feat: Add graceful shutdown in drainer (#498)

crates/common_utils/src/signals.rs

@@ -0,0 +1,38 @@
+//! Provide Interface for worker services to handle signals
+
+use futures::StreamExt;
+use router_env::logger;
+pub use tokio::sync::oneshot;
+
+///
+/// This functions is meant to run in parallel to the application.
+/// It will send a signal to the receiver when a SIGTERM or SIGINT is received
+///
+pub async fn signal_handler(mut sig: signal_hook_tokio::Signals, sender: oneshot::Sender<()>) {
+    if let Some(signal) = sig.next().await {
+        logger::info!(
+            "Received signal: {:?}",
+            signal_hook::low_level::signal_name(signal)
+        );
+        match signal {
+            signal_hook::consts::SIGTERM | signal_hook::consts::SIGINT => match sender.send(()) {
+                Ok(_) => {
+                    logger::info!("Request for force shutdown received")
+                }
+                Err(_) => {
+                    logger::error!(
+                        "The receiver is closed, a termination call might already be sent"
+                    )
+                }
+            },
+            _ => {}
+        }
+    }
+}
+
+///
+/// This function is used to generate a list of signals that the signal_handler should listen for
+///
+pub fn get_allowed_signals() -> Result<signal_hook_tokio::SignalsInfo, std::io::Error> {
+    signal_hook_tokio::Signals::new([signal_hook::consts::SIGTERM, signal_hook::consts::SIGINT])
+}