add version of restic to the Prometheus metrics (#495)

Add the restic version as a new metric `restic_build_info`.

This allows to track the versions of both restic
and resticprofile: PromQL can be used to identify
outdated installations.

refs #485

Author: antondollmaier

monitor/prom/metrics.go

@@ -22,13 +22,14 @@ const (
 )
 
 type Metrics struct {
-	labels   prometheus.Labels
-	registry *prometheus.Registry
-	info     *prometheus.GaugeVec
-	backup   BackupMetrics
+	labels     prometheus.Labels
+	registry   *prometheus.Registry
+	info       *prometheus.GaugeVec
+	resticInfo *prometheus.GaugeVec
+	backup     BackupMetrics
 }
 
-func NewMetrics(profile, group, version string, configLabels map[string]string) *Metrics {
+func NewMetrics(profile, group, version string, resticversion string, configLabels map[string]string) *Metrics {
 	// default labels for all metrics
 	labels := prometheus.Labels{profileLabel: profile}
 	if group != "" {
@@ -50,10 +51,18 @@ func NewMetrics(profile, group, version string, configLabels map[string]string)
 	// send the information about the build right away
 	p.info.With(mergeLabels(cloneLabels(labels), map[string]string{goVersionLabel: runtime.Version(), versionLabel: version})).Set(1)
 
+	p.resticInfo = prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Name:      "restic_build_info",
+		Help:      "restic build information.",
+	}, append(keys, versionLabel))
+	// send the information about the build right away
+	p.resticInfo.With(mergeLabels(cloneLabels(labels), map[string]string{versionLabel: resticversion})).Set(1)
+
 	p.backup = newBackupMetrics(keys)
 
 	registry.MustRegister(
 		p.info,
+		p.resticInfo,
 		p.backup.duration,
 		p.backup.filesNew,
 		p.backup.filesChanged,

monitor/prom/metrics_test.go

@@ -10,7 +10,7 @@ import (
 )
 
 func TestSaveSingleBackup(t *testing.T) {
-	p := NewMetrics("test", "", "", nil)
+	p := NewMetrics("test", "", "", "", nil)
 	p.BackupResults(StatusSuccess, monitor.Summary{
 		Duration:   11 * time.Second,
 		BytesAdded: 100,
@@ -21,7 +21,7 @@ func TestSaveSingleBackup(t *testing.T) {
 }
 
 func TestSaveSingleBackupWithConfigLabel(t *testing.T) {
-	p := NewMetrics("test", "", "", map[string]string{"test_label": "test_value"})
+	p := NewMetrics("test", "", "", "", map[string]string{"test_label": "test_value"})
 	p.BackupResults(StatusSuccess, monitor.Summary{
 		Duration:   11 * time.Second,
 		BytesAdded: 100,
@@ -32,7 +32,7 @@ func TestSaveSingleBackupWithConfigLabel(t *testing.T) {
 }
 
 func TestSaveBackupGroup(t *testing.T) {
-	p := NewMetrics("test", "group", "", nil)
+	p := NewMetrics("test", "group", "", "", nil)
 	p.BackupResults(StatusSuccess, monitor.Summary{
 		Duration:   11 * time.Second,
 		BytesAdded: 100,

run_profile.go

@@ -193,7 +193,7 @@ func runProfile(ctx *Context) error {
 		wrapper.addProgress(status.NewProgress(profile, status.NewStatus(profile.StatusFile)))
 	}
 	if profile.PrometheusPush != "" || profile.PrometheusSaveToFile != "" {
-		wrapper.addProgress(prom.NewProgress(profile, prom.NewMetrics(profile.Name, ctx.request.group, version, profile.PrometheusLabels)))
+		wrapper.addProgress(prom.NewProgress(profile, prom.NewMetrics(profile.Name, ctx.request.group, version, ctx.global.ResticVersion, profile.PrometheusLabels)))
 	}
 
 	err = wrapper.runProfile()