fix: prevent nil pointer dereference in health checks

When checking the health status of each declared resource, kstatus
might return nil for certain resources (for whatever reason). In that
case, this information is now conveyed in the health status event.

#374

Signed-off-by: Max Jonas Werner <[email protected]>

Author: Max Jonas Werner

controllers/kustomization_healthcheck.go

@@ -64,6 +64,9 @@ func (hc *KustomizeHealthCheck) Assess(pollInterval time.Duration) error {
 		func(statusCollector *collector.ResourceStatusCollector, e event.Event) {
 			var rss []*event.ResourceStatus
 			for _, rs := range statusCollector.ResourceStatuses {
+				if rs == nil {
+					continue
+				}
 				if rs.Error == nil {
 					lastStatus[rs.Identifier] = rs
 				}
@@ -86,11 +89,15 @@ func (hc *KustomizeHealthCheck) Assess(pollInterval time.Duration) error {
 
 	if ctx.Err() == context.DeadlineExceeded {
 		errors := []string{}
-		for _, rs := range coll.ResourceStatuses {
-			if lastStatus[rs.Identifier].Status != status.CurrentStatus {
-				id := hc.objMetadataToString(rs.Identifier)
+		for id, rs := range coll.ResourceStatuses {
+			if rs == nil {
+				errors = append(errors, fmt.Sprintf("no status for %s available", id))
+				continue
+			}
+			if lastStatus[id].Status != status.CurrentStatus {
+				idString := hc.objMetadataToString(rs.Identifier)
 				var bld strings.Builder
-				bld.WriteString(fmt.Sprintf("%s (status '%s')", id, lastStatus[rs.Identifier].Status))
+				bld.WriteString(fmt.Sprintf("%s (status '%s')", idString, lastStatus[id].Status))
 				if rs.Error != nil {
 					bld.WriteString(fmt.Sprintf(": %s", rs.Error))
 				}