[#1154] node: Add info metric

Signed-off-by: Alexander Chuprov <a.chuprov@yadro.com>

internal/metrics/application.go

@@ -0,0 +1,21 @@
+package metrics
+
+import (
+	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type ApplicationInfo struct {
+	versionValue *prometheus.GaugeVec
+}
+
+func NewApplicationInfo(version string) *ApplicationInfo {
+	appInfo := &ApplicationInfo{
+		versionValue: metrics.NewGaugeVec(prometheus.GaugeOpts{
+			Name: "app_info",
+			Help: "General information about the application.",
+		}, []string{"version"}),
+	}
+	appInfo.versionValue.With(prometheus.Labels{"version": version})
+	return appInfo
+}

internal/metrics/node.go

@@ -1,6 +1,7 @@
 package metrics
 
 import (
+	"git.frostfs.info/TrueCloudLab/frostfs-node/misc"
 	morphmetrics "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/morph/metrics"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/logger"
 	"git.frostfs.info/TrueCloudLab/frostfs-observability/metrics"
@@ -24,6 +25,7 @@ type NodeMetrics struct {
 	morphClient   *morphClientMetrics
 	morphCache    *morphCacheMetrics
 	log           logger.LogMetrics
+	appInfo       *ApplicationInfo
 }
 
 func NewNodeMetrics() *NodeMetrics {
@@ -49,6 +51,7 @@ func NewNodeMetrics() *NodeMetrics {
 		morphClient:  newMorphClientMetrics(),
 		morphCache:   newMorphCacheMetrics(namespace),
 		log:          logger.NewLogMetrics(namespace),
+		appInfo:      NewApplicationInfo(misc.Version),
 	}
 }