Add Dockerfile

.woodpecker.yml

@@ -0,0 +1,10 @@
+steps:
+  build:
+    image: "golang:1.21.5-alpine"
+    commands:
+      - go build main.go
+  lint:
+    image: "golang:1.21.5-alpine"
+    commands:
+      - go fmt ./main.go
+      - go vet ./main.go

Dockerfile

@@ -0,0 +1,9 @@
+FROM golang@sha256:fe5bea2e1ab3ffebe0267393fea88fcb197e2dbbb1e2dbabeec6dd9ccb0e1871 AS builder
+
+COPY . /build
+WORKDIR /build
+RUN go build -o cert-exporter main.go
+
+FROM alpine@sha256:beefdbd8a1da6d2915566fde36db9db0b524eb737fc57cd1367effd16dc0d06d
+COPY --from=builder /build/cert-exporter /opt/cert-exporter
+ENTRYPOINT ["/opt/cert-exporter"]

README.md

@@ -1,4 +1,23 @@
-# certs-status-exporter
+# cert-status-exporter
 
 A Prometheus exporter that checks the expiry and validity of configured domains
-once a day.
+once a day.
+
+## Usage
+
+To export certificate status metrics, run `cert-status-exporter --domain <domain>:<port>:<alpn>[:<name>]`.
+The format means: "Connect to `<domain>` on port `<port>` while advertising `<alpn>` as ALPN during the
+TLS negotiations. If `<name>` is specified, then the metric will be labeled as `<name>`, instead of `<domain>`.
+`<alpn>` is a semi-colon separated list of ALPN protocols.
+
+By default, `cert-status-exporter` will bind to `0.0.0.0:8888` and expose the metrics at `0.0.0.0:8888/metrics`. To change
+the binding address, you can specify `--host` and `--port` to change how `cert-status-exporter` binds the socket.
+
+### Example
+
+- `cert-status-exporter --host 127.0.0.1 --port 8383 --domain "gnu.org:443:http/1.1;http/1.0;http/0.9"`: Check the certificate of `gnu.org:443`, while presenting the HTTP ALPN protocol names during the TLS negotiation. The metrics are exported with the label `name` equal to `gnu.org`.
+- `cert-status-exporter --domain "example.org:5223:xmpp-client:xmpp"`: Check the certificate of `example.org:5223`, while presenting `xmpp-client` as the  ALPN protocol during the TLS negotiation. Moreover, export the certificate state with the label `name` equal to `xmpp`.
+
+## License
+
+See `LICENSE`.

main.go

@@ -28,7 +28,7 @@ type CertificateMetrics struct {
 	IsValid  prometheus.Gauge
 }
 
-func NewCertificateMetrics(domain string, port int, alpn []string) CertificateMetrics {
+func NewCertificateMetrics(domain string, port int, alpn []string, name string) CertificateMetrics {
 	metrics := CertificateMetrics{
 		Domain: domain,
 		Port:   port,
@@ -36,13 +36,13 @@ func NewCertificateMetrics(domain string, port int, alpn []string) CertificateMe
 		ExpiryIn: prometheus.NewGauge(
 			prometheus.GaugeOpts{
 				Name:        "cert_status_expiry_in",
-				ConstLabels: prometheus.Labels{"domain": domain},
+				ConstLabels: prometheus.Labels{"name": name},
 			},
 		),
 		IsValid: prometheus.NewGauge(
 			prometheus.GaugeOpts{
 				Name:        "cert_status_is_valid",
-				ConstLabels: prometheus.Labels{"domain": domain},
+				ConstLabels: prometheus.Labels{"name": name},
 			},
 		),
 	}
@@ -88,8 +88,9 @@ func (c *CertificateMetrics) checkTls() {
 	}
 }
 
-func updateMetrics(metrics *[]CertificateMetrics) {
+func updateMetrics(metrics *[]CertificateMetrics, lastUpdated prometheus.Gauge) {
 	log.Debugf("Updating metrics for %d domains...", len(*metrics))
+	lastUpdated.SetToCurrentTime()
 	for _, metric := range *metrics {
 		metric.checkTls()
 	}
@@ -108,15 +109,29 @@ func run(ctx *cli.Context) error {
 
 	// Setup metrics
 	registry := prometheus.NewRegistry()
+	lastUpdatedMetric := prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Name: "certs_status_last_updated",
+		},
+	)
+	registry.MustRegister(lastUpdatedMetric)
+
 	metrics := make([]CertificateMetrics, 0)
 	for _, d := range domains {
 		log.Debugf("Parsing '%s'...", d)
 		parts := strings.Split(d, ":")
-		if len(parts) != 3 {
+		if len(parts) < 3 {
 			log.Errorf("Invalid domain format for '%s'", d)
 			return errors.New("Invalid domain format: Expects <domain>:<port>:<alpn>")
 		}
 
+		name := ""
+		if len(parts) == 4 {
+			name = parts[3]
+		} else {
+			name = parts[0]
+		}
+
 		port, err := strconv.Atoi(parts[1])
 		if err != nil {
 			log.Errorf("Failed to parse port of '%s'", d)
@@ -126,11 +141,12 @@ func run(ctx *cli.Context) error {
 		// Create the metric, and register it
 		// TODO: Make this prettier
 		alpn := strings.Split(parts[2], ";")
-		log.Debugf("Using ALPNs: %v", alpn)
+		log.Debugf("Registering: domain='%s' port='%d' alpn=%v name='%s'", parts[0], port, alpn, name)
 		metric := NewCertificateMetrics(
 			parts[0],
 			port,
 			alpn,
+			name,
 		)
 		metric.register(registry)
 		metrics = append(metrics, metric)
@@ -147,20 +163,20 @@ func run(ctx *cli.Context) error {
 		gocron.DurationJob(24*time.Hour),
 		gocron.NewTask(
 			func() {
-				updateMetrics(&metrics)
+				updateMetrics(&metrics, lastUpdatedMetric)
 			},
 		),
+		gocron.WithStartAt(gocron.WithStartImmediately()),
 	)
 	if err != nil {
 		log.Error("Failed to create periodic task")
 		return err
 	}
 
-	// Perform an initial run to populate the metrics
+	// Start the scheduler
-	log.Info("Performing initial requests...")
+	scheduler.Start()
-	updateMetrics(&metrics)
-	log.Debug("Done")
 
+	// Handle HTTP requests
 	http.Handle(
 		"/metrics", promhttp.HandlerFor(
 			registry,