Is it possible to get the current request that is being served by node.js?

An interesting way to do this would be the new Domains feature. http://nodejs.org/api/domain.html

Domains, while providing excellent error recovery, can be used as a type of "Thread Local Storage" - basically storing data for each request.

Create some middleware that adds every request/response to a domain.

app.use(function(req, res, next) {
  var reqd = domain.create();
  reqd.add(req);
  reqd.add(res);
  reqd._req = req; // Add request object to custom property
  // TODO: hook error event on reqd (see docs)
  next();
});

In the log function, you can now get the current domain and pull out the request object.

function log_message(level, message) {
  // Pull the request from the current domain.
  var request = process.domain._req;

  // TODO: log message
};

Domains are still experimental, but it doesn't sound like much will change between now and the 1.0 release.

Similar to the domains answer, it's now a lot easier to do this using continuation-local-storage: https://datahero.com/blog/2014/05/22/node-js-preserving-data-across-async-callbacks/

At DataHero we save a transaction id, user id, and session id with all log messages. You don't need to pass the request object all the way down, so it helps keep your models / business layer clean, too.

create a midleware:

app.use(function(req, res, next) {
       var tid = uuid.v4();
     var cls = require('continuation-local-storage');
       var namespace = cls.createNamespace('com.storage');
      var pre_ip;
          if(get_ip(req))
          { ip_info= get_ip(req).clientIp;
              pre_ip=ip_info
          }
          namespace.bindEmitter(req);
          namespace.bindEmitter(res);
        namespace.run(function() {
               console.log(logobj);
              namespace.set('tid', tid);
              namespace.set('ip',ip_info);
           namespace.set('logobj',logobj);   
              next();
          });
      });

And use it :

var cls = require('continuation-local-storage');
 var namespace = cls.getNamespace('com.storage');
      namespace.get('ip');