From e6919bd378b232daf06e78cb1bdc68b00d9b76e3 Mon Sep 17 00:00:00 2001
From: Andrew Chorny <kha9326@zenoss.com>
Date: Fri, 4 Oct 2024 13:56:44 +0300
Subject: [PATCH] Health monitoring: Start method should block

---
 health/manager.go | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/health/manager.go b/health/manager.go
index b586566..395fccb 100644
--- a/health/manager.go
+++ b/health/manager.go
@@ -61,6 +61,7 @@ func FrameworkStart(ctx context.Context, cfg *Config, m Manager, writer w.Health
 		defer cancel()
 
 		m.Start(ctx, measurementsCh, healthCh, targetCh)
+		<-m.Done()
 	}()
 
 	doneWg.Add(1)
@@ -98,6 +99,8 @@ type Manager interface {
 	IsStarted() bool
 	// AddTargets provides a simple interface to register monitored targets
 	AddTargets(targets []*target.Target)
+
+	Done() <-chan struct{}
 }
 
 // NewManager creates a new Manager instance with internal target registry.
@@ -131,10 +134,8 @@ type healthManager struct {
 }
 
 func (hm *healthManager) Start(
-	ctx context.Context,
-	measureOut <-chan *TargetMeasurement,
-	healthIn chan<- *target.Health,
-	targetIn chan<- *target.Target,
+	ctx context.Context, measureOut <-chan *TargetMeasurement,
+	healthIn chan<- *target.Health, targetIn chan<- *target.Target,
 ) {
 	hm.mu.Lock()
 	hm.targetIn = targetIn
@@ -155,13 +156,14 @@ func (hm *healthManager) Start(
 	}()
 
 	hm.started.Store(true)
+
 	go func() {
 		hm.wg.Wait()
 		hm.started.Store(false)
-		hm.stopWait <- struct{}{}
+		close(hm.stopWait)
 	}()
 
-	hm.sendTargetsInfo() // if some targets where added before start we need to register them
+	hm.sendTargetsInfo() // if some targets were added before start we need to register them
 }
 
 func (hm *healthManager) Shutdown() {
@@ -172,6 +174,10 @@ func (hm *healthManager) Shutdown() {
 	close(hm.targetIn)
 }
 
+func (hm *healthManager) Done() <-chan struct{} {
+	return hm.stopWait
+}
+
 func (hm *healthManager) IsStarted() bool {
 	return hm.started.Load()
 }
@@ -239,7 +245,7 @@ func (hm *healthManager) updateTargetHealthData(measure *TargetMeasurement) erro
 		}
 		targetHealth, err = hm.buildTargetFromMeasure(measure)
 		if err != nil {
-			return fmt.Errorf("Unable to register target automatically: %w", err)
+			return fmt.Errorf("unable to register target automatically: %w", err)
 		}
 		hm.registry.setRawHealthForTarget(targetHealth)
 	}
@@ -250,12 +256,12 @@ func (hm *healthManager) updateTargetHealthData(measure *TargetMeasurement) erro
 	case Metric:
 		err := hm.updateTargetsMetric(targetHealth, measure)
 		if err != nil {
-			return fmt.Errorf("Unable to update target metric: %w", err)
+			return fmt.Errorf("unable to update target metric: %w", err)
 		}
 	case CounterChange:
 		err := hm.updateTargetsCounter(targetHealth, measure)
 		if err != nil {
-			return fmt.Errorf("Unable to update target counter: %w", err)
+			return fmt.Errorf("unable to update target counter: %w", err)
 		}
 	case Message:
 		if measure.Message.AffectHealth {