gracefull shutdown of SSE loop

fwa.service

@@ -12,7 +12,7 @@ Restart=on-failure
 RestartSec=5
 User=root
 Group=root
-RuntimeDirectory=/var/lib/fwa
+WorkingDirectory=/var/lib/fwa
 
 Environment="PM3_BIN=/usr/local/bin/pm3/pm3"
 #Environment="LOG_LEVEL=warn"

src/pm3.rs

@@ -2,8 +2,10 @@ use log::{debug, info, trace, warn};
 use std::env;
 use std::error::Error;
 use std::process::Stdio;
-use tokio::io::{AsyncBufReadExt, BufReader};
+use tokio::io::{AsyncBufReadExt, AsyncWriteExt, BufReader};
 use tokio::process::Command;
+use tokio::select;
+use tokio::signal::unix::{SignalKind, signal};
 use tokio::sync::broadcast;
 
 /// Runs the pm3 binary and monitors it's output
@@ -27,31 +29,43 @@ pub async fn run_pm3(tx: broadcast::Sender<String>) -> Result<(), Box<dyn Error>
         .arg("lf hitag reader -@")
         .stdout(Stdio::piped())
         .stderr(Stdio::null())
-        .stdin(Stdio::null())
+        .stdin(Stdio::piped())
         .spawn()?;
 
     let stdout = cmd.stdout.take().ok_or("Failed to get stdout")?;
+    let mut stdin = cmd.stdin.take().ok_or("Failed to get stdin")?;
 
     let mut reader = BufReader::new(stdout).lines();
 
-    let mut last_id: String = "".to_owned();
+    let mut sigterm = signal(SignalKind::terminate())?;
 
-    while let Some(line) = reader.next_line().await? {
-        trace!("PM3: {line}");
-        if let Some(uid) = super::parser::parse_line(&line) {
-            if last_id == uid {
-                tx.send(uid.clone())?;
+    let child_handle = tokio::spawn(async move {
+        let mut last_id: String = "".to_owned();
+        while let Some(line) = reader.next_line().await.unwrap_or(None) {
+            trace!("PM3: {line}");
+            if let Some(uid) = super::parser::parse_line(&line) {
+                if last_id == uid {
+                    let _ = tx.send(uid.clone());
+                }
+                last_id = uid;
             }
-            last_id = uid.to_owned();
         }
-    }
+    });
+
+    select! {
+        _ = child_handle => {}
+        _ = sigterm.recv() => {
+            debug!("Graceful shutdown of PM3");
+            let _ = stdin.write_all(b"\n").await;
+            let _ = stdin.flush().await;
+        }
+    };
 
     let status = cmd.wait().await?;
-
     if status.success() {
         Ok(())
     } else {
-        Err("PM3 exited with a non zero exit code".into())
+        Err("PM3 exited with a non-zero exit code".into())
     }
 }
 

src/webserver.rs

@@ -2,7 +2,7 @@ use log::{error, info, warn};
 use rocket::http::Status;
 use rocket::response::stream::{Event, EventStream};
 use rocket::serde::json::Json;
-use rocket::{Config, State, post};
+use rocket::{Config, Shutdown, State, post};
 use rocket::{get, http::ContentType, response::content::RawHtml, routes};
 use rust_embed::Embed;
 use serde::Deserialize;
@@ -10,6 +10,7 @@ use std::borrow::Cow;
 use std::env;
 use std::ffi::OsStr;
 use std::sync::Arc;
+use tokio::select;
 use tokio::sync::Mutex;
 use tokio::sync::broadcast::Sender;
 
@@ -84,13 +85,20 @@ fn static_files(file: std::path::PathBuf) -> Option<(ContentType, Vec<u8>)> {
 }
 
 #[get("/api/idevent")]
-fn id_event(sse_broadcaster: &State<Sender<String>>) -> EventStream![] {
+fn id_event(sse_broadcaster: &State<Sender<String>>, shutdown: Shutdown) -> EventStream![] {
     let mut rx = sse_broadcaster.subscribe();
     EventStream! {
         loop {
-            let msg = rx.recv().await;
-            if let Ok(id) = msg {
-                yield Event::data(id);
+            select! {
+                msg = rx.recv() => {
+                    if let Ok(id) = msg {
+                        yield Event::data(id);
+                    }
+                }
+                _ = &mut shutdown.clone() => {
+                    // Shutdown signal received, exit the loop
+                    break;
+                }
             }
         }
     }