vmod_rtstatus

Varnish Real-Time Status Module

Author: Arianna Aondio
Date: 2015-12-09
Version: 1.1.1

SYNOPSIS

import rtstatus;

DESCRIPTION

A vmod that lets you query your Varnish server for a JSON object containing counters.

Visiting the URL /rtstatus.json on the Varnish server will produce an application/json response of the following format:

{
"Uptime" : 0+00:09:38,
"hitrate": 0.00,
"load": 1,
"varnish_version" : "varnish-4.0.1 revision c6f20e4",
"server_id": "arianna-ThinkPad-X230",
"client_id": "127.0.0.1",
"backend": [{"director_name" : "simple" , "name":"default", "value": "healthy"},
    {"director_name" : "simple" , "name":"server1", "value": "healthy"},
    {"director_name" : "simple" , "name":"server2", "value": "healthy"}],
"MAIN.uptime": {"type": "MAIN", "descr": "Child process uptime", "value": 578},
"VBE.server1(192.168.0.10,,8081).vcls": {"type": "VBE", "ident": "server1(192.168.0.10,,8081)", "descr": "VCL references", "value": 1},
"VBE.server1(192.168.0.10,,8081).happy": {"type": "VBE", "ident": "server1(192.168.0.10,,8081)", "descr": "Happy health probes", "value": 0},
"VBE.server1(192.168.0.10,,8081).bereq_hdrbytes": {"type": "VBE", "ident": "server1(192.168.0.10,,8081)", "descr": "Request header bytes", "value": 0},
}

Visiting the URL /rtstatus on the Varnish server will produce an application/javascript response of the following format:

FUNCTIONS

rtstatus

Prototype:

rtstatus(REAL delta)

delta is the interval of seconds used for hitrate and load calculations. It has to be > 0 and < 60 seconds.

Return value: STRING

html()

Prototype:

html( )

Return value: STRING

INSTALLATION

The source tree is based on autotools to configure the building, and does also have the necessary bits in place to do functional unit tests using the varnishtest tool.

Make targets:

make - builds the vmod
make install - installs your vmod in VMODDIR
make check - runs the unit tests in src/tests/*.vtc

In your VCL you could then use this vmod along the following lines:

vcl 4.0;
import std;
import rtstatus;

sub vcl_recv {
    if (req.url ~ "/rtstatus.json") {
            return(synth(700, "OK"));           }
    if (req.url ~ "/rtstatus") {
        return(synth(800, "OK"));
    }
}
sub vcl_synth {
    if (resp.status == 700){
        set resp.status = 200;
        set resp.http.Content-Type = "application/json; charset=utf-8";
        synthetic(rtstatus.rtstatus(5));
        return (deliver);
    }
    if (resp.status == 800) {
        set resp.status = 200;
        set resp.http.Content-Type = "text/html; charset=utf-8";
        synthetic(rtstatus.html());
        return (deliver);
        }
}

varnish/libvmod-rtstatus