NAME

       dnsjit.core.log - Core logging facility

SYNOPSIS

   Usage to control global log level
         local log = require("dnsjit.core.log")
         log.enable("all")
         log.disable("debug")

   Usage to control module log level
         local example = require("example") -- Example as below
         example.log():enable("all")
         example.log():disable("debug")

   Usage to control object instance log level
         local example = require("example") -- Example as below
         local obj = example.new()
         obj:log():enable("all")
         obj:log():disable("debug")

   Usage in C module
       NOTE  naming  of  variables and module only globals are required to exactly as described in order for the
       macros to work; self is the pointer to the object instance, self->_log is  the  object  instance  logging
       configuration struct, _log is the module logging configuration struct.

       Include logging:
         #include "core/log.h"

       Add the logging struct to the module struct:
         typedef struct example {
             core_log_t _log;
             ...
         } example_t;

       Add a module logging configuration and a struct default:
         static core_log_t _log = LOG_T_INIT("example");
         static example_t _defaults = {
             LOG_T_INIT_OBJ("example"),
             ...
         };

       Use new/free and/or init/destroy functions (depends if you create the object in Lua or not):
         example_t* example_new() {
             example_t* self = calloc(1, sizeof(example_t));

             *self = _defaults;
             ldebug("new()");

             return self;
         }

         void example_free(example_t* self) {
             ldebug("free()");
             free(self);
         }

         int example_init(example_t* self) {
             *self = _defaults;

             ldebug("init()");

             return 0;
         }

         void example_destroy(example_t* self) {
             ldebug("destroy()");
             ...
         }

       In the Lua part of the C module you need to create a function that returns either the object instance Log
       or the modules Log.

       Add C function to get module only Log:
         core_log_t* example_log() {
             return &_log;
         }

       For the structures metatable add the following function:
         local ffi = require("ffi")
         local C = ffi.C

         function Example:log()
             if self == nil then
                 return C.example_log()
             end
             return self._log
         end

   Usage in pure Lua module
         local log = require("dnsjit.core.log")
         local ffi = require("ffi")
         local C = ffi.C

         local Example = {}
         local module_log = log.new("example")

         function Example.new()
             local self = setmetatable({
                 _log = log.new("example", module_log),
             }, { __index = Example })

             self._log:debug("new()")

             return self
         end

         function Example:log()
             if self == nil then
                 return module_log
             end
             return self._log
         end

DESCRIPTION

       Core logging facility used by all modules.

   Log levels
       all    Keyword to enable/disable all changeable log levels.

       debug  Used for debug information.

       info   Used for informational processing messages.

       notice Used for messages of that may have impact on processing.

       warning
              Used for messages that has impact on processing.

       critical
              Used for messages that have severe impact on processing, this level can not be disabled.

       fatal  Used to display a message before stopping all processing and  existing,  this  level  can  not  be
              disabled.

   C macros
       Object instance macros
              The   following   macros   uses   &self->_log:   ldebug(msg...),  linfo(msg...),  lnotice(msg...),
              lwarning(msg...), lcritical(msg...), lfatal(msg...).

       Object pointer instance macros
              The  following  macros  uses  self->_log:   lpdebug(msg...),   lpinfo(msg...),   lpnotice(msg...),
              lpwarning(msg...), lpcritical(msg...), lpfatal(msg...).

       Module macros
              The    following   macros   uses   &_log:   mldebug(msg...),   mlinfo(msg...),   mlnotice(msg...),
              mlwarning(msg...), mlcritical(msg...), mlfatal(msg...).

       Global macros
              The following macros uses  the  global  logging  configuration:  gldebug(msg...),  glinfo(msg...),
              glnotice(msg...), glwarning(msg...), glcritical(msg...), glfatal(msg...).

   Functions
       Log.new(name, module)
              Create a new Log object with the given module name and an optional shared module Log object.

       Log:enable(level)
              Enable specified log level.

       Log:disable(level)
              Disable specified log level.

       Log:clear(level)
              Clear specified log level, which means it will revert back to default or inherited settings.

       Log:display_file_line(bool)
              Enable or disable the displaying of file and line for messages.

       Log.errstr(errno)
              Convert error number to its text representation.

       Log.debug(self, ...)
              Generate a debug message.

       Log.info(self, ...)
              Generate an info message.

       Log.notice(self, ...)
              Generate a notice message.

       Log.warning(self, ...)
              Generate a warning message.

       Log.critical(self, ...)
              Generate a critical message.

       Log.fatal(self, ...)
              Generate a fatal message.

AUTHORS and CONTRIBUTORS

       Jerry Lundström (DNS-OARC), Tomáš Křížek (CZ.NIC), Petr Špaček (ISC)

       Maintained by DNS-OARC

              https://www.dns-oarc.net/

BUGS

       For issues and feature requests please use:

              https://github.com/DNS-OARC/dnsjit/issues

       For question and help please use:

              admin@dns-oarc.net