ceph/src/boost/libs/log/example/settings_file_formatter_factory/main.cpp

   1 /*
   2  *          Copyright Andrey Semashev 2007 - 2015.
   3  * Distributed under the Boost Software License, Version 1.0.
   4  *    (See accompanying file LICENSE_1_0.txt or copy at
   5  *          http://www.boost.org/LICENSE_1_0.txt)
   6  */
   7 /*!
   8  * \file   main.cpp
   9  * \author Andrey Semashev
  10  * \date   12.05.2010
  11  *
  12  * \brief  An example of initializing the library from a settings file,
  13  *         with a custom formatter for an attribute.
  14  */
  15
  16 // #define BOOST_ALL_DYN_LINK 1
  17
  18 #include <string>
  19 #include <iostream>
  20 #include <fstream>
  21 #include <stdexcept>
  22 #include <boost/ref.hpp>
  23 #include <boost/bind.hpp>
  24 #include <boost/smart_ptr/make_shared_object.hpp>
  25 #include <boost/log/core.hpp>
  26 #include <boost/log/common.hpp>
  27 #include <boost/log/attributes.hpp>
  28 #include <boost/log/core/record.hpp>
  29 #include <boost/log/attributes/value_visitation.hpp>
  30 #include <boost/log/utility/setup/from_stream.hpp>
  31 #include <boost/log/utility/setup/common_attributes.hpp>
  32 #include <boost/log/utility/setup/formatter_parser.hpp>
  33
  34 namespace logging = boost::log;
  35 namespace attrs = boost::log::attributes;
  36 namespace src = boost::log::sources;
  37
  38 enum severity_level
  39 {
  40     normal,
  41     notification,
  42     warning,
  43     error,
  44     critical
  45 };
  46
  47 BOOST_LOG_INLINE_GLOBAL_LOGGER_DEFAULT(test_lg, src::severity_logger< >)
  48
  49 //! Our custom formatter for the scope list
  50 struct scope_list_formatter
  51 {
  52     typedef void result_type;
  53     typedef attrs::named_scope::value_type scope_stack;
  54
  55     explicit scope_list_formatter(logging::attribute_name const& name) :
  56         name_(name)
  57     {
  58     }
  59     void operator()(logging::record_view const& rec, logging::formatting_ostream& strm) const
  60     {
  61         // We need to acquire the attribute value from the log record
  62         logging::visit< scope_stack >
  63         (
  64             name_,
  65             rec.attribute_values(),
  66             boost::bind(&scope_list_formatter::format, _1, boost::ref(strm))
  67         );
  68     }
  69
  70 private:
  71     //! This is where our custom formatting takes place
  72     static void format(scope_stack const& scopes, logging::formatting_ostream& strm)
  73     {
  74         scope_stack::const_iterator it = scopes.begin(), end = scopes.end();
  75         for (; it != end; ++it)
  76         {
  77             strm << "\t" << it->scope_name << " [" << it->file_name << ":" << it->line << "]\n";
  78         }
  79     }
  80
  81 private:
  82     logging::attribute_name name_;
  83 };
  84
  85 class my_scopes_formatter_factory :
  86     public logging::formatter_factory< char >
  87 {
  88 public:
  89     /*!
  90      * This function creates a formatter for the MyScopes attribute.
  91      * It effectively associates the attribute with the scope_list_formatter class
  92      */
  93     formatter_type create_formatter(
  94         logging::attribute_name const& attr_name, args_map const& args)
  95     {
  96         return formatter_type(scope_list_formatter(attr_name));
  97     }
  98 };
  99
 100 //! The function initializes the logging library
 101 void init_logging()
 102 {
 103     // First thing - register the custom formatter for MyScopes
 104     logging::register_formatter_factory("MyScopes", boost::make_shared< my_scopes_formatter_factory >());
 105
 106     // Then load the settings from the file
 107     std::ifstream settings("settings.txt");
 108     if (!settings.is_open())
 109         throw std::runtime_error("Could not open settings.txt file");
 110     logging::init_from_stream(settings);
 111
 112     // Add some attributes
 113     logging::add_common_attributes();
 114
 115     logging::core::get()->add_global_attribute("MyScopes", attrs::named_scope());
 116 }
 117
 118 //! The function tests logging
 119 void try_logging()
 120 {
 121     BOOST_LOG_FUNCTION();
 122
 123     src::severity_logger< >& lg = test_lg::get();
 124
 125     BOOST_LOG_SEV(lg, critical) << "This is a critical severity record";
 126
 127     BOOST_LOG_NAMED_SCOPE("random name");
 128     BOOST_LOG_SEV(lg, error) << "This is a error severity record";
 129 }
 130
 131 int main(int argc, char* argv[])
 132 {
 133     try
 134     {
 135         init_logging();
 136         try_logging();
 137     }
 138     catch (std::exception& e)
 139     {
 140         std::cout << "FAILURE: " << e.what() << std::endl;
 141         return -1;
 142     }
 143
 144     return 0;
 145 }