child_process: add timeout to spawn and fork

Add support for timeout to spawn and fork. Fixes: #27639

Author: Nitzan Uziely

doc/api/child_process.md

@@ -374,6 +374,9 @@ controller.abort();
 <!-- YAML
 added: v0.5.0
 changes:
+ - version: REPLACEME
+ pr-url: https://github.com/nodejs/node/pull/37256
+ description: timeout was added.
  - version: v15.11.0
  pr-url: https://github.com/nodejs/node/pull/37325
  description: killSignal for AbortSignal was added.
@@ -410,8 +413,8 @@ changes:
  See [Advanced serialization][] for more details. **Default:** `'json'`.
  * `signal` {AbortSignal} Allows closing the child process using an
  AbortSignal.
- * `killSignal` {string} The signal value to be used when the spawned
- process will be killed by the abort signal. **Default:** `'SIGTERM'`.
+ * `killSignal` {string|integer} The signal value to be used when the spawned
+ process will be killed by timeout or abort signal. **Default:** `'SIGTERM'`.
  * `silent` {boolean} If `true`, stdin, stdout, and stderr of the child will be
  piped to the parent, otherwise they will be inherited from the parent, see
  the `'pipe'` and `'inherit'` options for [`child_process.spawn()`][]'s
@@ -423,6 +426,8 @@ changes:
  * `uid` {number} Sets the user identity of the process (see setuid(2)).
  * `windowsVerbatimArguments` {boolean} No quoting or escaping of arguments is
  done on Windows. Ignored on Unix. **Default:** `false`.
+ * `timeout` {number} In milliseconds the maximum amount of time the process
+ is allowed to run. **Default:** `undefined`.
 * Returns: {ChildProcess}
 
 The `child_process.fork()` method is a special case of
@@ -478,6 +483,9 @@ if (process.argv[2] === 'child') {
 <!-- YAML
 added: v0.1.90
 changes:
+ - version: REPLACEME
+ pr-url: https://github.com/nodejs/node/pull/37256
+ description: timeout was added.
  - version: v15.11.0
  pr-url: https://github.com/nodejs/node/pull/37325
  description: killSignal for AbortSignal was added.
@@ -528,8 +536,10 @@ changes:
  normally be created on Windows systems. **Default:** `false`.
  * `signal` {AbortSignal} allows aborting the child process using an
  AbortSignal.
- * `killSignal` {string} The signal value to be used when the spawned
- process will be killed by the abort signal. **Default:** `'SIGTERM'`.
+ * `timeout` {number} In milliseconds the maximum amount of time the process
+ is allowed to run. **Default:** `undefined`.
+ * `killSignal` {string|integer} The signal value to be used when the spawned
+ process will be killed by timeout or abort signal. **Default:** `'SIGTERM'`.
 
 * Returns: {ChildProcess}
 

lib/child_process.js

@@ -599,15 +599,14 @@ function abortChildProcess(child, killSignal) {
 
 
 function spawn(file, args, options) {
- const child = new ChildProcess();
  options = normalizeSpawnArguments(file, args, options);
+ validateTimeout(options.timeout, 'options.timeout');
+ validateAbortSignal(options.signal, 'options.signal');
+ const killSignal = sanitizeKillSignal(options.killSignal);
+ const child = new ChildProcess();
 
  if (options.signal) {
  const signal = options.signal;
- // Validate signal, if present
- validateAbortSignal(signal, 'options.signal');
- const killSignal = sanitizeKillSignal(options.killSignal);
- // Do nothing and throw if already aborted
  if (signal.aborted) {
  onAbortListener();
  } else {
@@ -626,6 +625,26 @@ function spawn(file, args, options) {
  debug('spawn', options);
  child.spawn(options);
 
+ if (options.timeout > 0) {
+ let timeoutId = setTimeout(() => {
+ if (timeoutId) {
+ try {
+ child.kill(killSignal);
+ } catch (err) {
+ child.emit('error', err);
+ }
+ timeoutId = null;
+ }
+ }, options.timeout);
+
+ child.once('exit', () => {
+ if (timeoutId) {
+ clearTimeout(timeoutId);
+ timeoutId = null;
+ }
+ });
+ }
+
  return child;
 }
 

test/parallel/test-child-process-fork-timeout-kill-signal.js

@@ -0,0 +1,50 @@
+'use strict';
+
+const { mustCall } = require('../common');
+const { strictEqual, throws } = require('assert');
+const fixtures = require('../common/fixtures');
+const { fork } = require('child_process');
+const { getEventListeners } = require('events');
+
+{
+ // Verify default signal
+ const cp = fork(fixtures.path('child-process-stay-alive-forever.js'), {
+ timeout: 5,
+ });
+ cp.on('exit', mustCall((code, ks) => strictEqual(ks, 'SIGTERM')));
+}
+
+{
+ // Verify correct signal + closes after at least 4 ms.
+ const cp = fork(fixtures.path('child-process-stay-alive-forever.js'), {
+ timeout: 5,
+ killSignal: 'SIGKILL',
+ });
+ cp.on('exit', mustCall((code, ks) => strictEqual(ks, 'SIGKILL')));
+}
+
+{
+ // Verify timeout verification
+ throws(() => fork(fixtures.path('child-process-stay-alive-forever.js'), {
+ timeout: 'badValue',
+ }), /ERR_OUT_OF_RANGE/);
+
+ throws(() => fork(fixtures.path('child-process-stay-alive-forever.js'), {
+ timeout: {},
+ }), /ERR_OUT_OF_RANGE/);
+}
+
+{
+ // Verify abort signal gets unregistered
+ const signal = new EventTarget();
+ signal.aborted = false;
+
+ const cp = fork(fixtures.path('child-process-stay-alive-forever.js'), {
+ timeout: 6,
+ signal,
+ });
+ strictEqual(getEventListeners(signal, 'abort').length, 1);
+ cp.on('exit', mustCall(() => {
+ strictEqual(getEventListeners(signal, 'abort').length, 0);
+ }));
+}

test/parallel/test-child-process-spawn-timeout-kill-signal.js

@@ -0,0 +1,50 @@
+'use strict';
+
+const { mustCall } = require('../common');
+const { strictEqual, throws } = require('assert');
+const fixtures = require('../common/fixtures');
+const { spawn } = require('child_process');
+const { getEventListeners } = require('events');
+
+const aliveForeverFile = 'child-process-stay-alive-forever.js';
+{
+ // Verify default signal + closes
+ const cp = spawn(process.execPath, [fixtures.path(aliveForeverFile)], {
+ timeout: 5,
+ });
+ cp.on('exit', mustCall((code, ks) => strictEqual(ks, 'SIGTERM')));
+}
+
+{
+ // Verify SIGKILL signal + closes
+ const cp = spawn(process.execPath, [fixtures.path(aliveForeverFile)], {
+ timeout: 6,
+ killSignal: 'SIGKILL',
+ });
+ cp.on('exit', mustCall((code, ks) => strictEqual(ks, 'SIGKILL')));
+}
+
+{
+ // Verify timeout verification
+ throws(() => spawn(process.execPath, [fixtures.path(aliveForeverFile)], {
+ timeout: 'badValue',
+ }), /ERR_OUT_OF_RANGE/);
+
+ throws(() => spawn(process.execPath, [fixtures.path(aliveForeverFile)], {
+ timeout: {},
+ }), /ERR_OUT_OF_RANGE/);
+}
+
+{
+ // Verify abort signal gets unregistered
+ const controller = new AbortController();
+ const { signal } = controller;
+ const cp = spawn(process.execPath, [fixtures.path(aliveForeverFile)], {
+ timeout: 6,
+ signal,
+ });
+ strictEqual(getEventListeners(signal, 'abort').length, 1);
+ cp.on('exit', mustCall(() => {
+ strictEqual(getEventListeners(signal, 'abort').length, 0);
+ }));
+}