Fix logger initialization in exec input (#6492)

internal/config/config_test.go

@@ -158,6 +158,11 @@ func TestConfig_LoadDirectory(t *testing.T) {
 		MeasurementSuffix: "_myothercollector",
 	}
 	eConfig.Tags = make(map[string]string)
+
+	exec := c.Inputs[1].Input.(*exec.Exec)
+	require.NotNil(t, exec.Log)
+	exec.Log = nil
+
 	assert.Equal(t, ex, c.Inputs[1].Input,
 		"Merged Testdata did not produce a correct exec struct.")
 	assert.Equal(t, eConfig, c.Inputs[1].Config,

plugins/inputs/exec/exec.go

@@ -10,13 +10,12 @@ import (
 	"sync"
 	"time"
 
-	"github.com/kballard/go-shellquote"
-
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/plugins/inputs"
 	"github.com/influxdata/telegraf/plugins/parsers"
 	"github.com/influxdata/telegraf/plugins/parsers/nagios"
+	"github.com/kballard/go-shellquote"
 )
 
 const sampleConfig = `
@@ -50,7 +49,7 @@ type Exec struct {
 	parser parsers.Parser
 
 	runner Runner
-	log    telegraf.Logger
+	Log    telegraf.Logger `toml:"-"`
 }
 
 func NewExec() *Exec {
@@ -161,7 +160,7 @@ func (e *Exec) ProcessCommand(command string, acc telegraf.Accumulator, wg *sync
 	if isNagios {
 		metrics, err = nagios.TryAddState(runErr, metrics)
 		if err != nil {
-			e.log.Errorf("Failed to add nagios state: %s", err)
+			e.Log.Errorf("Failed to add nagios state: %s", err)
 		}
 	}
 

plugins/inputs/exec/exec_test.go

@@ -96,7 +96,7 @@ func TestExec(t *testing.T) {
 		MetricName: "exec",
 	})
 	e := &Exec{
-		log:      testutil.Logger{},
+		Log:      testutil.Logger{},
 		runner:   newRunnerMock([]byte(validJson), nil, nil),
 		Commands: []string{"testcommand arg1"},
 		parser:   parser,
@@ -126,7 +126,7 @@ func TestExecMalformed(t *testing.T) {
 		MetricName: "exec",
 	})
 	e := &Exec{
-		log:      testutil.Logger{},
+		Log:      testutil.Logger{},
 		runner:   newRunnerMock([]byte(malformedJson), nil, nil),
 		Commands: []string{"badcommand arg1"},
 		parser:   parser,
@@ -143,7 +143,7 @@ func TestCommandError(t *testing.T) {
 		MetricName: "exec",
 	})
 	e := &Exec{
-		log:      testutil.Logger{},
+		Log:      testutil.Logger{},
 		runner:   newRunnerMock(nil, nil, fmt.Errorf("exit status code 1")),
 		Commands: []string{"badcommand"},
 		parser:   parser,