From 3c8f94ab2febf428488125ae0feb3e130307eb35 Mon Sep 17 00:00:00 2001
From: Koushik Dutta <koushd@gmail.com>
Date: Tue, 20 Aug 2024 23:20:04 -0700
Subject: [PATCH] server: Fix electron display var

---
 server/package-lock.json                     |  4 +--
 server/src/plugin/runtime/electron-worker.ts | 31 ++++++++++++++++++--
 server/src/plugin/runtime/runtime-host.ts    |  2 +-
 3 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/server/package-lock.json b/server/package-lock.json
index 4a3e8def4..9e30905ec 100644
--- a/server/package-lock.json
+++ b/server/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@scrypted/server",
-  "version": "0.115.27",
+  "version": "0.115.28",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@scrypted/server",
-      "version": "0.115.27",
+      "version": "0.115.28",
       "hasInstallScript": true,
       "license": "ISC",
       "dependencies": {
diff --git a/server/src/plugin/runtime/electron-worker.ts b/server/src/plugin/runtime/electron-worker.ts
index 867bc620d..2ffdc5f8a 100644
--- a/server/src/plugin/runtime/electron-worker.ts
+++ b/server/src/plugin/runtime/electron-worker.ts
@@ -5,15 +5,17 @@ import { RpcMessage, RpcPeer } from "../../rpc";
 import { SidebandSocketSerializer } from "../socket-serializer";
 import { ChildProcessWorker } from "./child-process-worker";
 import { RuntimeWorkerOptions } from "./runtime-worker";
+import type { ScryptedRuntime } from '../../runtime';
 
 export class ElectronForkWorker extends ChildProcessWorker {
+    static allocatedDisplays = new Set<number>();
+    allocatedDisplay: number;
 
-    constructor(mainFilename: string, pluginId: string, options: RuntimeWorkerOptions) {
+    constructor(mainFilename: string, pluginId: string, options: RuntimeWorkerOptions, runtime: ScryptedRuntime) {
         super(pluginId, options);
 
         const { env, pluginDebug } = options;
 
-
         const execArgv: string[] = process.execArgv.slice();
         if (pluginDebug) {
             // execArgv.push(`--inspect=0.0.0.0:${pluginDebug.inspectPort}`);
@@ -23,8 +25,22 @@ export class ElectronForkWorker extends ChildProcessWorker {
         const electronBin: string = require('electron');
         const args = [electronBin];
         if (process.platform === 'linux') {
+            // crappy but should work.
+            for (let i = 50; i < 100; i++) {
+                if (!ElectronForkWorker.allocatedDisplays.has(i)) {
+                    this.allocatedDisplay = i;
+                    break;
+                }
+            }
+
+            if (!this.allocatedDisplay)
+                throw new Error('unable to allocate DISPLAY for xvfb-run');
+
+            ElectronForkWorker.allocatedDisplays.add(this.allocatedDisplay);
+
             // requires xvfb-run as electron does not support the chrome --headless flag.
-            args.unshift('xvfb-run', '-n', '0');
+            // dummy up a DISPLAY env variable. this value numerical because of the way it is.
+            args.unshift('xvfb-run', '-n', this.allocatedDisplay.toString());
             // https://github.com/gpuweb/gpuweb/wiki/Implementation-Status#chromium-chrome-edge-etc
             args.push('--no-sandbox', '--enable-unsafe-webgpu', '--ignore-gpu-blocklist', '--enable-features=Vulkan', '--disable-vulkan-surface');
         }
@@ -47,6 +63,9 @@ export class ElectronForkWorker extends ChildProcessWorker {
             // execArgv,
         });
 
+        this.worker.on('exit', () => {
+        });
+
         this.worker.send({
             pluginId,
             options,
@@ -55,6 +74,12 @@ export class ElectronForkWorker extends ChildProcessWorker {
         this.setupWorker();
     }
 
+    kill(): void {
+        super.kill();
+        if (this.worker)
+            ElectronForkWorker.allocatedDisplays.delete(this.allocatedDisplay);
+    }
+
     setupRpcPeer(peer: RpcPeer): void {
         this.worker.on('message', (message, sendHandle) => {
             if ((message as any).type && sendHandle) {
diff --git a/server/src/plugin/runtime/runtime-host.ts b/server/src/plugin/runtime/runtime-host.ts
index 4a042c549..ce4428578 100644
--- a/server/src/plugin/runtime/runtime-host.ts
+++ b/server/src/plugin/runtime/runtime-host.ts
@@ -13,7 +13,7 @@ export function getBuiltinRuntimeHosts() {
     pluginHosts.set('custom', (_, pluginId, options, runtime) => new CustomRuntimeWorker(pluginId, options, runtime));
     pluginHosts.set('python', (_, pluginId, options) => new PythonRuntimeWorker(pluginId, options));
     pluginHosts.set('node', (mainFilename, pluginId, options) => new NodeForkWorker(mainFilename, pluginId, options));
-    pluginHosts.set('electron', (mainFilename, pluginId, options) => new ElectronForkWorker(mainFilename, pluginId, options));
+    pluginHosts.set('electron', (mainFilename, pluginId, options, runtime) => new ElectronForkWorker(mainFilename, pluginId, options, runtime));
 
     return pluginHosts;
 }