Only print final collection when runing --test (#4991)

agent/agent.go

@@ -138,11 +138,13 @@ func (a *Agent) Run(ctx context.Context) error {
 }
 
 // Test runs the inputs once and prints the output to stdout in line protocol.
-func (a *Agent) Test() error {
+func (a *Agent) Test(ctx context.Context) error {
 	var wg sync.WaitGroup
 	metricC := make(chan telegraf.Metric)
+	nulC := make(chan telegraf.Metric)
 	defer func() {
 		close(metricC)
+		close(nulC)
 		wg.Wait()
 	}()
 
@@ -156,11 +158,23 @@ func (a *Agent) Test() error {
 			octets, err := s.Serialize(metric)
 			if err == nil {
 				fmt.Print("> ", string(octets))
+
 			}
 		}
 	}()
 
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		for range nulC {
+		}
+	}()
+
 	for _, input := range a.Config.Inputs {
+		select {
+		case <-ctx.Done():
+			return nil
+		default:
 			if _, ok := input.Input.(telegraf.ServiceInput); ok {
 				log.Printf("W!: [agent] skipping plugin [[%s]]: service inputs not supported in --test mode",
 					input.Name())
@@ -172,20 +186,27 @@ func (a *Agent) Test() error {
 				a.Config.Agent.Interval.Duration)
 			input.SetDefaultTags(a.Config.Tags)
 
-		if err := input.Input.Gather(acc); err != nil {
-			return err
-		}
-
 			// Special instructions for some inputs. cpu, for example, needs to be
 			// run twice in order to return cpu usage percentages.
 			switch input.Name() {
 			case "inputs.cpu", "inputs.mongodb", "inputs.procstat":
+				nulAcc := NewAccumulator(input, nulC)
+				nulAcc.SetPrecision(a.Config.Agent.Precision.Duration,
+					a.Config.Agent.Interval.Duration)
+				if err := input.Input.Gather(nulAcc); err != nil {
+					return err
+				}
+
 				time.Sleep(500 * time.Millisecond)
 				if err := input.Input.Gather(acc); err != nil {
 					return err
 				}
+			default:
+				if err := input.Input.Gather(acc); err != nil {
+					return err
+				}
+			}
 		}
-
 	}
 
 	return nil

cmd/telegraf/telegraf.go

@@ -83,7 +83,8 @@ func reloadLoop(
 		ctx, cancel := context.WithCancel(context.Background())
 
 		signals := make(chan os.Signal)
-		signal.Notify(signals, os.Interrupt, syscall.SIGHUP, syscall.SIGTERM)
+		signal.Notify(signals, os.Interrupt, syscall.SIGHUP,
+			syscall.SIGTERM, syscall.SIGINT)
 		go func() {
 			select {
 			case sig := <-signals:
@@ -154,7 +155,7 @@ func runAgent(ctx context.Context,
 	)
 
 	if *fTest {
-		return ag.Test()
+		return ag.Test(ctx)
 	}
 
 	log.Printf("I! Starting Telegraf %s\n", version)