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#pragma once
#include "ConfigProcessor.h"
#include <Common/ThreadPool.h>
#include <Common/ZooKeeper/Common.h>
#include <Common/ZooKeeper/ZooKeeperNodeCache.h>
#include <time.h>
#include <string>
#include <thread>
#include <mutex>
#include <condition_variable>
#include <list>
namespace Poco { class Logger; }
namespace DB
{
class Context;
/** Every two seconds checks configuration files for update.
* If configuration is changed, then config will be reloaded by ConfigProcessor
* and the reloaded config will be applied via Updater functor.
* It doesn't take into account changes of --config-file and <users_config>.
*/
class ConfigReloader
{
public:
using Updater = std::function<void(ConfigurationPtr, bool)>;
ConfigReloader(
std::string_view path_,
const std::vector<std::string>& extra_paths_,
const std::string & preprocessed_dir,
zkutil::ZooKeeperNodeCache && zk_node_cache,
const zkutil::EventPtr & zk_changed_event,
Updater && updater,
bool already_loaded);
~ConfigReloader();
/// Starts periodic reloading in the background thread.
void start();
/// Stops periodic reloading reloading in the background thread.
/// This function is automatically called by the destructor.
void stop();
/// Reload immediately. For SYSTEM RELOAD CONFIG query.
void reload() { reloadIfNewer(/* force */ true, /* throw_on_error */ true, /* fallback_to_preprocessed */ false, /* initial_loading = */ false); }
private:
void run();
void reloadIfNewer(bool force, bool throw_on_error, bool fallback_to_preprocessed, bool initial_loading);
struct FileWithTimestamp;
struct FilesChangesTracker
{
std::set<FileWithTimestamp> files;
void addIfExists(const std::string & path_to_add);
bool isDifferOrNewerThan(const FilesChangesTracker & rhs);
};
FilesChangesTracker getNewFileList() const;
static constexpr auto reload_interval = std::chrono::seconds(2);
Poco::Logger * log = &Poco::Logger::get("ConfigReloader");
std::string config_path;
std::vector<std::string> extra_paths;
std::string preprocessed_dir;
FilesChangesTracker files;
zkutil::ZooKeeperNodeCache zk_node_cache;
bool need_reload_from_zk = false;
zkutil::EventPtr zk_changed_event = std::make_shared<Poco::Event>();
Updater updater;
std::atomic<bool> quit{false};
ThreadFromGlobalPool thread;
/// Locked inside reloadIfNewer.
std::mutex reload_mutex;
};
}
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