collector: publish documented counter types for udp and hyperv metrics (#2661)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Signed-off-by: Jan-Otto Kröpke <mail@jkroepke.de>

internal/collector/hyperv/hyperv_legacy_network_adapter.go

@@ -106,7 +106,7 @@ func (c *Collector) collectLegacyNetworkAdapter(ch chan<- prometheus.Metric) err
 	for _, data := range c.perfDataObjectLegacyNetworkAdapter {
 		ch <- prometheus.MustNewConstMetric(
 			c.legacyNetworkAdapterBytesDropped,
-			prometheus.GaugeValue,
+			prometheus.CounterValue,
 			data.LegacyNetworkAdapterBytesDropped,
 			data.Name,
 		)

internal/collector/hyperv/hyperv_test.go

@@ -75,6 +75,29 @@ func TestCollectorVirtualStorageDeviceLatency(t *testing.T) {
 	}
 }
 
+// TestCollectorLegacyNetworkAdapter checks that the legacy network adapter
+// metrics are published with the counter type documented in
+// docs/collector.hyperv.md; bytes_dropped_total used to be published as a
+// gauge. The CI fixture VM carries a legacy network adapter.
+func TestCollectorLegacyNetworkAdapter(t *testing.T) {
+	metrics := testutils.TestCollector(t, hyperv.New, &hyperv.Config{CollectorsEnabled: []string{"legacy_network_adapter"}})
+
+	for _, name := range []string{
+		"windows_hyperv_legacy_network_adapter_bytes_dropped_total",
+		"windows_hyperv_legacy_network_adapter_bytes_received_total",
+		"windows_hyperv_legacy_network_adapter_bytes_sent_total",
+		"windows_hyperv_legacy_network_adapter_frames_dropped_total",
+		"windows_hyperv_legacy_network_adapter_frames_received_total",
+		"windows_hyperv_legacy_network_adapter_frames_sent_total",
+	} {
+		testutils.RequireFixtureMetric(t, metrics, hyperv.Name, name, nil)
+
+		if family, ok := metrics[name]; ok {
+			require.Equal(t, dto.MetricType_COUNTER, family.GetType(), name)
+		}
+	}
+}
+
 // TestCloseReleasesQuery ensures Close releases the PDH queries of the sub-collectors.
 func TestCloseReleasesQuery(t *testing.T) {
 	t.Parallel()

internal/collector/udp/udp.go

@@ -171,7 +171,7 @@ func (c *Collector) writeUDPCounters(ch chan<- prometheus.Metric, metrics []perf
 
 	ch <- prometheus.MustNewConstMetric(
 		c.datagramsReceivedTotal,
-		prometheus.GaugeValue,
+		prometheus.CounterValue,
 		metrics[0].DatagramsReceivedPerSec,
 		af,
 	)

internal/collector/udp/udp_test.go

@@ -22,6 +22,8 @@ import (
 
 	"github.com/prometheus-community/windows_exporter/internal/collector/udp"
 	"github.com/prometheus-community/windows_exporter/internal/utils/testutils"
+	dto "github.com/prometheus/client_model/go"
+	"github.com/stretchr/testify/require"
 )
 
 func BenchmarkCollector(b *testing.B) {
@@ -29,5 +31,18 @@ func BenchmarkCollector(b *testing.B) {
 }
 
 func TestCollector(t *testing.T) {
-	testutils.TestCollector(t, udp.New, nil)
+	metrics := testutils.TestCollector(t, udp.New, nil)
+
+	// All four datagram totals are cumulative raw PDH values and documented as
+	// counters in docs/collector.udp.md; datagram_received_total used to be
+	// published as a gauge.
+	for _, name := range []string{
+		"windows_udp_datagram_no_port_total",
+		"windows_udp_datagram_received_errors_total",
+		"windows_udp_datagram_received_total",
+		"windows_udp_datagram_sent_total",
+	} {
+		require.Contains(t, metrics, name)
+		require.Equal(t, dto.MetricType_COUNTER, metrics[name].GetType(), name)
+	}
 }