Fix: Update the progress bar each second

This patch tries to work around a longer-than-1-sec blocking future while
waiting for the channel .recv() call in the LogReceiver.

The issue at hand is: If the channel does not produce log output for longer than
1 second, the progress bar won't be `tick()`ed for that amount of time.
That leads to progress bars that seem to block (no update of the time in the
progress bar output), which might confuse users.

This patch works around that by wrapping the recv() in a timeout future and then
catch the timeout, ping the progress bar and try to `recv()` again.

Signed-off-by: Matthias Beyer <matthias.beyer@atos.net>

1 files changed, 23 insertions, 1 deletions

diff --git a/src/endpoint/scheduler.rs b/src/endpoint/scheduler.rs
index 5f0882b..0215938 100644
--- a/src/endpoint/scheduler.rs
+++ b/src/endpoint/scheduler.rs
@@ -331,7 +331,29 @@ impl<'a> LogReceiver<'a> {
         let mut accu = vec![];
         let mut logfile = self.get_logfile().await.transpose()?;
 
-        while let Some(logitem) = self.log_receiver.recv().await {
+        // The timeout for the log-receive-timeout
+        //
+        // We're using a rather small timeout of just 250ms here, because we have some worktime
+        // overhead as well, and we want to ping the progressbar for the process in a way so that
+        // it updates each second.
+        // Having a timeout of 1 sec proofed to be too long to update the time field in the
+        // progress bar secondly.
+        let timeout_duration = std::time::Duration::from_millis(250);
+
+        loop {
+            // Timeout for receiving from the log receiver channel
+            // This way we can update (`tick()`) the progress bar and show the user that things are
+            // happening, even if there was no log output for several seconds.
+            let logitem = match tokio::time::timeout(timeout_duration, self.log_receiver.recv()).await {
+                Err(_ /* elapsed */) => {
+                    self.bar.tick(); // just ping the progressbar here
+                    continue
+                },
+
+                Ok(None) => break, // if the log is empty, we're done
+                Ok(Some(logitem)) => logitem,
+            };
+
             if let Some(lf) = logfile.as_mut() {
                 lf.write_all(logitem.display()?.to_string().as_bytes())
                     .await?;