Support Processor & Aggregator Plugins

closes #1726

internal/models/filter.go

@@ -96,7 +96,7 @@ func (f *Filter) Compile() error {
 // Apply applies the filter to the given measurement name, fields map, and
 // tags map. It will return false if the metric should be "filtered out", and
 // true if the metric should "pass".
-// It will modify tags in-place if they need to be deleted.
+// It will modify tags & fields in-place if they need to be deleted.
 func (f *Filter) Apply(
 	measurement string,
 	fields map[string]interface{},

internal/models/makemetric.go

@@ -0,0 +1,150 @@
+package models
+
+import (
+	"log"
+	"math"
+	"time"
+
+	"github.com/influxdata/telegraf"
+)
+
+// makemetric is used by both RunningAggregator & RunningInput
+// to make metrics.
+//   nameOverride: override the name of the measurement being made.
+//   namePrefix:   add this prefix to each measurement name.
+//   nameSuffix:   add this suffix to each measurement name.
+//   pluginTags:   these are tags that are specific to this plugin.
+//   daemonTags:   these are daemon-wide global tags, and get applied after pluginTags.
+//   filter:       this is a filter to apply to each metric being made.
+//   applyFilter:  if false, the above filter is not applied to each metric.
+//                 This is used by Aggregators, because aggregators use filters
+//                 on incoming metrics instead of on created metrics.
+func makemetric(
+	measurement string,
+	fields map[string]interface{},
+	tags map[string]string,
+	nameOverride string,
+	namePrefix string,
+	nameSuffix string,
+	pluginTags map[string]string,
+	daemonTags map[string]string,
+	filter Filter,
+	applyFilter bool,
+	debug bool,
+	mType telegraf.ValueType,
+	t time.Time,
+) telegraf.Metric {
+	if len(fields) == 0 || len(measurement) == 0 {
+		return nil
+	}
+	if tags == nil {
+		tags = make(map[string]string)
+	}
+
+	// Override measurement name if set
+	if len(nameOverride) != 0 {
+		measurement = nameOverride
+	}
+	// Apply measurement prefix and suffix if set
+	if len(namePrefix) != 0 {
+		measurement = namePrefix + measurement
+	}
+	if len(nameSuffix) != 0 {
+		measurement = measurement + nameSuffix
+	}
+
+	// Apply plugin-wide tags if set
+	for k, v := range pluginTags {
+		if _, ok := tags[k]; !ok {
+			tags[k] = v
+		}
+	}
+	// Apply daemon-wide tags if set
+	for k, v := range daemonTags {
+		if _, ok := tags[k]; !ok {
+			tags[k] = v
+		}
+	}
+
+	// Apply the metric filter(s)
+	// for aggregators, the filter does not get applied when the metric is made.
+	// instead, the filter is applied to metric incoming into the plugin.
+	//   ie, it gets applied in the RunningAggregator.Apply function.
+	if applyFilter {
+		if ok := filter.Apply(measurement, fields, tags); !ok {
+			return nil
+		}
+	}
+
+	for k, v := range fields {
+		// Validate uint64 and float64 fields
+		// convert all int & uint types to int64
+		switch val := v.(type) {
+		case uint:
+			fields[k] = int64(val)
+			continue
+		case uint8:
+			fields[k] = int64(val)
+			continue
+		case uint16:
+			fields[k] = int64(val)
+			continue
+		case uint32:
+			fields[k] = int64(val)
+			continue
+		case int:
+			fields[k] = int64(val)
+			continue
+		case int8:
+			fields[k] = int64(val)
+			continue
+		case int16:
+			fields[k] = int64(val)
+			continue
+		case int32:
+			fields[k] = int64(val)
+			continue
+		case uint64:
+			// InfluxDB does not support writing uint64
+			if val < uint64(9223372036854775808) {
+				fields[k] = int64(val)
+			} else {
+				fields[k] = int64(9223372036854775807)
+			}
+			continue
+		case float32:
+			fields[k] = float64(val)
+			continue
+		case float64:
+			// NaNs are invalid values in influxdb, skip measurement
+			if math.IsNaN(val) || math.IsInf(val, 0) {
+				if debug {
+					log.Printf("Measurement [%s] field [%s] has a NaN or Inf "+
+						"field, skipping",
+						measurement, k)
+				}
+				delete(fields, k)
+				continue
+			}
+		}
+
+		fields[k] = v
+	}
+
+	var m telegraf.Metric
+	var err error
+	switch mType {
+	case telegraf.Counter:
+		m, err = telegraf.NewCounterMetric(measurement, tags, fields, t)
+	case telegraf.Gauge:
+		m, err = telegraf.NewGaugeMetric(measurement, tags, fields, t)
+	default:
+		m, err = telegraf.NewMetric(measurement, tags, fields, t)
+	}
+	if err != nil {
+		log.Printf("Error adding point [%s]: %s\n", measurement, err.Error())
+		return nil
+	}
+
+	return m
+}

internal/models/running_aggregator.go

@@ -0,0 +1,79 @@
+package models
+
+import (
+	"time"
+
+	"github.com/influxdata/telegraf"
+)
+
+type RunningAggregator struct {
+	Aggregator telegraf.Aggregator
+	Config     *AggregatorConfig
+}
+
+// AggregatorConfig containing configuration parameters for the running
+// aggregator plugin.
+type AggregatorConfig struct {
+	Name string
+
+	DropOriginal      bool
+	NameOverride      string
+	MeasurementPrefix string
+	MeasurementSuffix string
+	Tags              map[string]string
+	Filter            Filter
+}
+
+func (r *RunningAggregator) Name() string {
+	return "aggregators." + r.Config.Name
+}
+
+func (r *RunningAggregator) MakeMetric(
+	measurement string,
+	fields map[string]interface{},
+	tags map[string]string,
+	mType telegraf.ValueType,
+	t time.Time,
+) telegraf.Metric {
+	m := makemetric(
+		measurement,
+		fields,
+		tags,
+		r.Config.NameOverride,
+		r.Config.MeasurementPrefix,
+		r.Config.MeasurementSuffix,
+		r.Config.Tags,
+		nil,
+		r.Config.Filter,
+		false,
+		false,
+		mType,
+		t,
+	)
+
+	m.SetAggregate(true)
+
+	return m
+}
+
+// Apply applies the given metric to the aggregator.
+// Before applying to the plugin, it will run any defined filters on the metric.
+// Apply returns true if the original metric should be dropped.
+func (r *RunningAggregator) Apply(in telegraf.Metric) bool {
+	if r.Config.Filter.IsActive() {
+		// check if the aggregator should apply this metric
+		name := in.Name()
+		fields := in.Fields()
+		tags := in.Tags()
+		t := in.Time()
+		if ok := r.Config.Filter.Apply(name, fields, tags); !ok {
+			// aggregator should not apply this metric
+			return false
+		}
+
+		in, _ = telegraf.NewMetric(name, tags, fields, t)
+	}
+
+	r.Aggregator.Apply(in)
+	return r.Config.DropOriginal
+}

internal/models/running_aggregator_test.go

@@ -0,0 +1,150 @@
+package models
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/influxdata/telegraf"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestApply(t *testing.T) {
+	a := &TestAggregator{}
+	ra := RunningAggregator{
+		Config: &AggregatorConfig{
+			Name: "TestRunningAggregator",
+			Filter: Filter{
+				NamePass: []string{"*"},
+			},
+		},
+		Aggregator: a,
+	}
+	assert.NoError(t, ra.Config.Filter.Compile())
+
+	m := ra.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		time.Now(),
+	)
+	assert.False(t, ra.Apply(m))
+	assert.Equal(t, int64(101), a.sum)
+}
+
+func TestApplyDropOriginal(t *testing.T) {
+	ra := RunningAggregator{
+		Config: &AggregatorConfig{
+			Name: "TestRunningAggregator",
+			Filter: Filter{
+				NamePass: []string{"RI*"},
+			},
+			DropOriginal: true,
+		},
+		Aggregator: &TestAggregator{},
+	}
+	assert.NoError(t, ra.Config.Filter.Compile())
+
+	m := ra.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		time.Now(),
+	)
+	assert.True(t, ra.Apply(m))
+
+	// this metric name doesn't match the filter, so Apply will return false
+	m2 := ra.MakeMetric(
+		"foobar",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		time.Now(),
+	)
+	assert.False(t, ra.Apply(m2))
+}
+
+// make an untyped, counter, & gauge metric
+func TestMakeMetricA(t *testing.T) {
+	now := time.Now()
+	ra := RunningAggregator{
+		Config: &AggregatorConfig{
+			Name: "TestRunningAggregator",
+		},
+	}
+	assert.Equal(t, "aggregators.TestRunningAggregator", ra.Name())
+
+	m := ra.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+	assert.Equal(
+		t,
+		m.Type(),
+		telegraf.Untyped,
+	)
+
+	m = ra.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Counter,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+	assert.Equal(
+		t,
+		m.Type(),
+		telegraf.Counter,
+	)
+
+	m = ra.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Gauge,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+	assert.Equal(
+		t,
+		m.Type(),
+		telegraf.Gauge,
+	)
+}
+
+type TestAggregator struct {
+	sum int64
+}
+
+func (t *TestAggregator) Description() string                  { return "" }
+func (t *TestAggregator) SampleConfig() string                 { return "" }
+func (t *TestAggregator) Start(acc telegraf.Accumulator) error { return nil }
+func (t *TestAggregator) Stop()                                {}
+
+func (t *TestAggregator) Apply(in telegraf.Metric) {
+	for _, v := range in.Fields() {
+		if vi, ok := v.(int64); ok {
+			t.sum += vi
+		}
+	}
+}

internal/models/running_input.go

@@ -1,15 +1,19 @@
 package models
 
 import (
+	"fmt"
 	"time"
 
 	"github.com/influxdata/telegraf"
 )
 
 type RunningInput struct {
-	Name   string
 	Input  telegraf.Input
 	Config *InputConfig
+
+	trace       bool
+	debug       bool
+	defaultTags map[string]string
 }
 
 // InputConfig containing a name, interval, and filter
@@ -22,3 +26,59 @@ type InputConfig struct {
 	Filter            Filter
 	Interval          time.Duration
 }
+
+func (r *RunningInput) Name() string {
+	return "inputs." + r.Config.Name
+}
+
+// MakeMetric either returns a metric, or returns nil if the metric doesn't
+// need to be created (because of filtering, an error, etc.)
+func (r *RunningInput) MakeMetric(
+	measurement string,
+	fields map[string]interface{},
+	tags map[string]string,
+	mType telegraf.ValueType,
+	t time.Time,
+) telegraf.Metric {
+	m := makemetric(
+		measurement,
+		fields,
+		tags,
+		r.Config.NameOverride,
+		r.Config.MeasurementPrefix,
+		r.Config.MeasurementSuffix,
+		r.Config.Tags,
+		r.defaultTags,
+		r.Config.Filter,
+		true,
+		r.debug,
+		mType,
+		t,
+	)
+
+	if r.trace && m != nil {
+		fmt.Println("> " + m.String())
+	}
+
+	return m
+}
+
+func (r *RunningInput) Debug() bool {
+	return r.debug
+}
+
+func (r *RunningInput) SetDebug(debug bool) {
+	r.debug = debug
+}
+
+func (r *RunningInput) Trace() bool {
+	return r.trace
+}
+
+func (r *RunningInput) SetTrace(trace bool) {
+	r.trace = trace
+}
+
+func (r *RunningInput) SetDefaultTags(tags map[string]string) {
+	r.defaultTags = tags
+}

internal/models/running_input_test.go

@@ -0,0 +1,326 @@
+package models
+
+import (
+	"fmt"
+	"math"
+	"testing"
+	"time"
+
+	"github.com/influxdata/telegraf"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMakeMetricNoFields(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+		},
+	}
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Nil(t, m)
+}
+
+// make an untyped, counter, & gauge metric
+func TestMakeMetric(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+		},
+	}
+	ri.SetDebug(true)
+	assert.Equal(t, true, ri.Debug())
+	ri.SetTrace(true)
+	assert.Equal(t, true, ri.Trace())
+	assert.Equal(t, "inputs.TestRunningInput", ri.Name())
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+	assert.Equal(
+		t,
+		m.Type(),
+		telegraf.Untyped,
+	)
+
+	m = ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Counter,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+	assert.Equal(
+		t,
+		m.Type(),
+		telegraf.Counter,
+	)
+
+	m = ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Gauge,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+	assert.Equal(
+		t,
+		m.Type(),
+		telegraf.Gauge,
+	)
+}
+
+func TestMakeMetricWithPluginTags(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+			Tags: map[string]string{
+				"foo": "bar",
+			},
+		},
+	}
+	ri.SetDebug(true)
+	assert.Equal(t, true, ri.Debug())
+	ri.SetTrace(true)
+	assert.Equal(t, true, ri.Trace())
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		nil,
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest,foo=bar value=101i %d", now.UnixNano()),
+	)
+}
+
+func TestMakeMetricFilteredOut(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+			Tags: map[string]string{
+				"foo": "bar",
+			},
+			Filter: Filter{NamePass: []string{"foobar"}},
+		},
+	}
+	ri.SetDebug(true)
+	assert.Equal(t, true, ri.Debug())
+	ri.SetTrace(true)
+	assert.Equal(t, true, ri.Trace())
+	assert.NoError(t, ri.Config.Filter.Compile())
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		nil,
+		telegraf.Untyped,
+		now,
+	)
+	assert.Nil(t, m)
+}
+
+func TestMakeMetricWithDaemonTags(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+		},
+	}
+	ri.SetDefaultTags(map[string]string{
+		"foo": "bar",
+	})
+	ri.SetDebug(true)
+	assert.Equal(t, true, ri.Debug())
+	ri.SetTrace(true)
+	assert.Equal(t, true, ri.Trace())
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest,foo=bar value=101i %d", now.UnixNano()),
+	)
+}
+
+// make an untyped, counter, & gauge metric
+func TestMakeMetricInfFields(t *testing.T) {
+	inf := math.Inf(1)
+	ninf := math.Inf(-1)
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+		},
+	}
+	ri.SetDebug(true)
+	assert.Equal(t, true, ri.Debug())
+	ri.SetTrace(true)
+	assert.Equal(t, true, ri.Trace())
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{
+			"value": int(101),
+			"inf":   inf,
+			"ninf":  ninf,
+		},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest value=101i %d", now.UnixNano()),
+	)
+}
+
+func TestMakeMetricAllFieldTypes(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name: "TestRunningInput",
+		},
+	}
+	ri.SetDebug(true)
+	assert.Equal(t, true, ri.Debug())
+	ri.SetTrace(true)
+	assert.Equal(t, true, ri.Trace())
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{
+			"a": int(10),
+			"b": int8(10),
+			"c": int16(10),
+			"d": int32(10),
+			"e": uint(10),
+			"f": uint8(10),
+			"g": uint16(10),
+			"h": uint32(10),
+			"i": uint64(10),
+			"j": float32(10),
+			"k": uint64(9223372036854775810),
+			"l": "foobar",
+			"m": true,
+		},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		fmt.Sprintf("RITest a=10i,b=10i,c=10i,d=10i,e=10i,f=10i,g=10i,h=10i,i=10i,j=10,k=9223372036854775807i,l=\"foobar\",m=true %d", now.UnixNano()),
+		m.String(),
+	)
+}
+
+func TestMakeMetricNameOverride(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name:         "TestRunningInput",
+			NameOverride: "foobar",
+		},
+	}
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("foobar value=101i %d", now.UnixNano()),
+	)
+}
+
+func TestMakeMetricNamePrefix(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name:              "TestRunningInput",
+			MeasurementPrefix: "foobar_",
+		},
+	}
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("foobar_RITest value=101i %d", now.UnixNano()),
+	)
+}
+
+func TestMakeMetricNameSuffix(t *testing.T) {
+	now := time.Now()
+	ri := RunningInput{
+		Config: &InputConfig{
+			Name:              "TestRunningInput",
+			MeasurementSuffix: "_foobar",
+		},
+	}
+
+	m := ri.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		now,
+	)
+	assert.Equal(
+		t,
+		m.String(),
+		fmt.Sprintf("RITest_foobar value=101i %d", now.UnixNano()),
+	)
+}

internal/models/running_output_test.go

@@ -132,7 +132,6 @@ func TestRunningOutput_PassFilter(t *testing.T) {
 func TestRunningOutput_TagIncludeNoMatch(t *testing.T) {
 	conf := &OutputConfig{
 		Filter: Filter{
-
 			TagInclude: []string{"nothing*"},
 		},
 	}
@@ -154,7 +153,6 @@ func TestRunningOutput_TagIncludeNoMatch(t *testing.T) {
 func TestRunningOutput_TagExcludeMatch(t *testing.T) {
 	conf := &OutputConfig{
 		Filter: Filter{
-
 			TagExclude: []string{"tag*"},
 		},
 	}
@@ -176,7 +174,6 @@ func TestRunningOutput_TagExcludeMatch(t *testing.T) {
 func TestRunningOutput_TagExcludeNoMatch(t *testing.T) {
 	conf := &OutputConfig{
 		Filter: Filter{
-
 			TagExclude: []string{"nothing*"},
 		},
 	}
@@ -198,7 +195,6 @@ func TestRunningOutput_TagExcludeNoMatch(t *testing.T) {
 func TestRunningOutput_TagIncludeMatch(t *testing.T) {
 	conf := &OutputConfig{
 		Filter: Filter{
-
 			TagInclude: []string{"tag*"},
 		},
 	}

internal/models/running_processor.go

@@ -0,0 +1,37 @@
+package models
+
+import (
+	"github.com/influxdata/telegraf"
+)
+
+type RunningProcessor struct {
+	Name      string
+	Processor telegraf.Processor
+	Config    *ProcessorConfig
+}
+
+// FilterConfig containing a name and filter
+type ProcessorConfig struct {
+	Name   string
+	Filter Filter
+}
+
+func (rp *RunningProcessor) Apply(in ...telegraf.Metric) []telegraf.Metric {
+	ret := []telegraf.Metric{}
+
+	for _, metric := range in {
+		if rp.Config.Filter.IsActive() {
+			// check if the filter should be applied to this metric
+			if ok := rp.Config.Filter.Apply(metric.Name(), metric.Fields(), metric.Tags()); !ok {
+				// this means filter should not be applied
+				ret = append(ret, metric)
+				continue
+			}
+		}
+		// This metric should pass through the filter, so call the filter Apply
+		// function and append results to the output slice.
+		ret = append(ret, rp.Processor.Apply(metric)...)
+	}
+
+	return ret
+}

internal/models/running_processor_test.go

@@ -0,0 +1,117 @@
+package models
+
+import (
+	"testing"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/testutil"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type TestProcessor struct {
+}
+
+func (f *TestProcessor) SampleConfig() string { return "" }
+func (f *TestProcessor) Description() string  { return "" }
+
+// Apply renames:
+//   "foo" to "fuz"
+//   "bar" to "baz"
+// And it also drops measurements named "dropme"
+func (f *TestProcessor) Apply(in ...telegraf.Metric) []telegraf.Metric {
+	out := make([]telegraf.Metric, 0)
+	for _, m := range in {
+		switch m.Name() {
+		case "foo":
+			out = append(out, testutil.TestMetric(1, "fuz"))
+		case "bar":
+			out = append(out, testutil.TestMetric(1, "baz"))
+		case "dropme":
+			// drop the metric!
+		default:
+			out = append(out, m)
+		}
+	}
+	return out
+}
+
+func NewTestRunningProcessor() *RunningProcessor {
+	out := &RunningProcessor{
+		Name:      "test",
+		Processor: &TestProcessor{},
+		Config:    &ProcessorConfig{Filter: Filter{}},
+	}
+	return out
+}
+
+func TestRunningProcessor(t *testing.T) {
+	inmetrics := []telegraf.Metric{
+		testutil.TestMetric(1, "foo"),
+		testutil.TestMetric(1, "bar"),
+		testutil.TestMetric(1, "baz"),
+	}
+
+	expectedNames := []string{
+		"fuz",
+		"baz",
+		"baz",
+	}
+	rfp := NewTestRunningProcessor()
+	filteredMetrics := rfp.Apply(inmetrics...)
+
+	actualNames := []string{
+		filteredMetrics[0].Name(),
+		filteredMetrics[1].Name(),
+		filteredMetrics[2].Name(),
+	}
+	assert.Equal(t, expectedNames, actualNames)
+}
+
+func TestRunningProcessor_WithNameDrop(t *testing.T) {
+	inmetrics := []telegraf.Metric{
+		testutil.TestMetric(1, "foo"),
+		testutil.TestMetric(1, "bar"),
+		testutil.TestMetric(1, "baz"),
+	}
+
+	expectedNames := []string{
+		"foo",
+		"baz",
+		"baz",
+	}
+	rfp := NewTestRunningProcessor()
+
+	rfp.Config.Filter.NameDrop = []string{"foo"}
+	assert.NoError(t, rfp.Config.Filter.Compile())
+
+	filteredMetrics := rfp.Apply(inmetrics...)
+
+	actualNames := []string{
+		filteredMetrics[0].Name(),
+		filteredMetrics[1].Name(),
+		filteredMetrics[2].Name(),
+	}
+	assert.Equal(t, expectedNames, actualNames)
+}
+
+func TestRunningProcessor_DroppedMetric(t *testing.T) {
+	inmetrics := []telegraf.Metric{
+		testutil.TestMetric(1, "dropme"),
+		testutil.TestMetric(1, "foo"),
+		testutil.TestMetric(1, "bar"),
+	}
+
+	expectedNames := []string{
+		"fuz",
+		"baz",
+	}
+	rfp := NewTestRunningProcessor()
+	filteredMetrics := rfp.Apply(inmetrics...)
+
+	actualNames := []string{
+		filteredMetrics[0].Name(),
+		filteredMetrics[1].Name(),
+	}
+	assert.Equal(t, expectedNames, actualNames)
+}