Create high-level varnish events in librato

gistfile1.js

var readline = require('readline');
var spawn = require('child_process').spawn;
var request = require('request');

var config = {
    interval: 10000,
    email: 'email-address@example.com',
    apitoken: 'the-librato-readonly-api-token'
};

var varnishncsa = spawn('varnishncsa', ['-F', '%{Varnish:handling}x %m %{Host}i %U %s']);

var varnish_output = readline.createInterface({
    input: varnishncsa.stdout,
    output: process.stdout,
    terminal: false
});

var stats = {};

function flush_stats() {
    var gauges = [];
    for (var key in stats) {
        gauges.push({ name: key,
                      value: stats[key]});
        stats[key] = 0;
    }
    request.post({ url: 'https://metrics-api.librato.com/v1/metrics',
                   json: { measure_time: (new Date().getTime()) / 1000,
                           gauges: gauges,
                           source: "varnish-highlevel-stats"
                         },
                   auth: { user: config.email,
                           pass: config.apitoken }
                 },
                function (error, response, body) {
                    if (error) {
                        console.log('error:', error, 'body:', body);
                    }
                });
}

setInterval(flush_stats, config.interval);

function inc(key) {
    stats[key] = (stats[key] || 0) + 1;
}

function process_varnish_request(varnish_handling, method, host, url, status) {
    if (url.match(/^\/(static|beta|assets|frontend)\//)) {
        // this is just noise
        return;
    }
    if (varnish_handling != '-') {
        inc("varnish." + varnish_handling);
    }
    inc("host." + host.replace(/:.*/, ""));
    inc("status." + status);
    if (url == "/widget/api/v1") {
        inc('widget.request');
    } else if (url == '/api/v2/search') {
        inc('api.search');
    } else if (url == '/search/') {
        inc('web.search.start');
    } else {
        url.replace(/^\/search\/\d+\/(.*)/, function (match, what) {
            inc('web.search.' + what.replace(/\//g, '.'));
        });
    }
}

varnish_output.on('line', function (line) {
    process_varnish_request.apply(null, line.split(" "));
});

varnishncsa.on('exit', function (e) {
    console.log('varnishncsa unexpectedly exited with exit code', e);
});