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Diffstat (limited to 'src/lib/log/logger_level_impl.h')
| -rw-r--r-- | src/lib/log/logger_level_impl.h | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src/lib/log/logger_level_impl.h b/src/lib/log/logger_level_impl.h new file mode 100644 index 0000000..77da5f7 --- /dev/null +++ b/src/lib/log/logger_level_impl.h @@ -0,0 +1,126 @@ +// Copyright (C) 2011-2017 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#ifndef LOGGER_LEVEL_IMPL_H +#define LOGGER_LEVEL_IMPL_H + +#include <log4cplus/logger.h> +#include <log4cplus/version.h> +#include <log/logger_level.h> + +namespace isc { +namespace log { + +/// \brief Implementation aspects of logging levels +/// +/// This extends the log4cplus level set to allow 100 debug levels. +/// +/// First some terminology, as the use of the term "level" gets confusing. The +/// code and comments here use the term "level" in two contexts: +/// +/// Logging level: The category of messages to log. By default log4cplus +/// defines the following logging levels: OFF_LOG_LEVEL, FATAL_LOG_LEVEL, +/// ERROR_LOG_LEVEL, WARN_LOG_LEVEL, INFO_LOG_LEVEL, DEBUG_LOG_LEVEL, +/// TRACE_LOG_LEVEL, ALL_LOG_LEVEL (which here will be abbreviated OFF, FATAL +/// etc.). Within the context of Kea, OFF, TRACE and ALL are not used +/// and the idea of DEBUG has been extended, as will be seen below. In +/// Kea terms, this is known as "severity"; the "logging level" usage will +/// usually be used when talking about log4cplus aspects of the idea (as +/// log4cplus uses that terminology). +/// +/// Debug level: This is a number that ranges from 0 to 99 and is used by the +/// application to control the detail of debug output. A value of 0 gives the +/// highest-level debug output; a value of 99 gives the most verbose and most +/// detailed. Debug messages (or whatever debug level) are only ever output +/// when the logging level is set to DEBUG. (Note that the numbers 0 and 99 +/// are not hard-coded - they are the constants MIN_DEBUG_LEVEL and +/// MAX_DEBUG_LEVEL.) +/// +/// With log4cplus, the various logging levels have a numeric value associated +/// with them, such that FATAL > ERROR > WARNING etc. This suggests that the +/// idea of debug levels can be incorporated into the existing logging level +/// scheme by assigning them appropriate numeric values, i.e. +/// +/// WARNING > INFO > DEBUG > DEBUG - 1 > DEBUG - 2 > ... > DEBUG - 99 +/// +/// Setting a numeric level of DEBUG enables the basic messages; setting higher +/// debug levels (corresponding to lower numeric logging levels) will enable +/// progressively more messages. The lowest debug level (0) is chosen such that +/// it corresponds to the default level of DEBUG. +/// +/// This class comprises nothing more than static methods to aid the conversion +/// of logging levels between log4cplus and Kea, and to register those +/// levels with log4cplus. + +class LoggerLevelImpl { +public: + +typedef log4cplus::tstring LogLevelString; + + /// \brief Convert Kea level to log4cplus logging level + /// + /// Converts the Kea severity level into a log4cplus logging level. + /// If the severity is DEBUG, the current Kea debug level is taken + /// into account when doing the conversion. + /// + /// \param level Kea severity and debug level + /// + /// \return Equivalent log4cplus logging level. + static + log4cplus::LogLevel convertFromBindLevel(const isc::log::Level& level); + + /// \brief Convert log4cplus logging level to Kea logging level + /// + /// Converts the log4cplus log level into a Kea severity level. + /// The log4cplus log level may be non-standard in which case it is + /// encoding a Kea debug level as well. + /// + /// \param loglevel log4cplus log level + /// + /// \return Equivalent Kea severity and debug level + static + isc::log::Level convertToBindLevel(const log4cplus::LogLevel loglevel); + + /// \brief Convert string to log4cplus logging level + /// + /// Kea extends the set of logging levels in log4cplus with a group + /// of debug levels. These are given names DEBUG0 through DEBUG99 (with + /// DEBUG0 being equivalent to DEBUG, the standard log level. If the name + /// is DEBUGn but n lies outside the range of debug levels, debug level + /// specifies is coerced to the nearest valid value. If the string is just + /// not recognized, a NOT_SET_LOG_LEVEL is returned. + /// + /// \param level String representing the logging level. + /// + /// \return Corresponding log4cplus log level + static + log4cplus::LogLevel logLevelFromString(const log4cplus::tstring& level); + + /// \brief Convert log level to string + /// + /// If the log level is one of the extended debug levels, the string DEBUG + /// is returned, otherwise the empty string. + /// + /// \param level Extended logging level + /// + /// \return Equivalent string. +#if LOG4CPLUS_VERSION < LOG4CPLUS_MAKE_VERSION(2, 0, 0) + static LogLevelString logLevelToString(log4cplus::LogLevel level); +#else + static const LogLevelString& logLevelToString(log4cplus::LogLevel level); +#endif + + /// \brief Initialize extended logging levels + /// + /// This must be called once, after log4cplus has been initialized. It + /// registers the level/string converter functions. + static void init(); +}; + +} // namespace log +} // namespace isc + +#endif // LOGGER_LEVEL_IMPL_H |