controller: improve absent metric PromRule naming

README.md

@@ -61,7 +61,7 @@ labels:
   severity: info
 annotations:
   summary: missing foo_bar
-  description: The metric 'foo_bar' is missing
+  description: The metric 'foo_bar' is missing. Alerts using it may not fire as intended.
 ```
 
 ## Installation
@@ -121,8 +121,8 @@ For example, if a namespace has alert rules defined across several
 `Infra`. The absent metric alerts for this namespace would be aggregated in two
 new `PrometheusRule` resources called:
 
-- `openstack-absent-metrics-alert-rules`
-- `infra-absent-metrics-alert-rules`
+- `openstack-absent-metric-alert-rules`
+- `infra-absent-metric-alert-rules`
 
 ### Template
 
@@ -138,7 +138,7 @@ labels:
   severity: info
 annotations:
   summary: missing $metric
-  description: The metric '$metric' is missing
+  description: The metric '$metric' is missing. Alerts using it may not fire as intended.
 ```
 
 Consider the metric `limes_successful_scrapes:rate5m` with tier `os` and

internal/controller/controller.go

@@ -211,7 +211,7 @@ func (c *Controller) processNextWorkItem() bool {
 }
 
 // syncHandler gets a PrometheusRule from the queue and updates the
-// corresponding absent metrics alert PrometheusRule for it.
+// corresponding absent metric alert PrometheusRule for it.
 func (c *Controller) syncHandler(key string) error {
 	// Convert the namespace/name string into a distinct namespace and name.
 	namespace, name, err := cache.SplitMetaNamespaceKey(key)
@@ -228,7 +228,7 @@ func (c *Controller) syncHandler(key string) error {
 	case apierrors.IsNotFound(err):
 		// The resource may no longer exist, in which case we clean up any
 		// orphaned absent alert rules.
-		c.logger.Info("msg", "PrometheusRule no longer exists in work queue", "key", key)
+		c.logger.Info("msg", "PrometheusRule no longer exists", "key", key)
 		return c.deleteAbsentAlertRulesNamespace(namespace, name)
 	default:
 		// Requeue object for later processing.
@@ -243,9 +243,9 @@ func (c *Controller) syncHandler(key string) error {
 		return nil
 	}
 
-	// Get the PrometheusRule resource that defines the absent metrics alert
+	// Get the PrometheusRule resource that defines the absent metric alert
 	// rules for this namespace.
-	absentPromRuleName := fmt.Sprintf("%s-absent-metrics-alert-rules", promServerName)
+	absentPromRuleName := fmt.Sprintf("%s-absent-metric-alert-rules", promServerName)
 	absentPromRule, err := c.promClientset.MonitoringV1().PrometheusRules(namespace).
 		Get(context.Background(), absentPromRuleName, metav1.GetOptions{})
 

internal/controller/prometheusrule.go

@@ -45,8 +45,7 @@ func (c *Controller) createAbsentPrometheusRule(namespace, name, promServerName
 		},
 	}
 
-	_, err := c.promClientset.MonitoringV1().PrometheusRules(namespace).
-		Create(context.Background(), pr, metav1.CreateOptions{})
+	_, err := c.promClientset.MonitoringV1().PrometheusRules(namespace).Create(context.Background(), pr, metav1.CreateOptions{})
 	if err != nil {
 		return errors.Wrap(err, "could not create new absent PrometheusRule")
 	}
@@ -87,13 +86,12 @@ func (c *Controller) updateAbsentPrometheusRule(
 	}
 	pr.Spec.Groups = new
 
-	_, err := c.promClientset.MonitoringV1().PrometheusRules(namespace).
-		Update(context.Background(), pr, metav1.UpdateOptions{})
+	_, err := c.promClientset.MonitoringV1().PrometheusRules(namespace).Update(context.Background(), pr, metav1.UpdateOptions{})
 	if err != nil {
 		return errors.Wrap(err, "could not update absent PrometheusRule")
 	}
 
-	c.logger.Info("msg", "successfully updated absent alert rules",
+	c.logger.Info("msg", "successfully updated absent metric alert rules",
 		"key", fmt.Sprintf("%s/%s", namespace, pr.Name))
 	return nil
 }
@@ -136,17 +134,21 @@ func (c *Controller) deleteAbsentAlertRules(namespace, promRuleName string, abse
 
 	var err error
 	if len(pr.Spec.Groups) == 0 {
-		err = c.promClientset.MonitoringV1().PrometheusRules(namespace).
-			Delete(context.Background(), pr.Name, metav1.DeleteOptions{})
+		err = c.promClientset.MonitoringV1().PrometheusRules(namespace).Delete(context.Background(), pr.Name, metav1.DeleteOptions{})
+		if err == nil {
+			c.logger.Info("msg", "successfully deleted orphaned absent PrometheusRule",
+				"key", fmt.Sprintf("%s/%s", namespace, pr.Name))
+		}
 	} else {
-		_, err = c.promClientset.MonitoringV1().PrometheusRules(namespace).
-			Update(context.Background(), pr, metav1.UpdateOptions{})
+		_, err = c.promClientset.MonitoringV1().PrometheusRules(namespace).Update(context.Background(), pr, metav1.UpdateOptions{})
+		if err == nil {
+			c.logger.Info("msg", "successfully cleaned up orphaned absent metric alert rules",
+				"key", fmt.Sprintf("%s/%s", namespace, pr.Name))
+		}
 	}
 	if err != nil {
-		return errors.Wrap(err, "could not clean up orphaned absent alert rules")
+		return errors.Wrap(err, "could not clean up orphaned absent metric alert rules")
 	}
 
-	c.logger.Info("msg", "successfully cleaned up orphaned absent alert rules",
-		"key", fmt.Sprintf("%s/%s", namespace, pr.Name))
 	return nil
 }

test/controller_test.go

@@ -175,7 +175,7 @@ var _ = Describe("Controller", func() {
 			})
 
 			It("should delete orphaned absent metric alert rule from "+fixtures.OSAbsentPromRuleName+" in resmgmt namespace", func() {
-				// Since "openstack-absent-metrics-alert-rules" in "resmgmt"
+				// Since "openstack-absent-metric-alert-rules" in "resmgmt"
 				// namespace holds the aggregate absent metric alert rules for
 				// the "openstack-limes-api.alerts" and
 				// "openstack-limes-roleassign.alerts", deleting one resource

test/fixtures/doc.go

@@ -17,6 +17,6 @@ package fixtures
 
 // Common constants for reusability.
 const (
-	K8sAbsentPromRuleName = "kubernetes-absent-metrics-alert-rules"
-	OSAbsentPromRuleName  = "openstack-absent-metrics-alert-rules"
+	K8sAbsentPromRuleName = "kubernetes-absent-metric-alert-rules"
+	OSAbsentPromRuleName  = "openstack-absent-metric-alert-rules"
 )