Add powerdns input plugin

closes #614

plugins/inputs/powerdns/powerdns.go

@@ -0,0 +1,126 @@
+package powerdns
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"net"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+type Powerdns struct {
+	UnixSockets []string
+}
+
+var sampleConfig = `
+  # An array of sockets to gather stats about.
+  # Specify a path to unix socket.
+  #
+  # If no servers are specified, then '/var/run/pdns.controlsocket' is used as the path.
+  unix_sockets = ["/var/run/pdns.controlsocket"]
+`
+
+var defaultTimeout = 5 * time.Second
+
+func (p *Powerdns) SampleConfig() string {
+	return sampleConfig
+}
+
+func (p *Powerdns) Description() string {
+	return "Read metrics from one or many PowerDNS servers"
+}
+
+func (p *Powerdns) Gather(acc telegraf.Accumulator) error {
+	if len(p.UnixSockets) == 0 {
+		return p.gatherServer("/var/run/pdns.controlsocket", acc)
+	}
+
+	for _, serverSocket := range p.UnixSockets {
+		if err := p.gatherServer(serverSocket, acc); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (p *Powerdns) gatherServer(address string, acc telegraf.Accumulator) error {
+	conn, err := net.DialTimeout("unix", address, defaultTimeout)
+	if err != nil {
+		return err
+	}
+
+	defer conn.Close()
+
+	conn.SetDeadline(time.Now().Add(defaultTimeout))
+
+	// Read and write buffer
+	rw := bufio.NewReadWriter(bufio.NewReader(conn), bufio.NewWriter(conn))
+
+	// Send command
+	if _, err := fmt.Fprint(conn, "show * \n"); err != nil {
+		return nil
+	}
+	if err := rw.Flush(); err != nil {
+		return err
+	}
+
+	// Read data
+	buf := make([]byte, 0, 4096)
+	tmp := make([]byte, 1024)
+	for {
+		n, err := rw.Read(tmp)
+		if err != nil {
+			if err != io.EOF {
+				return err
+			}
+
+			break
+		}
+		buf = append(buf, tmp[:n]...)
+	}
+
+	metrics := string(buf)
+
+	// Process data
+	fields, err := parseResponse(metrics)
+	if err != nil {
+		return err
+	}
+
+	// Add server socket as a tag
+	tags := map[string]string{"server": address}
+
+	acc.AddFields("powerdns", fields, tags)
+
+	return nil
+}
+
+func parseResponse(metrics string) (map[string]interface{}, error) {
+	values := make(map[string]interface{})
+
+	s := strings.Split(metrics, ",")
+
+	for _, metric := range s[:len(s)-1] {
+		m := strings.Split(metric, "=")
+
+		i, err := strconv.ParseInt(m[1], 10, 64)
+		if err != nil {
+			return values, err
+		}
+		values[m[0]] = i
+	}
+
+	return values, nil
+}
+
+func init() {
+	inputs.Add("powerdns", func() telegraf.Input {
+		return &Powerdns{}
+	})
+}