Fix terminating stream loop on client disconnect.

As the spawn_blocking thread is not terminated when the frame_log_future
is dropped, it would keep the Redis connection open. By closing the
redis_rx channel on client-disconnect, we can check if the channel has
been closed inside the spawn_blocking thread, and return if this is the
case.

Closes #40.

chirpstack/src/api/internal.rs

@@ -675,6 +675,7 @@ impl InternalService for Internal {
                     // detect client disconnect
                     _ = close_rx.recv() => {
                         debug!("Client disconnected");
+                        redis_rx.close();
                         break;
                     }
                     // detect get_frame_logs function return

chirpstack/src/framelog.rs

@@ -9,7 +9,7 @@ use redis::streams::StreamReadReply;
 use serde_json::json;
 use tokio::sync::mpsc;
 use tokio::task;
-use tracing::{error, trace};
+use tracing::{debug, error, trace};
 
 use lrwn::EUI64;
 
@@ -256,6 +256,11 @@ pub async fn get_frame_logs(
             let mut c = get_redis_conn()?;
 
             loop {
+                if channel.is_closed() {
+                    debug!("Channel has been closed, returning");
+                    return Ok(());
+                }
+
                 let srr: StreamReadReply = redis::cmd("XREAD")
                     .arg("COUNT")
                     .arg(count)
@@ -362,6 +367,7 @@ pub async fn get_frame_logs(
                 // check every 1 second if there are new messages, which should be sufficient.
                 sleep(Duration::from_secs(1));
             }
+
         }
     }).await?
 }