Fix: Do not emit health_status event for each health check attempt.

Emit event only if there is a change in health_status
Fixes containers#24003

Signed-off-by: Harish Karumuthil <[email protected]>

Resolves containers#24005 (comment)

Pass additional isChanged flag to event creation function

Fix health check events for docker api

libpod/events.go

@@ -28,31 +28,32 @@ func (r *Runtime) newEventer() (events.Eventer, error) {
 
 // newContainerEvent creates a new event based on a container
 func (c *Container) newContainerEvent(status events.Status) {
-	if err := c.newContainerEventWithInspectData(status, "", false); err != nil {
+	if err := c.newContainerEventWithInspectData(status, events.EventMetadata{}, false); err != nil {
 		logrus.Errorf("Unable to write container event: %v", err)
 	}
 }
 
 // newContainerHealthCheckEvent creates a new healthcheck event with the given status
-func (c *Container) newContainerHealthCheckEvent(healthStatus string) {
-	if err := c.newContainerEventWithInspectData(events.HealthStatus, healthStatus, false); err != nil {
+func (c *Container) newContainerHealthCheckEvent(healthStatus string, isHcStatusChanged bool) {
+	if err := c.newContainerEventWithInspectData(events.HealthStatus, events.EventMetadata{HealthStatus: healthStatus, IsHealthStatusChanged: isHcStatusChanged}, false); err != nil {
 		logrus.Errorf("Unable to write container event: %v", err)
 	}
 }
 
 // newContainerEventWithInspectData creates a new event and sets the
 // ContainerInspectData field if inspectData is set.
-func (c *Container) newContainerEventWithInspectData(status events.Status, healthStatus string, inspectData bool) error {
+func (c *Container) newContainerEventWithInspectData(status events.Status, metadata events.EventMetadata, inspectData bool) error {
 	e := events.NewEvent(status)
 	e.ID = c.ID()
 	e.Name = c.Name()
 	e.Image = c.config.RootfsImageName
 	e.Type = events.Container
-	e.HealthStatus = healthStatus
+	e.HealthStatus = metadata.HealthStatus
 
 	e.Details = events.Details{
 		PodID:      c.PodID(),
 		Attributes: c.Labels(),
+		IsHealthStatusChanged: metadata.IsHealthStatusChanged,
 	}
 
 	if inspectData {

libpod/events/config.go

@@ -59,6 +59,8 @@ type Details struct {
 	// Attributes can be used to describe specifics about the event
 	// in the case of a container event, labels for example
 	Attributes map[string]string
+	// Whether state change happened for HealthStatus or not
+	IsHealthStatusChanged bool
 }
 
 // EventerOptions describe options that need to be passed to create
@@ -105,6 +107,15 @@ type Type string
 // Status describes the actual event action (stop, start, create, kill)
 type Status string
 
+// A general purpose datatype to store additional information to be passed while creating an event
+// more fields can be added as required
+type EventMetadata struct {
+	// Actual health status string ( healthy / unhealthy)
+	HealthStatus string
+	// Whether health status of container is toggeled or not
+	IsHealthStatusChanged bool
+}
+
 // When updating this list below please also update the shell completion list in
 // cmd/podman/common/completion.go and the StringToXXX function in events.go.
 const (

libpod/events/journal_linux.go

@@ -66,6 +66,7 @@ func (e EventJournalD) Write(ee Event) error {
 			m["PODMAN_LABELS"] = string(b)
 		}
 		m["PODMAN_HEALTH_STATUS"] = ee.HealthStatus
+		m["PODMAN_HEALTH_STATUS_CHANGED"] = strconv.FormatBool( ee.Details.IsHealthStatusChanged )
 
 		if len(ee.Details.ContainerInspectData) > 0 {
 			m["PODMAN_CONTAINER_INSPECT_DATA"] = ee.Details.ContainerInspectData
@@ -225,6 +226,7 @@ func newEventFromJournalEntry(entry *sdjournal.JournalEntry) (*Event, error) {
 			}
 		}
 		newEvent.HealthStatus = entry.Fields["PODMAN_HEALTH_STATUS"]
+		newEvent.Details.IsHealthStatusChanged, _ = strconv.ParseBool( entry.Fields["PODMAN_HEALTH_STATUS_CHANGED"] )
 		newEvent.Details.ContainerInspectData = entry.Fields["PODMAN_CONTAINER_INSPECT_DATA"]
 	case Network:
 		newEvent.ID = entry.Fields["PODMAN_ID"]

libpod/healthcheck.go

@@ -154,7 +154,7 @@ func (c *Container) runHealthCheck(ctx context.Context, isStartup bool) (define.
 	}
 
 	hcl := newHealthCheckLog(timeStart, timeEnd, returnCode, eventLog)
-	logStatus, err := c.updateHealthCheckLog(hcl, inStartPeriod, isStartup)
+	logStatus, isHCStausChanged, err := c.updateHealthCheckLog(hcl, inStartPeriod, isStartup)
 	if err != nil {
 		return hcResult, "", fmt.Errorf("unable to update health check log %s for %s: %w", c.healthCheckLogPath(), c.ID(), err)
 	}
@@ -165,7 +165,7 @@ func (c *Container) runHealthCheck(ctx context.Context, isStartup bool) (define.
 		return hcResult, logStatus, hcErr
 	}
 	if c.runtime.config.Engine.HealthcheckEvents {
-		c.newContainerHealthCheckEvent(logStatus)
+		c.newContainerHealthCheckEvent(logStatus, isHCStausChanged)
 	}
 
 	return hcResult, logStatus, hcErr
@@ -365,20 +365,21 @@ func (c *Container) isUnhealthy() (bool, error) {
 }
 
 // UpdateHealthCheckLog parses the health check results and writes the log
-func (c *Container) updateHealthCheckLog(hcl define.HealthCheckLog, inStartPeriod, isStartup bool) (string, error) {
+func (c *Container) updateHealthCheckLog(hcl define.HealthCheckLog, inStartPeriod, isStartup bool) (string, bool, error) {
 	c.lock.Lock()
 	defer c.lock.Unlock()
 
 	// If we are playing a kube yaml then let's honor the start period time for
 	// both failing and succeeding cases to match kube behavior.
 	// So don't update the health check log till the start period is over
 	if _, ok := c.config.Spec.Annotations[define.KubeHealthCheckAnnotation]; ok && inStartPeriod && !isStartup {
-		return "", nil
+		return "", false, nil
 	}
 
 	healthCheck, err := c.getHealthCheckLog()
+	oldHCStatus := healthCheck.Status
 	if err != nil {
-		return "", err
+		return "", false, err
 	}
 	if hcl.ExitCode == 0 {
 		//	set status to healthy, reset failing state to 0
@@ -397,15 +398,16 @@ func (c *Container) updateHealthCheckLog(hcl define.HealthCheckLog, inStartPerio
 			}
 		}
 	}
+	isHCStausChanged := oldHCStatus != healthCheck.Status
 	healthCheck.Log = append(healthCheck.Log, hcl)
 	if len(healthCheck.Log) > MaxHealthCheckNumberLogs {
 		healthCheck.Log = healthCheck.Log[1:]
 	}
 	newResults, err := json.Marshal(healthCheck)
 	if err != nil {
-		return "", fmt.Errorf("unable to marshall healthchecks for writing: %w", err)
+		return "", isHCStausChanged, fmt.Errorf("unable to marshall healthchecks for writing: %w", err)
 	}
-	return healthCheck.Status, os.WriteFile(c.healthCheckLogPath(), newResults, 0700)
+	return healthCheck.Status, isHCStausChanged, os.WriteFile(c.healthCheckLogPath(), newResults, 0700)
 }
 
 // HealthCheckLogPath returns the path for where the health check log is

libpod/runtime_ctr.go

@@ -576,7 +576,7 @@ func (r *Runtime) setupContainer(ctx context.Context, ctr *Container) (_ *Contai
 	}
 
 	if ctr.runtime.config.Engine.EventsContainerCreateInspectData {
-		if err := ctr.newContainerEventWithInspectData(events.Create, "", true); err != nil {
+		if err := ctr.newContainerEventWithInspectData(events.Create, events.EventMetadata{}, true); err != nil {
 			return nil, err
 		}
 	} else {

pkg/api/handlers/compat/events.go

@@ -93,6 +93,10 @@ func GetEvents(w http.ResponseWriter, r *http.Request) {
 			if evt == nil {
 				continue
 			}
+			if evt.Status == events.HealthStatus && !evt.IsHealthStatusChanged{
+				// Docker will only emit event when there is a state change
+				continue
+			}
 
 			e := entities.ConvertToEntitiesEvent(*evt)
 			// Some events differ between Libpod and Docker endpoints.