Check in the initial copy of the Dovecot exporter.

63ec0e9b · Ed Schouten · 63ec0e9b · 63ec0e9b
Commit 63ec0e9b authored Dec 20, 2016 by Ed Schouten
--- a/.gitignore
+++ b/.gitignore
+/dovecot_exporter
--- a/dovecot_exporter.go
+++ b/dovecot_exporter.go
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+var (
+	dovecotUpDesc = prometheus.NewDesc(
+		prometheus.BuildFQName("dovecot", "", "up"),
+		"Whether scraping Dovecot's metrics was successful.",
+		[]string{"scope"},
+		nil)
+	dovecotScopes = [...]string{"domain", "ip", "session", "user"}
+)
+
+func CollectFromReader(file io.Reader, ch chan<- prometheus.Metric) error {
+	scanner := bufio.NewScanner(file)
+	scanner.Split(bufio.ScanLines)
+
+	// Read first line of input, containing the aggregation and column names.
+	if !scanner.Scan() {
+		return fmt.Errorf("Failed to extract columns from input")
+	}
+	columnNames := strings.Fields(scanner.Text())
+	columns := []*prometheus.Desc{}
+	for _, columnName := range columnNames[1:] {
+		columns = append(
+			columns,
+			prometheus.NewDesc(
+				prometheus.BuildFQName("dovecot", columnNames[0], columnName),
+				"Help text not provided by this exporter.",
+				[]string{columnNames[0]},
+				nil,
+			))
+	}
+
+	// Read successive lines, containing the values.
+	for scanner.Scan() {
+		values := strings.Fields(scanner.Text())
+		if len(values) < 1 {
+			break
+		}
+		for i, value := range values[1:] {
+			f, err := strconv.ParseFloat(value, 64)
+			if err != nil {
+				return err
+			}
+			ch <- prometheus.MustNewConstMetric(
+				columns[i],
+				prometheus.UntypedValue,
+				f,
+				values[0])
+		}
+	}
+	return scanner.Err()
+}
+
+func CollectFromFile(path string, ch chan<- prometheus.Metric) error {
+	conn, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	return CollectFromReader(conn, ch)
+}
+
+func CollectFromSocket(path string, scope string, ch chan<- prometheus.Metric) error {
+	conn, err := net.Dial("unix", path)
+	if err != nil {
+		return err
+	}
+	_, err = conn.Write([]byte("EXPORT\t" + scope + "\n"))
+	if err != nil {
+		return err
+	}
+	return CollectFromReader(conn, ch)
+}
+
+type DovecotExporter struct {
+	socketPath string
+}
+
+func NewDovecotExporter(socketPath string) *DovecotExporter {
+	return &DovecotExporter{
+		socketPath: socketPath,
+	}
+}
+
+func (e *DovecotExporter) Describe(ch chan<- *prometheus.Desc) {
+	ch <- dovecotUpDesc
+}
+
+func (e *DovecotExporter) Collect(ch chan<- prometheus.Metric) {
+	for _, scope := range dovecotScopes {
+		err := CollectFromSocket(e.socketPath, scope, ch)
+		if err == nil {
+			ch <- prometheus.MustNewConstMetric(
+				dovecotUpDesc,
+				prometheus.GaugeValue,
+				1.0,
+				scope)
+		} else {
+			log.Printf("Failed to scrape socket: %s", err)
+			ch <- prometheus.MustNewConstMetric(
+				dovecotUpDesc,
+				prometheus.GaugeValue,
+				0.0,
+				scope)
+		}
+	}
+}
+
+func main() {
+	var (
+		listenAddress = flag.String("web.listen-address", ":9199", "Address to listen on for web interface and telemetry.")
+		metricsPath   = flag.String("web.telemetry-path", "/metrics", "Path under which to expose metrics.")
+		socketPath    = flag.String("dovecot.socket-path", "/var/run/dovecot/stats", "Path under which to expose metrics.")
+	)
+	flag.Parse()
+
+	exporter := NewDovecotExporter(*socketPath)
+	prometheus.MustRegister(exporter)
+
+	http.Handle(*metricsPath, prometheus.Handler())
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		w.Write([]byte(`
+			<html>
+			<head><title>Dovecot Exporter</title></head>
+			<body>
+			<h1>Dovecot Exporter</h1>
+			<p><a href='` + *metricsPath + `'>Metrics</a></p>
+			</body>
+			</html>`))
+	})
+	log.Fatal(http.ListenAndServe(*listenAddress, nil))
+}