VCS session tracking

vcs_session.vcl

vcl 4.0;

import cookie;
import std;

sub vcl_deliver
{
  cookie.parse(req.http.cookie);
  set req.http.X-vcsid = cookie.get("_vcsid");
  if (req.http.X-vcsid == "") {
    set req.http.X-vcsid = std.random(1, 10000000) + "." + std.random(1, 10000000);
    set resp.http.Set-Cookie = "_vcsid=" + req.http.X-vcsid + "; HttpOnly; Path=/";
  }
  std.log("vcs-key:SESSION/" + req.http.X-vcsid + "/" + req.http.Host + req.url);
}