From ee3ebf8d17a600746d5e51ba531565d5bb035b2b Mon Sep 17 00:00:00 2001
From: Niko Sams <niko.sams@gmail.com>
Date: Tue, 19 Nov 2024 11:09:28 +0100
Subject: [PATCH] Watch dev-pm.config.js and update in running daemon (#98)

This allows modifications without having to shutdown the deamon.
- processes are not restarted if the script command changes
- processes are stopped if the script is removed
- processes are not started if a new script is added
- identifier for updates is the name of a script
---
 .changeset/spotty-mirrors-care.md    | 11 ++++++++
 src/commands/start-daemon.command.ts | 40 +++++++++++++++++++++++-----
 src/daemon-command/script.ts         |  4 +++
 3 files changed, 49 insertions(+), 6 deletions(-)
 create mode 100644 .changeset/spotty-mirrors-care.md

diff --git a/.changeset/spotty-mirrors-care.md b/.changeset/spotty-mirrors-care.md
new file mode 100644
index 0000000..6d47d39
--- /dev/null
+++ b/.changeset/spotty-mirrors-care.md
@@ -0,0 +1,11 @@
+---
+"@comet/dev-process-manager": minor
+---
+
+Watch dev-pm.config.js and update in running daemon
+
+This allows modifications without having to shutdown the deamon.
+- processes are not restarted if the script command changes
+- processes are stopped if the script is removed
+- processes are not started if a new script is added
+- identifier for updates is the name of a script
diff --git a/src/commands/start-daemon.command.ts b/src/commands/start-daemon.command.ts
index 43f97ce..e8f93fb 100644
--- a/src/commands/start-daemon.command.ts
+++ b/src/commands/start-daemon.command.ts
@@ -1,5 +1,5 @@
 import colors from "colors";
-import { existsSync } from "fs";
+import { existsSync, watchFile } from "fs";
 import { createServer, Server } from "net";
 
 import { Config } from "../config.type";
@@ -21,15 +21,43 @@ export interface Daemon {
 export const startDaemon = async (): Promise<void> => {
     process.chdir(findConfigDir());
     const pmConfigFileName = "dev-pm.config.js";
-    const { scripts: scriptDefinitions }: Config = await import(`${process.cwd()}/${pmConfigFileName}`);
-    const scripts = scriptDefinitions.map((scriptDefinition, id) => {
-        return new Script({ ...scriptDefinition, id });
-    });
+    // eslint-disable-next-line @typescript-eslint/no-var-requires
+    const { scripts: scriptDefinitions }: Config = require(`${process.cwd()}/${pmConfigFileName}`);
     const daemon: Daemon = {
-        scripts,
+        scripts: scriptDefinitions.map((scriptDefinition, id) => {
+            return new Script({ ...scriptDefinition, id });
+        }),
         server: undefined,
     };
 
+    watchFile(`${process.cwd()}/${pmConfigFileName}`, async () => {
+        console.log(`${pmConfigFileName} file changed, reloading scripts`);
+        delete require.cache[require.resolve(`${process.cwd()}/${pmConfigFileName}`)];
+        // eslint-disable-next-line @typescript-eslint/no-var-requires
+        const { scripts: scriptDefinitions }: Config = require(`${process.cwd()}/${pmConfigFileName}`);
+
+        daemon.scripts = daemon.scripts.filter((script) => {
+            if (!scriptDefinitions.find((s) => s.name === script.name)) {
+                console.log("Removing script", script.name);
+                script.killProcess();
+                return false;
+            } else {
+                return true;
+            }
+        });
+
+        scriptDefinitions.forEach((scriptDefinition, id) => {
+            const script = daemon.scripts.find((s) => s.name === scriptDefinition.name);
+            if (script) {
+                console.log("Updating script definition", script.name);
+                script.updateScriptDefinition({ ...scriptDefinition, id });
+            } else {
+                console.log("Adding new script", scriptDefinition.name);
+                daemon.scripts.push(new Script({ ...scriptDefinition, id }));
+            }
+        });
+    });
+
     if (existsSync(`.pm.sock`)) {
         console.log(
             "Could not start dev-pm server. A '.pm.sock' file already exists. \nThere are 2 possible reasons for this:\nA: Another dev-pm instance is already running. \nB: dev-pm crashed and left the file behind. In this case please remove the file manually.",
diff --git a/src/daemon-command/script.ts b/src/daemon-command/script.ts
index 5c69e3e..3b75485 100644
--- a/src/daemon-command/script.ts
+++ b/src/daemon-command/script.ts
@@ -30,6 +30,10 @@ export class Script {
         this.logPrefix = color(`${this.name}: `);
     }
 
+    updateScriptDefinition(scriptDefinition: ScriptDefinition) {
+        this.scriptDefinition = scriptDefinition;
+    }
+
     get id(): number {
         return this.scriptDefinition.id;
     }