hcloud discovery: Add new labelpresent label (#9028)

* Add new labelpresent label

Signed-off-by: Lukas Kämmerling <lukas.kaemmerling@hetzner-cloud.de>

discovery/hetzner/hcloud.go

@@ -47,6 +47,7 @@ const (
 	hetznerLabelHcloudDiskGB                        = hetznerHcloudLabelPrefix + "disk_size_gb"
 	hetznerLabelHcloudType                          = hetznerHcloudLabelPrefix + "server_type"
 	hetznerLabelHcloudLabel                         = hetznerHcloudLabelPrefix + "label_"
+	hetznerLabelHcloudLabelPresent                  = hetznerHcloudLabelPrefix + "labelpresent_"
 )
 
 // Discovery periodically performs Hetzner Cloud requests. It implements
@@ -124,6 +125,9 @@ func (d *hcloudDiscovery) refresh(ctx context.Context) ([]*targetgroup.Group, er
 			}
 		}
 		for labelKey, labelValue := range server.Labels {
+			presentLabel := model.LabelName(hetznerLabelHcloudLabelPresent + strutil.SanitizeLabelName(labelKey))
+			labels[presentLabel] = model.LabelValue("true")
+
 			label := model.LabelName(hetznerLabelHcloudLabel + strutil.SanitizeLabelName(labelKey))
 			labels[label] = model.LabelValue(labelValue)
 		}

discovery/hetzner/hcloud_test.go

@@ -77,6 +77,7 @@ func TestHCloudSDRefresh(t *testing.T) {
 			"__meta_hetzner_hcloud_disk_size_gb":                     model.LabelValue("25"),
 			"__meta_hetzner_hcloud_server_type":                      model.LabelValue("cx11"),
 			"__meta_hetzner_hcloud_private_ipv4_mynet":               model.LabelValue("10.0.0.2"),
+			"__meta_hetzner_hcloud_labelpresent_my_key":              model.LabelValue("true"),
 			"__meta_hetzner_hcloud_label_my_key":                     model.LabelValue("my-value"),
 		},
 		{
@@ -99,6 +100,10 @@ func TestHCloudSDRefresh(t *testing.T) {
 			"__meta_hetzner_hcloud_memory_size_gb":                   model.LabelValue("1"),
 			"__meta_hetzner_hcloud_disk_size_gb":                     model.LabelValue("50"),
 			"__meta_hetzner_hcloud_server_type":                      model.LabelValue("cpx11"),
+			"__meta_hetzner_hcloud_labelpresent_key":                 model.LabelValue("true"),
+			"__meta_hetzner_hcloud_labelpresent_other_key":           model.LabelValue("true"),
+			"__meta_hetzner_hcloud_label_key":                        model.LabelValue(""),
+			"__meta_hetzner_hcloud_label_other_key":                  model.LabelValue("value"),
 		},
 		{
 			"__address__":                                            model.LabelValue("1.2.3.6:80"),

discovery/hetzner/mock_test.go

@@ -310,7 +310,10 @@ func (m *SDMock) HandleHcloudServers() {
         "delete": false,
         "rebuild": false
       },
-      "labels": {},
+      "labels": {
+        "key": "",
+        "other-key": "value"
+      },
       "volumes": [],
       "load_balancers": []
     },

docs/configuration/configuration.md

@@ -1211,6 +1211,7 @@ The labels below are only available for targets with `role` set to `hcloud`:
 * `__meta_hetzner_hcloud_disk_size_gb`: the disk size of the server (in GB)
 * `__meta_hetzner_hcloud_private_ipv4_<networkname>`: the private ipv4 address of the server within a given network
 * `__meta_hetzner_hcloud_label_<labelname>`: each label of the server
+* `__meta_hetzner_hcloud_labelpresent_<labelname>`: `true` for each label of the server
 
 The labels below are only available for targets with `role` set to `robot`: