sessioncount-cookie.vcl

#
# Simple concurrent session tracking with Varnish.
#
vcl 4.0;

import std;
import cookie;
import header;

backend default {
    .host = "localhost";
    .port = "80";
}

sub vcl_recv { call session_recv; }
sub vcl_deliver { call session_deliver; }



sub session_recv {
    cookie.parse(req.http.cookie);
    unset req.http.x-new-session;
    if (!cookie.isset("sess")) {
        set req.http.x-new-session = true;
    }
    cookie.delete("sess");
    set req.http.cookie = cookie.get_string();
}

sub session_deliver {
    // XXX: Will we overcount concurrent requests?
    if (req.http.x-new-session) {
        header.append(resp.http.Set-Cookie, "sess=1; Expires=" + cookie.format_rfc1123(now, 5m) + ";");
        std.log("new session: " + client.ip + " port " + std.port(client.ip));
    }
}