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#pragma once
#include "backend.h"
#include "element.h"
#include "priority.h"
#include "record.h"
#include "thread.h"
#include <util/generic/fwd.h>
#include <util/generic/ptr.h>
#include <functional>
#include <cstdarg>
using TLogFormatter = std::function<TString(ELogPriority priority, TStringBuf)>;
// Logging facilities interface.
//
// ```cpp
// TLog base;
// ...
// auto log = base;
// log.SetFormatter([reqId](ELogPriority p, TStringBuf msg) {
// return TStringBuilder() << "reqid=" << reqId << "; " << msg;
// });
//
// log.Write(TLOG_INFO, "begin");
// HandleRequest(...);
// log.Write(TLOG_INFO, "end");
// ```
//
// Users are encouraged to copy `TLog` instance.
class TLog {
public:
// Construct empty logger all writes will be spilled.
TLog();
// Construct file logger.
TLog(const TString& fname, ELogPriority priority = LOG_MAX_PRIORITY);
// Construct any type of logger
TLog(THolder<TLogBackend> backend);
TLog(const TLog&);
TLog(TLog&&);
~TLog();
TLog& operator=(const TLog&);
TLog& operator=(TLog&&);
// Change underlying backend.
// NOTE: not thread safe.
void ResetBackend(THolder<TLogBackend> backend) noexcept;
// Reset underlying backend, `IsNullLog()` will return `true` after this call.
// NOTE: not thread safe.
THolder<TLogBackend> ReleaseBackend() noexcept;
// Check if underlying backend is defined and is not null.
// NOTE: not thread safe with respect to `ResetBackend` and `ReleaseBackend`.
bool IsNullLog() const noexcept;
// Write message to the log.
//
// @param[in] priority Message priority to use.
// @param[in] message Message to write.
// @param[in] metaFlags Message meta flags.
void Write(ELogPriority priority, TStringBuf message, TLogRecord::TMetaFlags metaFlags = {}) const;
// Write message to the log using `DefaultPriority()`.
void Write(const char* data, size_t len, TLogRecord::TMetaFlags metaFlags = {}) const;
// Write message to the log, but pass the message in a c-style.
void Write(ELogPriority priority, const char* data, size_t len, TLogRecord::TMetaFlags metaFlags = {}) const;
// Write message to the log in a c-like printf style.
void Y_PRINTF_FORMAT(3, 4) AddLog(ELogPriority priority, const char* format, ...) const;
// Write message to the log in a c-like printf style with `DefaultPriority()` priority.
void Y_PRINTF_FORMAT(2, 3) AddLog(const char* format, ...) const;
// Call `ReopenLog()` of the underlying backend.
void ReopenLog();
// Call `ReopenLogNoFlush()` of the underlying backend.
void ReopenLogNoFlush();
// Call `QueueSize()` of the underlying backend.
size_t BackEndQueueSize() const;
// Set log default priority.
// NOTE: not thread safe.
void SetDefaultPriority(ELogPriority priority) noexcept;
// Get default priority
ELogPriority DefaultPriority() const noexcept;
// Call `FiltrationLevel()` of the underlying backend.
ELogPriority FiltrationLevel() const noexcept;
// Set current log formatter.
void SetFormatter(TLogFormatter formatter) noexcept;
template <class T>
inline TLogElement operator<<(const T& t) const {
TLogElement ret(this);
ret << t;
return ret;
}
public:
// These methods are deprecated and present here only for compatibility reasons (for 13 years
// already ...). Do not use them.
bool OpenLog(const char* path, ELogPriority lp = LOG_MAX_PRIORITY);
bool IsOpen() const noexcept;
void AddLogVAList(const char* format, va_list lst);
void CloseLog();
private:
class TImpl;
TIntrusivePtr<TImpl> Impl_;
TLogFormatter Formatter_;
};
THolder<TLogBackend> CreateLogBackend(const TString& fname, ELogPriority priority = LOG_MAX_PRIORITY, bool threaded = false);
THolder<TLogBackend> CreateFilteredOwningThreadedLogBackend(const TString& fname, ELogPriority priority = LOG_MAX_PRIORITY, size_t queueLen = 0);
THolder<TOwningThreadedLogBackend> CreateOwningThreadedLogBackend(const TString& fname, size_t queueLen = 0);
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