1 files changed, 101 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/modules/powerdns_recursor/collect.go b/src/go/collectors/go.d.plugin/modules/powerdns_recursor/collect.go
new file mode 100644
index 000000000..ec2e99c90
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/modules/powerdns_recursor/collect.go
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package powerdns_recursor
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+
+	"github.com/netdata/netdata/go/go.d.plugin/pkg/web"
+)
+
+const (
+	urlPathLocalStatistics = "/api/v1/servers/localhost/statistics"
+)
+
+func (r *Recursor) collect() (map[string]int64, error) {
+	statistics, err := r.scrapeStatistics()
+	if err != nil {
+		return nil, err
+	}
+
+	collected := make(map[string]int64)
+
+	r.collectStatistics(collected, statistics)
+
+	if !isPowerDNSRecursorMetrics(collected) {
+		return nil, errors.New("returned metrics aren't PowerDNS Recursor metrics")
+	}
+
+	return collected, nil
+}
+
+func isPowerDNSRecursorMetrics(collected map[string]int64) bool {
+	// PowerDNS Authoritative Server has same endpoint and returns data in the same format.
+	_, ok1 := collected["over-capacity-drops"]
+	_, ok2 := collected["tcp-questions"]
+	return ok1 && ok2
+}
+
+func (r *Recursor) 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 {
+			r.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 {
+			r.Debugf("%s value (%v) parse error: %v", s.Name, s.Value, err)
+			continue
+		}
+
+		collected[s.Name] = v
+	}
+}
+
+func (r *Recursor) scrapeStatistics() ([]statisticMetric, error) {
+	req, _ := web.NewHTTPRequest(r.Request)
+	req.URL.Path = urlPathLocalStatistics
+
+	var statistics statisticMetrics
+	if err := r.doOKDecode(req, &statistics); err != nil {
+		return nil, err
+	}
+
+	return statistics, nil
+}
+
+func (r *Recursor) doOKDecode(req *http.Request, in interface{}) error {
+	resp, err := r.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()
+	}
+}