use AddError everywhere (#2372)

plugins/inputs/cloudwatch/cloudwatch.go

@@ -13,7 +13,6 @@ import (
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal"
 	internalaws "github.com/influxdata/telegraf/internal/config/aws"
-	"github.com/influxdata/telegraf/internal/errchan"
 	"github.com/influxdata/telegraf/internal/limiter"
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
@@ -186,8 +185,6 @@ func (c *CloudWatch) Gather(acc telegraf.Accumulator) error {
 	if err != nil {
 		return err
 	}
-	metricCount := len(metrics)
-	errChan := errchan.New(metricCount)
 
 	now := time.Now()
 
@@ -202,12 +199,12 @@ func (c *CloudWatch) Gather(acc telegraf.Accumulator) error {
 		<-lmtr.C
 		go func(inm *cloudwatch.Metric) {
 			defer wg.Done()
-			c.gatherMetric(acc, inm, now, errChan.C)
+			acc.AddError(c.gatherMetric(acc, inm, now))
 		}(m)
 	}
 	wg.Wait()
 
-	return errChan.Error()
+	return nil
 }
 
 func init() {
@@ -285,13 +282,11 @@ func (c *CloudWatch) gatherMetric(
 	acc telegraf.Accumulator,
 	metric *cloudwatch.Metric,
 	now time.Time,
-	errChan chan error,
-) {
+) error {
 	params := c.getStatisticsInput(metric, now)
 	resp, err := c.client.GetMetricStatistics(params)
 	if err != nil {
-		errChan <- err
-		return
+		return err
 	}
 
 	for _, point := range resp.Datapoints {
@@ -326,7 +321,7 @@ func (c *CloudWatch) gatherMetric(
 		acc.AddFields(formatMeasurement(c.Namespace), fields, tags, *point.Timestamp)
 	}
 
-	errChan <- nil
+	return nil
 }
 
 /*