feat: add metricscardinality to heartbeat

Signed-off-by: Alex Castilio dos Santos <[email protected]>

pkg/telemetry/telemetry.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/microsoft/ApplicationInsights-Go/appinsights"
 	"github.com/microsoft/ApplicationInsights-Go/appinsights/contracts"
+	"github.com/microsoft/retina/pkg/exporter"
 	"github.com/microsoft/retina/pkg/log"
 )
 
@@ -174,6 +175,17 @@ func (t *TelemetryClient) heartbeat(ctx context.Context) {
 	if err != nil {
 		t.trackWarning(err, "failed to get cpu usage")
 	}
+
+	metricFamilies, err := exporter.CombinedGatherer.Gather()
+	if err != nil {
+		t.trackWarning(err, "failed to get metrics cardinality")
+	}
+	metricscardinality := 0
+	for _, mf := range metricFamilies {
+		metricscardinality += len(mf.Metric)
+	}
+	props["metricscardinality"] = fmt.Sprintf("%d", metricscardinality)
+
 	maps.Copy(props, cpuProps)
 	maps.Copy(props, t.profile.GetMemoryUsage())
 	t.TrackEvent("heartbeat", props)