Filter out labels and annotations with empty names

models/labels.go

@@ -30,3 +30,23 @@ const (
 	ValuesAnnotation      = "__values__"
 	ValueStringAnnotation = "__value_string__"
 )
+
+// filterAlertmanagerKV returns true if a label or annotation should be excluded
+// because its name or value is empty.
+func filterAlertmanagerKV(name, value string) bool {
+	return name == "" || value == ""
+}
+
+// FilterAlertmanagerLabel returns true if the label should be excluded from
+// Alertmanager payloads. Labels are filtered when the name is empty,
+// the value is empty, or the name matches NamespaceUIDLabel.
+func FilterAlertmanagerLabel(name, value string) bool {
+	return filterAlertmanagerKV(name, value) || name == NamespaceUIDLabel
+}
+
+// FilterAlertmanagerAnnotation returns true if the annotation should be
+// excluded from Alertmanager payloads. Annotations are filtered when the
+// name or value is empty.
+func FilterAlertmanagerAnnotation(name, value string) bool {
+	return filterAlertmanagerKV(name, value)
+}

models/labels_test.go

@@ -0,0 +1,95 @@
+package models
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestFilterAlertmanagerLabel(t *testing.T) {
+	cases := []struct {
+		name  string
+		label string
+		value string
+		want  bool
+	}{
+		{
+			name:  "empty label name",
+			label: "",
+			value: "v",
+			want:  true,
+		},
+		{
+			name:  "empty label value",
+			label: "alertname",
+			value: "",
+			want:  true,
+		},
+		{
+			name:  "NamespaceUIDLabel",
+			label: NamespaceUIDLabel,
+			value: "some-uid",
+			want:  true,
+		},
+		{
+			name:  "valid label",
+			label: "severity",
+			value: "critical",
+			want:  false,
+		},
+		{
+			name:  "both empty",
+			label: "",
+			value: "",
+			want:  true,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := FilterAlertmanagerLabel(tc.label, tc.value)
+			require.Equal(t, tc.want, got)
+		})
+	}
+}
+
+func TestFilterAlertmanagerAnnotation(t *testing.T) {
+	cases := []struct {
+		name       string
+		annotation string
+		value      string
+		want       bool
+	}{
+		{
+			name:       "empty annotation name",
+			annotation: "",
+			value:      "v",
+			want:       true,
+		},
+		{
+			name:       "empty annotation value",
+			annotation: "summary",
+			value:      "",
+			want:       true,
+		},
+		{
+			name:       "valid annotation",
+			annotation: "summary",
+			value:      "alert fired",
+			want:       false,
+		},
+		{
+			name:       "NamespaceUIDLabel is not filtered for annotations",
+			annotation: NamespaceUIDLabel,
+			value:      "some-uid",
+			want:       false,
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := FilterAlertmanagerAnnotation(tc.annotation, tc.value)
+			require.Equal(t, tc.want, got)
+		})
+	}
+}

notify/grafana_alertmanager.go

@@ -908,15 +908,15 @@ func PostableAlertsToAlertmanagerAlerts(postableAlerts amv2.PostableAlerts, now
 		}
 
 		for k, v := range a.Labels {
-			if len(v) == 0 || k == models.NamespaceUIDLabel { // Skip empty and namespace UID labels.
+			if models.FilterAlertmanagerLabel(k, v) {
 				continue
 			}
 
 			alert.Labels[model.LabelName(k)] = model.LabelValue(v)
 		}
 
 		for k, v := range a.Annotations {
-			if len(v) == 0 { // Skip empty annotation.
+			if models.FilterAlertmanagerAnnotation(k, v) {
 				continue
 			}
 			alert.Annotations[model.LabelName(k)] = model.LabelValue(v)

notify/grafana_alertmanager_test.go

@@ -184,6 +184,85 @@ func TestPutAlert(t *testing.T) {
 					},
 				}
 			},
+		}, {
+			title: "Removing NamespaceUIDLabel",
+			postableAlerts: amv2.PostableAlerts{
+				{
+					Alert: amv2.Alert{
+						Labels: amv2.LabelSet{"alertname": "Alert1", models.NamespaceUIDLabel: "some-uid"},
+					},
+				},
+			},
+			expAlerts: func(now time.Time) []*types.Alert {
+				return []*types.Alert{
+					{
+						Alert: model.Alert{
+							Annotations:  model.LabelSet{},
+							Labels:       model.LabelSet{"alertname": "Alert1"},
+							StartsAt:     now,
+							EndsAt:       now.Add(defaultResolveTimeout),
+							GeneratorURL: "",
+						},
+						UpdatedAt: now,
+						Timeout:   true,
+					},
+				}
+			},
+		}, {
+			title: "Removing labels with empty name",
+			postableAlerts: amv2.PostableAlerts{
+				{
+					Alert: amv2.Alert{
+						Labels:       amv2.LabelSet{"alertname": "Alert1", "": "empty-name-value"},
+						GeneratorURL: "http://localhost/url1",
+					},
+					StartsAt: strfmt.DateTime{},
+					EndsAt:   strfmt.DateTime{},
+				},
+			},
+			expAlerts: func(now time.Time) []*types.Alert {
+				return []*types.Alert{
+					{
+						Alert: model.Alert{
+							Annotations:  model.LabelSet{},
+							Labels:       model.LabelSet{"alertname": "Alert1"},
+							StartsAt:     now,
+							EndsAt:       now.Add(defaultResolveTimeout),
+							GeneratorURL: "http://localhost/url1",
+						},
+						UpdatedAt: now,
+						Timeout:   true,
+					},
+				}
+			},
+		}, {
+			title: "Removing annotations with empty name",
+			postableAlerts: amv2.PostableAlerts{
+				{
+					Annotations: amv2.LabelSet{"summary": "valid", "": "empty-name-annotation"},
+					Alert: amv2.Alert{
+						Labels:       amv2.LabelSet{"alertname": "Alert1"},
+						GeneratorURL: "http://localhost/url1",
+					},
+					StartsAt: strfmt.DateTime{},
+					EndsAt:   strfmt.DateTime{},
+				},
+			},
+			expAlerts: func(now time.Time) []*types.Alert {
+				return []*types.Alert{
+					{
+						Alert: model.Alert{
+							Annotations:  model.LabelSet{"summary": "valid"},
+							Labels:       model.LabelSet{"alertname": "Alert1"},
+							StartsAt:     now,
+							EndsAt:       now.Add(defaultResolveTimeout),
+							GeneratorURL: "http://localhost/url1",
+						},
+						UpdatedAt: now,
+						Timeout:   true,
+					},
+				}
+			},
 		}, {
 			title: "Allow spaces in label and annotation name",
 			postableAlerts: amv2.PostableAlerts{