Implement target selection, autodiscovery via aggregator, implement listTargets

cmd/aggregator/subscriber.go

@@ -15,12 +15,13 @@ import (
 // the collector degraded (zeroing its contribution) after 3 consecutive
 // failures.
 type CollectorSub struct {
-	addr   string
-	merger *Merger
+	addr     string
+	merger   *Merger
+	registry *TargetRegistry
 }
 
-func NewCollectorSub(addr string, merger *Merger) *CollectorSub {
-	return &CollectorSub{addr: addr, merger: merger}
+func NewCollectorSub(addr string, merger *Merger, registry *TargetRegistry) *CollectorSub {
+	return &CollectorSub{addr: addr, merger: merger, registry: registry}
 }
 
 // Run blocks until ctx is cancelled.
@@ -92,6 +93,7 @@ func (cs *CollectorSub) stream(ctx context.Context) (bool, error) {
 			return gotOne, err
 		}
 		gotOne = true
+		cs.registry.SetName(cs.addr, snap.Source)
 		cs.merger.Apply(snap)
 	}
 }