15345: Add .../containers/kill management API to dispatcher.

[arvados.git] / lib / dispatchcloud / worker / pool.go

diff --git a/lib/dispatchcloud/worker/pool.go b/lib/dispatchcloud/worker/pool.go
index 201e8aad276eb5f8ca353e3ff8c41fc9dee00f2a..97ca7f60a2a916fd6feece03e016c7fe3673e22d 100644 (file)
--- a/lib/dispatchcloud/worker/pool.go
+++ b/lib/dispatchcloud/worker/pool.go
@@ -154,7 +154,7 @@ type Pool struct {
        creating     map[string]createCall // unfinished (cloud.InstanceSet)Create calls (key is instance secret)
        workers      map[cloud.InstanceID]*worker
        loaded       bool                 // loaded list of instances from InstanceSet at least once
-       exited       map[string]time.Time // containers whose crunch-run proc has exited, but KillContainer has not been called
+       exited       map[string]time.Time // containers whose crunch-run proc has exited, but ForgetContainer has not been called
        atQuotaUntil time.Time
        atQuotaErr   cloud.QuotaError
        stop         chan bool
@@ -446,7 +446,7 @@ func (wp *Pool) CountWorkers() map[State]int {
 // In the returned map, the time value indicates when the Pool
 // observed that the container process had exited. A container that
 // has not yet exited has a zero time value. The caller should use
-// KillContainer() to garbage-collect the entries for exited
+// ForgetContainer() to garbage-collect the entries for exited
 // containers.
 func (wp *Pool) Running() map[string]time.Time {
        wp.setupOnce.Do(wp.setup)
@@ -493,18 +493,15 @@ func (wp *Pool) StartContainer(it arvados.InstanceType, ctr arvados.Container) b
 //
 // KillContainer returns immediately; the act of killing the container
 // takes some time, and runs in the background.
-func (wp *Pool) KillContainer(uuid string, reason string) {
+//
+// KillContainer returns false if the container has already ended.
+func (wp *Pool) KillContainer(uuid string, reason string) bool {
        wp.mtx.Lock()
        defer wp.mtx.Unlock()
        logger := wp.logger.WithFields(logrus.Fields{
                "ContainerUUID": uuid,
                "Reason":        reason,
        })
-       if _, ok := wp.exited[uuid]; ok {
-               logger.Debug("clearing placeholder for exited crunch-run process")
-               delete(wp.exited, uuid)
-               return
-       }
        for _, wkr := range wp.workers {
                rr := wkr.running[uuid]
                if rr == nil {
@@ -512,10 +509,30 @@ func (wp *Pool) KillContainer(uuid string, reason string) {
                }
                if rr != nil {
                        rr.Kill(reason)
-                       return
+                       return true
                }
        }
        logger.Debug("cannot kill: already disappeared")
+       return false
+}
+
+// ForgetContainer clears the placeholder for the given exited
+// container, so it isn't returned by subsequent calls to Running().
+//
+// ForgetContainer has no effect if the container has not yet exited.
+//
+// The "container exited at time T" placeholder (which necessitates
+// ForgetContainer) exists to make it easier for the caller
+// (scheduler) to distinguish a container that exited without
+// finalizing its state from a container that exited too recently for
+// its final state to have appeared in the scheduler's queue cache.
+func (wp *Pool) ForgetContainer(uuid string) {
+       wp.mtx.Lock()
+       defer wp.mtx.Unlock()
+       if _, ok := wp.exited[uuid]; ok {
+               wp.logger.WithField("ContainerUUID", uuid).Debug("clearing placeholder for exited crunch-run process")
+               delete(wp.exited, uuid)
+       }
 }
 
 func (wp *Pool) registerMetrics(reg *prometheus.Registry) {