fix: Call response modifier plugin when resp is not nil

Allows merged response from multible backends to be modified if at least one of the backends replied, resp is not nil and the error would be for instance a mergeErr. Signed-off-by: Daniel Ferreira <[email protected]>
luraproject · Aug 11, 2022 · f095e8e · f095e8e
1 parent 0a38ce2
commit f095e8e
Show file tree

Hide file tree

Showing 2 changed files with 66 additions and 12 deletions.
diff --git a/proxy/plugin.go b/proxy/plugin.go
@@ -88,12 +88,7 @@ func newPluginMiddleware(logger logging.Logger, tag, pattern string, cfg map[str
 
 		if totReqModifiers == 0 {
 			return func(ctx context.Context, r *Request) (*Response, error) {
-				resp, err := next[0](ctx, r)
-				if err != nil {
-					return resp, err
-				}
-
-				return executeResponseModifiers(respModifiers, resp)
+				return nextProxyWithResponseModifiers(ctx, r, next[0], respModifiers)
 			}
 		}
 
@@ -116,16 +111,22 @@ func newPluginMiddleware(logger logging.Logger, tag, pattern string, cfg map[str
 				return nil, err
 			}
 
-			resp, err := next[0](ctx, r)
-			if err != nil {
-				return resp, err
-			}
-
-			return executeResponseModifiers(respModifiers, resp)
+			return nextProxyWithResponseModifiers(ctx, r, next[0], respModifiers)
 		}
 	}
 }
 
+func nextProxyWithResponseModifiers(ctx context.Context, r *Request, next Proxy, respModifiers []func(interface{}) (interface{}, error)) (*Response, error) {
+	resp, err := next(ctx, r)
+	// merged responses of multiple backends will have a non nil resp if at least one of the backends responds
+	// successfully
+	if err != nil && resp == nil {
+		return resp, err
+	}
+
+	return executeResponseModifiers(respModifiers, resp)
+}
+
 func executeRequestModifiers(reqModifiers []func(interface{}) (interface{}, error), r *Request) (*Request, error) {
 	var tmp RequestWrapper
 	tmp = &requestWrapper{

diff --git a/proxy/plugin_test.go b/proxy/plugin_test.go
@@ -73,6 +73,59 @@ func TestNewPluginMiddleware_logger(t *testing.T) {
 	}
 }
 
+func TestNewPluginMiddleware_merge_error(t *testing.T) {
+	plugin.LoadWithLogger("./plugin/tests", ".so", plugin.RegisterModifier, logging.NoOp)
+
+	validator := func(ctx context.Context, r *Request) (*Response, error) {
+		return &Response{
+			Data:       map[string]interface{}{"foo": "bar"},
+			IsComplete: true,
+			Metadata: Metadata{
+				Headers:    map[string][]string{},
+				StatusCode: 0,
+			},
+		}, mergeError{errs: []error{fmt.Errorf("some backend error")}}
+	}
+
+	bknd := NewBackendPluginMiddleware(
+		logging.NoOp,
+		&config.Backend{
+			ExtraConfig: map[string]interface{}{
+				plugin.Namespace: map[string]interface{}{
+					"name": []interface{}{"lura-request-modifier-example-response"},
+				},
+			},
+		},
+	)(validator)
+
+	p := NewPluginMiddleware(
+		logging.NoOp,
+		&config.EndpointConfig{
+			ExtraConfig: map[string]interface{}{
+				plugin.Namespace: map[string]interface{}{
+					"name": []interface{}{
+						"lura-request-modifier-example-response",
+					},
+				},
+			},
+		},
+	)(bknd)
+
+	resp, err := p(context.Background(), &Request{Path: "/bar"})
+	if err != nil {
+		t.Error(err.Error())
+	}
+
+	if resp == nil {
+		t.Errorf("unexpected response: %v", resp)
+		return
+	}
+
+	if v, ok := resp.Data["foo"].(string); !ok || v != "bar" {
+		t.Errorf("unexpected foo value: %v", resp.Data["foo"])
+	}
+}
+
 func TestNewPluginMiddleware_error_request(t *testing.T) {
 	plugin.LoadWithLogger("./plugin/tests", ".so", plugin.RegisterModifier, logging.NoOp)