boost/log/sinks/syslog_backend.hpp
/*
* 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)
*/
/*!
* \file syslog_backend.hpp
* \author Andrey Semashev
* \date 08.01.2008
*
* The header contains implementation of a Syslog sink backend along with its setup facilities.
*/
#ifndef BOOST_LOG_SINKS_SYSLOG_BACKEND_HPP_INCLUDED_
#define BOOST_LOG_SINKS_SYSLOG_BACKEND_HPP_INCLUDED_
#include <boost/log/detail/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
#ifndef BOOST_LOG_WITHOUT_SYSLOG
#include <string>
#include <boost/log/detail/asio_fwd.hpp>
#include <boost/log/detail/light_function.hpp>
#include <boost/log/detail/parameter_tools.hpp>
#include <boost/log/sinks/basic_sink_backend.hpp>
#include <boost/log/sinks/syslog_constants.hpp>
#include <boost/log/sinks/attribute_mapping.hpp>
#include <boost/log/attributes/attribute_value_set.hpp>
#include <boost/log/keywords/facility.hpp>
#include <boost/log/keywords/use_impl.hpp>
#include <boost/log/keywords/ident.hpp>
#include <boost/log/keywords/ip_version.hpp>
#include <boost/log/detail/header.hpp>
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
namespace sinks {
//! Supported IP protocol versions
enum ip_versions
{
v4,
v6
};
namespace syslog {
//! The enumeration defined the possible implementation types for the syslog backend
enum impl_types
{
#ifdef BOOST_LOG_USE_NATIVE_SYSLOG
native = 0 //!< Use native syslog API
#ifndef BOOST_LOG_NO_ASIO
,
#endif
#endif
#ifndef BOOST_LOG_NO_ASIO
udp_socket_based = 1 //!< Use UDP sockets, according to RFC3164
#endif
};
/*!
* \brief Straightforward severity level mapping
*
* This type of mapping assumes that attribute with a particular name always
* provides values that map directly onto the Syslog levels. The mapping
* simply returns the extracted attribute value converted to the Syslog severity level.
*/
template< typename AttributeValueT = int >
class direct_severity_mapping :
public basic_direct_mapping< level, AttributeValueT >
{
//! Base type
typedef basic_direct_mapping< level, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit direct_severity_mapping(attribute_name const& name) :
base_type(name, info)
{
}
};
/*!
* \brief Customizable severity level mapping
*
* The class allows to setup a custom mapping between an attribute and Syslog severity levels.
* The mapping should be initialized similarly to the standard \c map container, by using
* indexing operator and assignment.
*/
template< typename AttributeValueT = int >
class custom_severity_mapping :
public basic_custom_mapping< level, AttributeValueT >
{
//! Base type
typedef basic_custom_mapping< level, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit custom_severity_mapping(attribute_name const& name) :
base_type(name, info)
{
}
};
} // namespace syslog
/*!
* \brief An implementation of a syslog sink backend
*
* The backend provides support for the syslog protocol, defined in RFC3164.
* The backend sends log records to a remote host via UDP. The host name can
* be specified by calling the \c set_target_address method. By default log
* records will be sent to localhost:514. The local address can be specified
* as well, by calling the \c set_local_address method. By default syslog
* packets will be sent from any local address available.
*
* It is safe to create several sink backends with the same local addresses -
* the backends within the process will share the same socket. The same applies
* to different processes that use the syslog backends to send records from
* the same socket. However, it is not guaranteed to work if some third party
* facility is using the socket.
*
* On systems with native syslog implementation it may be preferable to utilize
* the POSIX syslog API instead of direct socket management in order to bypass
* possible security limitations that may be in action. To do so one has to pass
* the <tt>use_impl = native</tt> to the backend constructor. Note, however,
* that in that case you will only have one chance to specify syslog facility and
* process identification string - on the first native syslog backend construction.
* Other native syslog backends will ignore these parameters.
* Obviously, the \c set_local_address and \c set_target_address
* methods have no effect for native backends. Using <tt>use_impl = native</tt>
* on platforms with no native support for POSIX syslog API will have no effect.
*/
class syslog_backend :
public basic_formatted_sink_backend< char >
{
//! Base type
typedef basic_formatted_sink_backend< char > base_type;
//! Implementation type
struct implementation;
public:
//! Character type
typedef base_type::char_type char_type;
//! String type that is used to pass message test
typedef base_type::string_type string_type;
//! Syslog severity level mapper type
typedef boost::log::aux::light_function< syslog::level (record_view const&) > severity_mapper_type;
private:
//! Pointer to the implementation
implementation* m_pImpl;
public:
/*!
* Constructor. Creates a UDP socket-based backend with <tt>syslog::user</tt> facility code.
* IPv4 protocol will be used.
*/
BOOST_LOG_API syslog_backend();
/*!
* Constructor. Creates a sink backend with the specified named parameters.
* The following named parameters are supported:
*
* \li \c facility - Specifies the facility code. If not specified, <tt>syslog::user</tt> will be used.
* \li \c use_impl - Specifies the backend implementation. Can be one of:
* \li \c native - Use the native syslog API, if available. If no native API
* is available, it is equivalent to \c udp_socket_based.
* \li \c udp_socket_based - Use the UDP socket-based implementation, conforming to
* RFC3164 protocol specification. This is the default.
* \li \c ip_version - Specifies IP protocol version to use, in case if socket-based implementation
* is used. Can be either \c v4 (the default one) or \c v6.
* \li \c ident - Process identification string. This parameter is only supported by native syslog implementation.
*/
#ifndef BOOST_LOG_DOXYGEN_PASS
BOOST_LOG_PARAMETRIZED_CONSTRUCTORS_CALL(syslog_backend, construct)
#else
template< typename... ArgsT >
explicit syslog_backend(ArgsT... const& args);
#endif
/*!
* Destructor
*/
BOOST_LOG_API ~syslog_backend();
/*!
* The method installs the function object that maps application severity levels to syslog levels
*/
BOOST_LOG_API void set_severity_mapper(severity_mapper_type const& mapper);
#if !defined(BOOST_LOG_NO_ASIO)
/*!
* The method sets the local host name which log records will be sent from. The host name
* is resolved to obtain the final IP address.
*
* \note Does not have effect if the backend was constructed to use native syslog API
*
* \param addr The local address
* \param port The local port number
*/
BOOST_LOG_API void set_local_address(std::string const& addr, unsigned short port = 514);
/*!
* The method sets the local address which log records will be sent from.
*
* \note Does not have effect if the backend was constructed to use native syslog API
*
* \param addr The local address
* \param port The local port number
*/
BOOST_LOG_API void set_local_address(boost::asio::ip::address const& addr, unsigned short port = 514);
/*!
* The method sets the remote host name where log records will be sent to. The host name
* is resolved to obtain the final IP address.
*
* \note Does not have effect if the backend was constructed to use native syslog API
*
* \param addr The remote host address
* \param port The port number on the remote host
*/
BOOST_LOG_API void set_target_address(std::string const& addr, unsigned short port = 514);
/*!
* The method sets the address of the remote host where log records will be sent to.
*
* \note Does not have effect if the backend was constructed to use native syslog API
*
* \param addr The remote host address
* \param port The port number on the remote host
*/
BOOST_LOG_API void set_target_address(boost::asio::ip::address const& addr, unsigned short port = 514);
#endif // !defined(BOOST_LOG_NO_ASIO)
/*!
* The method passes the formatted message to the syslog API or sends to a syslog server
*/
BOOST_LOG_API void consume(record_view const& rec, string_type const& formatted_message);
private:
#ifndef BOOST_LOG_DOXYGEN_PASS
//! The method creates the backend implementation
template< typename ArgsT >
void construct(ArgsT const& args)
{
construct(
args[keywords::facility | syslog::user],
#if !defined(BOOST_LOG_NO_ASIO)
args[keywords::use_impl | syslog::udp_socket_based],
#else
args[keywords::use_impl | syslog::native],
#endif
args[keywords::ip_version | v4],
args[keywords::ident | std::string()]);
}
BOOST_LOG_API void construct(
syslog::facility facility, syslog::impl_types use_impl, ip_versions ip_version, std::string const& ident);
#endif // BOOST_LOG_DOXYGEN_PASS
};
} // namespace sinks
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_WITHOUT_SYSLOG
#endif // BOOST_LOG_SINKS_SYSLOG_BACKEND_HPP_INCLUDED_