Hi,
I have a (hopefully) simple question about getting context information into
my logging.
Say I have a class Agent:
class Agent {
public:
long id() const { return myId_; }
void doSomething();
private:
static LoggerPtr agentLogger_;
};
This agent is connected to by a number of IP clients, and there are a number
of agents in the system (each with their own ID)
I can use NDC to log the IP of the connecting client for all my logging
within the doSomething function, which is good. However I would also like to
include the agent's ID implicitly without having to include it in each call
to .info() or .debug() etc.
So rather than...
agentLogger->info( "Agent " + id() + " processing request" );
(please assume that there is a nice way to concatenate a log4cxx string with
a long, that's merely for ease of reading)
I would rather write
agentLogger->info( "processing request" );
and end up with the same line in my log file, i.e. containing the "Agent 12 "
as context. This would work together with the NDC to show the agent and
client, so the logging may resemble:
1563 192.168.1.1 Agent 12 processing request
This class-context would have to not be on a thread level as multiple threads
may be accessing several agents for the same client IP.
I had thought of creating an extra member for the Agent class, something like
std::string loggingContext_;
and a macro to insert this at the front of any actual logging. Or maybe a
simple class AgentLogger that defers to a static LoggerPtr with context
(this, however, is pretty much the same thing) Both these seem a bit ugly
however, and I was hoping someone would have a more elegant solution for me.
Thank you all for your time,
Ben
