Merge branch '8784-dir-listings'

[arvados.git] / sdk / go / dispatch / dispatch.go

diff --git a/sdk/go/dispatch/dispatch.go b/sdk/go/dispatch/dispatch.go
index 49c756e892f232e26c9fffa74feeffed46400309..356d087a46f31c7f97ce92ad975300f0a0959990 100644 (file)
--- a/sdk/go/dispatch/dispatch.go
+++ b/sdk/go/dispatch/dispatch.go
@@ -1,3 +1,7 @@
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+
 // Package dispatch is a helper library for building Arvados container
 // dispatchers.
 package dispatch
@@ -203,28 +207,41 @@ 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) {
-       d.mtx.Lock()
-       defer d.mtx.Unlock()
-
-       if d.trackers == nil {
-               d.trackers = make(map[string]*runTracker)
-       }
-
-       _, alreadyTracking := d.trackers[uuid]
-       if alreadyTracking {
-               return
-       }
-
+// 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 {
-               log.Printf("Error getting container %s: %s", uuid, err)
-               return
+               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)
+       }
        d.trackers[uuid] = d.start(cntr)
+       switch cntr.State {
+       case Queued, Cancelled, Complete:
+               d.trackers[uuid].close()
+       }
+       return nil
 }
 
 type runTracker struct {