replace gatherer.target with .targetName

- add plan to manager

Should fix a possible race condition on the target.

internals/overlord/logstate/gatherer.go

@@ -39,7 +39,7 @@ const parserSize = 4 * 1024
 // Its client may also flush itself when its internal buffer reaches a certain
 // size.
 type logGatherer struct {
-	target     *plan.LogTarget
+	targetName string
 	tickPeriod time.Duration
 	cancel     chan struct{}
 	client     logClient
@@ -56,7 +56,7 @@ func newLogGatherer(target *plan.LogTarget) (*logGatherer, error) {
 	}
 
 	return &logGatherer{
-		target:     target,
+		targetName: target.Name,
 		tickPeriod: 1 * time.Second,
 		cancel:     make(chan struct{}),
 		client:     client,
@@ -69,11 +69,11 @@ func (g *logGatherer) planChanged(pl *plan.Plan, buffers map[string]*servicelog.
 	g.pullersLock.Lock()
 	defer g.pullersLock.Unlock()
 
-	g.target = pl.LogTargets[g.target.Name]
 	newPullers := map[string]*logPuller{}
 
 	for _, service := range pl.Services {
-		if !service.LogsTo(g.target) {
+		target := pl.LogTargets[g.targetName]
+		if !service.LogsTo(target) {
 			continue
 		}
 
@@ -100,7 +100,7 @@ func (g *logGatherer) planChanged(pl *plan.Plan, buffers map[string]*servicelog.
 		err := puller.tomb.Killf("gatherer closed")
 		if err != nil {
 			logger.Noticef("Error shutting down puller for target %q, service %q: %v",
-				g.target.Name, svc, err)
+				g.targetName, svc, err)
 		}
 	}
 	g.pullers = newPullers
@@ -122,21 +122,21 @@ func (g *logGatherer) loop() {
 			// Timeout - flush
 			err := g.client.Flush()
 			if err != nil {
-				logger.Noticef("Cannot send logs to target %q: %v", g.target.Name, err)
+				logger.Noticef("Cannot send logs to target %q: %v", g.targetName, err)
 			}
 
 		case <-g.cancel:
 			// Gatherer has been stopped - flush any remaining logs
 			err := g.client.Flush()
 			if err != nil {
-				logger.Noticef("Cannot send logs to target %q: %v", g.target.Name, err)
+				logger.Noticef("Cannot send logs to target %q: %v", g.targetName, err)
 			}
 			return
 
 		case entry := <-g.entryCh:
 			err := g.client.Write(entry)
 			if err != nil {
-				logger.Noticef("Cannot write logs to target %q: %v", g.target.Name, err)
+				logger.Noticef("Cannot write logs to target %q: %v", g.targetName, err)
 			}
 		}
 	}

internals/overlord/logstate/manager.go

@@ -26,6 +26,7 @@ type LogManager struct {
 	mu        sync.Mutex
 	gatherers map[string]*logGatherer
 	buffers   map[string]*servicelog.RingBuffer
+	plan      *plan.Plan
 }
 
 func NewLogManager() *LogManager {
@@ -72,6 +73,7 @@ func (m *LogManager) PlanChanged(pl *plan.Plan) {
 		gatherer.stop()
 	}
 	m.gatherers = newGatherers
+	m.plan = pl
 }
 
 // ServiceStarted notifies the log manager that the named service has started,
@@ -83,7 +85,8 @@ func (m *LogManager) ServiceStarted(service *plan.Service, buffer *servicelog.Ri
 	m.buffers[service.Name] = buffer
 
 	for _, gatherer := range m.gatherers {
-		if !service.LogsTo(gatherer.target) {
+		target := m.plan.LogTargets[gatherer.targetName]
+		if !service.LogsTo(target) {
 			continue
 		}
 		gatherer.serviceStarted(service, buffer)