From e1c479dc3187545dd77caad2ba2cb77e8148eb8c Mon Sep 17 00:00:00 2001
From: Brian Hudson <brian.r.hudson@gmail.com>
Date: Mon, 22 Jan 2024 22:46:06 -0500
Subject: [PATCH] Require --no-node-snapshot in node 20+

When started using node 20+ checks if the --no-node-snapshot option was provided and throws an error if not.

Signed-off-by: Brian Hudson <brian.r.hudson@gmail.com>
---
 .changeset/unlucky-pens-search.md             |  6 +++
 .../scaffolder-backend/src/service/helpers.ts | 40 +++++++++++++++++++
 .../scaffolder-backend/src/service/router.ts  | 16 +++++++-
 3 files changed, 61 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/unlucky-pens-search.md

diff --git a/.changeset/unlucky-pens-search.md b/.changeset/unlucky-pens-search.md
new file mode 100644
index 0000000000..4786c14691
--- /dev/null
+++ b/.changeset/unlucky-pens-search.md
@@ -0,0 +1,6 @@
+---
+'@backstage/plugin-scaffolder-backend': patch
+---
+
+When using node 20+ the `scaffolder-backend` will now throw an error at startup if the `--no-node-snapshot` option was
+not provided to node.
diff --git a/plugins/scaffolder-backend/src/service/helpers.ts b/plugins/scaffolder-backend/src/service/helpers.ts
index 3412fec2d3..62f8d78810 100644
--- a/plugins/scaffolder-backend/src/service/helpers.ts
+++ b/plugins/scaffolder-backend/src/service/helpers.ts
@@ -107,3 +107,43 @@ export async function findTemplate(options: {
 
   return template as TemplateEntityV1beta3;
 }
+
+/**
+ * Checks if the '--no-node-snapshot' option is included in the NODE_OPTIONS environment variable
+ * or not included in the command line arguments.
+ *
+ * @remarks
+ * This function checks whether the '--no-node-snapshot' option is part of the NODE_OPTIONS environment
+ * variable or is missing from the command line arguments. If either condition is met, the function returns `true`.
+ * This check is especially important when using the "isolated-vm" package with Node.js version 20.x or later.
+ *
+ * According to the "isolated-vm" documentation on GitHub (https://github.com/laverdet/isolated-vm),
+ * if you are using a version of Node.js 20.x or later and you don't pass the '--no-node-snapshot' option,
+ * it can cause the process to crash. This function helps prevent such crashes by ensuring that the option
+ * is correctly provided.
+ *
+ * @returns {boolean} Returns `true` if the '--no-node-snapshot' option is included in the NODE_OPTIONS
+ * environment variable or not included in the command line arguments. Otherwise, it returns `false`.
+ */
+export function isNoNodeSnapshotOptionProvided(): boolean {
+  return (
+    process.env.NODE_OPTIONS?.includes('--no-node-snapshot') ||
+    process.argv.includes('--no-node-snapshot')
+  );
+}
+
+/**
+ * Gets the major version of the currently running Node.js process.
+ *
+ * @remarks
+ * This function extracts the major version from `process.versions.node` (a string representing the Node.js version),
+ * which includes the major, minor, and patch versions. It splits this string by the `.` character to get an array
+ * of these versions, and then parses the first element of this array (the major version) to a number.
+ *
+ * @returns {number} The major version of the currently running Node.js process.
+ */
+export function getMajorNodeVersion(): number {
+  const version = process.versions.node;
+  return parseInt(version.split('.')[0], 10);
+}
+
diff --git a/plugins/scaffolder-backend/src/service/router.ts b/plugins/scaffolder-backend/src/service/router.ts
index de0087e7de..5f27154c5b 100644
--- a/plugins/scaffolder-backend/src/service/router.ts
+++ b/plugins/scaffolder-backend/src/service/router.ts
@@ -61,7 +61,13 @@ import {
 } from '../scaffolder';
 import { createDryRunner } from '../scaffolder/dryrun';
 import { StorageTaskBroker } from '../scaffolder/tasks/StorageTaskBroker';
-import { findTemplate, getEntityBaseUrl, getWorkingDirectory } from './helpers';
+import {
+  findTemplate,
+  getEntityBaseUrl,
+  getMajorNodeVersion,
+  getWorkingDirectory,
+  isNoNodeSnapshotOptionProvided
+} from './helpers';
 import {
   IdentityApi,
   IdentityApiGetIdentityRequest,
@@ -258,6 +264,14 @@ export async function createRouter(
 
   const logger = parentLogger.child({ plugin: 'scaffolder' });
 
+  const nodeVersion = getMajorNodeVersion();
+  if (nodeVersion >= 20 && !isNoNodeSnapshotOptionProvided()) {
+    throw new Error(
+      'When using node v20+ Scaffolder requires that node be started with the --no-node-snapshot option. Please restart ' +
+      'Backstage providing the node --no-node-snapshot option.',
+    );
+  }
+
   const identity: IdentityApi =
     options.identity || buildDefaultIdentityClient(options);
   const workingDirectory = await getWorkingDirectory(config, logger);