add support for prometheus exporter-toolkit web config

Author: tomcz

README.md

@@ -87,7 +87,7 @@ USAGE:
    openldap_exporter [global options] [arguments...]
 
 VERSION:
-   v2.0-7-gf81504e (f81504e)
+   v2.1.2
 
 GLOBAL OPTIONS:
    --promAddr value    Bind address for Prometheus HTTP metrics server (default: ":9330") [$PROM_ADDR]
@@ -97,6 +97,7 @@ GLOBAL OPTIONS:
    --ldapUser value    OpenLDAP bind username (optional) [$LDAP_USER]
    --ldapPass value    OpenLDAP bind password (optional) [$LDAP_PASS]
    --interval value    Scrape interval (default: 30s) [$INTERVAL]
+   --webCfgFile FILE   Prometheus metrics web config FILE (optional) [$WEB_CFG_FILE]
    --config YAML_FILE  Optional configuration from a YAML_FILE
    --help, -h          show help (default: false)
    --version, -v       print the version (default: false)
@@ -116,7 +117,12 @@ ldapUser: "cn=monitoring,cn=Monitor"
 ldapPass: "sekret"
 ```
 
+NOTES:
+
+* `--ldapNet` allows you to configure `tcp` or `unix` socket connections to your co-located OpenLDAP server.
+* `--webCfgFile` can be used to provide authentiction and TLS configuration for the [prometheus web exporter](https://github.com/prometheus/exporter-toolkit/tree/master/web).
+
 ## Build
 
-1. Install Go 1.13 from https://golang.org/
+1. Install Go 1.16 from https://golang.org/
 2. Build the binaries: `make build`

cmd/openldap_exporter/main.go

@@ -1,25 +1,30 @@
 package main
 
 import (
+	"context"
 	"log"
 	"os"
+	"os/signal"
+	"syscall"
 	"time"
 
 	exporter "github.com/tomcz/openldap_exporter"
 
 	"github.com/urfave/cli/v2"
 	"github.com/urfave/cli/v2/altsrc"
+	"golang.org/x/sync/errgroup"
 )
 
 const (
-	promAddr = "promAddr"
-	ldapNet  = "ldapNet"
-	ldapAddr = "ldapAddr"
-	ldapUser = "ldapUser"
-	ldapPass = "ldapPass"
-	interval = "interval"
-	metrics  = "metrPath"
-	config   = "config"
+	promAddr   = "promAddr"
+	ldapNet    = "ldapNet"
+	ldapAddr   = "ldapAddr"
+	ldapUser   = "ldapUser"
+	ldapPass   = "ldapPass"
+	interval   = "interval"
+	metrics    = "metrPath"
+	webCfgFile = "webCfgFile"
+	config     = "config"
 )
 
 func main() {
@@ -64,6 +69,11 @@ func main() {
 			Usage:   "Scrape interval",
 			EnvVars: []string{"INTERVAL"},
 		}),
+		altsrc.NewStringFlag(&cli.StringFlag{
+			Name:    webCfgFile,
+			Usage:   "Prometheus metrics web config `FILE` (optional)",
+			EnvVars: []string{"WEB_CFG_FILE"},
+		}),
 		&cli.StringFlag{
 			Name:  config,
 			Usage: "Optional configuration from a `YAML_FILE`",
@@ -94,8 +104,7 @@ func optionalYamlSourceFunc(flagFileName string) func(context *cli.Context) (alt
 }
 
 func runMain(c *cli.Context) error {
-	log.Println("starting Prometheus HTTP metrics server on", c.String(promAddr))
-	go exporter.StartMetricsServer(c.String(promAddr), c.String(metrics))
+	server := exporter.NewMetricsServer(c.String(promAddr), c.String(metrics), c.String(webCfgFile))
 
 	scraper := &exporter.Scraper{
 		Net:  c.String(ldapNet),
@@ -104,7 +113,33 @@ func runMain(c *cli.Context) error {
 		Pass: c.String(ldapPass),
 		Tick: c.Duration(interval),
 	}
-	log.Println("starting OpenLDAP scraper for", scraper.Addr)
-	scraper.Start()
-	return nil
+
+	ctx, cancel := context.WithCancel(context.Background())
+	var group errgroup.Group
+	group.Go(func() error {
+		defer cancel()
+		log.Printf("starting Prometheus HTTP metrics server on %s\n", c.String(promAddr))
+		return server.Start()
+	})
+	group.Go(func() error {
+		defer cancel()
+		log.Printf("starting OpenLDAP scraper for %s://%s\n", scraper.Net, scraper.Addr)
+		return scraper.Start(ctx)
+	})
+	group.Go(func() error {
+		defer func() {
+			cancel()
+			server.Stop()
+		}()
+		signalChan := make(chan os.Signal, 1)
+		signal.Notify(signalChan, syscall.SIGINT, syscall.SIGTERM)
+		select {
+		case <-signalChan:
+			log.Println("shutdown received")
+			return nil
+		case <-ctx.Done():
+			return nil
+		}
+	})
+	return group.Wait()
 }

go.mod

@@ -3,9 +3,11 @@ module github.com/tomcz/openldap_exporter
 go 1.16
 
 require (
-	github.com/hashicorp/go-multierror v1.0.0
-	github.com/prometheus/client_golang v1.2.1
+	github.com/go-kit/kit v0.10.0
+	github.com/prometheus/client_golang v1.7.1
+	github.com/prometheus/exporter-toolkit v0.5.1
 	github.com/urfave/cli/v2 v2.2.0
+	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e
 	gopkg.in/asn1-ber.v1 v1.0.0-20181015200546-f715ec2f112d // indirect
 	gopkg.in/ldap.v2 v2.5.1
 )

go.sum

@@ -1,13 +1,13 @@
 package openldap_exporter
 
 import (
+	"context"
 	"fmt"
 	"log"
 	"strconv"
 	"strings"
 	"time"
 
-	"github.com/hashicorp/go-multierror"
 	"github.com/prometheus/client_golang/prometheus"
 	"gopkg.in/ldap.v2"
 )
@@ -113,39 +113,47 @@ type Scraper struct {
 	Tick time.Duration
 }
 
-func (s *Scraper) Start() {
-	for range time.Tick(s.Tick) {
-		s.runOnce()
+func (s *Scraper) Start(ctx context.Context) error {
+	ticker := time.NewTicker(s.Tick)
+	for {
+		select {
+		case <-ticker.C:
+			s.runOnce()
+		case <-ctx.Done():
+			return nil
+		}
 	}
 }
 
 func (s *Scraper) runOnce() {
-	if err := s.scrape(); err != nil {
-		scrapeCounter.WithLabelValues("fail").Inc()
-		log.Println("scrape failed, error is:", err)
-	} else {
+	if s.scrape() {
 		scrapeCounter.WithLabelValues("ok").Inc()
+	} else {
+		scrapeCounter.WithLabelValues("fail").Inc()
 	}
 }
 
-func (s *Scraper) scrape() error {
+func (s *Scraper) scrape() bool {
 	l, err := ldap.Dial(s.Net, s.Addr)
 	if err != nil {
-		return fmt.Errorf("dial failed: %w", err)
+		log.Printf("dial failed: %v\n", err)
+		return false
 	}
 	defer l.Close()
 
 	if s.User != "" && s.Pass != "" {
 		err = l.Bind(s.User, s.Pass)
 		if err != nil {
-			return fmt.Errorf("bind failed: %w", err)
+			log.Printf("bind failed: %v\n", err)
+			return false
 		}
 	}
 
-	var ret error
+	ret := true
 	for _, q := range queries {
 		if err := scrapeQuery(l, q); err != nil {
-			ret = multierror.Append(ret, err)
+			log.Println(err.Error())
+			ret = false
 		}
 	}
 	return ret

scraper.go

@@ -1,11 +1,17 @@
 package openldap_exporter
 
 import (
+	"context"
+	"errors"
 	"fmt"
 	"log"
 	"net/http"
+	"strings"
+	"time"
 
+	kitlog "github.com/go-kit/kit/log"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"github.com/prometheus/exporter-toolkit/web"
 )
 
 var commit string
@@ -15,14 +21,32 @@ func GetVersion() string {
 	return fmt.Sprintf("%s (%s)", tag, commit)
 }
 
-func StartMetricsServer(bindAddr, metricsPath string) {
+type Server struct {
+	server  *http.Server
+	cfgPath string
+}
+
+func (s *Server) Start() error {
+	err := web.ListenAndServe(s.server, s.cfgPath, kitlog.LoggerFunc(logger))
+	if errors.Is(err, http.ErrServerClosed) {
+		return nil
+	}
+	return err
+}
+
+func (s *Server) Stop() {
+	ctx, cancel := context.WithTimeout(context.Background(), 100*time.Millisecond)
+	s.server.Shutdown(ctx)
+	cancel()
+}
+
+func NewMetricsServer(bindAddr, metricsPath, tlsConfigPath string) *Server {
 	mux := http.NewServeMux()
 	mux.Handle(metricsPath, promhttp.Handler())
 	mux.HandleFunc("/version", showVersion)
-
-	err := http.ListenAndServe(bindAddr, mux)
-	if err != nil {
-		log.Fatalln("http listener failed, error is:", err)
+	return &Server{
+		server:  &http.Server{Addr: bindAddr, Handler: mux},
+		cfgPath: tlsConfigPath,
 	}
 }
 
@@ -34,3 +58,21 @@ func showVersion(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 	fmt.Fprintln(w, GetVersion())
 }
+
+func logger(kvs ...interface{}) error {
+	if len(kvs) == 0 {
+		return nil
+	}
+	if len(kvs)%2 != 0 {
+		kvs = append(kvs, nil)
+	}
+	var buf strings.Builder
+	for i := 0; i < len(kvs); i += 2 {
+		if i > 0 {
+			buf.WriteString(" ")
+		}
+		fmt.Fprintf(&buf, "%v=%v", kvs[i], kvs[i+1])
+	}
+	log.Println(buf.String())
+	return nil
+}