feat(targetConfig): allow unmarshaling with labels that support templating

config/target.go

@@ -6,31 +6,43 @@ type TargetConfig struct {
 }
 
 // UnmarshalYAML implements yaml.Unmarshaler interface.
-func (d *TargetConfig) UnmarshalYAML(unmashal func(interface{}) error) error {
+func (t *TargetConfig) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	// If the input is a string, treat it as the Addr
 	var s string
-	if err := unmashal(&s); err == nil {
-		d.Addr = s
+	if err := unmarshal(&s); err == nil {
+		t.Addr = s
+		t.Labels = nil
 		return nil
 	}
-
-	var x map[string]map[string]string
-	if err := unmashal(&x); err != nil {
+	// Temporary map to capture raw data
+	raw := make(map[string]string)
+	if err := unmarshal(&raw); err != nil {
 		return err
 	}
 
-	for addr, l := range x {
-		d.Addr = addr
-		d.Labels = l
+	// Extract "host" key into Addr
+	if addr, ok := raw["host"]; ok {
+		t.Addr = addr
+		delete(raw, "host") // Remove from labels
 	}
 
+	// Store remaining keys as labels
+	t.Labels = raw
 	return nil
 }
 
-func (d TargetConfig) MarshalYAML() (interface{}, error) {
-	if d.Labels == nil {
-		return d.Addr, nil
+func (t TargetConfig) MarshalYAML() (interface{}, error) {
+	// If there are no labels, just return the address as a string
+	if len(t.Labels) == 0 {
+		return t.Addr, nil
+	}
+
+	// Otherwise, construct a map with "host" as Addr and other labels
+	m := make(map[string]string)
+	m["host"] = t.Addr
+	for k, v := range t.Labels {
+		m[k] = v
 	}
-	ret := make(map[string]map[string]string)
-	ret[d.Addr] = d.Labels
-	return ret, nil
+
+	return m, nil
 }

config/testdata/config_test.yml

@@ -3,8 +3,8 @@ targets:
   - 8.8.8.8
   - 8.8.4.4
   - 2001:4860:4860::8888
-  - "2001:4860:4860::8844":
-      foo: "bar"
+  - host: "2001:4860:4860::8844"
+    foo: "bar"
 
 dns:
   refresh: 2m15s