Add systemd-compatible service manager notification after bewCloud has successfully started

fresh.config.ts

@@ -1,3 +1,4 @@
+import { tmpdir } from 'node:os';
 import { defineConfig } from 'fresh/server.ts';
 import tailwind from 'fresh/plugins/tailwind.ts';
 
@@ -9,6 +10,54 @@ if (!isBuildMode) {
   await startCrons();
 }
 
+async function notifyServiceManagerReady(message) {
+  const socketAddr = Deno.env.get("NOTIFY_SOCKET");
+  if(typeof(socketAddr) !== "string") {
+    return;  // Service manager doesn’t expect any messages
+  }
+
+  // Alternative using systemd CLI (systemd specific, requires CLI utils in $PATH)
+  /*await (new Deno.Command("systemd-notify", {
+    args: ["--ready", `MESSAGE=${message.replace("\n", " ")}`]
+  })).spawn();*/
+
+  // Map socket path syntax
+  if(socketAddr[0] === "@") {
+    socketAddr = `\0${socketAddr.slice(1)}`;
+  } else if(socketAddr[0] !== "/") {
+    return;  // Invalid path
+  }
+
+  // Send message to service manager (requires Deno `--unstable-net`)
+  //
+  // Passing a valid `path` here is required, even though it is not used (Deno bug/limitation).
+  let senderAddr = `${tmpdir()}/bewcloud-notify-${crypto.randomUUID()}.sock`;
+  let connection = Deno.listenDatagram({ transport: "unixpacket", path: senderAddr });
+  await Deno.remove(senderAddr);
+  await connection.send(
+    new TextEncoder().encode(`READY=1\nSTATUS=${message.replace("\n", " ")}`),
+    { transport: "unixpacket", path: socketAddr }
+  );
+  await connection.close();
+}
+
 export default defineConfig({
   plugins: [tailwind()],
+  server: {
+    onListen: (params) => {
+      // Format listening address
+      const fmtHostPort = (hostname, port) =>
+        hostname.includes(":") ? `[${hostname}]:${port}` : `${hostname}:${port}`;
+
+      const addr = (
+        params.transport === "unix"  ? `http+unix://${encodeURIComponent(params.path)}` :
+        params.transport === "vsock" ? `http+vsock://${params.cid}:${parms.port}` :
+        params.transport === "tcp"   ? `http://${fmtHostPort(params.hostname, params.port)}/` : null
+      );
+
+      const message = "bewCloud listening for requests" + (addr ? ` on ${addr}` : "");
+      console.info(message);
+      notifyServiceManagerReady(message);
+    },
+  },
 });