Logger Class Reference

Asynchronous thread-safe logging facility. More...

#include <logger.h>

Classes
struct	LogEntry
	A single log entry. More...
struct	LogFormat
	Context passed to formatters, combining entry data with resolved thread name. More...

Public Types
enum	LogLevel {   Force = 0 , Debug = 1 , Info = 2 , Warn = 3 ,   Err = 4 }
	Severity levels for log messages. More...
using	LogFormatter = std::function< String(const LogFormat &fmt)>
	Function type for formatting log messages.

Public Member Functions
	Logger ()
	Constructs a Logger and starts the worker thread.
	~Logger ()
	Destructor. Signals the worker thread to terminate and waits for it to finish.
int	level () const
	Returns the current minimum log level.
void	log (LogLevel loglevel, const char *file, int line, const String &msg)
	Enqueues a single log message.
void	log (LogLevel loglevel, const char *file, int line, const StringList &lines)
	Enqueues multiple log messages with the same timestamp.
void	setLogFile (const String &filename)
	Sets the log output file.
void	setLogLevel (LogLevel level)
	Changes the minimum log level.
void	setConsoleLoggingEnabled (bool val)
	Enables or disables console (stderr) log output.
LogFormatter	fileFormatter () const
	Returns the current file log formatter.
LogFormatter	consoleFormatter () const
	Returns the current console log formatter.
void	setFileFormatter (LogFormatter formatter)
	Sets a custom formatter for file log output.
void	setConsoleFormatter (LogFormatter formatter)
	Sets a custom formatter for console log output.
Error	sync (unsigned int timeoutMs=0)
	Blocks until all queued log commands have been processed.

Static Public Member Functions
static Logger &	defaultLogger ()
	Returns the singleton default Logger instance.
static char	levelToChar (LogLevel level)
	Converts a LogLevel to its single character representation.
static void	setThreadName (const String &name)
	Updates the cached thread name used in log output.
static LogFormatter	defaultFileFormatter ()
	Returns the default file log formatter.
static LogFormatter	defaultConsoleFormatter ()
	Returns the default console log formatter.

Detailed Description

Asynchronous thread-safe logging facility.

All log messages are enqueued and written by a dedicated worker thread.

Example

// Use convenience macros (most common)
promekiInfo("Processing frame %d", frameNum);
promekiWarn("Buffer underrun at %s", tc.toString().first.cStr());
promekiErr("Failed to open %s", path.cStr());
 
// Configure the logger
Logger::defaultLogger().setLogFile("/tmp/app.log");
Logger::defaultLogger().setLogLevel(Logger::Debug);

Supports multiple log levels, optional console output, and file logging.

Member Typedef Documentation

LogFormatter

using Logger::LogFormatter = std::function<String(const LogFormat &fmt)>

Function type for formatting log messages.

A formatter receives a LogFormat and returns a fully formatted string ready for output.

Member Enumeration Documentation

LogLevel

enum Logger::LogLevel

Severity levels for log messages.

Enumerator
Force	Forced messages are always logged.
Debug	Debug-level messages.
Info	Informational messages.
Warn	Warning messages.
Err	Error messages.

Member Function Documentation

defaultConsoleFormatter()

static LogFormatter Logger::defaultConsoleFormatter ( )

static

Returns the default console log formatter.

Produces ANSI-colored lines suitable for terminal output.

defaultFileFormatter()

static LogFormatter Logger::defaultFileFormatter ( )

static

Returns the default file log formatter.

Produces plain text lines in the format: TIMESTAMP SOURCE:LINE [LEVEL] MESSAGE

defaultLogger()

static Logger & Logger::defaultLogger ( )

static

Returns the singleton default Logger instance.

Returns

A reference to the default Logger.

level()

int Logger::level ( ) const

inline

Returns the current minimum log level.

Returns

The log level as an integer.

levelToChar()

static char Logger::levelToChar ( LogLevel  level )

static

Converts a LogLevel to its single character representation.

Parameters

level

The log level to convert.

Returns

A character such as D (debug), W (warning), I (info), etc

log() [1/2]

void Logger::log	(	LogLevel	loglevel,
		const char *	file,
		int	line,
		const String &	msg
	)

Enqueues a single log message.

Captures the calling thread's native ID and name automatically.

Parameters

loglevel	The severity level of the message.
file	The source file name (typically FILE).
line	The source line number (typically LINE).
msg	The log message text.

log() [2/2]

void Logger::log	(	LogLevel	loglevel,
		const char *	file,
		int	line,
		const StringList &	lines
	)

Enqueues multiple log messages with the same timestamp.

Captures the calling thread's native ID and name automatically.

Parameters

loglevel	The severity level of the messages.
file	The source file name (typically FILE).
line	The source line number (typically LINE).
lines	A StringList where each entry becomes a separate log line.

setConsoleFormatter()

void Logger::setConsoleFormatter ( LogFormatter  formatter )

inline

Sets a custom formatter for console log output.

Parameters

formatter

The formatter function. Pass an empty std::function to restore the default.

setConsoleLoggingEnabled()

void Logger::setConsoleLoggingEnabled ( bool  val )

inline

Enables or disables console (stderr) log output.

Parameters

val	true to enable console logging, false to disable.

setFileFormatter()

void Logger::setFileFormatter ( LogFormatter  formatter )

inline

Sets a custom formatter for file log output.

Parameters

formatter

The formatter function. Pass an empty std::function to restore the default.

setLogFile()

void Logger::setLogFile ( const String &  filename )

inline

Sets the log output file.

Parameters

filename

Path to the log file. The file is opened by the worker thread.

setLogLevel()

void Logger::setLogLevel ( LogLevel  level )

inline

Changes the minimum log level.

Parameters

level

The new minimum log level. Messages below this are discarded.

setThreadName()

static void Logger::setThreadName ( const String &  name )

static

Updates the cached thread name used in log output.

The logger caches the calling thread's name on first use. Call this to update the cached name if the thread is renamed after its first log message. Thread::setName() calls this automatically.

Parameters

name	The new thread name.

sync()

Error Logger::sync ( unsigned int  timeoutMs = 0 )

inline

Blocks until all queued log commands have been processed.

Parameters

timeoutMs

Maximum time to wait in milliseconds. A value of zero (the default) waits indefinitely.

Returns

Error::Ok if the sync completed, Error::Timeout if the timeout elapsed first.

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The documentation for this class was generated from the following file:

• include/promeki/core/logger.h