boost/log/sinks/event_log_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 event_log_backend.hpp
* \author Andrey Semashev
* \date 07.11.2008
*
* The header contains a logging sink backend that uses Windows NT event log API
* for signaling application events.
*/
#ifndef BOOST_LOG_SINKS_EVENT_LOG_BACKEND_HPP_INCLUDED_
#define BOOST_LOG_SINKS_EVENT_LOG_BACKEND_HPP_INCLUDED_
#include <boost/log/detail/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
#ifndef BOOST_LOG_WITHOUT_EVENT_LOG
#include <map>
#include <vector>
#include <string>
#include <iosfwd>
#include <boost/filesystem/path.hpp>
#include <boost/log/detail/light_function.hpp>
#include <boost/log/detail/parameter_tools.hpp>
#include <boost/log/attributes/attribute_value_set.hpp>
#include <boost/log/keywords/message_file.hpp>
#include <boost/log/keywords/log_name.hpp>
#include <boost/log/keywords/log_source.hpp>
#include <boost/log/keywords/registration.hpp>
#include <boost/log/keywords/target.hpp>
#include <boost/log/sinks/basic_sink_backend.hpp>
#include <boost/log/sinks/frontend_requirements.hpp>
#include <boost/log/sinks/attribute_mapping.hpp>
#include <boost/log/sinks/event_log_constants.hpp>
#include <boost/log/core/record_view.hpp>
#include <boost/log/expressions/formatter.hpp>
#include <boost/log/detail/header.hpp>
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
namespace sinks {
namespace event_log {
//! Event log source registration modes
enum registration_mode
{
never, //!< Never register event source, even if it's not registered
on_demand, //!< Register if the source is not registered yet
forced //!< Register always, event if the source is already registered
};
/*!
* \brief Straightforward event type mapping
*
* This type of mapping assumes that attribute with a particular name always
* provides values that map directly onto the native event types. The mapping
* simply returns the extracted attribute value converted to the native event type.
*/
template< typename AttributeValueT = int >
class direct_event_type_mapping :
public basic_direct_mapping< event_type, AttributeValueT >
{
//! Base type
typedef basic_direct_mapping< event_type, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit direct_event_type_mapping(attribute_name const& name) :
base_type(name, info)
{
}
};
/*!
* \brief Customizable event type mapping
*
* The class allows to setup a custom mapping between an attribute and native event types.
* The mapping should be initialized similarly to the standard \c map container, by using
* indexing operator and assignment.
*/
template< typename AttributeValueT = int >
class custom_event_type_mapping :
public basic_custom_mapping< event_type, AttributeValueT >
{
//! Base type
typedef basic_custom_mapping< event_type, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit custom_event_type_mapping(attribute_name const& name) :
base_type(name, info)
{
}
};
/*!
* \brief Straightforward event ID mapping
*
* This type of mapping assumes that attribute with a particular name always
* provides values that map directly onto the event identifiers. The mapping
* simply returns the extracted attribute value converted to the event ID.
*/
template< typename AttributeValueT = int >
class direct_event_id_mapping :
public basic_direct_mapping< event_id, AttributeValueT >
{
//! Base type
typedef basic_direct_mapping< event_id, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit direct_event_id_mapping(attribute_name const& name) :
base_type(name, make_event_id(0))
{
}
};
/*!
* \brief Customizable event ID mapping
*
* The class allows to setup a custom mapping between an attribute and event identifiers.
* The mapping should be initialized similarly to the standard \c map container, by using
* indexing operator and assignment.
*/
template< typename AttributeValueT = int >
class custom_event_id_mapping :
public basic_custom_mapping< event_id, AttributeValueT >
{
//! Base type
typedef basic_custom_mapping< event_id, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit custom_event_id_mapping(attribute_name const& name) :
base_type(name, make_event_id(0))
{
}
};
/*!
* \brief Straightforward event category mapping
*
* This type of mapping assumes that attribute with a particular name always
* provides values that map directly onto the event categories. The mapping
* simply returns the extracted attribute value converted to the event category.
*/
template< typename AttributeValueT = int >
class direct_event_category_mapping :
public basic_direct_mapping< event_category, AttributeValueT >
{
//! Base type
typedef basic_direct_mapping< event_category, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit direct_event_category_mapping(attribute_name const& name) :
base_type(name, make_event_category(0))
{
}
};
/*!
* \brief Customizable event category mapping
*
* The class allows to setup a custom mapping between an attribute and event categories.
* The mapping should be initialized similarly to the standard \c map container, by using
* indexing operator and assignment.
*/
template< typename AttributeValueT = int >
class custom_event_category_mapping :
public basic_custom_mapping< event_category, AttributeValueT >
{
//! Base type
typedef basic_custom_mapping< event_category, AttributeValueT > base_type;
public:
/*!
* Constructor
*
* \param name Attribute name
*/
explicit custom_event_category_mapping(attribute_name const& name) :
base_type(name, make_event_category(0))
{
}
};
/*!
* \brief An event composer
*
* This class is a function object that extracts event identifier from the attribute values set
* and formats insertion strings for the particular event. Each insertion string is formatted with
* a distinct formatter, which can be created just like regular sinks formatters.
*
* Before using, the composer must be initialized with the following information:
* \li Event identifier extraction logic. One can use \c basic_direct_event_id_mapping or
* \c basic_custom_event_id_mapping classes in order to create such extractor and pass it
* to the composer constructor.
* \li Event identifiers and insertion string formatters. The composer provides the following
* syntax to provide this information:
*
* \code
* event_composer comp;
* comp[MY_EVENT_ID1] % formatter1 % ... % formatterN;
* comp[MY_EVENT_ID2] % formatter1 % ... % formatterN;
* ...
* \endcode
*
* The event identifiers in square brackets are provided by the message compiler generated
* header (the actual names are specified in the .mc file). The formatters represent
* the insertion strings that will be used to replace placeholders in event messages,
* thus the number and the order of the formatters must correspond to the message definition.
*/
template< typename CharT >
class BOOST_LOG_API basic_event_composer
{
public:
//! Character type
typedef CharT char_type;
//! String type to be used as a message text holder
typedef std::basic_string< char_type > string_type;
//! Event identifier mapper type
typedef boost::log::aux::light_function< event_id (record_view const&) > event_id_mapper_type;
//! Type of an insertion composer (a formatter)
typedef basic_formatter< char_type > formatter_type;
//! Type of the composed insertions list
typedef std::vector< string_type > insertion_list;
private:
//! \cond
//! The class that implements formatting of insertion strings
class insertion_composer;
//! Type of the events map
typedef std::map< event_id, insertion_composer > event_map;
//! A smart reference that puts formatters into the composer
class event_map_reference;
friend class event_map_reference;
class event_map_reference
{
private:
//! Event identifier
event_id m_ID;
//! A reference to the object that created the reference
basic_event_composer< char_type >& m_Owner;
//! A hint for the owner to optimize insertion
insertion_composer* m_Composer;
public:
//! Initializing constructor
explicit event_map_reference(event_id id, basic_event_composer< char_type >& owner) :
m_ID(id),
m_Owner(owner),
m_Composer(0)
{
}
//! The operator puts the formatter into the composer
template< typename FormatterT >
event_map_reference& operator% (FormatterT const& fmt)
{
m_Composer = m_Owner.add_formatter(m_ID, m_Composer, formatter_type(fmt));
return *this;
}
};
//! \endcond
private:
//! The mapper that will extract the event identifier
event_id_mapper_type m_EventIDMapper;
//! The map of event identifiers and their insertion composers
event_map m_EventMap;
public:
/*!
* Default constructor. Creates an empty map of events.
*
* \param id_mapper An event identifier mapping function that will be used to extract event ID from attribute values
*/
explicit basic_event_composer(event_id_mapper_type const& id_mapper);
/*!
* Copy constructor. Performs a deep copy of the object.
*/
basic_event_composer(basic_event_composer const& that);
/*!
* Destructor
*/
~basic_event_composer();
/*!
* Assignment. Provides strong exception guarantee.
*/
basic_event_composer& operator= (basic_event_composer that);
/*!
* Swaps \c *this and \c that objects.
*/
void swap(basic_event_composer& that);
/*!
* Initiates creation of a new event description. The result of the operator can be used to
* add formatters for insertion strings construction. The returned reference type is implementation detail.
*
* \param id Event identifier.
*/
event_map_reference operator[] (event_id id);
/*!
* Initiates creation of a new event description. The result of the operator can be used to
* add formatters for insertion strings construction. The returned reference type is implementation detail.
*
* \param id Event identifier.
*/
event_map_reference operator[] (int id);
/*!
* Event composition operator. Extracts an event identifier from the attribute values by calling event ID mapper.
* Then runs all formatters that were registered for the event with the extracted ID. The results of formatting
* are returned in the \a insertions parameter.
*
* \param rec Log record view
* \param insertions A sequence of formatted insertion strings
* \return An event identifier that was extracted from \c attributes
*/
event_id operator() (record_view const& rec, insertion_list& insertions) const;
private:
#ifndef BOOST_LOG_DOXYGEN_PASS
//! Adds a formatter to the insertion composers list
insertion_composer* add_formatter(event_id id, insertion_composer* composer, formatter_type const& fmt);
#endif // BOOST_LOG_DOXYGEN_PASS
};
#ifdef BOOST_LOG_USE_CHAR
typedef basic_event_composer< char > event_composer; //!< Convenience typedef for narrow-character logging
#endif
#ifdef BOOST_LOG_USE_WCHAR_T
typedef basic_event_composer< wchar_t > wevent_composer; //!< Convenience typedef for wide-character logging
#endif
} // namespace event_log
/*!
* \brief An implementation of a simple logging sink backend that emits events into Windows NT event log
*
* The sink uses Windows NT 5 (Windows 2000) and later event log API to emit events
* to an event log. The sink acts as an event source in terms of the API, it implements all needed resources
* and source registration in the Windows registry that is needed for the event delivery.
*
* The backend performs message text formatting. The composed text is then passed as the first
* and only string parameter of the event. The resource embedded into the backend describes the event
* so that the parameter is inserted into the event description text, thus making it visible
* in the event log.
*
* The backend allows to customize mapping of application severity levels to the native Windows event types.
* This allows to write portable code even if OS-specific sinks, such as this one, are used.
*
* \note Since the backend registers itself into Windows registry as the resource file that contains
* event description, it is important to keep the library binary in a stable place of the filesystem.
* Otherwise Windows might not be able to load event resources from the library and display
* events correctly.
*
* \note It is known that Windows is not able to find event resources in the application executable,
* which is linked against the static build of the library. Users are advised to use dynamic
* builds of the library to solve this problem.
*/
template< typename CharT >
class basic_simple_event_log_backend :
public basic_formatted_sink_backend< CharT, concurrent_feeding >
{
//! Base type
typedef basic_formatted_sink_backend< CharT, concurrent_feeding > base_type;
//! Implementation type
struct implementation;
public:
//! Character type
typedef typename base_type::char_type char_type;
//! String type to be used as a message text holder
typedef typename base_type::string_type string_type;
//! Mapper type for the event type
typedef boost::log::aux::light_function< event_log::event_type (record_view const&) > event_type_mapper_type;
private:
//! Pointer to the backend implementation that hides various types from windows.h
implementation* m_pImpl;
public:
/*!
* Default constructor. Registers event source with name based on the application
* executable file name in the Application log. If such a registration is already
* present, it is not overridden.
*/
BOOST_LOG_API basic_simple_event_log_backend();
/*!
* Constructor. Registers event log source with the specified parameters.
* The following named parameters are supported:
*
* \li \c target - Specifies an UNC path to the remote server which log records should be sent to.
* The local machine will be used to process log records, if not specified.
* \li \c log_name - Specifies the log in which the source should be registered.
* The result of \c get_default_log_name is used, if the parameter is not specified.
* \li \c log_source - Specifies the source name. The result of \c get_default_source_name
* is used, if the parameter is not specified.
* \li \c registration - Specifies the event source registration mode in the Windows registry.
* Can have values of the \c registration_mode enum. Default value: \c on_demand.
*
* \param args A set of named parameters.
*/
#ifndef BOOST_LOG_DOXYGEN_PASS
BOOST_LOG_PARAMETRIZED_CONSTRUCTORS_CALL(basic_simple_event_log_backend, construct)
#else
template< typename... ArgsT >
explicit basic_simple_event_log_backend(ArgsT... const& args);
#endif
/*!
* Destructor. Unregisters event source. The log source description is not removed from the Windows registry.
*/
BOOST_LOG_API ~basic_simple_event_log_backend();
/*!
* The method installs the function object that maps application severity levels to WinAPI event types
*/
BOOST_LOG_API void set_event_type_mapper(event_type_mapper_type const& mapper);
/*!
* \returns Default log name: Application
*/
BOOST_LOG_API static string_type get_default_log_name();
/*!
* \returns Default log source name that is based on the application executable file name and the sink name
*/
BOOST_LOG_API static string_type get_default_source_name();
/*!
* The method puts the formatted message to the event log
*/
BOOST_LOG_API void consume(record_view const& rec, string_type const& formatted_message);
private:
#ifndef BOOST_LOG_DOXYGEN_PASS
//! Constructs backend implementation
template< typename ArgsT >
void construct(ArgsT const& args)
{
construct(
args[keywords::target | string_type()],
args[keywords::log_name || &basic_simple_event_log_backend::get_default_log_name],
args[keywords::log_source || &basic_simple_event_log_backend::get_default_source_name],
args[keywords::registration | event_log::on_demand]);
}
BOOST_LOG_API void construct(
string_type const& target,
string_type const& log_name,
string_type const& source_name,
event_log::registration_mode reg_mode);
#endif // BOOST_LOG_DOXYGEN_PASS
};
/*!
* \brief An implementation of a logging sink backend that emits events into Windows NT event log
*
* The sink uses Windows NT 5 (Windows 2000) and later event log API to emit events
* to an event log. The sink acts as an event source. Unlike \c basic_simple_event_log_backend,
* this sink backend allows users to specify the custom event message file and supports
* mapping attribute values onto several insertion strings. Although it requires considerably
* more scaffolding than the simple backend, this allows to support localizable event descriptions.
*
* Besides the file name of the module with event resources, the backend provides the following
* customizations:
* \li Remote server UNC address, log name and source name. These parameters have similar meaning
* to \c basic_simple_event_log_backend.
* \li Event type and category mappings. These are function object that allow to map attribute
* values to the according event parameters. One can use mappings in the \c event_log namespace.
* \li Event composer. This function object extracts event identifier and formats string insertions,
* that will be used by the API to compose the final event message text.
*/
template< typename CharT >
class basic_event_log_backend :
public basic_sink_backend< synchronized_feeding >
{
//! Base type
typedef basic_sink_backend< synchronized_feeding > base_type;
//! Implementation type
struct implementation;
public:
//! Character type
typedef CharT char_type;
//! String type
typedef std::basic_string< char_type > string_type;
//! Type of the composed insertions list
typedef std::vector< string_type > insertion_list;
//! Mapper type for the event type
typedef boost::log::aux::light_function< event_log::event_type (record_view const&) > event_type_mapper_type;
//! Mapper type for the event category
typedef boost::log::aux::light_function< event_log::event_category (record_view const&) > event_category_mapper_type;
//! Event composer type
typedef boost::log::aux::light_function< event_log::event_id (record_view const&, insertion_list&) > event_composer_type;
private:
//! Pointer to the backend implementation that hides various types from windows.h
implementation* m_pImpl;
public:
/*!
* Constructor. Registers event source with name based on the application
* executable file name in the Application log. If such a registration is already
* present, it is not overridden.
*/
template< typename T >
explicit basic_event_log_backend(std::basic_string< T > const& message_file_name)
{
construct(keywords::message_file = message_file_name);
}
/*!
* Constructor. Registers event source with name based on the application
* executable file name in the Application log. If such a registration is already
* present, it is not overridden.
*/
explicit basic_event_log_backend(filesystem::path const& message_file_name)
{
construct(keywords::message_file = message_file_name);
}
/*!
* Constructor. Registers event log source with the specified parameters.
* The following named parameters are supported:
*
* \li \c message_file - Specifies the file name that contains resources that
* describe events and categories. This parameter is mandatory unless \c registration is \c never.
* \li \c target - Specifies an UNC path to the remote server to which log records should be sent to.
* The local machine will be used to process log records, if not specified.
* \li \c log_name - Specifies the log in which the source should be registered.
* The result of \c get_default_log_name is used, if the parameter is not specified.
* \li \c log_source - Specifies the source name. The result of \c get_default_source_name
* is used, if the parameter is not specified.
* \li \c registration - Specifies the event source registration mode in the Windows registry.
* Can have values of the \c registration_mode enum. Default value: \c on_demand.
*
* \param args A set of named parameters.
*/
#ifndef BOOST_LOG_DOXYGEN_PASS
BOOST_LOG_PARAMETRIZED_CONSTRUCTORS_CALL(basic_event_log_backend, construct)
#else
template< typename... ArgsT >
explicit basic_event_log_backend(ArgsT... const& args);
#endif
/*!
* Destructor. Unregisters event source. The log source description is not removed from the Windows registry.
*/
BOOST_LOG_API ~basic_event_log_backend();
/*!
* The method creates an event in the event log
*
* \param rec Log record to consume
*/
BOOST_LOG_API void consume(record_view const& rec);
/*!
* The method installs the function object that maps application severity levels to WinAPI event types
*/
BOOST_LOG_API void set_event_type_mapper(event_type_mapper_type const& mapper);
/*!
* The method installs the function object that extracts event category from attribute values
*/
BOOST_LOG_API void set_event_category_mapper(event_category_mapper_type const& mapper);
/*!
* The method installs the function object that extracts event identifier from the attributes and creates
* insertion strings that will replace placeholders in the event message.
*/
BOOST_LOG_API void set_event_composer(event_composer_type const& composer);
/*!
* \returns Default log name: Application
*/
BOOST_LOG_API static string_type get_default_log_name();
/*!
* \returns Default log source name that is based on the application executable file name and the sink name
*/
BOOST_LOG_API static string_type get_default_source_name();
private:
#ifndef BOOST_LOG_DOXYGEN_PASS
//! Constructs backend implementation
template< typename ArgsT >
void construct(ArgsT const& args)
{
construct(
filesystem::path(args[keywords::message_file | filesystem::path()]),
args[keywords::target | string_type()],
args[keywords::log_name || &basic_event_log_backend::get_default_log_name],
args[keywords::log_source || &basic_event_log_backend::get_default_source_name],
args[keywords::registration | event_log::on_demand]);
}
BOOST_LOG_API void construct(
filesystem::path const& message_file_name,
string_type const& target,
string_type const& log_name,
string_type const& source_name,
event_log::registration_mode reg_mode);
#endif // BOOST_LOG_DOXYGEN_PASS
};
#ifdef BOOST_LOG_USE_CHAR
typedef basic_simple_event_log_backend< char > simple_event_log_backend; //!< Convenience typedef for narrow-character logging
typedef basic_event_log_backend< char > event_log_backend; //!< Convenience typedef for narrow-character logging
#endif
#ifdef BOOST_LOG_USE_WCHAR_T
typedef basic_simple_event_log_backend< wchar_t > wsimple_event_log_backend; //!< Convenience typedef for wide-character logging
typedef basic_event_log_backend< wchar_t > wevent_log_backend; //!< Convenience typedef for wide-character logging
#endif
} // namespace sinks
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_WITHOUT_EVENT_LOG
#endif // BOOST_LOG_SINKS_EVENT_LOG_BACKEND_HPP_INCLUDED_