added terminal services collector for number of session count

Fix versioning in binary

.promu.yml

@@ -4,11 +4,11 @@ build:
     binaries:
         - name: wmi_exporter
     ldflags: |
-        -X {{repoPath}}/vendor/github.com/prometheus/common/version.Version={{.Version}}
-        -X {{repoPath}}/vendor/github.com/prometheus/common/version.Revision={{.Revision}}
-        -X {{repoPath}}/vendor/github.com/prometheus/common/version.Branch={{.Branch}}
-        -X {{repoPath}}/vendor/github.com/prometheus/common/version.BuildUser={{user}}@{{host}}
-        -X {{repoPath}}/vendor/github.com/prometheus/common/version.BuildDate={{date "20060102-15:04:05"}}
+        -X github.com/prometheus/common/version.Version={{.Version}}
+        -X github.com/prometheus/common/version.Revision={{.Revision}}
+        -X github.com/prometheus/common/version.Branch={{.Branch}}
+        -X github.com/prometheus/common/version.BuildUser={{user}}@{{host}}
+        -X github.com/prometheus/common/version.BuildDate={{date "20060102-15:04:05"}}
 tarball:
     files:
         - LICENSE

collector/terminal_services.go

@@ -0,0 +1,84 @@
+// +build windows
+
+package collector
+
+import (
+	"errors"
+
+	"github.com/StackExchange/wmi"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/common/log"
+)
+
+func init() {
+	registerCollector("terminal_services", NewTerminalServicesCollector)
+}
+
+// A TerminalServicesCollector is a Prometheus collector for WMI
+// Win32_PerfRawData_LocalSessionManager_TerminalServices &  Win32_PerfRawData_TermService_TerminalServicesSession  metrics
+type TerminalServicesCollector struct {
+	Local_session_count *prometheus.Desc
+}
+
+// NewTerminalServicesCollector ...
+func NewTerminalServicesCollector() (Collector, error) {
+	const subsystem = "terminal_services"
+	return &TerminalServicesCollector{
+		Local_session_count: prometheus.NewDesc(
+			prometheus.BuildFQName(Namespace, subsystem, "local_session_count"),
+			"Number of Terminal Services sessions",
+			[]string{"session"},
+			nil,
+		),
+	}, nil
+}
+
+// Collect sends the metric values for each metric
+// to the provided prometheus Metric channel.
+func (c *TerminalServicesCollector) Collect(ctx *ScrapeContext, ch chan<- prometheus.Metric) error {
+	if desc, err := c.collectTSSessionCount(ch); err != nil {
+		log.Error("failed collecting terminal services session count metrics:", desc, err)
+		return err
+	}
+	return nil
+}
+
+type Win32_PerfRawData_LocalSessionManager_TerminalServices struct {
+	ActiveSessions   uint32
+	InactiveSessions uint32
+	TotalSessions    uint32
+}
+
+func (c *TerminalServicesCollector) collectTSSessionCount(ch chan<- prometheus.Metric) (*prometheus.Desc, error) {
+	var dst []Win32_PerfRawData_LocalSessionManager_TerminalServices
+	q := queryAll(&dst)
+	if err := wmi.Query(q, &dst); err != nil {
+		return nil, err
+	}
+	if len(dst) == 0 {
+		return nil, errors.New("WMI query returned empty result set")
+	}
+
+	ch <- prometheus.MustNewConstMetric(
+		c.Local_session_count,
+		prometheus.GaugeValue,
+		float64(dst[0].ActiveSessions),
+		"active",
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.Local_session_count,
+		prometheus.GaugeValue,
+		float64(dst[0].InactiveSessions),
+		"inactive",
+	)
+
+	ch <- prometheus.MustNewConstMetric(
+		c.Local_session_count,
+		prometheus.GaugeValue,
+		float64(dst[0].TotalSessions),
+		"total",
+	)
+
+	return nil, nil
+}