[AGENT++] Log Messages

[Michelsen Robert]

Hi,

>Is there a simple way to redirect Agent++ log messages into an application's own >logic.  For instance, my application has its own logging subsystem and it runs >as a daemon.  Is there a good way to grab Agent++'s logging messages on their >way to stdout?

i had the same problem (log4cpp)  

I implemented the following technique (looking at log.h and log.cpp):

--------

derive from "AgentLogImpl":

e.g. class AgentppToLog4cpp : public AgentLogImpl

override

virtual LogEntry* create_log_entry(unsigned char _type) const;
virtual AgentLog& operator+=(const LogEntry* log);

--------

derive from "LogEntryImpl":

class Log4cppLogEntryImpl : public LogEntryImpl

override

Log4cppLogEntryImpl( unsigned char _type) : LogEntryImpl( _type) {}
virtual ~Log4cppLogEntryImpl() {};
virtual void init(void) {}

to customize the log entry initialization itself (like you want)

--------

In "create_log_entry" you return an instance of (your own) LogEntryImpl class impl

e.g.

LogEntry* AgentppToLog4cpp::create_log_entry( unsigned char t) const
{
	// return our own LogEntryImpl instance (message text only)
	return new Log4cppLogEntryImpl (t);
}

by overriding "operator+=" you can reroute the whole stuff to your own logging hierarchy.

e.g.

AgentLog& AgentppToLog4cpp::operator+=( const LogEntry* log)
{
	switch( log->get_class())
	{
		case ERROR_LOG:
	
			sm_Logger.error( "%s\n", log->get_value());
			break;

		case WARNING_LOG:
			
			sm_Logger.warn( "%s\n", log->get_value());
			break;

		// and so forth ....
		// (sm_Logger is a static instance of my own logger)
	}
}

--------

Before you initialize the Agent++/SNMP++ network subsystems, initialize the logging with your own log impl:

DefaultLog::init( new Agentpp2Log4cpp());

Be aware when instanciating any agent++ objects (like MIB -> ThreadPool -> TaskManager on calling LOG_BEGIN) before the logging they will initialize the default (static logger) with default agent++ impl resulting in "loss" of initial messages.

Be aware of global (static) object destruction order, keep your (custom) logging system alive as long as any (static) agent++ instances live (that might call LOG).

There might be better ways but this worked for me...

Regards,

Robert Michelsen