use AddError everywhere (#2372)

plugins/inputs/graylog/graylog.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"encoding/base64"
 	"encoding/json"
-	"errors"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -149,31 +148,17 @@ func (h *GrayLog) Gather(acc telegraf.Accumulator) error {
 		h.client.SetHTTPClient(client)
 	}
 
-	errorChannel := make(chan error, len(h.Servers))
-
 	for _, server := range h.Servers {
 		wg.Add(1)
 		go func(server string) {
 			defer wg.Done()
-			if err := h.gatherServer(acc, server); err != nil {
-				errorChannel <- err
-			}
+			acc.AddError(h.gatherServer(acc, server))
 		}(server)
 	}
 
 	wg.Wait()
-	close(errorChannel)
 
-	// Get all errors and return them as one giant error
-	errorStrings := []string{}
-	for err := range errorChannel {
-		errorStrings = append(errorStrings, err.Error())
-	}
-
-	if len(errorStrings) == 0 {
-		return nil
-	}
-	return errors.New(strings.Join(errorStrings, "\n"))
+	return nil
 }
 
 // Gathers data from a particular server

plugins/inputs/graylog/graylog_test.go

@@ -157,7 +157,7 @@ func TestNormalResponse(t *testing.T) {
 
 	for _, service := range graylog {
 		var acc testutil.Accumulator
-		err := service.Gather(&acc)
+		err := acc.GatherError(service.Gather)
 		require.NoError(t, err)
 		for k, v := range expectedFields {
 			acc.AssertContainsTaggedFields(t, k, v, validTags[k])
@@ -170,9 +170,9 @@ func TestHttpJson500(t *testing.T) {
 	graylog := genMockGrayLog(validJSON, 500)
 
 	var acc testutil.Accumulator
-	err := graylog[0].Gather(&acc)
+	err := acc.GatherError(graylog[0].Gather)
 
-	assert.NotNil(t, err)
+	assert.Error(t, err)
 	assert.Equal(t, 0, acc.NFields())
 }
 
@@ -181,9 +181,9 @@ func TestHttpJsonBadJson(t *testing.T) {
 	graylog := genMockGrayLog(invalidJSON, 200)
 
 	var acc testutil.Accumulator
-	err := graylog[0].Gather(&acc)
+	err := acc.GatherError(graylog[0].Gather)
 
-	assert.NotNil(t, err)
+	assert.Error(t, err)
 	assert.Equal(t, 0, acc.NFields())
 }
 
@@ -192,8 +192,8 @@ func TestHttpJsonEmptyResponse(t *testing.T) {
 	graylog := genMockGrayLog(empty, 200)
 
 	var acc testutil.Accumulator
-	err := graylog[0].Gather(&acc)
+	err := acc.GatherError(graylog[0].Gather)
 
-	assert.NotNil(t, err)
+	assert.Error(t, err)
 	assert.Equal(t, 0, acc.NFields())
 }