Added feature to allow metrics collection every X iterations in specified objects.

plugins/inputs/win_perf_counters/README.md

@@ -59,6 +59,13 @@ Example: `Counters = ["% Idle Time", "% Disk Read Time", "% Disk Write Time"]`
 This must be specified for every counter you want the results of,
 it is not possible to ask for all counters in the ObjectName.
 
+### GetMetricEvery
+*Optional*
+
+This parameter can be used where you only want to read an object on every X iteration, say every 10 iterations of whatever the interval is set for in Telegraf. If Telegraf fetches its data every 10s, it translates to only getting the data for this metric every 100s. Useful if the metric you are obtaining is expensive to get back.
+
+Example `GetMetricEvery = 10`
+
 ### Measurement
 *Optional*
 

plugins/inputs/win_perf_counters/win_perf_counters.go

@@ -87,6 +87,7 @@ type perfobject struct {
 	ObjectName     string
 	Counters       []string
 	Instances      []string
+	GetMetricEvery int
 	Measurement    string
 	WarnOnMissing  bool
 	FailOnMissing  bool
@@ -104,15 +105,20 @@ type item struct {
 	objectName     string
 	counter        string
 	instance       string
+	getmetricevery int
+	metriccounter  int
 	measurement    string
 	include_total  bool
 	handle         win.PDH_HQUERY
 	counterHandle  win.PDH_HCOUNTER
 }
 
-func (m *Win_PerfCounters) AddItem(metrics *itemList, query string, objectName string, counter string, instance string,
+func (m *Win_PerfCounters) AddItem(metrics *itemList, query string,
+	objectName string, counter string, instance string, getmetricevery int,
 	measurement string, include_total bool) {
 
+	var metriccounter int = 1
+
 	var handle win.PDH_HQUERY
 	var counterHandle win.PDH_HCOUNTER
 	ret := win.PdhOpenQuery(0, 0, &handle)
@@ -120,8 +126,9 @@ func (m *Win_PerfCounters) AddItem(metrics *itemList, query string, objectName s
 
 	_ = ret
 
-	temp := &item{query, objectName, counter, instance, measurement,
-		include_total, handle, counterHandle}
+	temp := &item{query, objectName, counter, instance, getmetricevery,
+		metriccounter, measurement, include_total, handle, counterHandle}
+
 	index := len(gItemList)
 	gItemList[index] = temp
 
@@ -190,6 +197,13 @@ func (m *Win_PerfCounters) ParseConfig(metrics *itemList) error {
 						query = "\\" + objectname + "(" + instance + ")\\" + counter
 					}
 
+					var getmetricevery int
+					if PerfObject.GetMetricEvery == 0 {
+						getmetricevery = 1
+					} else {
+						getmetricevery = PerfObject.GetMetricEvery
+					}
+
 					var exists uint32 = win.PdhValidatePath(query)
 
 					if exists == win.ERROR_SUCCESS {
@@ -197,7 +211,8 @@ func (m *Win_PerfCounters) ParseConfig(metrics *itemList) error {
 							fmt.Printf("Valid: %s\n", query)
 						}
 						m.AddItem(metrics, query, objectname, counter, instance,
-							PerfObject.Measurement, PerfObject.IncludeTotal)
+							getmetricevery, PerfObject.Measurement,
+							PerfObject.IncludeTotal)
 					} else {
 						err := m.InvalidObject(exists, query, PerfObject, instance, counter)
 						return err
@@ -271,6 +286,8 @@ func (m *Win_PerfCounters) Gather(acc telegraf.Accumulator) error {
 	// For iterate over the known metrics and get the samples.
 	for _, metric := range gItemList {
 		// collect
+		if metric.getmetricevery == metric.metriccounter {
+			metric.metriccounter = 1
 			ret := win.PdhCollectQueryData(metric.handle)
 			if ret == win.ERROR_SUCCESS {
 				ret = win.PdhGetFormattedCounterArrayDouble(metric.counterHandle, &bufSize,
@@ -323,7 +340,9 @@ func (m *Win_PerfCounters) Gather(acc telegraf.Accumulator) error {
 					bufCount = 0
 					bufSize = 0
 				}
-
+			}
+		} else {
+			metric.metriccounter++
 		}
 	}