worker: allow specifying resource limits

doc/api/errors.md

@@ -1998,6 +1998,11 @@ meaning of the error depends on the specific function.
 The `execArgv` option passed to the `Worker` constructor contains
 invalid flags.
 
+<a id="ERR_WORKER_OUT_OF_MEMORY"></a>
+### ERR_WORKER_OUT_OF_MEMORY
+
+The `Worker` instance terminated because it reached its memory limit.
+
 <a id="ERR_WORKER_PATH"></a>
 ### ERR_WORKER_PATH
 

doc/api/worker_threads.md

@@ -157,6 +157,22 @@ console.log(receiveMessageOnPort(port2));
 When this function is used, no `'message'` event will be emitted and the
 `onmessage` listener will not be invoked.
 
+### worker.resourceLimits
+<!-- YAML
+added: REPLACEME
+-->
+
+* {Object|undefined}
+  * `maxYoungGenerationSizeMb` {number}
+  * `maxOldGenerationSizeMb` {number}
+  * `codeRangeSizeMb` {number}
+
+Provides the set of JS engine resource constraints inside this Worker thread.
+If the `resourceLimits` option was passed to the [`Worker`][] constructor,
+this matches its values.
+
+If this is used in the main thread, its value is an empty object.
+
 ## worker.SHARE_ENV
 <!-- YAML
 added: v11.14.0
@@ -488,6 +504,13 @@ if (isMainThread) {
 ```
 
 ### new Worker(filename\[, options\])
+<!-- YAML
+added: v10.5.0
+changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/26628
+    description: The `resourceLimits` option was introduced.
+-->
 
 * `filename` {string} The path to the Worker’s main script. Must be
   either an absolute path or a relative path (i.e. relative to the
@@ -519,6 +542,16 @@ if (isMainThread) {
     occur as described in the [HTML structured clone algorithm][], and an error
     will be thrown if the object cannot be cloned (e.g. because it contains
     `function`s).
+  * `resourceLimits` {Object} An optional set of resource limits for the new
+    JS engine instance. Reaching these limits will lead to termination of the
+    `Worker` instance. These limits only affect the JS engine, and no external
+    data, including no `ArrayBuffer`s. Even if these limits are set, the process
+    may still abort if it encounters a global out-of-memory situation.
+    * `maxOldGenerationSizeMb` {number} The maximum size of the main heap in MB.
+    * `maxYoungGenerationSizeMb` {number} The maximum size of a heap space for
+      recently created objects.
+    * `codeRangeSizeMb` {number} The size of a pre-allocated memory range
+      used for generated code.
 
 ### Event: 'error'
 <!-- YAML
@@ -583,6 +616,22 @@ Opposite of `unref()`, calling `ref()` on a previously `unref()`ed worker will
 behavior). If the worker is `ref()`ed, calling `ref()` again will have
 no effect.
 
+### worker.resourceLimits
+<!-- YAML
+added: REPLACEME
+-->
+
+* {Object}
+  * `maxYoungGenerationSizeMb` {number}
+  * `maxOldGenerationSizeMb` {number}
+  * `codeRangeSizeMb` {number}
+
+Provides the set of JS engine resource constraints for this Worker thread.
+If the `resourceLimits` option was passed to the [`Worker`][] constructor,
+this matches its values.
+
+If the worker has stopped, the return value is an empty object.
+
 ### worker.stderr
 <!-- YAML
 added: v10.5.0

lib/internal/errors.js

@@ -1226,6 +1226,8 @@ E('ERR_VM_MODULE_STATUS', 'Module status %s', Error);
 E('ERR_WORKER_INVALID_EXEC_ARGV', (errors) =>
   `Initiated Worker with invalid execArgv flags: ${errors.join(', ')}`,
   Error);
+E('ERR_WORKER_OUT_OF_MEMORY', 'Worker terminated due to reaching memory limit',
+  Error);
 E('ERR_WORKER_PATH',
   'The worker script filename must be an absolute path or a relative ' +
   'path starting with \'./\' or \'../\'. Received "%s"',

lib/internal/worker.js

@@ -2,19 +2,20 @@
 
 /* global SharedArrayBuffer */
 
-const { Object } = primordials;
+const { Math, Object } = primordials;
 
 const EventEmitter = require('events');
 const assert = require('internal/assert');
 const path = require('path');
 
+const errorCodes = require('internal/errors').codes;
 const {
   ERR_WORKER_PATH,
   ERR_WORKER_UNSERIALIZABLE_ERROR,
   ERR_WORKER_UNSUPPORTED_EXTENSION,
   ERR_WORKER_INVALID_EXEC_ARGV,
   ERR_INVALID_ARG_TYPE,
-} = require('internal/errors').codes;
+} = errorCodes;
 const { validateString } = require('internal/validators');
 const { getOptionValue } = require('internal/options');
 
@@ -37,8 +38,13 @@ const { pathToFileURL } = require('url');
 const {
   ownsProcessState,
   isMainThread,
+  resourceLimits: resourceLimitsRaw,
   threadId,
   Worker: WorkerImpl,
+  kMaxYoungGenerationSizeMb,
+  kMaxOldGenerationSizeMb,
+  kCodeRangeSizeMb,
+  kTotalResourceLimitCount
 } = internalBinding('worker');
 
 const kHandle = Symbol('kHandle');
@@ -102,7 +108,8 @@ class Worker extends EventEmitter {
 
     const url = options.eval ? null : pathToFileURL(filename);
     // Set up the C++ handle for the worker, as well as some internal wiring.
-    this[kHandle] = new WorkerImpl(url, options.execArgv);
+    this[kHandle] = new WorkerImpl(url, options.execArgv,
+                                   parseResourceLimits(options.resourceLimits));
     if (this[kHandle].invalidExecArgv) {
       throw new ERR_WORKER_INVALID_EXEC_ARGV(this[kHandle].invalidExecArgv);
     }
@@ -113,7 +120,7 @@ class Worker extends EventEmitter {
     } else if (env !== undefined) {
       this[kHandle].setEnvVars(env);
     }
-    this[kHandle].onexit = (code) => this[kOnExit](code);
+    this[kHandle].onexit = (code, customErr) => this[kOnExit](code, customErr);
     this[kPort] = this[kHandle].messagePort;
     this[kPort].on('message', (data) => this[kOnMessage](data));
     this[kPort].start();
@@ -157,11 +164,15 @@ class Worker extends EventEmitter {
     this[kHandle].startThread();
   }
 
-  [kOnExit](code) {
+  [kOnExit](code, customErr) {
     debug(`[${threadId}] hears end event for Worker ${this.threadId}`);
     drainMessagePort(this[kPublicPort]);
     drainMessagePort(this[kPort]);
     this[kDispose]();
+    if (customErr) {
+      debug(`[${threadId}] failing with custom error ${customErr}`);
+      this.emit('error', new errorCodes[customErr]());
+    }
     this.emit('exit', code);
     this.removeAllListeners();
   }
@@ -280,6 +291,12 @@ class Worker extends EventEmitter {
   get stderr() {
     return this[kParentSideStdio].stderr;
   }
+
+  get resourceLimits() {
+    if (this[kHandle] === null) return {};
+
+    return makeResourceLimits(this[kHandle].getResourceLimits());
+  }
 }
 
 function pipeWithoutWarning(source, dest) {
@@ -294,10 +311,35 @@ function pipeWithoutWarning(source, dest) {
   dest._maxListeners = destMaxListeners;
 }
 
+const resourceLimitsArray = new Float64Array(kTotalResourceLimitCount);
+function parseResourceLimits(obj) {
+  const ret = resourceLimitsArray;
+  ret.fill(-1);
+  if (typeof obj !== 'object' || obj === null) return ret;
+
+  if (typeof obj.maxOldGenerationSizeMb === 'number')
+    ret[kMaxOldGenerationSizeMb] = Math.max(obj.maxOldGenerationSizeMb, 2);
+  if (typeof obj.maxYoungGenerationSizeMb === 'number')
+    ret[kMaxYoungGenerationSizeMb] = obj.maxYoungGenerationSizeMb;
+  if (typeof obj.codeRangeSizeMb === 'number')
+    ret[kCodeRangeSizeMb] = obj.codeRangeSizeMb;
+  return ret;
+}
+
+function makeResourceLimits(float64arr) {
+  return {
+    maxYoungGenerationSizeMb: float64arr[kMaxYoungGenerationSizeMb],
+    maxOldGenerationSizeMb: float64arr[kMaxOldGenerationSizeMb],
+    codeRangeSizeMb: float64arr[kCodeRangeSizeMb]
+  };
+}
+
 module.exports = {
   ownsProcessState,
   isMainThread,
   SHARE_ENV,
+  resourceLimits:
+    !isMainThread ? makeResourceLimits(resourceLimitsRaw) : {},
   threadId,
   Worker,
 };

lib/worker_threads.js

@@ -3,6 +3,7 @@
 const {
   isMainThread,
   SHARE_ENV,
+  resourceLimits,
   threadId,
   Worker
 } = require('internal/worker');
@@ -20,6 +21,7 @@ module.exports = {
   MessageChannel,
   moveMessagePortToContext,
   receiveMessageOnPort,
+  resourceLimits,
   threadId,
   SHARE_ENV,
   Worker,