PMM-11137 fetch version from buildInfo (#604)

Author: YaroslavPodorvanov

exporter/diagnostic_data_collector_test.go

@@ -292,7 +292,7 @@ func TestDisconnectedDiagnosticDataCollector(t *testing.T) {
 	mongodb_mongod_storage_engine{engine="Engine is unavailable"} 1
 	# HELP mongodb_version_info The server version
 	# TYPE mongodb_version_info gauge
-	mongodb_version_info{edition="",mongodb="server version is unavailable",vendor=""} 1` + "\n")
+	mongodb_version_info{edition="",mongodb="",vendor=""} 1` + "\n")
 	// Filter metrics for 2 reasons:
 	// 1. The result is huge
 	// 2. We need to check against know values. Don't use metrics that return counters like uptime

exporter/v1_compatibility.go

@@ -799,7 +799,7 @@ func specialMetrics(ctx context.Context, client *mongo.Client, m bson.M, l *logr
 	}
 
 	metrics = append(metrics, storageEngine(m))
-	metrics = append(metrics, serverVersion(m, buildInfo))
+	metrics = append(metrics, serverVersion(buildInfo))
 	metrics = append(metrics, myState(ctx, client))
 
 	if mm := replSetMetrics(m); mm != nil {
@@ -825,7 +825,6 @@ func retrieveMongoDBBuildInfo(ctx context.Context, client *mongo.Client, l *logr
 		return buildInfo{}, errors.Wrap(err, "Failed to run buildInfo command")
 	}
 
-	var edition string
 	modules, ok := buildInfoDoc["modules"].(bson.A)
 	if !ok {
 		return buildInfo{}, errors.Wrap(err, "Failed to cast module information variable")
@@ -837,7 +836,7 @@ func retrieveMongoDBBuildInfo(ctx context.Context, client *mongo.Client, l *logr
 	} else {
 		bi.Edition = CommunityEdition
 	}
-	l.Debug("MongoDB edition: ", edition)
+	l.Debug("MongoDB edition: ", bi.Edition)
 
 	_, ok = buildInfoDoc["psmdbVersion"]
 	if ok {
@@ -846,6 +845,11 @@ func retrieveMongoDBBuildInfo(ctx context.Context, client *mongo.Client, l *logr
 		bi.Vendor = MongoDBVendor
 	}
 
+	bi.Version, ok = buildInfoDoc["version"].(string)
+	if !ok {
+		return buildInfo{}, errors.Wrap(err, "Failed to cast version information variable")
+	}
+
 	return bi, nil
 }
 
@@ -866,16 +870,11 @@ func storageEngine(m bson.M) prometheus.Metric {
 	return metric
 }
 
-func serverVersion(m bson.M, bi buildInfo) prometheus.Metric { //nolint:ireturn
-	v := walkTo(m, []string{"serverStatus", "version"})
+func serverVersion(bi buildInfo) prometheus.Metric { //nolint:ireturn
 	name := "mongodb_version_info"
 	help := "The server version"
 
-	serverVersion, ok := v.(string)
-	if !ok {
-		serverVersion = "server version is unavailable"
-	}
-	labels := map[string]string{"mongodb": serverVersion, "edition": bi.Edition, "vendor": bi.Vendor}
+	labels := map[string]string{"mongodb": bi.Version, "edition": bi.Edition, "vendor": bi.Vendor}
 
 	d := prometheus.NewDesc(name, help, nil, labels)
 	metric, _ := prometheus.NewConstMetric(d, prometheus.GaugeValue, float64(1))
@@ -1354,6 +1353,7 @@ type rawStatus struct {
 }
 
 type buildInfo struct {
+	Version string
 	Edition string
 	Vendor  string
 }