[GitHub] [nifi-minifi-cpp] szaszm commented on a change in pull request #875: MINIFICPP-1332 Prevent errneous behavior by stopping FlowController in low disk space conditions

[GitBox <gi...@apache.org>]

szaszm commented on a change in pull request #875:
URL: https://github.com/apache/nifi-minifi-cpp/pull/875#discussion_r478518109



##########
File path: libminifi/src/DiskSpaceWatchdog.cpp
##########
@@ -0,0 +1,133 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "DiskSpaceWatchdog.h"
+
+#include <chrono>
+#include <cinttypes>
+#include <type_traits>
+
+#include "core/Property.h"
+#include "FlowController.h"
+#include "core/logging/Logger.h"
+#include "properties/Configure.h"
+#include "utils/file/PathUtils.h"
+
+namespace org {
+namespace apache {
+namespace nifi {
+namespace minifi {
+
+namespace {
+namespace chr = std::chrono;
+struct Config {
+  chr::milliseconds interval;
+  std::uintmax_t stop_threshold_bytes;
+  std::uintmax_t restart_threshold_bytes;
+};
+
+utils::optional<chr::milliseconds> string_to_milliseconds(const std::string& str) {
+  uint64_t millisec_value{};
+  const bool success = core::Property::getTimeMSFromString(str, millisec_value);
+  if (!success) return utils::nullopt;
+  return utils::make_optional(chr::milliseconds{millisec_value});
+}
+
+template<typename T, typename = typename std::enable_if<std::is_integral<T>::value>::type>
+utils::optional<T> string_to_int(const std::string& str) {
+  T result{};
+  const bool success = core::Property::StringToInt(str, result);
+  if (!success) return utils::nullopt;
+  return utils::make_optional(result);
+}
+
+Config read_config(const Configure& conf) {
+  const auto interval_ms = conf.get(Configure::minifi_disk_space_watchdog_interval_ms) >>= string_to_milliseconds;
+  const auto stop_bytes = conf.get(Configure::minifi_disk_space_watchdog_stop_threshold_bytes) >>= string_to_int<std::uintmax_t>;
+  const auto restart_bytes = conf.get(Configure::minifi_disk_space_watchdog_restart_threshold_bytes) >>= string_to_int<std::uintmax_t>;
+  if (restart_bytes < stop_bytes) { throw std::runtime_error{"disk space watchdog stop threshold must be <= restart threshold"}; }
+  constexpr auto mebibytes = 1024 * 1024;
+  return {
+      interval_ms.value_or(chr::seconds{1}),
+      stop_bytes.value_or(15 * mebibytes),
+      restart_bytes.value_or(20 * mebibytes)
+  };
+}
+
+struct callback {
+  Config cfg;
+  gsl::not_null<FlowController*> flow_controller;
+  bool stopped;

Review comment:
       It would cause the callback type to no longer be an aggregate in C++11 (fixed in C++14).
   https://godbolt.org/z/MGo5cf
   https://en.cppreference.com/w/cpp/language/aggregate_initialization
   
   in particular:
   > no default member initializers (since C++11) (until C++14)




----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

For queries about this service, please contact Infrastructure at:
users@infra.apache.org