Handle graceful server shutdown form C++

api/src/lib.rs

@@ -1,5 +1,5 @@
 use std::panic;
-use utils::copy_database_if_not_exists;
+use utils::{copy_database_if_not_exists, SHUTDOWN_CHANNEL};
 
 pub mod app_state;
 pub mod auth;
@@ -18,6 +18,20 @@ pub enum RustError {
     Error = 1,
 }
 
+// Externally callable function to shut down the server for using from C++.
+#[no_mangle]
+pub extern "C" fn shutdown_server() {
+    // Send a shutdown signal to the server
+    let _ = tokio::runtime::Builder::new_multi_thread()
+        .enable_all()
+        .build()
+        .unwrap()
+        .block_on(async {
+            let sender = SHUTDOWN_CHANNEL.lock().await;
+            sender.send(()).await.ok();
+        });
+}
+
 // Externally callable function to run the server for using from C++, returning a RustError.
 #[no_mangle]
 pub extern "C" fn run_server() -> RustError {

api/src/server.rs

@@ -6,7 +6,7 @@ use axum::{
     Router,
 };
 
-use tokio::{net::TcpListener, signal};
+use tokio::{net::TcpListener, signal, sync::mpsc};
 use tower_http::{
     cors::{Any, CorsLayer},
     services::ServeDir,
@@ -15,7 +15,7 @@ use tower_http::{
 use crate::{
     app_state::{self, AppState},
     file::routes::file_routes,
-    utils::{run_migrations, SPA_DIR},
+    utils::{run_migrations, SHUTDOWN_CHANNEL, SPA_DIR},
 };
 
 use super::modbus_register::routes::modbus_register_routes;
@@ -57,7 +57,9 @@ pub async fn create_app(app_state: AppState) -> Result<Router, Box<dyn Error>> {
 
 pub async fn server_start() -> Result<(), Box<dyn Error>> {
     // Initialize tracing
-    tracing_subscriber::fmt::init();
+    if let Err(_) = tracing_subscriber::fmt().try_init() {
+        // Handle the error or ignore it if reinitialization is not needed
+    }
 
     // Load environment variables from .env file
     dotenvy::dotenv().ok();
@@ -89,6 +91,11 @@ pub async fn server_start() -> Result<(), Box<dyn Error>> {
 }
 
 async fn shutdown_signal(state: AppState) {
+    let (shutdown_tx, mut shutdown_rx) = mpsc::channel(1);
+
+    // Store the sender in the SHUTDOWN_CHANNEL
+    *SHUTDOWN_CHANNEL.lock().await = shutdown_tx;
+
     let ctrl_c = async {
         signal::ctrl_c()
             .await
@@ -109,6 +116,7 @@ async fn shutdown_signal(state: AppState) {
     tokio::select! {
         _ = ctrl_c => {},
         _ = terminate => {},
+        _ = shutdown_rx.recv() => {}, // Listen for the shutdown signal
     }
 
     // Drop the database connection gracefully

api/src/utils.rs

@@ -1,6 +1,7 @@
 use lazy_static::lazy_static;
 use migration::{Migrator, MigratorTrait};
-use std::{env, fs, path::Path};
+use std::{env, fs, path::Path, sync::Arc};
+use tokio::sync::{mpsc, Mutex};
 
 use crate::db_connection::establish_connection;
 
@@ -15,6 +16,8 @@ lazy_static! {
     // SPA_DIR is set from environment variable or defaults to a local directory.
     pub static ref SPA_DIR: String =
         env::var("SPA_DIR").unwrap_or_else(|_| "./ResourceFile/webview/www".to_string());
+
+    pub static ref SHUTDOWN_CHANNEL: Arc<Mutex<mpsc::Sender<()>>> = Arc::new(Mutex::new(mpsc::channel(1).0));
 }
 
 // Copies the database file to the destination if it does not already exist.