From 16696e3840528936b2ce3fd3904efc255fc403ed Mon Sep 17 00:00:00 2001
From: Kevin Yue <yuezk001@gmail.com>
Date: Sun, 14 May 2023 13:15:57 +0800
Subject: [PATCH] refactor: only run single instance of server

---
 common/src/connection.rs |  2 +-
 common/src/server.rs     | 14 +++++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/common/src/connection.rs b/common/src/connection.rs
index d228055..0bd71ab 100644
--- a/common/src/connection.rs
+++ b/common/src/connection.rs
@@ -81,6 +81,7 @@ async fn handle_status_change(
     response_tx: mpsc::Sender<Response>,
     cancel_token: CancellationToken,
 ) {
+    // Send the initial status
     send_status(&status_rx, &response_tx).await;
     println!("Waiting for status change");
     let start_time = std::time::Instant::now();
@@ -104,7 +105,6 @@ async fn handle_status_change(
 
 async fn send_status(status_rx: &watch::Receiver<VpnStatus>, response_tx: &mpsc::Sender<Response>) {
     let status = *status_rx.borrow();
-    println!("received = {:?}", status);
     if let Err(err) = response_tx
         .send(Response::from(ResponseData::Status(status)))
         .await
diff --git a/common/src/server.rs b/common/src/server.rs
index fd30bd9..b881643 100644
--- a/common/src/server.rs
+++ b/common/src/server.rs
@@ -1,6 +1,7 @@
 use crate::{connection::handle_connection, vpn::Vpn};
 use std::{future::Future, os::unix::prelude::PermissionsExt, path::Path, sync::Arc};
-use tokio::{fs, net::UnixListener};
+use tokio::fs;
+use tokio::net::{UnixListener, UnixStream};
 
 #[derive(Debug, Default)]
 pub(crate) struct ServerContext {
@@ -26,6 +27,12 @@ impl Server {
         }
     }
 
+    // Check if an instance of the server is already running.
+    // by trying to connect to the socket.
+    async fn is_running(&self) -> bool {
+        UnixStream::connect(&self.socket_path).await.is_ok()
+    }
+
     async fn start(&self) -> Result<(), Box<dyn std::error::Error>> {
         if Path::new(&self.socket_path).exists() {
             fs::remove_file(&self.socket_path).await?;
@@ -65,6 +72,11 @@ pub async fn run(
 ) -> Result<(), Box<dyn std::error::Error>> {
     let server = Server::new(socket_path.to_string());
 
+    if server.is_running().await {
+        println!("Server is already running");
+        return Ok(());
+    }
+
     tokio::select! {
         res = server.start() => {
             if let Err(err) = res {