X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/25af6c40181b95f13ec3e9e366c53cb50868d065..123153139bbee3674c81325653d87fa19ffbe0e4:/sdk/go/dispatch/dispatch.go

diff --git a/sdk/go/dispatch/dispatch.go b/sdk/go/dispatch/dispatch.go
index 5c3611ce3d..261444a05f 100644
--- a/sdk/go/dispatch/dispatch.go
+++ b/sdk/go/dispatch/dispatch.go
@@ -131,7 +131,7 @@ func (d *Dispatcher) checkForUpdates(filters [][]interface{}) {
 			log.Printf("Error getting list of containers: %q", err)
 			return
 		}
-		more = list.ItemsAvailable > len(list.Items)
+		more = len(list.Items) > 0 && list.ItemsAvailable > len(list.Items)+offset
 		d.checkListForUpdates(list.Items)
 	}
 }
@@ -203,28 +203,41 @@ func (d *Dispatcher) Unlock(uuid string) error {
 	return d.Arv.Call("POST", "containers", uuid, "unlock", nil, nil)
 }
 
-// TrackContainer starts a tracker for given uuid if one is not already existing, despite its state.
-func (d *Dispatcher) TrackContainer(uuid string) {
+// TrackContainer ensures a tracker is running for the given UUID,
+// regardless of the current state of the container (except: if the
+// container is locked by a different dispatcher, a tracker will not
+// be started). If the container is not in Locked or Running state,
+// the new tracker will close down immediately.
+//
+// This allows the dispatcher to put its own RunContainer func into a
+// cleanup phase (for example, to kill local processes created by a
+// prevous dispatch process that are still running even though the
+// container state is final) without the risk of having multiple
+// goroutines monitoring the same UUID.
+func (d *Dispatcher) TrackContainer(uuid string) error {
+	var cntr arvados.Container
+	err := d.Arv.Call("GET", "containers", uuid, "", nil, &cntr)
+	if err != nil {
+		return err
+	}
+	if cntr.LockedByUUID != "" && cntr.LockedByUUID != d.auth.UUID {
+		return nil
+	}
+
 	d.mtx.Lock()
 	defer d.mtx.Unlock()
-
+	if _, alreadyTracking := d.trackers[uuid]; alreadyTracking {
+		return nil
+	}
 	if d.trackers == nil {
 		d.trackers = make(map[string]*runTracker)
 	}
-
-	_, alreadyTracking := d.trackers[uuid]
-	if alreadyTracking {
-		return
+	d.trackers[uuid] = d.start(cntr)
+	switch cntr.State {
+	case Queued, Cancelled, Complete:
+		d.trackers[uuid].close()
 	}
-
-	var cntr arvados.Container
-	err := d.Arv.Call("GET", "containers", uuid, "", nil, &cntr)
-	if err != nil {
-		log.Printf("Error getting container %s: %s", uuid, err)
-		return
-	}
-
-	d.trackers[uuid] = d.start(c)
+	return nil
 }
 
 type runTracker struct {