mssql: add counter based on server version (#1799)

Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/collector/mssql/mssql_instance.go

@@ -0,0 +1,52 @@
+// Copyright 2024 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build windows
+
+package mssql
+
+import (
+	"github.com/prometheus-community/windows_exporter/internal/types"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+type collectorInstance struct {
+	instances *prometheus.GaugeVec
+}
+
+func (c *Collector) buildInstance() error {
+	c.instances = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: types.Namespace,
+			Subsystem: Name,
+			Name:      "instance_info",
+			Help:      "A metric with a constant '1' value labeled with mssql instance information",
+		},
+		[]string{"edition", "mssql_instance", "patch", "version"},
+	)
+
+	for _, instance := range c.mssqlInstances {
+		c.instances.WithLabelValues(instance.edition, instance.name, instance.patchVersion, instance.majorVersion.String()).Set(1)
+	}
+
+	return nil
+}
+
+func (c *Collector) collectInstance(ch chan<- prometheus.Metric) error {
+	c.instances.Collect(ch)
+
+	return nil
+}
+
+func (c *Collector) closeInstance() {
+}