controller: fix conditional statement

CHANGELOG.md

@@ -7,6 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.2] - 2020-08-21
+
+### Fixed
+
+- A bug that was introduced in the previous release.
+
 ## [0.5.1] - 2020-08-21
 
 ### Changed
@@ -47,7 +53,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Initial release.
 
-[unreleased]: https://github.com/sapcc/absent-metrics-operator/compare/v0.5.1...HEAD
+[unreleased]: https://github.com/sapcc/absent-metrics-operator/compare/v0.5.2...HEAD
+[0.5.2]: https://github.com/sapcc/absent-metrics-operator/compare/v0.5.1...v0.5.2
 [0.5.1]: https://github.com/sapcc/absent-metrics-operator/compare/v0.5.0...v0.5.1
 [0.5.0]: https://github.com/sapcc/absent-metrics-operator/compare/v0.4.0...v0.5.0
 [0.4.0]: https://github.com/sapcc/absent-metrics-operator/compare/v0.3.0...v0.4.0

internal/controller/controller.go

@@ -330,17 +330,12 @@ func (c *Controller) syncHandler(key string) error {
 	rg := promRule.Spec.Groups
 	// Fast path: check that the PrometheusRule contains at least one alert
 	// rule; no need to continue further otherwise.
-	hasAlerts := false
-	for _, g := range rg {
-		for _, r := range g.Rules {
-			if r.Alert != "" {
-				hasAlerts = true
-			}
+	if !hasAlerts(rg) {
+		if existingAbsentPromRule {
+			// We still need to clean up any orphaned absent alerts that may exist.
+			return c.cleanUpOrphanedAbsentAlerts(name, absentPromRule)
 		}
-	}
-	if !hasAlerts {
-		// We still need to clean up any orphaned absent alerts that may exist.
-		return c.cleanUpOrphanedAbsentAlerts(name, absentPromRule)
+		return nil
 	}
 
 	defaultTier := absentPromRule.Tier
@@ -393,3 +388,15 @@ func (c *Controller) syncHandler(key string) error {
 	c.metrics.SuccessfulPrometheusRuleReconcileTime.WithLabelValues(namespace, name).SetToCurrentTime()
 	return nil
 }
+
+// hasAlerts checks if a slice RuleGroup has any alert definitions.
+func hasAlerts(rg []monitoringv1.RuleGroup) bool {
+	for _, g := range rg {
+		for _, r := range g.Rules {
+			if r.Alert != "" {
+				return true
+			}
+		}
+	}
+	return false
+}