Add status logging for checks

Signed-off-by: Knut Ahlers <knut@ahlers.me>

cert.go

@@ -7,6 +7,8 @@ import (
 	"net/url"
 	"strings"
 	"time"
+
+	log "github.com/sirupsen/logrus"
 )
 
 type probeResult uint
@@ -37,6 +39,8 @@ func (p probeResult) String() string {
 }
 
 func checkCertificate(probeURL *url.URL) (probeResult, *x509.Certificate) {
+	checkLogger := log.WithFields(log.Fields{"probe_url": probeURL})
+
 	req, _ := http.NewRequest("HEAD", probeURL.String(), nil)
 	req.Header.Set("User-Agent", fmt.Sprintf("Mozilla/5.0 (compatible; PromCertcheck/%s; +https://github.com/Luzifer/promcertcheck)", version))
 
@@ -44,6 +48,7 @@ func checkCertificate(probeURL *url.URL) (probeResult, *x509.Certificate) {
 	switch err.(type) {
 	case nil, redirectFoundError:
 	default:
+		checkLogger.WithError(err).Error("HTTP request failed")
 		if !strings.Contains(err.Error(), "Found a redirect.") {
 			return generalFailure, nil
 		}
@@ -67,6 +72,7 @@ func checkCertificate(probeURL *url.URL) (probeResult, *x509.Certificate) {
 	}
 
 	if verifyCert == nil {
+		checkLogger.Debug("Certificate not found")
 		return certificateNotFound, nil
 	}
 
@@ -78,12 +84,15 @@ func checkCertificate(probeURL *url.URL) (probeResult, *x509.Certificate) {
 	}
 
 	if !verificationResult {
+		checkLogger.Debug("Certificate invalid")
 		return certificateInvalid, verifyCert
 	}
 
 	if verifyCert.NotAfter.Sub(time.Now()) < config.ExpireWarning {
+		checkLogger.Debug("Certificate expires soon")
 		return certificateExpiresSoon, verifyCert
 	}
 
+	checkLogger.Debug("Certificate OK")
 	return certificateOK, verifyCert
 }

http.go

@@ -4,10 +4,10 @@ package main
 
 import (
 	"encoding/json"
-	"log"
 	"net/http"
 
 	"github.com/flosch/pongo2"
+	log "github.com/sirupsen/logrus"
 )
 
 func htmlHandler(res http.ResponseWriter, r *http.Request) {

main.go

@@ -3,7 +3,6 @@ package main // import "github.com/Luzifer/promcertcheck"
 import (
 	"crypto/x509"
 	"fmt"
-	"log"
 	"net/http"
 	"net/url"
 	"strings"
@@ -13,12 +12,14 @@ import (
 	"github.com/gorilla/mux"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/robfig/cron"
+	log "github.com/sirupsen/logrus"
 )
 
 var (
 	config = struct {
 		Debug         bool          `flag:"debug" default:"false" description:"Output debugging data"`
 		ExpireWarning time.Duration `flag:"expire-warning" default:"744h" description:"When to warn about a soon expiring certificate"`
+		LogLevel      string        `flag:"log-level" default:"info" description:"Verbosity of logs to use (debug, info, warning, error, ...)"`
 		Probes        []string      `flag:"probe" default:"" description:"URLs to check for certificate issues"`
 	}{}
 	version       = "dev"
@@ -42,6 +43,12 @@ func init() {
 	if err := rconfig.Parse(&config); err != nil {
 		log.Fatalf("Unable to parse CLI parameters: %s", err)
 	}
+
+	if logLevel, err := log.ParseLevel(config.LogLevel); err == nil {
+		log.SetLevel(logLevel)
+	} else {
+		log.Fatalf("Unable to parse log level: %s", err)
+	}
 }
 
 func main() {