Refactor handling of MinMax functionality into RunningAggregator

allows for easier addition of a sliding window at a later time.

Also makes `period` be a generic argument for all aggregator plugins.

agent/agent.go

@@ -259,9 +259,6 @@ func (a *Agent) flusher(shutdown chan struct{}, metricC chan telegraf.Metric) er
 		for {
 			select {
 			case <-shutdown:
-				for _, agg := range a.Config.Aggregators {
-					agg.Aggregator.Stop()
-				}
 				if len(outMetricC) > 0 {
 					// keep going until outMetricC is flushed
 					continue
@@ -273,7 +270,7 @@ func (a *Agent) flusher(shutdown chan struct{}, metricC chan telegraf.Metric) er
 				var dropOriginal bool
 				if !m.IsAggregate() {
 					for _, agg := range a.Config.Aggregators {
-						if ok := agg.Apply(copyMetric(m)); ok {
+						if ok := agg.Add(copyMetric(m)); ok {
 							dropOriginal = true
 						}
 					}
@@ -315,22 +312,6 @@ func (a *Agent) flusher(shutdown chan struct{}, metricC chan telegraf.Metric) er
 	}
 }
 
-func copyMetric(m telegraf.Metric) telegraf.Metric {
-	t := time.Time(m.Time())
-
-	tags := make(map[string]string)
-	fields := make(map[string]interface{})
-	for k, v := range m.Tags() {
-		tags[k] = v
-	}
-	for k, v := range m.Fields() {
-		fields[k] = v
-	}
-
-	out, _ := telegraf.NewMetric(m.Name(), tags, fields, t)
-	return out
-}
-
 // Run runs the agent daemon, gathering every Interval
 func (a *Agent) Run(shutdown chan struct{}) error {
 	var wg sync.WaitGroup
@@ -367,18 +348,6 @@ func (a *Agent) Run(shutdown chan struct{}) error {
 		time.Sleep(time.Duration(i - (time.Now().UnixNano() % i)))
 	}
 
-	// Start all Aggregators
-	for _, aggregator := range a.Config.Aggregators {
-		acc := NewAccumulator(aggregator, metricC)
-		acc.SetPrecision(a.Config.Agent.Precision.Duration,
-			a.Config.Agent.Interval.Duration)
-		if err := aggregator.Aggregator.Start(acc); err != nil {
-			log.Printf("[%s] failed to start, exiting\n%s\n",
-				aggregator.Name(), err.Error())
-			return err
-		}
-	}
-
 	wg.Add(1)
 	go func() {
 		defer wg.Done()
@@ -403,6 +372,33 @@ func (a *Agent) Run(shutdown chan struct{}) error {
 		}(input, interval)
 	}
 
+	wg.Add(len(a.Config.Aggregators))
+	for _, aggregator := range a.Config.Aggregators {
+		go func(agg *models.RunningAggregator) {
+			defer wg.Done()
+			acc := NewAccumulator(agg, metricC)
+			acc.SetPrecision(a.Config.Agent.Precision.Duration,
+				a.Config.Agent.Interval.Duration)
+			agg.Run(acc, shutdown)
+		}(aggregator)
+	}
+
 	wg.Wait()
 	return nil
 }
+
+func copyMetric(m telegraf.Metric) telegraf.Metric {
+	t := time.Time(m.Time())
+
+	tags := make(map[string]string)
+	fields := make(map[string]interface{})
+	for k, v := range m.Tags() {
+		tags[k] = v
+	}
+	for k, v := range m.Fields() {
+		fields[k] = v
+	}
+
+	out, _ := telegraf.NewMetric(m.Name(), tags, fields, t)
+	return out
+}

aggregator.go

@@ -1,16 +1,22 @@
 package telegraf
 
+// Aggregator is an interface for implementing an Aggregator plugin.
+// the RunningAggregator wraps this interface and guarantees that
+// Add, Push, and Reset can not be called concurrently, so locking is not
+// required when implementing an Aggregator plugin.
 type Aggregator interface {
-	// SampleConfig returns the default configuration of the Input
+	// SampleConfig returns the default configuration of the Input.
 	SampleConfig() string
 
-	// Description returns a one-sentence description on the Input
+	// Description returns a one-sentence description on the Input.
 	Description() string
 
-	// Apply the metric to the aggregator
+	// Add the metric to the aggregator.
-	Apply(in Metric)
+	Add(in Metric)
 
-	// Start starts the service filter with the given accumulator
+	// Push pushes the current aggregates to the accumulator.
-	Start(acc Accumulator) error
+	Push(acc Accumulator)
-	Stop()
+
+	// Reset resets the aggregators caches and aggregates.
+	Reset()
 }

internal/config/config.go

@@ -693,7 +693,7 @@ func (c *Config) addAggregator(name string, table *ast.Table) error {
 	}
 	aggregator := creator()
 
-	aggregatorConfig, err := buildAggregator(name, table)
+	conf, err := buildAggregator(name, table)
 	if err != nil {
 		return err
 	}
@@ -702,12 +702,7 @@ func (c *Config) addAggregator(name string, table *ast.Table) error {
 		return err
 	}
 
-	rf := &models.RunningAggregator{
+	c.Aggregators = append(c.Aggregators, models.NewRunningAggregator(aggregator, conf))
-		Aggregator: aggregator,
-		Config:     aggregatorConfig,
-	}
-
-	c.Aggregators = append(c.Aggregators, rf)
 	return nil
 }
 
@@ -818,7 +813,6 @@ func (c *Config) addInput(name string, table *ast.Table) error {
 
 // buildAggregator TODO doc
 func buildAggregator(name string, tbl *ast.Table) (*models.AggregatorConfig, error) {
-	conf := &models.AggregatorConfig{Name: name}
 	unsupportedFields := []string{"tagexclude", "taginclude"}
 	for _, field := range unsupportedFields {
 		if _, ok := tbl.Fields[field]; ok {
@@ -826,6 +820,34 @@ func buildAggregator(name string, tbl *ast.Table) (*models.AggregatorConfig, err
 		}
 	}
 
+	conf := &models.AggregatorConfig{Name: name}
+
+	if node, ok := tbl.Fields["period"]; ok {
+		if kv, ok := node.(*ast.KeyValue); ok {
+			if str, ok := kv.Value.(*ast.String); ok {
+				dur, err := time.ParseDuration(str.Value)
+				if err != nil {
+					return nil, err
+				}
+
+				conf.Period = dur
+			}
+		}
+	}
+
+	if node, ok := tbl.Fields["delay"]; ok {
+		if kv, ok := node.(*ast.KeyValue); ok {
+			if str, ok := kv.Value.(*ast.String); ok {
+				dur, err := time.ParseDuration(str.Value)
+				if err != nil {
+					return nil, err
+				}
+
+				conf.Delay = dur
+			}
+		}
+	}
+
 	if node, ok := tbl.Fields["drop_original"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if b, ok := kv.Value.(*ast.Boolean); ok {
@@ -871,6 +893,8 @@ func buildAggregator(name string, tbl *ast.Table) (*models.AggregatorConfig, err
 		}
 	}
 
+	delete(tbl.Fields, "period")
+	delete(tbl.Fields, "delay")
 	delete(tbl.Fields, "drop_original")
 	delete(tbl.Fields, "name_prefix")
 	delete(tbl.Fields, "name_suffix")

internal/models/running_aggregator.go

@@ -7,8 +7,21 @@ import (
 )
 
 type RunningAggregator struct {
-	Aggregator telegraf.Aggregator
+	a      telegraf.Aggregator
-	Config     *AggregatorConfig
+	Config *AggregatorConfig
+
+	metrics chan telegraf.Metric
+}
+
+func NewRunningAggregator(
+	a telegraf.Aggregator,
+	conf *AggregatorConfig,
+) *RunningAggregator {
+	return &RunningAggregator{
+		a:       a,
+		Config:  conf,
+		metrics: make(chan telegraf.Metric, 100),
+	}
 }
 
 // AggregatorConfig containing configuration parameters for the running
@@ -22,6 +35,9 @@ type AggregatorConfig struct {
 	MeasurementSuffix string
 	Tags              map[string]string
 	Filter            Filter
+
+	Period time.Duration
+	Delay  time.Duration
 }
 
 func (r *RunningAggregator) Name() string {
@@ -56,10 +72,10 @@ func (r *RunningAggregator) MakeMetric(
 	return m
 }
 
-// Apply applies the given metric to the aggregator.
+// Add 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 {
+func (r *RunningAggregator) Add(in telegraf.Metric) bool {
 	if r.Config.Filter.IsActive() {
 		// check if the aggregator should apply this metric
 		name := in.Name()
@@ -74,6 +90,49 @@ func (r *RunningAggregator) Apply(in telegraf.Metric) bool {
 		in, _ = telegraf.NewMetric(name, tags, fields, t)
 	}
 
-	r.Aggregator.Apply(in)
+	r.metrics <- in
 	return r.Config.DropOriginal
 }
+func (r *RunningAggregator) add(in telegraf.Metric) {
+	r.a.Add(in)
+}
+
+func (r *RunningAggregator) push(acc telegraf.Accumulator) {
+	r.a.Push(acc)
+}
+
+func (r *RunningAggregator) reset() {
+	r.a.Reset()
+}
+
+func (r *RunningAggregator) Run(
+	acc telegraf.Accumulator,
+	shutdown chan struct{},
+) {
+	if r.Config.Delay == 0 {
+		r.Config.Delay = time.Millisecond * 100
+	}
+	if r.Config.Period == 0 {
+		r.Config.Period = time.Second * 30
+	}
+
+	time.Sleep(r.Config.Delay)
+	periodT := time.NewTicker(r.Config.Period)
+	defer periodT.Stop()
+
+	for {
+		select {
+		case <-shutdown:
+			if len(r.metrics) > 0 {
+				// wait until metrics are flushed before exiting
+				continue
+			}
+			return
+		case m := <-r.metrics:
+			r.add(m)
+		case <-periodT.C:
+			r.push(acc)
+			r.reset()
+		}
+	}
+}

internal/models/running_aggregator_test.go

@@ -2,26 +2,28 @@ package models
 
 import (
 	"fmt"
+	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
 	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/testutil"
 
 	"github.com/stretchr/testify/assert"
 )
 
-func TestApply(t *testing.T) {
+func TestAdd(t *testing.T) {
 	a := &TestAggregator{}
-	ra := RunningAggregator{
+	ra := NewRunningAggregator(a, &AggregatorConfig{
-		Config: &AggregatorConfig{
+		Name: "TestRunningAggregator",
-			Name: "TestRunningAggregator",
+		Filter: Filter{
-			Filter: Filter{
+			NamePass: []string{"*"},
-				NamePass: []string{"*"},
-			},
 		},
-		Aggregator: a,
+	})
-	}
 	assert.NoError(t, ra.Config.Filter.Compile())
+	acc := testutil.Accumulator{}
+	go ra.Run(&acc, make(chan struct{}))
 
 	m := ra.MakeMetric(
 		"RITest",
@@ -30,21 +32,64 @@ func TestApply(t *testing.T) {
 		telegraf.Untyped,
 		time.Now(),
 	)
-	assert.False(t, ra.Apply(m))
+	assert.False(t, ra.Add(m))
-	assert.Equal(t, int64(101), a.sum)
+
+	for {
+		if atomic.LoadInt64(&a.sum) > 0 {
+			break
+		}
+	}
+	assert.Equal(t, int64(101), atomic.LoadInt64(&a.sum))
 }
 
-func TestApplyDropOriginal(t *testing.T) {
+func TestAddAndPushOnePeriod(t *testing.T) {
-	ra := RunningAggregator{
+	a := &TestAggregator{}
-		Config: &AggregatorConfig{
+	ra := NewRunningAggregator(a, &AggregatorConfig{
-			Name: "TestRunningAggregator",
+		Name: "TestRunningAggregator",
-			Filter: Filter{
+		Filter: Filter{
-				NamePass: []string{"RI*"},
+			NamePass: []string{"*"},
-			},
-			DropOriginal: true,
 		},
-		Aggregator: &TestAggregator{},
+		Period: time.Millisecond * 500,
+	})
+	assert.NoError(t, ra.Config.Filter.Compile())
+	acc := testutil.Accumulator{}
+	shutdown := make(chan struct{})
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		ra.Run(&acc, shutdown)
+	}()
+
+	m := ra.MakeMetric(
+		"RITest",
+		map[string]interface{}{"value": int(101)},
+		map[string]string{},
+		telegraf.Untyped,
+		time.Now(),
+	)
+	assert.False(t, ra.Add(m))
+
+	for {
+		if acc.NMetrics() > 0 {
+			break
+		}
 	}
+	acc.AssertContainsFields(t, "TestMetric", map[string]interface{}{"sum": int64(101)})
+
+	close(shutdown)
+	wg.Wait()
+}
+
+func TestAddDropOriginal(t *testing.T) {
+	ra := NewRunningAggregator(&TestAggregator{}, &AggregatorConfig{
+		Name: "TestRunningAggregator",
+		Filter: Filter{
+			NamePass: []string{"RI*"},
+		},
+		DropOriginal: true,
+	})
 	assert.NoError(t, ra.Config.Filter.Compile())
 
 	m := ra.MakeMetric(
@@ -54,9 +99,9 @@ func TestApplyDropOriginal(t *testing.T) {
 		telegraf.Untyped,
 		time.Now(),
 	)
-	assert.True(t, ra.Apply(m))
+	assert.True(t, ra.Add(m))
 
-	// this metric name doesn't match the filter, so Apply will return false
+	// this metric name doesn't match the filter, so Add will return false
 	m2 := ra.MakeMetric(
 		"foobar",
 		map[string]interface{}{"value": int(101)},
@@ -64,17 +109,15 @@ func TestApplyDropOriginal(t *testing.T) {
 		telegraf.Untyped,
 		time.Now(),
 	)
-	assert.False(t, ra.Apply(m2))
+	assert.False(t, ra.Add(m2))
 }
 
 // make an untyped, counter, & gauge metric
 func TestMakeMetricA(t *testing.T) {
 	now := time.Now()
-	ra := RunningAggregator{
+	ra := NewRunningAggregator(&TestAggregator{}, &AggregatorConfig{
-		Config: &AggregatorConfig{
+		Name: "TestRunningAggregator",
-			Name: "TestRunningAggregator",
+	})
-		},
-	}
 	assert.Equal(t, "aggregators.TestRunningAggregator", ra.Name())
 
 	m := ra.MakeMetric(
@@ -136,15 +179,21 @@ type TestAggregator struct {
 	sum int64
 }
 
-func (t *TestAggregator) Description() string                  { return "" }
+func (t *TestAggregator) Description() string  { return "" }
-func (t *TestAggregator) SampleConfig() string                 { return "" }
+func (t *TestAggregator) SampleConfig() string { return "" }
-func (t *TestAggregator) Start(acc telegraf.Accumulator) error { return nil }
+func (t *TestAggregator) Reset()               {}
-func (t *TestAggregator) Stop()                                {}
 
-func (t *TestAggregator) Apply(in telegraf.Metric) {
+func (t *TestAggregator) Push(acc telegraf.Accumulator) {
+	acc.AddFields("TestMetric",
+		map[string]interface{}{"sum": t.sum},
+		map[string]string{},
+	)
+}
+
+func (t *TestAggregator) Add(in telegraf.Metric) {
 	for _, v := range in.Fields() {
 		if vi, ok := v.(int64); ok {
-			t.sum += vi
+			atomic.AddInt64(&t.sum, vi)
 		}
 	}
 }

plugins/aggregators/minmax/minmax.go

@@ -1,28 +1,21 @@
 package minmax
 
 import (
-	"sync"
-	"time"
-
 	"github.com/influxdata/telegraf"
-	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/plugins/aggregators"
 )
 
 type MinMax struct {
-	Period internal.Duration
-
-	// metrics waiting to be processed
-	metrics  chan telegraf.Metric
-	shutdown chan struct{}
-	wg       sync.WaitGroup
-
 	// caches for metric fields, names, and tags
 	fieldCache map[uint64]map[string]minmax
 	nameCache  map[uint64]string
 	tagCache   map[uint64]map[string]string
+}
 
-	acc telegraf.Accumulator
+func NewMinMax() telegraf.Aggregator {
+	mm := &MinMax{}
+	mm.Reset()
+	return mm
 }
 
 type minmax struct {
@@ -43,11 +36,7 @@ func (m *MinMax) Description() string {
 	return "Keep the aggregate min/max of each metric passing through."
 }
 
-func (m *MinMax) Apply(in telegraf.Metric) {
+func (m *MinMax) Add(in telegraf.Metric) {
-	m.metrics <- in
-}
-
-func (m *MinMax) apply(in telegraf.Metric) {
 	id := in.HashID()
 	if _, ok := m.nameCache[id]; !ok {
 		// hit an uncached metric, create caches for first time:
@@ -90,84 +79,23 @@ func (m *MinMax) apply(in telegraf.Metric) {
 	}
 }
 
-func (m *MinMax) Start(acc telegraf.Accumulator) error {
+func (m *MinMax) Push(acc telegraf.Accumulator) {
-	m.metrics = make(chan telegraf.Metric, 10)
+	for id, _ := range m.nameCache {
-	m.shutdown = make(chan struct{})
+		fields := map[string]interface{}{}
-	m.clearCache()
+		for k, v := range m.fieldCache[id] {
-	m.acc = acc
+			fields[k+"_min"] = v.min
-	m.wg.Add(1)
+			fields[k+"_max"] = v.max
-	if m.Period.Duration > 0 {
+		}
-		go m.periodHandler()
+		acc.AddFields(m.nameCache[id], fields, m.tagCache[id])
-	} else {
-		go m.continuousHandler()
 	}
-	return nil
 }
 
-func (m *MinMax) Stop() {
+func (m *MinMax) Reset() {
-	close(m.shutdown)
-	m.wg.Wait()
-}
-
-func (m *MinMax) addfields(id uint64) {
-	fields := map[string]interface{}{}
-	for k, v := range m.fieldCache[id] {
-		fields[k+"_min"] = v.min
-		fields[k+"_max"] = v.max
-	}
-	m.acc.AddFields(m.nameCache[id], fields, m.tagCache[id])
-}
-
-func (m *MinMax) clearCache() {
 	m.fieldCache = make(map[uint64]map[string]minmax)
 	m.nameCache = make(map[uint64]string)
 	m.tagCache = make(map[uint64]map[string]string)
 }
 
-// periodHandler only adds the aggregate metrics on the configured Period.
-//   thus if telegraf's collection interval is 10s, and period is 30s, there
-//   will only be one aggregate sent every 3 metrics.
-func (m *MinMax) periodHandler() {
-	// TODO make this sleep less of a hack!
-	time.Sleep(time.Millisecond * 200)
-	defer m.wg.Done()
-	ticker := time.NewTicker(m.Period.Duration)
-	defer ticker.Stop()
-	for {
-		select {
-		case in := <-m.metrics:
-			m.apply(in)
-		case <-m.shutdown:
-			if len(m.metrics) > 0 {
-				continue
-			}
-			return
-		case <-ticker.C:
-			for id, _ := range m.nameCache {
-				m.addfields(id)
-			}
-			m.clearCache()
-		}
-	}
-}
-
-// continuousHandler sends one metric for every metric that passes through it.
-func (m *MinMax) continuousHandler() {
-	defer m.wg.Done()
-	for {
-		select {
-		case in := <-m.metrics:
-			m.apply(in)
-			m.addfields(in.HashID())
-		case <-m.shutdown:
-			if len(m.metrics) > 0 {
-				continue
-			}
-			return
-		}
-	}
-}
-
 func compare(a, b float64) int {
 	if a < b {
 		return -1
@@ -190,6 +118,6 @@ func convert(in interface{}) (float64, bool) {
 
 func init() {
 	aggregators.Add("minmax", func() telegraf.Aggregator {
-		return &MinMax{}
+		return NewMinMax()
 	})
 }

plugins/aggregators/minmax/minmax_test.go

@@ -5,10 +5,7 @@ import (
 	"time"
 
 	"github.com/influxdata/telegraf"
-	"github.com/influxdata/telegraf/internal"
 	"github.com/influxdata/telegraf/testutil"
-
-	"github.com/stretchr/testify/assert"
 )
 
 var m1, _ = telegraf.NewMetric("m1",
@@ -48,34 +45,22 @@ var m2, _ = telegraf.NewMetric("m1",
 )
 
 func BenchmarkApply(b *testing.B) {
-	minmax := MinMax{}
+	minmax := NewMinMax()
-	minmax.clearCache()
 
 	for n := 0; n < b.N; n++ {
-		minmax.apply(m1)
+		minmax.Add(m1)
-		minmax.apply(m2)
+		minmax.Add(m2)
 	}
 }
 
-// Test two metrics getting added, when running with a period, and the metrics
+// Test two metrics getting added.
-// are added in the same period.
 func TestMinMaxWithPeriod(t *testing.T) {
 	acc := testutil.Accumulator{}
-	minmax := MinMax{
+	minmax := NewMinMax()
-		Period: internal.Duration{Duration: time.Millisecond * 500},
-	}
-	assert.NoError(t, minmax.Start(&acc))
-	defer minmax.Stop()
 
-	minmax.Apply(m1)
+	minmax.Add(m1)
-	minmax.Apply(m2)
+	minmax.Add(m2)
-
+	minmax.Push(&acc)
-	for {
-		if acc.NMetrics() > 0 {
-			break
-		}
-		time.Sleep(time.Millisecond)
-	}
 
 	expectedFields := map[string]interface{}{
 		"a_max": float64(1),
@@ -107,23 +92,14 @@ func TestMinMaxWithPeriod(t *testing.T) {
 	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
 }
 
-// Test two metrics getting added, when running with a period, and the metrics
+// Test two metrics getting added with a push/reset in between (simulates
-// are added in two different periods.
+// getting added in different periods.)
 func TestMinMaxDifferentPeriods(t *testing.T) {
 	acc := testutil.Accumulator{}
-	minmax := MinMax{
+	minmax := NewMinMax()
-		Period: internal.Duration{Duration: time.Millisecond * 100},
-	}
-	assert.NoError(t, minmax.Start(&acc))
-	defer minmax.Stop()
 
-	minmax.Apply(m1)
+	minmax.Add(m1)
-	for {
+	minmax.Push(&acc)
-		if acc.NMetrics() > 0 {
-			break
-		}
-		time.Sleep(time.Millisecond)
-	}
 	expectedFields := map[string]interface{}{
 		"a_max": float64(1),
 		"a_min": float64(1),
@@ -152,13 +128,9 @@ func TestMinMaxDifferentPeriods(t *testing.T) {
 	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
 
 	acc.ClearMetrics()
-	minmax.Apply(m2)
+	minmax.Reset()
-	for {
+	minmax.Add(m2)
-		if acc.NMetrics() > 0 {
+	minmax.Push(&acc)
-			break
-		}
-		time.Sleep(time.Millisecond)
-	}
 	expectedFields = map[string]interface{}{
 		"a_max": float64(1),
 		"a_min": float64(1),
@@ -188,82 +160,3 @@ func TestMinMaxDifferentPeriods(t *testing.T) {
 	}
 	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
 }
-
-// Test two metrics getting added, when running without a period.
-func TestMinMaxWithoutPeriod(t *testing.T) {
-	acc := testutil.Accumulator{}
-	minmax := MinMax{}
-	assert.NoError(t, minmax.Start(&acc))
-	defer minmax.Stop()
-
-	minmax.Apply(m1)
-	for {
-		if acc.NMetrics() > 0 {
-			break
-		}
-		time.Sleep(time.Millisecond)
-	}
-	expectedFields := map[string]interface{}{
-		"a_max": float64(1),
-		"a_min": float64(1),
-		"b_max": float64(1),
-		"b_min": float64(1),
-		"c_max": float64(1),
-		"c_min": float64(1),
-		"d_max": float64(1),
-		"d_min": float64(1),
-		"e_max": float64(1),
-		"e_min": float64(1),
-		"f_max": float64(2),
-		"f_min": float64(2),
-		"g_max": float64(2),
-		"g_min": float64(2),
-		"h_max": float64(2),
-		"h_min": float64(2),
-		"i_max": float64(2),
-		"i_min": float64(2),
-		"j_max": float64(3),
-		"j_min": float64(3),
-	}
-	expectedTags := map[string]string{
-		"foo": "bar",
-	}
-	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
-
-	acc.ClearMetrics()
-	minmax.Apply(m2)
-	for {
-		if acc.NMetrics() > 0 {
-			break
-		}
-		time.Sleep(time.Millisecond)
-	}
-	expectedFields = map[string]interface{}{
-		"a_max": float64(1),
-		"a_min": float64(1),
-		"b_max": float64(3),
-		"b_min": float64(1),
-		"c_max": float64(3),
-		"c_min": float64(1),
-		"d_max": float64(3),
-		"d_min": float64(1),
-		"e_max": float64(3),
-		"e_min": float64(1),
-		"f_max": float64(2),
-		"f_min": float64(1),
-		"g_max": float64(2),
-		"g_min": float64(1),
-		"h_max": float64(2),
-		"h_min": float64(1),
-		"i_max": float64(2),
-		"i_min": float64(1),
-		"j_max": float64(3),
-		"j_min": float64(1),
-		"k_max": float64(200),
-		"k_min": float64(200),
-	}
-	expectedTags = map[string]string{
-		"foo": "bar",
-	}
-	acc.AssertContainsTaggedFields(t, "m1", expectedFields, expectedTags)
-}