fix panic on streaming processers using logging (#8176)

models/log.go

@@ -79,7 +79,7 @@ func logName(pluginType, name, alias string) string {
 	return pluginType + "." + name + "::" + alias
 }
 
-func setLoggerOnPlugin(i interface{}, log telegraf.Logger) {
+func SetLoggerOnPlugin(i interface{}, log telegraf.Logger) {
 	valI := reflect.ValueOf(i)
 
 	if valI.Type().Kind() != reflect.Ptr {
@@ -96,6 +96,9 @@ func setLoggerOnPlugin(i interface{}, log telegraf.Logger) {
 		if field.CanSet() {
 			field.Set(reflect.ValueOf(log))
 		}
+	default:
+		log.Debugf("Plugin %q defines a 'Log' field on its struct of an unexpected type %q. Expected telegraf.Logger",
+			valI.Type().Name(), field.Type().String())
 	}
 
 	return

models/running_aggregator.go

@@ -35,7 +35,7 @@ func NewRunningAggregator(aggregator telegraf.Aggregator, config *AggregatorConf
 		aggErrorsRegister.Incr(1)
 	})
 
-	setLoggerOnPlugin(aggregator, logger)
+	SetLoggerOnPlugin(aggregator, logger)
 
 	return &RunningAggregator{
 		Aggregator: aggregator,

models/running_input.go

@@ -35,7 +35,7 @@ func NewRunningInput(input telegraf.Input, config *InputConfig) *RunningInput {
 		inputErrorsRegister.Incr(1)
 		GlobalGatherErrors.Incr(1)
 	})
-	setLoggerOnPlugin(input, logger)
+	SetLoggerOnPlugin(input, logger)
 
 	return &RunningInput{
 		Input:  input,

models/running_output.go

@@ -72,7 +72,7 @@ func NewRunningOutput(
 	logger.OnErr(func() {
 		writeErrorsRegister.Incr(1)
 	})
-	setLoggerOnPlugin(output, logger)
+	SetLoggerOnPlugin(output, logger)
 
 	if config.MetricBufferLimit > 0 {
 		bufferLimit = config.MetricBufferLimit

models/running_processor.go

@@ -39,7 +39,7 @@ func NewRunningProcessor(processor telegraf.StreamingProcessor, config *Processo
 	logger.OnErr(func() {
 		processErrorsRegister.Incr(1)
 	})
-	setLoggerOnPlugin(processor, logger)
+	SetLoggerOnPlugin(processor, logger)
 
 	return &RunningProcessor{
 		Processor: processor,

models/running_processor_test.go

@@ -1,4 +1,4 @@
-package models
+package models_test
 
 import (
 	"sort"
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/models"
 	"github.com/influxdata/telegraf/plugins/processors"
 	"github.com/influxdata/telegraf/testutil"
 	"github.com/stretchr/testify/require"
@@ -52,7 +53,7 @@ func (p *MockProcessorToInit) Init() error {
 
 func TestRunningProcessor_Init(t *testing.T) {
 	mock := MockProcessorToInit{}
-	rp := &RunningProcessor{
+	rp := &models.RunningProcessor{
 		Processor: processors.NewStreamingProcessorFromProcessor(&mock),
 	}
 	rp.Init()
@@ -75,7 +76,7 @@ func TagProcessor(key, value string) *MockProcessor {
 func TestRunningProcessor_Apply(t *testing.T) {
 	type args struct {
 		Processor telegraf.StreamingProcessor
-		Config    *ProcessorConfig
+		Config    *models.ProcessorConfig
 	}
 
 	tests := []struct {
@@ -88,8 +89,8 @@ func TestRunningProcessor_Apply(t *testing.T) {
 			name: "inactive filter applies metrics",
 			args: args{
 				Processor: processors.NewStreamingProcessorFromProcessor(TagProcessor("apply", "true")),
-				Config: &ProcessorConfig{
-					Filter: Filter{},
+				Config: &models.ProcessorConfig{
+					Filter: models.Filter{},
 				},
 			},
 			input: []telegraf.Metric{
@@ -119,8 +120,8 @@ func TestRunningProcessor_Apply(t *testing.T) {
 			name: "filter applies",
 			args: args{
 				Processor: processors.NewStreamingProcessorFromProcessor(TagProcessor("apply", "true")),
-				Config: &ProcessorConfig{
-					Filter: Filter{
+				Config: &models.ProcessorConfig{
+					Filter: models.Filter{
 						NamePass: []string{"cpu"},
 					},
 				},
@@ -152,8 +153,8 @@ func TestRunningProcessor_Apply(t *testing.T) {
 			name: "filter doesn't apply",
 			args: args{
 				Processor: processors.NewStreamingProcessorFromProcessor(TagProcessor("apply", "true")),
-				Config: &ProcessorConfig{
-					Filter: Filter{
+				Config: &models.ProcessorConfig{
+					Filter: models.Filter{
 						NameDrop: []string{"cpu"},
 					},
 				},
@@ -183,7 +184,7 @@ func TestRunningProcessor_Apply(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			rp := &RunningProcessor{
+			rp := &models.RunningProcessor{
 				Processor: tt.args.Processor,
 				Config:    tt.args.Config,
 			}
@@ -204,25 +205,25 @@ func TestRunningProcessor_Apply(t *testing.T) {
 }
 
 func TestRunningProcessor_Order(t *testing.T) {
-	rp1 := &RunningProcessor{
-		Config: &ProcessorConfig{
+	rp1 := &models.RunningProcessor{
+		Config: &models.ProcessorConfig{
 			Order: 1,
 		},
 	}
-	rp2 := &RunningProcessor{
-		Config: &ProcessorConfig{
+	rp2 := &models.RunningProcessor{
+		Config: &models.ProcessorConfig{
 			Order: 2,
 		},
 	}
-	rp3 := &RunningProcessor{
-		Config: &ProcessorConfig{
+	rp3 := &models.RunningProcessor{
+		Config: &models.ProcessorConfig{
 			Order: 3,
 		},
 	}
 
-	procs := RunningProcessors{rp2, rp3, rp1}
+	procs := models.RunningProcessors{rp2, rp3, rp1}
 	sort.Sort(procs)
 	require.Equal(t,
-		RunningProcessors{rp1, rp2, rp3},
+		models.RunningProcessors{rp1, rp2, rp3},
 		procs)
 }

plugins/processors/streamingprocessor.go

@@ -2,6 +2,7 @@ package processors
 
 import (
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/models"
 )
 
 // NewStreamingProcessorFromProcessor is a converter that turns a standard
@@ -16,6 +17,7 @@ func NewStreamingProcessorFromProcessor(p telegraf.Processor) telegraf.Streaming
 type streamingProcessor struct {
 	processor telegraf.Processor
 	acc       telegraf.Accumulator
+	Log       telegraf.Logger
 }
 
 func (sp *streamingProcessor) SampleConfig() string {
@@ -46,6 +48,7 @@ func (sp *streamingProcessor) Stop() error {
 // to call the Init method of the wrapped processor if
 // needed
 func (sp *streamingProcessor) Init() error {
+	models.SetLoggerOnPlugin(sp.processor, sp.Log)
 	if p, ok := sp.processor.(telegraf.Initializer); ok {
 		err := p.Init()
 		if err != nil {