Read backends data even if buffered to temp file

rootfs/etc/nginx/lua/configuration.lua

@@ -7,6 +7,26 @@ function _M.get_backends_data()
   return configuration_data:get("backends")
 end
 
+local function fetch_request_body()
+  ngx.req.read_body()
+  local body = ngx.req.get_body_data()
+
+  if not body then
+    -- request body might've been written to tmp file if body > client_body_buffer_size
+    local file_name = ngx.req.get_body_file()
+    local file = io.open(file_name, "rb")
+
+    if not file then
+      return nil
+    end
+
+    body = file:read("*all")
+    file:close()
+  end
+
+  return body
+end
+
 function _M.call()
   if ngx.var.request_method ~= "POST" and ngx.var.request_method ~= "GET" then
     ngx.status = ngx.HTTP_BAD_REQUEST
@@ -26,11 +46,16 @@ function _M.call()
     return
   end
 
-  ngx.req.read_body()
+  local backends = fetch_request_body()
+  if not backends then
+    ngx.log(ngx.ERR, "dynamic-configuration: unable to read valid request body")
+    ngx.status = ngx.HTTP_BAD_REQUEST
+    return
+  end
 
-  local success, err = configuration_data:set("backends", ngx.req.get_body_data())
+  local success, err = configuration_data:set("backends", backends)
   if not success then
-    ngx.log(ngx.ERR, "error while saving configuration: " .. tostring(err))
+    ngx.log(ngx.ERR, "dynamic-configuration: error updating configuration: " .. tostring(err))
     ngx.status = ngx.HTTP_BAD_REQUEST
     return
   end

test/e2e/lua/dynamic_configuration.go

@@ -104,6 +104,41 @@ var _ = framework.IngressNginxDescribe("Dynamic Configuration", func() {
 			Expect(restOfLogs).ToNot(ContainSubstring("first sync of Nginx configuration"))
 		})
 
+		It("should be able to update endpoints even when the update POST size(request body) > size(client_body_buffer_size)", func() {
+			// Update client-body-buffer-size to 1 byte
+			err := f.UpdateNginxConfigMapData("client-body-buffer-size", "1")
+			Expect(err).NotTo(HaveOccurred())
+
+			replicas := 0
+			err = framework.UpdateDeployment(f.KubeClientSet, f.IngressController.Namespace, "http-svc", replicas, nil)
+			Expect(err).NotTo(HaveOccurred())
+
+			replicas = 4
+			err = framework.UpdateDeployment(f.KubeClientSet, f.IngressController.Namespace, "http-svc", replicas, nil)
+			Expect(err).NotTo(HaveOccurred())
+			time.Sleep(5 * time.Second)
+
+			resp, _, errs := gorequest.New().
+				Get(f.IngressController.HTTPURL).
+				Set("Host", "foo.com").
+				End()
+			Expect(len(errs)).Should(BeNumerically("==", 0))
+			Expect(resp.StatusCode).Should(Equal(http.StatusOK))
+
+			log, err := f.NginxLogs()
+			Expect(err).ToNot(HaveOccurred())
+			Expect(log).ToNot(BeEmpty())
+			index := strings.Index(log, "POST /configuration/backends HTTP/1.1")
+			restOfLogs := log[index:]
+
+			Expect(err).ToNot(HaveOccurred())
+			Expect(log).ToNot(BeEmpty())
+
+			By("POSTing new backends to Lua endpoint")
+			Expect(restOfLogs).To(ContainSubstring("a client request body is buffered to a temporary file"))
+			Expect(restOfLogs).ToNot(ContainSubstring("dynamic-configuration: unable to read valid request body"))
+		})
+
 		It("should handle annotation changes", func() {
 			ingress, err := f.KubeClientSet.ExtensionsV1beta1().Ingresses(f.IngressController.Namespace).Get("foo.com", metav1.GetOptions{})
 			Expect(err).ToNot(HaveOccurred())