Get templateHash for static tile request and errored named map instantiations

lib/models/mapconfig/provider/named-map-provider.js

@@ -4,7 +4,7 @@ const BaseMapConfigProvider = require('./base-mapconfig-adapter');
 const crypto = require('crypto');
 const dot = require('dot');
 const MapConfig = require('windshaft').model.MapConfig;
-const templateName = require('../../../backends/template-maps').templateName;
+const { templateName, fingerPrint: templateFingerPrint } = require('../../../backends/template-maps');
 
 // Configure bases for cache keys suitable for string interpolation
 const baseKey = '{{=it.dbname}}:{{=it.user}}:{{=it.templateName}}';
@@ -258,6 +258,14 @@ module.exports = class NamedMapMapConfigProvider extends BaseMapConfigProvider {
     getTemplateName () {
         return this.templateName;
     }
+
+    getTemplateHash () {
+        if (!this.template) {
+            throw new Error('Missing template, call "getTemplate()" method first');
+        }
+
+        return templateFingerPrint(this.template);
+    }
 };
 
 function createConfigHash (config) {