process: add custom directory in heapsnapshot

lib/internal/process/pre_execution.js

@@ -8,6 +8,7 @@ const {
   ObjectGetOwnPropertyDescriptor,
   SafeMap,
   StringPrototypeStartsWith,
+  DateNow,
   globalThis,
 } = primordials;
 
@@ -365,6 +366,7 @@ function initializeReportSignalHandlers() {
 
 function initializeHeapSnapshotSignalHandlers() {
   const signal = getOptionValue('--heapsnapshot-signal');
+  const diagnosticDir = getOptionValue('--diagnostic-dir');
 
   if (!signal)
     return;
@@ -373,7 +375,8 @@ function initializeHeapSnapshotSignalHandlers() {
   const { writeHeapSnapshot } = require('v8');
 
   function doWriteHeapSnapshot() {
-    writeHeapSnapshot();
+    const heapSnapshotFilename = getHeapSnapshotFilename(diagnosticDir);
+    writeHeapSnapshot(heapSnapshotFilename);
   }
   process.on(signal, doWriteHeapSnapshot);
 
@@ -650,6 +653,11 @@ function markBootstrapComplete() {
   internalBinding('performance').markBootstrapComplete();
 }
 
+function getHeapSnapshotFilename(diagnosticDir) {
+  if (!diagnosticDir) return undefined;
+  return `${diagnosticDir}/Heap.${DateNow()}.heapsnapshot`;
+}
+
 module.exports = {
   setupUserModules,
   prepareMainThreadExecution,

test/sequential/test-heapdump-flag-custom-dir.js

@@ -0,0 +1,41 @@
+'use strict';
+const common = require('../common');
+
+if (common.isWindows)
+  common.skip('test not supported on Windows');
+
+const assert = require('assert');
+
+if (process.argv[2] === 'child') {
+  const fs = require('fs');
+
+  assert.strictEqual(process.listenerCount('SIGUSR2'), 1);
+  process.kill(process.pid, 'SIGUSR2');
+  process.kill(process.pid, 'SIGUSR2');
+
+  // Asynchronously wait for the snapshot. Use an async loop to be a bit more
+  // robust in case platform or machine differences throw off the timing.
+  (function validate() {
+    const files = fs.readdirSync(process.cwd());
+
+    if (files.length === 0)
+      return setImmediate(validate);
+
+    assert.strictEqual(files.length, 2);
+
+    for (let i = 0; i < files.length; i++) {
+      assert.match(files[i], /^Heap\..+\.heapsnapshot$/);
+      JSON.parse(fs.readFileSync(files[i]));
+    }
+  })();
+} else {
+  const { spawnSync } = require('child_process');
+  const tmpdir = require('../common/tmpdir');
+
+  tmpdir.refresh();
+  const args = ['--heapsnapshot-signal', 'SIGUSR2', '--diagnostic-dir', tmpdir.path, __filename, 'child'];
+  const child = spawnSync(process.execPath, args, { cwd: tmpdir.path });
+
+  assert.strictEqual(child.status, 0);
+  assert.strictEqual(child.signal, null);
+}