fix: reuse OpenAI failover error body

backend/internal/service/openai_failover_cached_body_test.go

@@ -15,6 +15,14 @@ import (
 	"github.com/tidwall/gjson"
 )
 
+type panicOnReadCloser struct{}
+
+func (panicOnReadCloser) Read(_ []byte) (int, error) {
+	panic("response body should not be reread")
+}
+
+func (panicOnReadCloser) Close() error { return nil }
+
 func TestOpenAIGatewayService_Forward_FailoverReparsesCachedBodyForNextAccount(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 
@@ -102,6 +110,26 @@ func TestOpenAIGatewayService_Forward_FailoverReparsesCachedBodyForNextAccount(t
 	}
 }
 
+func TestOpenAIGatewayService_HandleFailoverSideEffects_DoesNotRereadResponseBody(t *testing.T) {
+	svc := &OpenAIGatewayService{}
+	account := &Account{
+		ID:       88,
+		Platform: PlatformOpenAI,
+		Type:     AccountTypeOAuth,
+	}
+	resp := &http.Response{
+		StatusCode: http.StatusTooManyRequests,
+		Header:     http.Header{},
+		Body:       panicOnReadCloser{},
+	}
+
+	require.NotPanics(t, func() {
+		svc.handleFailoverSideEffects(context.Background(), resp, account, []byte(`{"error":{"type":"rate_limit_error","message":"rate limited"}}`))
+	})
+
+	require.True(t, svc.isOpenAIAccountRuntimeBlocked(account))
+}
+
 func TestGetOpenAIRequestBodyMap_IgnoresLegacyContextCache(t *testing.T) {
 	gin.SetMode(gin.TestMode)
 

backend/internal/service/openai_gateway_service.go

@@ -2358,13 +2358,12 @@ func (s *OpenAIGatewayService) readUpstreamErrorBody(resp *http.Response) []byte
 	return body
 }
 
-func (s *OpenAIGatewayService) handleFailoverSideEffects(ctx context.Context, resp *http.Response, account *Account, requestedModel ...string) {
-	body := s.readUpstreamErrorBody(resp)
+func (s *OpenAIGatewayService) handleFailoverSideEffects(ctx context.Context, resp *http.Response, account *Account, responseBody []byte, requestedModel ...string) {
 	if len(requestedModel) > 0 {
-		s.handleOpenAIAccountUpstreamError(ctx, account, resp.StatusCode, resp.Header, body, requestedModel[0])
+		s.handleOpenAIAccountUpstreamError(ctx, account, resp.StatusCode, resp.Header, responseBody, requestedModel[0])
 		return
 	}
-	s.handleOpenAIAccountUpstreamError(ctx, account, resp.StatusCode, resp.Header, body)
+	s.handleOpenAIAccountUpstreamError(ctx, account, resp.StatusCode, resp.Header, responseBody)
 }
 
 // Forward forwards request to OpenAI API
@@ -3035,7 +3034,7 @@ func (s *OpenAIGatewayService) Forward(ctx context.Context, c *gin.Context, acco
 					Detail:             upstreamDetail,
 				})
 
-				s.handleFailoverSideEffects(ctx, resp, account, upstreamModel)
+				s.handleFailoverSideEffects(ctx, resp, account, respBody, upstreamModel)
 				return nil, &UpstreamFailoverError{
 					StatusCode:             resp.StatusCode,
 					ResponseBody:           respBody,

backend/internal/service/openai_images.go

@@ -638,7 +638,7 @@ func (s *OpenAIGatewayService) forwardOpenAIImagesAPIKey(
 				Kind:               "failover",
 				Message:            upstreamMsg,
 			})
-			s.handleFailoverSideEffects(upstreamCtx, resp, account, upstreamModel)
+			s.handleFailoverSideEffects(upstreamCtx, resp, account, respBody, upstreamModel)
 			return nil, &UpstreamFailoverError{
 				StatusCode:             resp.StatusCode,
 				ResponseBody:           respBody,

backend/internal/service/openai_images_responses.go

@@ -1358,7 +1358,7 @@ func (s *OpenAIGatewayService) forwardOpenAIImagesOAuth(
 				Kind:               "failover",
 				Message:            upstreamMsg,
 			})
-			s.handleFailoverSideEffects(upstreamCtx, resp, account, requestModel)
+			s.handleFailoverSideEffects(upstreamCtx, resp, account, respBody, requestModel)
 			return nil, &UpstreamFailoverError{
 				StatusCode:             resp.StatusCode,
 				ResponseBody:           respBody,