feat(config): interpolate recursively in interpolated map

internal/config/environment.go

@@ -101,33 +101,66 @@ func (ib *InterpolatedBool) UnmarshalYAML(value *yaml.Node) error {
 	return nil
 }
 
-type InterpolatedMap map[string]interface{}
+type InterpolatedMap struct {
+	Data   map[string]any
+	getEnv func(string) string
+}
 
 func (im *InterpolatedMap) UnmarshalYAML(value *yaml.Node) error {
-	var data map[string]interface{}
+	var data map[string]any
 
 	if err := value.Decode(&data); err != nil {
 		return errors.Wrapf(err, "could not decode value '%v' (line '%d') into map", value.Value, value.Line)
 	}
 
-	for key, value := range data {
-		strVal, ok := value.(string)
-		if !ok {
-			continue
-		}
-
-		if match := reVar.FindStringSubmatch(strVal); len(match) > 0 {
-			strVal = os.Getenv(match[1])
-		}
-
-		data[key] = strVal
+	if im.getEnv == nil {
+		im.getEnv = os.Getenv
 	}
 
-	*im = data
+	interpolated, err := im.interpolateRecursive(data)
+	if err != nil {
+		return errors.WithStack(err)
+	}
+
+	im.Data = interpolated.(map[string]any)
 
 	return nil
 }
 
+func (im *InterpolatedMap) interpolateRecursive(data any) (any, error) {
+	switch typ := data.(type) {
+	case map[string]any:
+		for key, value := range typ {
+			value, err := im.interpolateRecursive(value)
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			typ[key] = value
+		}
+
+	case string:
+		value, err := envsubst.Eval(typ, im.getEnv)
+		if err != nil {
+			return nil, errors.WithStack(err)
+		}
+
+		data = value
+
+	case []any:
+		for idx := range typ {
+			value, err := im.interpolateRecursive(typ[idx])
+			if err != nil {
+				return nil, errors.WithStack(err)
+			}
+
+			typ[idx] = value
+		}
+	}
+
+	return data, nil
+}
+
 type InterpolatedStringSlice []string
 
 func (iss *InterpolatedStringSlice) UnmarshalYAML(value *yaml.Node) error {