refactor(inputs.diskio): Differentiate guage and counter from counter.(…

…#15950)

plugins/inputs/diskio/diskio.go

@@ -127,15 +127,16 @@ func (d *DiskIO) Gather(acc telegraf.Accumulator) error {
 			"write_time":       io.WriteTime,
 			"io_time":          io.IoTime,
 			"weighted_io_time": io.WeightedIO,
-			"iops_in_progress": io.IopsInProgress,
 			"merged_reads":     io.MergedReadCount,
 			"merged_writes":    io.MergedWriteCount,
 		}
+		fieldsG := map[string]interface{}{
+			"iops_in_progress": io.IopsInProgress,
+		}
 		if lastValue, exists := d.lastIOCounterStat[k]; exists {
 			deltaRWCount := float64(io.ReadCount + io.WriteCount - lastValue.ReadCount - lastValue.WriteCount)
 			deltaRWTime := float64(io.ReadTime + io.WriteTime - lastValue.ReadTime - lastValue.WriteTime)
 			deltaIOTime := float64(io.IoTime - lastValue.IoTime)
-			fieldsG := make(map[string]interface{})
 			if deltaRWCount > 0 {
 				fieldsG["io_await"] = deltaRWTime / deltaRWCount
 				fieldsG["io_svctm"] = deltaIOTime / deltaRWCount
@@ -144,10 +145,8 @@ func (d *DiskIO) Gather(acc telegraf.Accumulator) error {
 			if itv > 0 {
 				fieldsG["io_util"] = 100 * deltaIOTime / itv
 			}
-			if len(fieldsG) > 0 {
-				acc.AddGauge("diskio", fieldsG, tags)
-			}
 		}
+		acc.AddGauge("diskio", fieldsG, tags)
 		acc.AddCounter("diskio", fieldsC, tags)
 	}
 	d.lastCollectTime = collectTime