorker'), {
       exposedMethods: ['worker'],
       forkOptions: {serialization: 'json', stdio: 'pipe'},
+      // The workerIdleMemoryLimit should've been converted to a number during
+      // the normalization phase.
+      idleMemoryLimit:
+        typeof this._globalConfig.workerIdleMemoryLimit === 'number'
+          ? this._globalConfig.workerIdleMemoryLimit
+          : undefined,
       maxRetries: 3,
       numWorkers: this._globalConfig.maxWorkers,
       setupArgs: [{serializableResolvers: Array.from(resolvers.values())}],