[libcamera-devel] [PATCH 4/5] libcamera: base: log: Add coloring to the log output

Laurent Pinchart laurent.pinchart at ideasonboard.com
Sun May 29 17:56:09 CEST 2022


Hi Umang,

On Sun, May 29, 2022 at 02:25:22PM +0200, Umang Jain wrote:
> On 5/26/22 00:25, Laurent Pinchart via libcamera-devel wrote:
> > Extend the logger to support coloring messages. The log level is
> > colorized with per-level colors, and the category with a fixed color.
> > This makes the log output more readable.
> >
> > Coloring is enabled by default when logging to std::cerr, and can be
> > disabled by setting the LIBCAMERA_LOG_NO_COLOR environment variable.
> > When logging to a file with LIBCAMERA_LOG_FILE, coloring is disabled. It
> > can be enabled for file logging using the logSetFile() function.
> >
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >   Documentation/environment_variables.rst |  21 +++--
> >   include/libcamera/logging.h             |   4 +-
> >   src/libcamera/base/log.cpp              | 114 +++++++++++++++++++-----
> >   src/libcamera/camera_manager.cpp        |   2 +-
> >   4 files changed, 109 insertions(+), 32 deletions(-)
> >
> > diff --git a/Documentation/environment_variables.rst b/Documentation/environment_variables.rst
> > index fa703a726845..7028c024b14e 100644
> > --- a/Documentation/environment_variables.rst
> > +++ b/Documentation/environment_variables.rst
> > @@ -19,6 +19,9 @@ LIBCAMERA_LOG_LEVELS
> >   
> >      Example value: ``*:DEBUG``
> >   
> > +LIBCAMERA_LOG_NO_COLOR
> > +   Disable coloring of log messages (`more <Notes about debugging_>`__).
> > +
> >   LIBCAMERA_IPA_CONFIG_PATH
> >      Define custom search locations for IPA configurations (`more <IPA configuration_>`__).
> >   
> > @@ -40,12 +43,20 @@ Further details
> >   Notes about debugging
> >   ~~~~~~~~~~~~~~~~~~~~~
> >   
> > -The environment variables ``LIBCAMERA_LOG_FILE`` and ``LIBCAMERA_LOG_LEVELS``
> > -are used to modify the destination and verbosity of messages provided by
> > -libcamera.
> > +The environment variables ``LIBCAMERA_LOG_FILE``, ``LIBCAMERA_LOG_LEVELS`` and
> > +``LIBCAMERA_LOG_NO_COLOR`` are used to modify the degault configuration of the
> 
> 
> s/degault/default
> 
> > +libcamera logger.
> >   
> > -The ``LIBCAMERA_LOG_LEVELS`` variable accepts a comma-separated list of
> > -'category:level' pairs.
> > +By default, libcamera logs all messages to the standard error (std::cerr).
> > +Messages are colored by default depending on the log level. Coloring can be
> > +disabled by setting the ``LIBCAMERA_LOG_NO_COLOR`` environment variable.
> > +
> > +The default log destination can also be directed to a file by setting the
> > +``LIBCAMERA_LOG_FILE`` environment variable to the log file name. This also
> > +disables coloring.
> > +
> > +Log levels are controlled through the ``LIBCAMERA_LOG_LEVELS`` variable, which
> > +accepts a comma-separated list of 'category:level' pairs.
> >   
> >   The `level <Log levels_>`__ part is mandatory and can either be specified by
> >   name or by numerical index associated with each level.
> > diff --git a/include/libcamera/logging.h b/include/libcamera/logging.h
> > index c36882b91974..cd842f67d553 100644
> > --- a/include/libcamera/logging.h
> > +++ b/include/libcamera/logging.h
> > @@ -16,8 +16,8 @@ enum LoggingTarget {
> >   	LoggingTargetStream,
> >   };
> >   
> > -int logSetFile(const char *path);
> > -int logSetStream(std::ostream *stream);
> > +int logSetFile(const char *path, bool color = false);
> > +int logSetStream(std::ostream *stream, bool color = false);
> >   int logSetTarget(LoggingTarget target);
> >   void logSetLevel(const char *category, const char *level);
> >   
> > diff --git a/src/libcamera/base/log.cpp b/src/libcamera/base/log.cpp
> > index 26f1420703b9..a9f5bbbd36f7 100644
> > --- a/src/libcamera/base/log.cpp
> > +++ b/src/libcamera/base/log.cpp
> > @@ -104,8 +104,8 @@ static const char *log_severity_name(LogSeverity severity)
> >   class LogOutput
> >   {
> >   public:
> > -	LogOutput(const char *path);
> > -	LogOutput(std::ostream *stream);
> > +	LogOutput(const char *path, bool color);
> > +	LogOutput(std::ostream *stream, bool color);
> >   	LogOutput();
> >   	~LogOutput();
> >   
> > @@ -119,14 +119,16 @@ private:
> >   
> >   	std::ostream *stream_;
> >   	LoggingTarget target_;
> > +	bool color_;
> >   };
> >   
> >   /**
> >    * \brief Construct a log output based on a file
> >    * \param[in] path Full path to log file
> > + * \param[in] color True to output colored messages
> >    */
> > -LogOutput::LogOutput(const char *path)
> > -	: target_(LoggingTargetFile)
> > +LogOutput::LogOutput(const char *path, bool color)
> > +	: target_(LoggingTargetFile), color_(color)
> >   {
> >   	stream_ = new std::ofstream(path);
> >   }
> > @@ -134,9 +136,10 @@ LogOutput::LogOutput(const char *path)
> >   /**
> >    * \brief Construct a log output based on a stream
> >    * \param[in] stream Stream to send log output to
> > + * \param[in] color True to output colored messages
> >    */
> > -LogOutput::LogOutput(std::ostream *stream)
> > -	: stream_(stream), target_(LoggingTargetStream)
> > +LogOutput::LogOutput(std::ostream *stream, bool color)
> > +	: stream_(stream), target_(LoggingTargetStream), color_(color)
> >   {
> >   }
> >   
> > @@ -144,7 +147,7 @@ LogOutput::LogOutput(std::ostream *stream)
> >    * \brief Construct a log output to syslog
> >    */
> >   LogOutput::LogOutput()
> > -	: stream_(nullptr), target_(LoggingTargetSyslog)
> > +	: stream_(nullptr), target_(LoggingTargetSyslog), color_(false)
> >   {
> >   	openlog("libcamera", LOG_PID, 0);
> >   }
> > @@ -179,28 +182,70 @@ bool LogOutput::isValid() const
> >   	}
> >   }
> >   
> > +namespace {
> > +
> > +constexpr const char *kColorReset = "\033[0m";
> > +constexpr const char *kColorRed = "\033[31m";
> > +constexpr const char *kColorGreen = "\033[32m";
> > +constexpr const char *kColorYellow = "\033[33m";
> > +constexpr const char *kColorBlue = "\033[34m";
> > +constexpr const char *kColorMagenta = "\033[35m";
> > +constexpr const char *kColorCyan = "\033[36m";
> > +constexpr const char *kColorWhite = "\033[37m";
> > +constexpr const char *kColorGrey = "\033[90m";
> > +constexpr const char *kColorBrightRed = "\033[91m";
> > +constexpr const char *kColorBrightGreen = "\033[92m";
> > +constexpr const char *kColorBrightYellow = "\033[93m";
> > +constexpr const char *kColorBrightBlue = "\033[94m";
> > +constexpr const char *kColorBrightMagenta = "\033[95m";
> > +constexpr const char *kColorBrightCyan = "\033[96m";
> > +constexpr const char *kColorBrightWhite = "\033[97m";
> > +
> > +} /* namespace */
> > +
> >   /**
> >    * \brief Write message to log output
> >    * \param[in] msg Message to write
> >    */
> >   void LogOutput::write(const LogMessage &msg)
> >   {
> > +	static const char *const severityColors[] = {
> > +		kColorBrightCyan,
> > +		kColorBrightGreen,
> > +		kColorBrightYellow,
> > +		kColorBrightRed,
> > +		kColorBrightMagenta,
> > +	};
> > +
> > +	const char *categoryColor = color_ ? kColorBrightWhite : "";
> > +	const char *fileColor = color_ ? kColorBrightBlue : "";
> > +	const char *msgColor = color_ ? kColorReset : "";
> > +	const char *severityColor = "";
> > +	LogSeverity severity = msg.severity();
> >   	std::string str;
> >   
> > +	if (color_) {
> > +		if (static_cast<unsigned int>(severity) < std::size(severityColors))
> > +			severityColor = severityColors[severity];
> > +		else
> > +			severityColor = kColorBrightWhite;
> > +	}
> > +
> >   	switch (target_) {
> >   	case LoggingTargetSyslog:
> > -		str = std::string(log_severity_name(msg.severity())) + " "
> > +		str = std::string(log_severity_name(severity)) + " "
> >   		    + msg.category().name() + " " + msg.fileInfo() + " "
> >   		    + msg.msg();
> > -		writeSyslog(msg.severity(), str);
> > +		writeSyslog(severity, str);
> >   		break;
> >   	case LoggingTargetStream:
> >   	case LoggingTargetFile:
> >   		str = "[" + utils::time_point_to_string(msg.timestamp()) + "] ["
> >   		    + std::to_string(Thread::currentId()) + "] "
> > -		    + log_severity_name(msg.severity()) + " "
> > -		    + msg.category().name() + " " + msg.fileInfo() + " "
> > -		    + msg.msg();
> > +		    + severityColor + log_severity_name(severity) + " "
> > +		    + categoryColor + msg.category().name() + " "
> > +		    + fileColor + msg.fileInfo() + " "
> > +		    + msgColor + msg.msg();
> >   		writeStream(str);
> >   		break;
> >   	default:
> > @@ -253,8 +298,8 @@ public:
> >   	void write(const LogMessage &msg);
> >   	void backtrace();
> >   
> > -	int logSetFile(const char *path);
> > -	int logSetStream(std::ostream *stream);
> > +	int logSetFile(const char *path, bool color);
> > +	int logSetStream(std::ostream *stream, bool color);
> >   	int logSetTarget(LoggingTarget target);
> >   	void logSetLevel(const char *category, const char *level);
> >   
> > @@ -298,35 +343,47 @@ bool Logger::destroyed_ = false;
> >   /**
> >    * \brief Direct logging to a file
> >    * \param[in] path Full path to the log file
> > + * \param[in] color True to output colored messages
> >    *
> >    * This function directs the log output to the file identified by \a path. The
> >    * previous log target, if any, is closed, and all new log messages will be
> >    * written to the new log file.
> >    *
> > + * \a color controls whether or not the messages will be colored with standard
> > + * ANSI escape codes. This is done regardless of whether \a path refers to a
> > + * standard file or a TTY, the caller is responsible for disabling coloring when
> > + * not suitable for the log target.
> > + *
> >    * If the function returns an error, the log target is not changed.
> >    *
> >    * \return Zero on success, or a negative error code otherwise
> >    */
> > -int logSetFile(const char *path)
> > +int logSetFile(const char *path, bool color)
> >   {
> > -	return Logger::instance()->logSetFile(path);
> > +	return Logger::instance()->logSetFile(path, color);
> >   }
> >   
> >   /**
> >    * \brief Direct logging to a stream
> >    * \param[in] stream Stream to send log output to
> > + * \param[in] color True to output colored messages
> >    *
> >    * This function directs the log output to \a stream. The previous log target,
> >    * if any, is closed, and all new log messages will be written to the new log
> >    * stream.
> >    *
> > + * \a color controls whether or not the messages will be colored with standard
> > + * ANSI escape codes. This is done regardless of whether \a stream refers to a
> > + * standard file or a TTY, the caller is responsible for disabling coloring when
> > + * not suitable for the log target.
> > + *
> >    * If the function returns an error, the log file is not changed
> >    *
> >    * \return Zero on success, or a negative error code otherwise.
> >    */
> > -int logSetStream(std::ostream *stream)
> > +int logSetStream(std::ostream *stream, bool color)
> >   {
> > -	return Logger::instance()->logSetStream(stream);
> > +	return Logger::instance()->logSetStream(stream, color);
> >   }
> >   
> >   /**
> > @@ -437,14 +494,16 @@ void Logger::backtrace()
> >   /**
> >    * \brief Set the log file
> >    * \param[in] path Full path to the log file
> > + * \param[in] color True to output colored messages
> >    *
> >    * \sa libcamera::logSetFile()
> >    *
> >    * \return Zero on success, or a negative error code otherwise.
> >    */
> > -int Logger::logSetFile(const char *path)
> > +int Logger::logSetFile(const char *path, bool color)
> >   {
> > -	std::shared_ptr<LogOutput> output = std::make_shared<LogOutput>(path);
> > +	std::shared_ptr<LogOutput> output =
> > +		std::make_shared<LogOutput>(path, color);
> >   	if (!output->isValid())
> >   		return -EINVAL;
> >   
> > @@ -455,14 +514,16 @@ int Logger::logSetFile(const char *path)
> >   /**
> >    * \brief Set the log stream
> >    * \param[in] stream Stream to send log output to
> > + * \param[in] color True to output colored messages
> >    *
> >    * \sa libcamera::logSetStream()
> >    *
> >    * \return Zero on success, or a negative error code otherwise.
> >    */
> > -int Logger::logSetStream(std::ostream *stream)
> > +int Logger::logSetStream(std::ostream *stream, bool color)
> >   {
> > -	std::shared_ptr<LogOutput> output = std::make_shared<LogOutput>(stream);
> > +	std::shared_ptr<LogOutput> output =
> > +		std::make_shared<LogOutput>(stream, color);
> >   	std::atomic_store(&output_, output);
> >   	return 0;
> >   }
> > @@ -514,10 +575,15 @@ void Logger::logSetLevel(const char *category, const char *level)
> >   
> >   /**
> >    * \brief Construct a logger
> > + *
> > + * If the environment variable is not set, log to std::cerr. The log messages
> > + * are then colored by default. This can be overridden by setting the
> > + * LIBCAMERA_LOG_NO_COLOR environment variable to disabled coloring.
> >    */
> >   Logger::Logger()
> >   {
> > -	logSetStream(&std::cerr);
> > +	bool color = !utils::secure_getenv("LIBCAMERA_LOG_NO_COLOR");
> > +	logSetStream(&std::cerr, color);
> >   
> >   	parseLogFile();
> >   	parseLogLevels();
> > @@ -543,7 +609,7 @@ void Logger::parseLogFile()
> >   		return;
> >   	}
> >   
> > -	logSetFile(file);
> > +	logSetFile(file, false);
> >   }
> >   
> >   /**
> > diff --git a/src/libcamera/camera_manager.cpp b/src/libcamera/camera_manager.cpp
> > index 70d73822193b..d934596e4145 100644
> > --- a/src/libcamera/camera_manager.cpp
> > +++ b/src/libcamera/camera_manager.cpp
> > @@ -290,7 +290,7 @@ CameraManager::~CameraManager()
> >    */
> >   int CameraManager::start()
> >   {
> > -	LOG(Camera, Info) << "libcamera " << version_;
> > +	LOG(Camera, Debug) << "libcamera " << version_;
> 
> 
> unrelated maybe ? Should be mentioned in commit message?

Should be dropped :-) I changed this for testing, with

	LOG(Camera, Debug) << "libcamera " << version_;
	LOG(Camera, Info) << "libcamera " << version_;
	LOG(Camera, Warning) << "libcamera " << version_;
	LOG(Camera, Error) << "libcamera " << version_;
	LOG(Camera, Fatal) << "libcamera " << version_;

and then deleted the wrong line.

> Minors....
> 
> Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>
> 
> >   
> >   	int ret = _d()->start();
> >   	if (ret)

-- 
Regards,
q
Laurent Pinchart


More information about the libcamera-devel mailing list