fix(inputs.vsphere): Eliminated duplicate samples

plugins/inputs/vsphere/README.md

@@ -11,8 +11,9 @@ vCenter servers.
 
 ## Supported versions of vSphere
 
-This plugin supports vSphere version 6.5, 6.7 and 7.0. It may work with versions
-5.1, 5.5 and 6.0, but neither are officially supported.
+This plugin supports vSphere version 6.5, 6.7, 7.0 and 8.0.
+It may work with versions 5.1, 5.5 and 6.0, but neither are
+officially supported.
 
 Compatibility information is available from the govmomi project
 [here](https://github.com/vmware/govmomi/tree/v0.26.0#compatibility)

plugins/inputs/vsphere/endpoint.go

@@ -257,7 +257,7 @@ func anythingEnabled(ex []string) bool {
 func newFilterOrPanic(include []string, exclude []string) filter.Filter {
 	f, err := filter.NewIncludeExcludeFilter(include, exclude)
 	if err != nil {
-		panic(fmt.Sprintf("Include/exclude filters are invalid: %s", err))
+		panic(fmt.Sprintf("Include/exclude filters are invalid: %v", err))
 	}
 	return f
 }
@@ -969,7 +969,10 @@ func (e *Endpoint) chunkify(ctx context.Context, res *resourceKind, now time.Tim
 			if !ok {
 				start = latest.Add(time.Duration(-res.sampling) * time.Second * (time.Duration(e.Parent.MetricLookback) - 1))
 			}
-			start = start.Truncate(20 * time.Second) // Truncate to maximum resolution
+
+			if !start.Truncate(time.Second).Before(now.Truncate(time.Second)) {
+				e.log.Debugf("Start >= end (rounded to seconds): %s > %s", start, now)
+			}
 
 			// Create bucket if we don't already have it
 			bucket, ok := timeBuckets[start.Unix()]
@@ -1243,7 +1246,8 @@ func (e *Endpoint) collectChunk(
 				count++
 
 				// Update hiwater marks
-				e.hwMarks.Put(moid, name, ts)
+				adjTs := ts.Add(interval).Truncate(interval).Add(-time.Second)
+				e.hwMarks.Put(moid, name, adjTs)
 			}
 			if nValues == 0 {
 				e.log.Debugf("Missing value for: %s, %s", name, objectRef.name)

plugins/inputs/vsphere/tscache.go

@@ -62,7 +62,10 @@ func (t *TSCache) Get(key string, metricName string) (time.Time, bool) {
 func (t *TSCache) Put(key string, metricName string, timestamp time.Time) {
 	t.mux.Lock()
 	defer t.mux.Unlock()
-	t.table[makeKey(key, metricName)] = timestamp
+	k := makeKey(key, metricName)
+	if timestamp.After(t.table[k]) {
+		t.table[k] = timestamp
+	}
 }
 
 func makeKey(resource string, metric string) string {