From 2cb38709a56d50271c836e78821b28e6a03b68f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jordi=20Guti=C3=A9rrez=20Hermoso?= <jordigh@octave.org>
Date: Thu, 13 Jun 2024 17:45:41 -0400
Subject: [PATCH] supervisor: new file

This is a new entrypoint, mostly intended for Docker, so we have one
simple process controlling the main Grist process. The purpose of this
is to be able to make Grist easily restartable with a new environment.
---
 sandbox/supervisor.mjs | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 sandbox/supervisor.mjs

diff --git a/sandbox/supervisor.mjs b/sandbox/supervisor.mjs
new file mode 100644
index 00000000..2508cb17
--- /dev/null
+++ b/sandbox/supervisor.mjs
@@ -0,0 +1,35 @@
+import {spawn} from 'child_process';
+
+let grist;
+
+function startGrist(newConfig={}) {
+  saveNewConfig(newConfig);
+  // H/T https://stackoverflow.com/a/36995148/11352427
+  grist = spawn('./sandbox/run.sh', {
+    stdio: ['inherit', 'inherit', 'inherit', 'ipc']
+  });
+  grist.on('message', function(data) {
+    if (data.action === 'restart') {
+      console.log('Restarting Grist with new environment');
+
+      // Note that we only set this event handler here, after we have
+      // a new environment to reload with. Small chance of a race here
+      // in case something else sends a SIGINT before we do it
+      // ourselves further below.
+      grist.on('exit', () => {
+        grist = startGrist(data.newConfig);
+      });
+
+      grist.kill('SIGINT');
+    }
+  });
+  return grist;
+}
+
+// Stub function
+function saveNewConfig(newConfig) {
+  // TODO: something here to actually persist the new config before
+  // restarting Grist.
+}
+
+startGrist();