close #30

grails-app/controllers/docker/registry/web/RepositoryController.groovy

@@ -136,10 +136,25 @@ class RepositoryController {
     }
     */
       log.info "Deleting manifest"
-      restService.delete("${name}/manifests/${digest}")
-      //todo: show error/success
-    } else
+      def result = restService.delete("${name}/manifests/${digest}")
+      if (!result.deleted) {
+        def text = ''
+        try {
+          boolean unsupported = result.response.json.errors[0].code == 'UNSUPPORTED'
+          text = unsupported ? "Deletion disabled in registry, <a href='https://docs.docker.com/registry/configuration/#delete'>more info</a>." : result.text
+        } catch (e) {
+          text = result.text
+        }
+        flash.message = "Error deleting ${name}:${tag}: ${text}"
+      } else {
+        flash.message = "Tag ${name}:${tag} has been deleted"
+        flash.success = true
+      }
+    } else {
       log.warn 'Readonly mode!'
+      flash.message = "Readonly mode!"
+    }
+    flash.deleteAction = true
     redirect action: 'tags', id: params.name
   }
 }

grails-app/services/docker/registry/web/RestService.groovy

@@ -40,7 +40,10 @@ class RestService {
   def delete(String path) {
     def rest = new RestBuilder()
     def res = rest.delete("${registryUrl}/${path}", requestCustomizer)
-    log.info res.statusCode
+
+    def statusCode = res.statusCode
+    log.info statusCode
+    [deleted: statusCode.'2xxSuccessful', response: res]
   }
 
   void init() {

grails-app/views/repository/tags.gsp

@@ -30,7 +30,11 @@
             <li><g:link action="index">Home</g:link></li>
             <li class="active">${params.id.decodeURL()}</li>
         </ol>
-
+        <g:if test="${flash.deleteAction}">
+            <div class="alert alert-${flash.success ? 'success' : 'danger'}" role="alert">
+                ${raw(flash.message)}
+            </div>
+        </g:if>
         <div class="page-header">
             <h1>Tags</h1>
         </div>