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// SPDX-License-Identifier: GPL-3.0-or-later
package powerdns
import (
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"strconv"
"github.com/netdata/go.d.plugin/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.NewHTTPRequest(ns.Request)
req.URL.Path = urlPathLocalStatistics
var statistics statisticMetrics
if err := ns.doOKDecode(req, &statistics); err != nil {
return nil, err
}
return statistics, nil
}
func (ns *AuthoritativeNS) doOKDecode(req *http.Request, in interface{}) error {
resp, err := ns.httpClient.Do(req)
if err != nil {
return fmt.Errorf("error on HTTP request '%s': %v", req.URL, err)
}
defer closeBody(resp)
if resp.StatusCode != http.StatusOK {
return fmt.Errorf("'%s' returned HTTP status code: %d", req.URL, resp.StatusCode)
}
if err := json.NewDecoder(resp.Body).Decode(in); err != nil {
return fmt.Errorf("error on decoding response from '%s': %v", req.URL, err)
}
return nil
}
func closeBody(resp *http.Response) {
if resp != nil && resp.Body != nil {
_, _ = io.Copy(io.Discard, resp.Body)
_ = resp.Body.Close()
}
}
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