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/*
* Copyright Andrey Semashev 2007 - 2015.
* Distributed under the Boost Software License, Version 1.0.
* (See accompanying file LICENSE_1_0.txt or copy at
* http://www.boost.org/LICENSE_1_0.txt)
*/
#include <cstddef>
#include <string>
#include <map>
#include <iostream>
#include <fstream>
#include <boost/smart_ptr/shared_ptr.hpp>
#include <boost/smart_ptr/make_shared_object.hpp>
#include <boost/log/sinks.hpp>
#include <boost/log/expressions.hpp>
#include <boost/log/attributes/scoped_attribute.hpp>
#include <boost/log/sources/logger.hpp>
#include <boost/log/sources/record_ostream.hpp>
#include <boost/log/utility/value_ref.hpp>
#include <boost/log/utility/manipulators/add_value.hpp>
namespace logging = boost::log;
namespace src = boost::log::sources;
namespace expr = boost::log::expressions;
namespace sinks = boost::log::sinks;
namespace keywords = boost::log::keywords;
//[ example_expressions_has_attr_stat_accumulator
// Declare attribute keywords
BOOST_LOG_ATTRIBUTE_KEYWORD(stat_stream, "StatisticStream", std::string)
BOOST_LOG_ATTRIBUTE_KEYWORD(change, "Change", int)
// A simple sink backend to accumulate statistic information
class my_stat_accumulator :
public sinks::basic_sink_backend< sinks::synchronized_feeding >
{
// A map of accumulated statistic values,
// ordered by the statistic information stream name
typedef std::map< std::string, int > stat_info_map;
stat_info_map m_stat_info;
public:
// Destructor
~my_stat_accumulator()
{
// Display the accumulated data
stat_info_map::const_iterator it = m_stat_info.begin(), end = m_stat_info.end();
for (; it != end; ++it)
{
std::cout << "Statistic stream: " << it->first
<< ", accumulated value: " << it->second << "\n";
}
std::cout.flush();
}
// The method is called for every log record being put into the sink backend
void consume(logging::record_view const& rec)
{
// First, acquire statistic information stream name
logging::value_ref< std::string, tag::stat_stream > name = rec[stat_stream];
if (name)
{
// Next, get the statistic value change
logging::value_ref< int, tag::change > change_amount = rec[change];
if (change_amount)
{
// Accumulate the statistic data
m_stat_info[name.get()] += change_amount.get();
}
}
}
};
// The function registers two sinks - one for statistic information,
// and another one for other records
void init()
{
boost::shared_ptr< logging::core > core = logging::core::get();
// Create a backend and attach a stream to it
boost::shared_ptr< sinks::text_ostream_backend > backend =
boost::make_shared< sinks::text_ostream_backend >();
backend->add_stream(
boost::shared_ptr< std::ostream >(new std::ofstream("test.log")));
// Create a frontend and setup filtering
typedef sinks::synchronous_sink< sinks::text_ostream_backend > log_sink_type;
boost::shared_ptr< log_sink_type > log_sink(new log_sink_type(backend));
// All records that don't have a "StatisticStream" attribute attached
// will go to the "test.log" file
log_sink->set_filter(!expr::has_attr(stat_stream));
core->add_sink(log_sink);
// Create another sink that will receive all statistic data
typedef sinks::synchronous_sink< my_stat_accumulator > stat_sink_type;
boost::shared_ptr< stat_sink_type > stat_sink(new stat_sink_type());
// All records with a "StatisticStream" string attribute attached
// will go to the my_stat_accumulator sink
stat_sink->set_filter(expr::has_attr(stat_stream));
core->add_sink(stat_sink);
}
// This simple macro will simplify putting statistic data into a logger
#define PUT_STAT(lg, stat_stream_name, change)\
if (true) {\
BOOST_LOG_SCOPED_LOGGER_TAG(lg, "StatisticStream", stat_stream_name);\
BOOST_LOG(lg) << logging::add_value("Change", (int)(change));\
} else ((void)0)
void logging_function()
{
src::logger lg;
// Put a regular log record, it will go to the "test.log" file
BOOST_LOG(lg) << "A regular log record";
// Put some statistic data
PUT_STAT(lg, "StreamOne", 10);
PUT_STAT(lg, "StreamTwo", 20);
PUT_STAT(lg, "StreamOne", -5);
}
//]
int main(int, char*[])
{
init();
logging_function();
return 0;
}
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