firehol/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package powerdns

import (
    "errors"
    "strconv"

    "github.com/netdata/netdata/go/plugins/plugin/go.d/pkg/web"
)

const (
    urlPathLocalStatistics = "/api/v1/servers/localhost/statistics"
)

func (ns *AuthoritativeNS) collect() (map[string]int64, error) {
    statistics, err := ns.scrapeStatistics()
    if err != nil {
        return nil, err
    }

    collected := make(map[string]int64)

    ns.collectStatistics(collected, statistics)

    if !isPowerDNSAuthoritativeNSMetrics(collected) {
        return nil, errors.New("returned metrics aren't PowerDNS Authoritative Server metrics")
    }

    return collected, nil
}

func isPowerDNSAuthoritativeNSMetrics(collected map[string]int64) bool {
    // PowerDNS Recursor has same endpoint and returns data in the same format.
    _, ok1 := collected["over-capacity-drops"]
    _, ok2 := collected["tcp-questions"]
    return !ok1 && !ok2
}

func (ns *AuthoritativeNS) collectStatistics(collected map[string]int64, statistics statisticMetrics) {
    for _, s := range statistics {
        // https://doc.powerdns.com/authoritative/http-api/statistics.html#statisticitem
        if s.Type != "StatisticItem" {
            continue
        }

        value, ok := s.Value.(string)
        if !ok {
            ns.Debugf("%s value (%v) unexpected type: want=string, got=%T.", s.Name, s.Value, s.Value)
            continue
        }

        v, err := strconv.ParseInt(value, 10, 64)
        if err != nil {
            ns.Debugf("%s value (%v) parse error: %v", s.Name, s.Value, err)
            continue
        }

        collected[s.Name] = v
    }
}

func (ns *AuthoritativeNS) scrapeStatistics() ([]statisticMetric, error) {
    req, _ := web.NewHTTPRequestWithPath(ns.RequestConfig, urlPathLocalStatistics)

    var stats statisticMetrics
    if err := web.DoHTTP(ns.httpClient).RequestJSON(req, &stats); err != nil {
        return nil, err
    }

    return stats, nil
}