From e4af487e55cac0a70f66908f92ebdea6edb170cb Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Tue, 18 Sep 2018 16:58:34 +0200
Subject: [PATCH 01/14] Allow checks to send metrics with no hostname

- move the default hostname responsibility from the aggregator / sampler
to the sender
- add a DisableDefaultHostname method to the Sender interface
- make dogstatsd handle hostname for events and service checks
---
 pkg/aggregator/aggregator.go                |  16 +--
 pkg/aggregator/aggregator_test.go           |   6 +-
 pkg/aggregator/check_sampler.go             |   9 +-
 pkg/aggregator/check_sampler_test.go        |  38 +-----
 pkg/aggregator/mocksender/mocked_methods.go |   5 +
 pkg/aggregator/mocksender/mocksender.go     |   2 +-
 pkg/aggregator/sender.go                    |  62 +++++++--
 pkg/aggregator/sender_test.go               |  80 +++++++++++-
 pkg/dogstatsd/parser.go                     |   6 +-
 pkg/dogstatsd/parser_test.go                | 136 ++++++++++++--------
 pkg/dogstatsd/server.go                     |   4 +-
 11 files changed, 235 insertions(+), 129 deletions(-)

diff --git a/pkg/aggregator/aggregator.go b/pkg/aggregator/aggregator.go
index e8d1af413cc005..1839817e023e2d 100644
--- a/pkg/aggregator/aggregator.go
+++ b/pkg/aggregator/aggregator.go
@@ -238,7 +238,7 @@ func (agg *BufferedAggregator) registerSender(id check.ID) error {
 	if _, ok := agg.checkSamplers[id]; ok {
 		return fmt.Errorf("Sender with ID '%s' has already been registered, will use existing sampler", id)
 	}
-	agg.checkSamplers[id] = newCheckSampler(agg.hostname)
+	agg.checkSamplers[id] = newCheckSampler()
 	return nil
 }
 
@@ -266,9 +266,6 @@ func (agg *BufferedAggregator) handleSenderSample(ss senderMetricSample) {
 
 // addServiceCheck adds the service check to the slice of current service checks
 func (agg *BufferedAggregator) addServiceCheck(sc metrics.ServiceCheck) {
-	if sc.Host == "" {
-		sc.Host = agg.hostname
-	}
 	if sc.Ts == 0 {
 		sc.Ts = time.Now().Unix()
 	}
@@ -279,9 +276,6 @@ func (agg *BufferedAggregator) addServiceCheck(sc metrics.ServiceCheck) {
 
 // addEvent adds the event to the slice of current events
 func (agg *BufferedAggregator) addEvent(e metrics.Event) {
-	if e.Host == "" {
-		e.Host = agg.hostname
-	}
 	if e.Ts == 0 {
 		e.Ts = time.Now().Unix()
 	}
@@ -375,6 +369,7 @@ func (agg *BufferedAggregator) flushServiceChecks() {
 	agg.addServiceCheck(metrics.ServiceCheck{
 		CheckName: "datadog.agent.up",
 		Status:    metrics.ServiceCheckOK,
+		Host:      agg.hostname,
 	})
 
 	serviceChecks := agg.GetServiceChecks()
@@ -504,12 +499,7 @@ func (agg *BufferedAggregator) run() {
 		case h := <-agg.hostnameUpdate:
 			aggregatorHostnameUpdate.Add(1)
 			agg.hostname = h
-			agg.mu.Lock()
-			for _, checkSampler := range agg.checkSamplers {
-				checkSampler.defaultHostname = h
-			}
-			agg.sampler.defaultHostname = h
-			agg.mu.Unlock()
+			changeAllSendersDefaultHostname(h)
 			agg.hostnameUpdateDone <- struct{}{}
 		}
 	}
diff --git a/pkg/aggregator/aggregator_test.go b/pkg/aggregator/aggregator_test.go
index b71a18f9c14dad..5dd8812d26430a 100644
--- a/pkg/aggregator/aggregator_test.go
+++ b/pkg/aggregator/aggregator_test.go
@@ -74,7 +74,7 @@ func TestAddServiceCheckDefaultValues(t *testing.T) {
 	})
 
 	require.Len(t, agg.serviceChecks, 2)
-	assert.Equal(t, "resolved-hostname", agg.serviceChecks[0].Host)
+	assert.Equal(t, "", agg.serviceChecks[0].Host)
 	assert.Equal(t, []string{"bar", "foo"}, agg.serviceChecks[0].Tags)
 	assert.NotZero(t, agg.serviceChecks[0].Ts) // should be set to the current time, let's just check that it's not 0
 	assert.Equal(t, "my-hostname", agg.serviceChecks[1].Host)
@@ -105,10 +105,10 @@ func TestAddEventDefaultValues(t *testing.T) {
 	})
 
 	require.Len(t, agg.events, 2)
-	// Default values are set on Host and Ts only
+	// Default values are set on Ts
 	event1 := agg.events[0]
 	assert.Equal(t, "An event occurred", event1.Title)
-	assert.Equal(t, "resolved-hostname", event1.Host)
+	assert.Equal(t, "", event1.Host)
 	assert.NotZero(t, event1.Ts) // should be set to the current time, let's just check that it's not 0
 	assert.Zero(t, event1.Priority)
 	assert.Zero(t, event1.Tags)
diff --git a/pkg/aggregator/check_sampler.go b/pkg/aggregator/check_sampler.go
index 6d6da2bd0306f6..39ce305a26b98c 100644
--- a/pkg/aggregator/check_sampler.go
+++ b/pkg/aggregator/check_sampler.go
@@ -18,16 +18,14 @@ type CheckSampler struct {
 	series          []*metrics.Serie
 	contextResolver *ContextResolver
 	metrics         metrics.ContextMetrics
-	defaultHostname string
 }
 
 // newCheckSampler returns a newly initialized CheckSampler
-func newCheckSampler(hostname string) *CheckSampler {
+func newCheckSampler() *CheckSampler {
 	return &CheckSampler{
 		series:          make([]*metrics.Serie, 0),
 		contextResolver: newContextResolver(),
 		metrics:         metrics.MakeContextMetrics(),
-		defaultHostname: hostname,
 	}
 }
 
@@ -59,11 +57,6 @@ func (cs *CheckSampler) commit(timestamp float64) {
 		serie.Name = context.Name + serie.NameSuffix
 		serie.Tags = context.Tags
 		serie.SourceTypeName = checksSourceTypeName // this source type is required for metrics coming from the checks
-		if context.Host != "" {
-			serie.Host = context.Host
-		} else {
-			serie.Host = cs.defaultHostname
-		}
 
 		cs.series = append(cs.series, serie)
 	}
diff --git a/pkg/aggregator/check_sampler_test.go b/pkg/aggregator/check_sampler_test.go
index 11250abbb7b995..677d90b03e0471 100644
--- a/pkg/aggregator/check_sampler_test.go
+++ b/pkg/aggregator/check_sampler_test.go
@@ -18,7 +18,7 @@ import (
 )
 
 func TestCheckGaugeSampling(t *testing.T) {
-	checkSampler := newCheckSampler("")
+	checkSampler := newCheckSampler()
 
 	mSample1 := metrics.MetricSample{
 		Name:       "my.metric.name",
@@ -85,7 +85,7 @@ func TestCheckGaugeSampling(t *testing.T) {
 }
 
 func TestCheckRateSampling(t *testing.T) {
-	checkSampler := newCheckSampler("")
+	checkSampler := newCheckSampler()
 
 	mSample1 := metrics.MetricSample{
 		Name:       "my.metric.name",
@@ -134,7 +134,7 @@ func TestCheckRateSampling(t *testing.T) {
 }
 
 func TestHistogramIntervalSampling(t *testing.T) {
-	checkSampler := newCheckSampler("")
+	checkSampler := newCheckSampler()
 
 	mSample1 := metrics.MetricSample{
 		Name:       "my.metric.name",
@@ -190,35 +190,3 @@ func TestHistogramIntervalSampling(t *testing.T) {
 
 	assert.True(t, foundCount)
 }
-
-func TestCheckSamplerHostname(t *testing.T) {
-	checkSampler := newCheckSampler("my.test.hostname")
-
-	mSample1 := metrics.MetricSample{
-		Name:       "my.metric.name",
-		Value:      1,
-		Mtype:      metrics.GaugeType,
-		Tags:       []string{"foo", "bar"},
-		SampleRate: 1,
-		Timestamp:  12345.0,
-	}
-	mSample2 := metrics.MetricSample{
-		Name:       "my.metric.name",
-		Value:      1,
-		Mtype:      metrics.GaugeType,
-		Tags:       []string{"foo", "bar"},
-		Host:       "metric-hostname",
-		SampleRate: 1,
-		Timestamp:  12345,
-	}
-
-	checkSampler.addSample(&mSample1)
-	checkSampler.addSample(&mSample2)
-	checkSampler.commit(12346.0)
-	series := checkSampler.flush()
-
-	require.Len(t, series, 2)
-	actualHostnames := []string{series[0].Host, series[1].Host}
-	assert.Contains(t, actualHostnames, "my.test.hostname")
-	assert.Contains(t, actualHostnames, "metric-hostname")
-}
diff --git a/pkg/aggregator/mocksender/mocked_methods.go b/pkg/aggregator/mocksender/mocked_methods.go
index ac671a879682db..93824bc5f5e7f3 100644
--- a/pkg/aggregator/mocksender/mocked_methods.go
+++ b/pkg/aggregator/mocksender/mocked_methods.go
@@ -49,6 +49,11 @@ func (m *MockSender) ServiceCheck(checkName string, status metrics.ServiceCheckS
 	m.Called(checkName, status, hostname, tags, message)
 }
 
+//DisableDefaultHostname enables the hostname mock call.
+func (m *MockSender) DisableDefaultHostname(d bool) {
+	m.Called(d)
+}
+
 //Event enables the event mock call.
 func (m *MockSender) Event(e metrics.Event) {
 	m.Called(e)
diff --git a/pkg/aggregator/mocksender/mocksender.go b/pkg/aggregator/mocksender/mocksender.go
index a5eb374194a3af..e9d69536e0fc64 100644
--- a/pkg/aggregator/mocksender/mocksender.go
+++ b/pkg/aggregator/mocksender/mocksender.go
@@ -50,7 +50,7 @@ func (m *MockSender) SetupAcceptAll() {
 	).Return()
 	m.On("Event", mock.AnythingOfType("metrics.Event")).Return()
 	m.On("GetMetricStats", mock.AnythingOfType("map[string]int64")).Return()
-
+	m.On("DisableDefaultHostname", mock.AnythingOfType("bool")).Return()
 	m.On("Commit").Return()
 }
 
diff --git a/pkg/aggregator/sender.go b/pkg/aggregator/sender.go
index 51faf828077d18..c913a726499a03 100644
--- a/pkg/aggregator/sender.go
+++ b/pkg/aggregator/sender.go
@@ -34,6 +34,7 @@ type Sender interface {
 	ServiceCheck(checkName string, status metrics.ServiceCheckStatus, hostname string, tags []string, message string)
 	Event(e metrics.Event)
 	GetMetricStats() map[string]int64
+	DisableDefaultHostname(disable bool)
 }
 
 type metricStats struct {
@@ -52,12 +53,14 @@ type RawSender interface {
 
 // checkSender implements Sender
 type checkSender struct {
-	id               check.ID
-	metricStats      metricStats
-	priormetricStats metricStats
-	smsOut           chan<- senderMetricSample
-	serviceCheckOut  chan<- metrics.ServiceCheck
-	eventOut         chan<- metrics.Event
+	id                     check.ID
+	defaultHostname        string
+	disableDefaultHostname bool
+	metricStats            metricStats
+	priormetricStats       metricStats
+	smsOut                 chan<- senderMetricSample
+	serviceCheckOut        chan<- metrics.ServiceCheck
+	eventOut               chan<- metrics.Event
 }
 
 type senderMetricSample struct {
@@ -77,9 +80,10 @@ func init() {
 	}
 }
 
-func newCheckSender(id check.ID, smsOut chan<- senderMetricSample, serviceCheckOut chan<- metrics.ServiceCheck, eventOut chan<- metrics.Event) *checkSender {
+func newCheckSender(id check.ID, defaultHostname string, smsOut chan<- senderMetricSample, serviceCheckOut chan<- metrics.ServiceCheck, eventOut chan<- metrics.Event) *checkSender {
 	return &checkSender{
 		id:               id,
+		defaultHostname:  defaultHostname,
 		smsOut:           smsOut,
 		serviceCheckOut:  serviceCheckOut,
 		eventOut:         eventOut,
@@ -127,12 +131,27 @@ func GetDefaultSender() (Sender, error) {
 	senderInit.Do(func() {
 		var defaultCheckID check.ID // the default value is the zero value
 		aggregatorInstance.registerSender(defaultCheckID)
-		senderInstance = newCheckSender(defaultCheckID, aggregatorInstance.checkMetricIn, aggregatorInstance.serviceCheckIn, aggregatorInstance.eventIn)
+		senderInstance = newCheckSender(defaultCheckID, aggregatorInstance.hostname, aggregatorInstance.checkMetricIn, aggregatorInstance.serviceCheckIn, aggregatorInstance.eventIn)
 	})
 
 	return senderInstance, nil
 }
 
+// changeAllSendersDefaultHostname is to be called by the aggregator
+// when its hostname changes. All existing senders will have their
+// default hostname updated.
+func changeAllSendersDefaultHostname(hostname string) {
+	if senderPool != nil {
+		senderPool.changeAllSendersDefaultHostname(hostname)
+	}
+}
+
+// DisableDefaultHostname allows check to override the default hostname that will be injected
+// when no hostname is specified at submission (for metrics, events and service checks).
+func (s *checkSender) DisableDefaultHostname(disable bool) {
+	s.disableDefaultHostname = disable
+}
+
 // Commit commits the metric samples that were added during a check run
 // Should be called at the end of every check run
 func (s *checkSender) Commit() {
@@ -184,6 +203,10 @@ func (s *checkSender) sendMetricSample(metric string, value float64, hostname st
 		Timestamp:  timeNowNano(),
 	}
 
+	if !s.disableDefaultHostname && metricSample.Host == "" {
+		metricSample.Host = s.defaultHostname
+	}
+
 	s.smsOut <- senderMetricSample{s.id, metricSample, false}
 
 	s.metricStats.Lock.Lock()
@@ -248,6 +271,10 @@ func (s *checkSender) ServiceCheck(checkName string, status metrics.ServiceCheck
 		Message:   message,
 	}
 
+	if !s.disableDefaultHostname && serviceCheck.Host == "" {
+		serviceCheck.Host = s.defaultHostname
+	}
+
 	s.serviceCheckOut <- serviceCheck
 
 	s.metricStats.Lock.Lock()
@@ -259,6 +286,10 @@ func (s *checkSender) ServiceCheck(checkName string, status metrics.ServiceCheck
 func (s *checkSender) Event(e metrics.Event) {
 	log.Trace("Event submitted: ", e.Title, " for hostname: ", e.Host, " tags: ", e.Tags)
 
+	if !s.disableDefaultHostname && e.Host == "" {
+		e.Host = s.defaultHostname
+	}
+
 	s.eventOut <- e
 
 	s.metricStats.Lock.Lock()
@@ -266,6 +297,19 @@ func (s *checkSender) Event(e metrics.Event) {
 	s.metricStats.Lock.Unlock()
 }
 
+// changeAllSendersDefaultHostname u
+func (sp *checkSenderPool) changeAllSendersDefaultHostname(hostname string) {
+	sp.m.Lock()
+	defer sp.m.Unlock()
+	for _, sender := range sp.senders {
+		cs, ok := sender.(*checkSender)
+		if !ok {
+			continue
+		}
+		cs.defaultHostname = hostname
+	}
+}
+
 func (sp *checkSenderPool) getSender(id check.ID) (Sender, error) {
 	sp.m.Lock()
 	defer sp.m.Unlock()
@@ -281,7 +325,7 @@ func (sp *checkSenderPool) mkSender(id check.ID) (Sender, error) {
 	defer sp.m.Unlock()
 
 	err := aggregatorInstance.registerSender(id)
-	sender := newCheckSender(id, aggregatorInstance.checkMetricIn, aggregatorInstance.serviceCheckIn, aggregatorInstance.eventIn)
+	sender := newCheckSender(id, aggregatorInstance.hostname, aggregatorInstance.checkMetricIn, aggregatorInstance.serviceCheckIn, aggregatorInstance.eventIn)
 	sp.senders[id] = sender
 	return sender, err
 }
diff --git a/pkg/aggregator/sender_test.go b/pkg/aggregator/sender_test.go
index dadc8bed9b033b..c190d9ae99633a 100644
--- a/pkg/aggregator/sender_test.go
+++ b/pkg/aggregator/sender_test.go
@@ -7,6 +7,7 @@ package aggregator
 
 import (
 	// stdlib
+	"fmt"
 	"sync"
 	"testing"
 
@@ -107,7 +108,7 @@ func TestGetAndSetSender(t *testing.T) {
 	senderMetricSampleChan := make(chan senderMetricSample, 10)
 	serviceCheckChan := make(chan metrics.ServiceCheck, 10)
 	eventChan := make(chan metrics.Event, 10)
-	testCheckSender := newCheckSender(checkID1, senderMetricSampleChan, serviceCheckChan, eventChan)
+	testCheckSender := newCheckSender(checkID1, "", senderMetricSampleChan, serviceCheckChan, eventChan)
 
 	err := SetSender(testCheckSender, checkID1)
 	assert.Nil(t, err)
@@ -122,7 +123,7 @@ func TestCheckSenderInterface(t *testing.T) {
 	senderMetricSampleChan := make(chan senderMetricSample, 10)
 	serviceCheckChan := make(chan metrics.ServiceCheck, 10)
 	eventChan := make(chan metrics.Event, 10)
-	checkSender := newCheckSender(checkID1, senderMetricSampleChan, serviceCheckChan, eventChan)
+	checkSender := newCheckSender(checkID1, "default-hostname", senderMetricSampleChan, serviceCheckChan, eventChan)
 	checkSender.Gauge("my.metric", 1.0, "my-hostname", []string{"foo", "bar"})
 	checkSender.Rate("my.rate_metric", 2.0, "my-hostname", []string{"foo", "bar"})
 	checkSender.Count("my.count_metric", 123.0, "my-hostname", []string{"foo", "bar"})
@@ -147,6 +148,7 @@ func TestCheckSenderInterface(t *testing.T) {
 	gaugeSenderSample := <-senderMetricSampleChan
 	assert.EqualValues(t, checkID1, gaugeSenderSample.id)
 	assert.Equal(t, metrics.GaugeType, gaugeSenderSample.metricSample.Mtype)
+	assert.Equal(t, "my-hostname", gaugeSenderSample.metricSample.Host)
 	assert.Equal(t, false, gaugeSenderSample.commit)
 
 	rateSenderSample := <-senderMetricSampleChan
@@ -188,3 +190,77 @@ func TestCheckSenderInterface(t *testing.T) {
 	event := <-eventChan
 	assert.Equal(t, submittedEvent, event)
 }
+
+func TestCheckSenderHostname(t *testing.T) {
+	defaultHostname := "default-host"
+
+	for nb, tc := range []struct {
+		disableDefaultHostname bool
+		submittedHostname      string
+		expectedHostname       string
+	}{
+		{
+			disableDefaultHostname: false,
+			submittedHostname:      "",
+			expectedHostname:       defaultHostname,
+		},
+		{
+			disableDefaultHostname: false,
+			submittedHostname:      "custom",
+			expectedHostname:       "custom",
+		},
+		{
+			disableDefaultHostname: true,
+			submittedHostname:      "",
+			expectedHostname:       "",
+		},
+		{
+			disableDefaultHostname: true,
+			submittedHostname:      "custom",
+			expectedHostname:       "custom",
+		},
+	} {
+		t.Run(fmt.Sprintf("case %d: %q -> %q", nb, tc.submittedHostname, tc.expectedHostname), func(t *testing.T) {
+			senderMetricSampleChan := make(chan senderMetricSample, 10)
+			serviceCheckChan := make(chan metrics.ServiceCheck, 10)
+			eventChan := make(chan metrics.Event, 10)
+			checkSender := newCheckSender(checkID1, defaultHostname, senderMetricSampleChan, serviceCheckChan, eventChan)
+			checkSender.DisableDefaultHostname(tc.disableDefaultHostname)
+
+			checkSender.Gauge("my.metric", 1.0, tc.submittedHostname, []string{"foo", "bar"})
+			checkSender.Commit()
+			checkSender.ServiceCheck("my_service.can_connect", metrics.ServiceCheckOK, tc.submittedHostname, []string{"foo", "bar"}, "message")
+			submittedEvent := metrics.Event{
+				Title:          "Something happened",
+				Text:           "Description of the event",
+				Ts:             12,
+				Priority:       metrics.EventPriorityLow,
+				Host:           tc.submittedHostname,
+				Tags:           []string{"foo", "bar"},
+				AlertType:      metrics.EventAlertTypeInfo,
+				AggregationKey: "event_agg_key",
+				SourceTypeName: "docker",
+			}
+			checkSender.Event(submittedEvent)
+
+			gaugeSenderSample := <-senderMetricSampleChan
+			assert.EqualValues(t, checkID1, gaugeSenderSample.id)
+			assert.Equal(t, metrics.GaugeType, gaugeSenderSample.metricSample.Mtype)
+			assert.Equal(t, tc.expectedHostname, gaugeSenderSample.metricSample.Host)
+			assert.Equal(t, false, gaugeSenderSample.commit)
+
+			serviceCheck := <-serviceCheckChan
+			assert.Equal(t, "my_service.can_connect", serviceCheck.CheckName)
+			assert.Equal(t, metrics.ServiceCheckOK, serviceCheck.Status)
+			assert.Equal(t, tc.expectedHostname, serviceCheck.Host)
+			assert.Equal(t, []string{"foo", "bar"}, serviceCheck.Tags)
+			assert.Equal(t, "message", serviceCheck.Message)
+
+			event := <-eventChan
+			assert.Equal(t, "Something happened", event.Title)
+			assert.Equal(t, int64(12), event.Ts)
+			assert.Equal(t, tc.expectedHostname, event.Host)
+			assert.Equal(t, []string{"foo", "bar"}, event.Tags)
+		})
+	}
+}
diff --git a/pkg/dogstatsd/parser.go b/pkg/dogstatsd/parser.go
index 2dae99f00d7163..7330d85f899aa8 100644
--- a/pkg/dogstatsd/parser.go
+++ b/pkg/dogstatsd/parser.go
@@ -84,7 +84,7 @@ func parseTags(rawTags []byte, extractHost bool, defaultHostname string) ([]stri
 	return tagsList, host
 }
 
-func parseServiceCheckMessage(message []byte) (*metrics.ServiceCheck, error) {
+func parseServiceCheckMessage(message []byte, defaultHostname string) (*metrics.ServiceCheck, error) {
 	// _sc|name|status|[metadata|...]
 
 	separatorCount := bytes.Count(message, fieldSeparator)
@@ -100,6 +100,7 @@ func parseServiceCheckMessage(message []byte) (*metrics.ServiceCheck, error) {
 
 	service := metrics.ServiceCheck{
 		CheckName: string(rawName),
+		Host:      defaultHostname,
 	}
 
 	if status, err := strconv.Atoi(string(rawStatus)); err != nil {
@@ -139,7 +140,7 @@ func parseServiceCheckMessage(message []byte) (*metrics.ServiceCheck, error) {
 	return &service, nil
 }
 
-func parseEventMessage(message []byte) (*metrics.Event, error) {
+func parseEventMessage(message []byte, defaultHostname string) (*metrics.Event, error) {
 	// _e{title.length,text.length}:title|text
 	//  [
 	//   |d:date_happened
@@ -186,6 +187,7 @@ func parseEventMessage(message []byte) (*metrics.Event, error) {
 	event := metrics.Event{
 		Priority:  metrics.EventPriorityNormal,
 		AlertType: metrics.EventAlertTypeInfo,
+		Host:      defaultHostname,
 		Title:     string(rawTitle),
 		Text:      string(bytes.Replace(rawText, []byte("\\n"), []byte("\n"), -1)),
 	}
diff --git a/pkg/dogstatsd/parser_test.go b/pkg/dogstatsd/parser_test.go
index f412196502b414..5ef793042244ad 100644
--- a/pkg/dogstatsd/parser_test.go
+++ b/pkg/dogstatsd/parser_test.go
@@ -322,11 +322,11 @@ func TestPacketStringEndings(t *testing.T) {
 }
 
 func TestServiceCheckMinimal(t *testing.T) {
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0"))
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0"), "default-hostname")
 
 	assert.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
-	assert.Equal(t, "", sc.Host)
+	assert.Equal(t, "default-hostname", sc.Host)
 	assert.Equal(t, int64(0), sc.Ts)
 	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
 	assert.Equal(t, "", sc.Message)
@@ -335,35 +335,35 @@ func TestServiceCheckMinimal(t *testing.T) {
 
 func TestServiceCheckError(t *testing.T) {
 	// not enough information
-	_, err := parseServiceCheckMessage([]byte("_sc|agent.up"))
+	_, err := parseServiceCheckMessage([]byte("_sc|agent.up"), "default-hostname")
 	assert.Error(t, err)
 
-	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|"))
+	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|"), "default-hostname")
 	assert.Error(t, err)
 
 	// not invalid status
-	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|OK"))
+	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|OK"), "default-hostname")
 	assert.Error(t, err)
 
 	// not unknown status
-	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|21"))
+	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|21"), "default-hostname")
 	assert.Error(t, err)
 
 	// invalid timestamp
-	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|0|d:some_time"))
+	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|0|d:some_time"), "default-hostname")
 	assert.NoError(t, err)
 
 	// unknown metadata
-	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|0|u:unknown"))
+	_, err = parseServiceCheckMessage([]byte("_sc|agent.up|0|u:unknown"), "default-hostname")
 	assert.NoError(t, err)
 }
 
 func TestServiceCheckMetadataTimestamp(t *testing.T) {
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|d:21"))
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|d:21"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
-	assert.Equal(t, "", sc.Host)
+	assert.Equal(t, "default-hostname", sc.Host)
 	assert.Equal(t, int64(21), sc.Ts)
 	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
 	assert.Equal(t, "", sc.Message)
@@ -371,7 +371,7 @@ func TestServiceCheckMetadataTimestamp(t *testing.T) {
 }
 
 func TestServiceCheckMetadataHostname(t *testing.T) {
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|h:localhost"))
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|h:localhost"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
@@ -382,8 +382,8 @@ func TestServiceCheckMetadataHostname(t *testing.T) {
 	assert.Equal(t, []string(nil), sc.Tags)
 }
 
-func TestServiceCheckMetadataTags(t *testing.T) {
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|#tag1,tag2:test,tag3"))
+func TestServiceCheckMetadataEmptyHostname(t *testing.T) {
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|h:"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
@@ -391,15 +391,27 @@ func TestServiceCheckMetadataTags(t *testing.T) {
 	assert.Equal(t, int64(0), sc.Ts)
 	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
 	assert.Equal(t, "", sc.Message)
+	assert.Equal(t, []string(nil), sc.Tags)
+}
+
+func TestServiceCheckMetadataTags(t *testing.T) {
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|#tag1,tag2:test,tag3"), "default-hostname")
+
+	require.Nil(t, err)
+	assert.Equal(t, "agent.up", sc.CheckName)
+	assert.Equal(t, "default-hostname", sc.Host)
+	assert.Equal(t, int64(0), sc.Ts)
+	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
+	assert.Equal(t, "", sc.Message)
 	assert.Equal(t, []string{"tag1", "tag2:test", "tag3"}, sc.Tags)
 }
 
 func TestServiceCheckMetadataMessage(t *testing.T) {
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|m:this is fine"))
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|m:this is fine"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
-	assert.Equal(t, "", sc.Host)
+	assert.Equal(t, "default-hostname", sc.Host)
 	assert.Equal(t, int64(0), sc.Ts)
 	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
 	assert.Equal(t, "this is fine", sc.Message)
@@ -408,7 +420,7 @@ func TestServiceCheckMetadataMessage(t *testing.T) {
 
 func TestServiceCheckMetadataMultiple(t *testing.T) {
 	// all type
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|d:21|h:localhost|#tag1:test,tag2|m:this is fine"))
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|d:21|h:localhost|#tag1:test,tag2|m:this is fine"), "default-hostname")
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
 	assert.Equal(t, "localhost", sc.Host)
@@ -418,7 +430,7 @@ func TestServiceCheckMetadataMultiple(t *testing.T) {
 	assert.Equal(t, []string{"tag1:test", "tag2"}, sc.Tags)
 
 	// multiple time the same tag
-	sc, err = parseServiceCheckMessage([]byte("_sc|agent.up|0|d:21|h:localhost|h:localhost2|d:22"))
+	sc, err = parseServiceCheckMessage([]byte("_sc|agent.up|0|d:21|h:localhost|h:localhost2|d:22"), "default-hostname")
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
 	assert.Equal(t, "localhost2", sc.Host)
@@ -429,14 +441,14 @@ func TestServiceCheckMetadataMultiple(t *testing.T) {
 }
 
 func TestEventMinimal(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test text", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -445,14 +457,14 @@ func TestEventMinimal(t *testing.T) {
 }
 
 func TestEventMultilinesText(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,24}:test title|test\\line1\\nline2\\nline3"))
+	e, err := parseEventMessage([]byte("_e{10,24}:test title|test\\line1\\nline2\\nline3"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test\\line1\nline2\nline3", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -461,14 +473,14 @@ func TestEventMultilinesText(t *testing.T) {
 }
 
 func TestEventPipeInTitle(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,24}:test|title|test\\line1\\nline2\\nline3"))
+	e, err := parseEventMessage([]byte("_e{10,24}:test|title|test\\line1\\nline2\\nline3"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test|title", e.Title)
 	assert.Equal(t, "test\\line1\nline2\nline3", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -478,78 +490,78 @@ func TestEventPipeInTitle(t *testing.T) {
 
 func TestEventError(t *testing.T) {
 	// missing length header
-	_, err := parseEventMessage([]byte("_e:title|text"))
+	_, err := parseEventMessage([]byte("_e:title|text"), "default-hostname")
 	assert.Error(t, err)
 
 	// greater length than packet
-	_, err = parseEventMessage([]byte("_e{10,10}:title|text"))
+	_, err = parseEventMessage([]byte("_e{10,10}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
 	// zero length
-	_, err = parseEventMessage([]byte("_e{0,0}:a|a"))
+	_, err = parseEventMessage([]byte("_e{0,0}:a|a"), "default-hostname")
 	assert.Error(t, err)
 
 	// missing title or text length
-	_, err = parseEventMessage([]byte("_e{5555:title|text"))
+	_, err = parseEventMessage([]byte("_e{5555:title|text"), "default-hostname")
 	assert.Error(t, err)
 
 	// missing wrong len format
-	_, err = parseEventMessage([]byte("_e{a,1}:title|text"))
+	_, err = parseEventMessage([]byte("_e{a,1}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
-	_, err = parseEventMessage([]byte("_e{1,a}:title|text"))
+	_, err = parseEventMessage([]byte("_e{1,a}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
 	// missing title or text length
-	_, err = parseEventMessage([]byte("_e{5,}:title|text"))
+	_, err = parseEventMessage([]byte("_e{5,}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
-	_, err = parseEventMessage([]byte("_e{,4}:title|text"))
+	_, err = parseEventMessage([]byte("_e{,4}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
-	_, err = parseEventMessage([]byte("_e{}:title|text"))
+	_, err = parseEventMessage([]byte("_e{}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
-	_, err = parseEventMessage([]byte("_e{,}:title|text"))
+	_, err = parseEventMessage([]byte("_e{,}:title|text"), "default-hostname")
 	assert.Error(t, err)
 
 	// not enough information
-	_, err = parseEventMessage([]byte("_e|text"))
+	_, err = parseEventMessage([]byte("_e|text"), "default-hostname")
 	assert.Error(t, err)
 
-	_, err = parseEventMessage([]byte("_e:|text"))
+	_, err = parseEventMessage([]byte("_e:|text"), "default-hostname")
 	assert.Error(t, err)
 
 	// invalid timestamp
-	_, err = parseEventMessage([]byte("_e{5,4}:title|text|d:abc"))
+	_, err = parseEventMessage([]byte("_e{5,4}:title|text|d:abc"), "default-hostname")
 	assert.NoError(t, err)
 
 	// invalid priority
-	_, err = parseEventMessage([]byte("_e{5,4}:title|text|p:urgent"))
+	_, err = parseEventMessage([]byte("_e{5,4}:title|text|p:urgent"), "default-hostname")
 	assert.NoError(t, err)
 
 	// invalid priority
-	_, err = parseEventMessage([]byte("_e{5,4}:title|text|p:urgent"))
+	_, err = parseEventMessage([]byte("_e{5,4}:title|text|p:urgent"), "default-hostname")
 	assert.NoError(t, err)
 
 	// invalid alert type
-	_, err = parseEventMessage([]byte("_e{5,4}:title|text|t:test"))
+	_, err = parseEventMessage([]byte("_e{5,4}:title|text|t:test"), "default-hostname")
 	assert.NoError(t, err)
 
 	// unknown metadata
-	_, err = parseEventMessage([]byte("_e{5,4}:title|text|x:1234"))
+	_, err = parseEventMessage([]byte("_e{5,4}:title|text|x:1234"), "default-hostname")
 	assert.NoError(t, err)
 }
 
 func TestEventMetadataTimestamp(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|d:21"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|d:21"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test text", e.Text)
 	assert.Equal(t, int64(21), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -558,14 +570,14 @@ func TestEventMetadataTimestamp(t *testing.T) {
 }
 
 func TestEventMetadataPriority(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|p:low"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|p:low"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test text", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityLow, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -574,7 +586,7 @@ func TestEventMetadataPriority(t *testing.T) {
 }
 
 func TestEventMetadataHostname(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|h:localhost"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|h:localhost"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
@@ -589,8 +601,8 @@ func TestEventMetadataHostname(t *testing.T) {
 	assert.Equal(t, "", e.EventType)
 }
 
-func TestEventMetadataAlertType(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|t:warning"))
+func TestEventMetadataEmptyHostname(t *testing.T) {
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|h:"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
@@ -599,6 +611,22 @@ func TestEventMetadataAlertType(t *testing.T) {
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
 	assert.Equal(t, "", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
+	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
+	assert.Equal(t, "", e.AggregationKey)
+	assert.Equal(t, "", e.SourceTypeName)
+	assert.Equal(t, "", e.EventType)
+}
+
+func TestEventMetadataAlertType(t *testing.T) {
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|t:warning"), "default-hostname")
+
+	require.Nil(t, err)
+	assert.Equal(t, "test title", e.Title)
+	assert.Equal(t, "test text", e.Text)
+	assert.Equal(t, int64(0), e.Ts)
+	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
+	assert.Equal(t, "default-hostname", e.Host)
+	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeWarning, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
 	assert.Equal(t, "", e.SourceTypeName)
@@ -606,14 +634,14 @@ func TestEventMetadataAlertType(t *testing.T) {
 }
 
 func TestEventMetadataAggregatioKey(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|k:some aggregation key"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|k:some aggregation key"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test text", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "some aggregation key", e.AggregationKey)
@@ -622,14 +650,14 @@ func TestEventMetadataAggregatioKey(t *testing.T) {
 }
 
 func TestEventMetadataSourceType(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|s:this is the source"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|s:this is the source"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test text", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string(nil), e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -638,14 +666,14 @@ func TestEventMetadataSourceType(t *testing.T) {
 }
 
 func TestEventMetadataTags(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|#tag1,tag2:test"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|#tag1,tag2:test"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
 	assert.Equal(t, "test text", e.Text)
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
-	assert.Equal(t, "", e.Host)
+	assert.Equal(t, "default-hostname", e.Host)
 	assert.Equal(t, []string{"tag1", "tag2:test"}, e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
@@ -654,7 +682,7 @@ func TestEventMetadataTags(t *testing.T) {
 }
 
 func TestEventMetadataMultiple(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|t:warning|d:12345|p:low|h:some.host|k:aggKey|s:source test|#tag1,tag2:test"))
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|t:warning|d:12345|p:low|h:some.host|k:aggKey|s:source test|#tag1,tag2:test"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
diff --git a/pkg/dogstatsd/server.go b/pkg/dogstatsd/server.go
index 3b8a38da3a40e7..f5591a32633a74 100644
--- a/pkg/dogstatsd/server.go
+++ b/pkg/dogstatsd/server.go
@@ -214,7 +214,7 @@ func (s *Server) worker(metricOut chan<- *metrics.MetricSample, eventOut chan<-
 				}
 
 				if bytes.HasPrefix(message, []byte("_sc")) {
-					serviceCheck, err := parseServiceCheckMessage(message)
+					serviceCheck, err := parseServiceCheckMessage(message, s.defaultHostname)
 					if err != nil {
 						log.Errorf("Dogstatsd: error parsing service check: %s", err)
 						dogstatsdServiceCheckParseErrors.Add(1)
@@ -226,7 +226,7 @@ func (s *Server) worker(metricOut chan<- *metrics.MetricSample, eventOut chan<-
 					dogstatsdServiceCheckPackets.Add(1)
 					serviceCheckOut <- *serviceCheck
 				} else if bytes.HasPrefix(message, []byte("_e")) {
-					event, err := parseEventMessage(message)
+					event, err := parseEventMessage(message, s.defaultHostname)
 					if err != nil {
 						log.Errorf("Dogstatsd: error parsing event: %s", err)
 						dogstatsdEventParseErrors.Add(1)

From 536c6f07cfbb53e253b4ef6ca8cd3e6de81aabcf Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Tue, 18 Sep 2018 17:14:47 +0200
Subject: [PATCH 02/14] remove from distsampler and timesampler too

---
 pkg/aggregator/aggregator.go        |   4 +-
 pkg/aggregator/dist_sampler.go      |  16 ++--
 pkg/aggregator/dist_sampler_test.go |  12 +--
 pkg/aggregator/time_sampler.go      |   7 +-
 pkg/aggregator/time_sampler_test.go | 115 +---------------------------
 5 files changed, 19 insertions(+), 135 deletions(-)

diff --git a/pkg/aggregator/aggregator.go b/pkg/aggregator/aggregator.go
index 1839817e023e2d..242fd921e06a4e 100644
--- a/pkg/aggregator/aggregator.go
+++ b/pkg/aggregator/aggregator.go
@@ -173,9 +173,9 @@ func NewBufferedAggregator(s *serializer.Serializer, hostname string, flushInter
 		checkMetricIn:      make(chan senderMetricSample, 100),    // TODO make buffer size configurable
 		serviceCheckIn:     make(chan metrics.ServiceCheck, 100),  // TODO make buffer size configurable
 		eventIn:            make(chan metrics.Event, 100),         // TODO make buffer size configurable
-		sampler:            *NewTimeSampler(bucketSize, hostname),
+		sampler:            *NewTimeSampler(bucketSize),
 		checkSamplers:      make(map[check.ID]*CheckSampler),
-		distSampler:        newDistSampler(bucketSize, hostname),
+		distSampler:        newDistSampler(bucketSize),
 		flushInterval:      flushInterval,
 		serializer:         s,
 		hostname:           hostname,
diff --git a/pkg/aggregator/dist_sampler.go b/pkg/aggregator/dist_sampler.go
index 8225bef518d8a7..a8a6eb760b7ba6 100644
--- a/pkg/aggregator/dist_sampler.go
+++ b/pkg/aggregator/dist_sampler.go
@@ -16,23 +16,21 @@ import (
 )
 
 type distSampler struct {
-	interval        int64
-	defaultHostname string
+	interval int64
 
 	m           sketchMap
 	ctxResolver *ContextResolver
 }
 
-func newDistSampler(interval int64, defaultHostname string) distSampler {
+func newDistSampler(interval int64) distSampler {
 	if interval == 0 {
 		interval = bucketSize
 	}
 
 	return distSampler{
-		interval:        interval,
-		defaultHostname: defaultHostname,
-		m:               make(sketchMap),
-		ctxResolver:     newContextResolver(),
+		interval:    interval,
+		m:           make(sketchMap),
+		ctxResolver: newContextResolver(),
 	}
 }
 
@@ -75,10 +73,6 @@ func (d *distSampler) newSeries(ck ckey.ContextKey, points []metrics.SketchPoint
 		ContextKey: ck,
 	}
 
-	if ss.Host == "" {
-		ss.Host = d.defaultHostname
-	}
-
 	return ss
 }
 
diff --git a/pkg/aggregator/dist_sampler_test.go b/pkg/aggregator/dist_sampler_test.go
index 1dfcbc5f18cf73..fd2afed589883b 100644
--- a/pkg/aggregator/dist_sampler_test.go
+++ b/pkg/aggregator/dist_sampler_test.go
@@ -9,21 +9,21 @@ import (
 	"sort"
 	"testing"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/DataDog/datadog-agent/pkg/aggregator/ckey"
 	"github.com/DataDog/datadog-agent/pkg/metrics"
 	"github.com/DataDog/datadog-agent/pkg/quantile"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
 )
 
 func TestDistSampler(t *testing.T) {
 	const (
-		defaultHost       = "default_host"
 		defaultBucketSize = 10
 	)
 
 	var (
-		d = newDistSampler(0, defaultHost)
+		d = newDistSampler(0)
 
 		insert = func(t *testing.T, ts float64, ctx Context, values ...float64) {
 			t.Helper()
@@ -85,7 +85,7 @@ func TestDistSampler(t *testing.T) {
 
 func TestDistSamplerBucketSampling(t *testing.T) {
 
-	distSampler := newDistSampler(10, "")
+	distSampler := newDistSampler(10)
 
 	mSample1 := metrics.MetricSample{
 		Name:       "test.metric.name",
@@ -128,7 +128,7 @@ func TestDistSamplerBucketSampling(t *testing.T) {
 }
 
 func TestDistSamplerContextSampling(t *testing.T) {
-	distSampler := newDistSampler(10, "")
+	distSampler := newDistSampler(10)
 
 	mSample1 := metrics.MetricSample{
 		Name:       "test.metric.name1",
diff --git a/pkg/aggregator/time_sampler.go b/pkg/aggregator/time_sampler.go
index 1e6a3a2287b97c..26afe5b0b75950 100644
--- a/pkg/aggregator/time_sampler.go
+++ b/pkg/aggregator/time_sampler.go
@@ -6,11 +6,10 @@
 package aggregator
 
 import (
-	"github.com/DataDog/datadog-agent/pkg/util/log"
-
 	"github.com/DataDog/datadog-agent/pkg/aggregator/ckey"
 	"github.com/DataDog/datadog-agent/pkg/config"
 	"github.com/DataDog/datadog-agent/pkg/metrics"
+	"github.com/DataDog/datadog-agent/pkg/util/log"
 )
 
 const defaultExpiry = 300.0 // number of seconds after which contexts are expired
@@ -28,18 +27,16 @@ type TimeSampler struct {
 	interval                    int64
 	contextResolver             *ContextResolver
 	metricsByTimestamp          map[int64]metrics.ContextMetrics
-	defaultHostname             string
 	counterLastSampledByContext map[ckey.ContextKey]float64
 	lastCutOffTime              int64
 }
 
 // NewTimeSampler returns a newly initialized TimeSampler
-func NewTimeSampler(interval int64, defaultHostname string) *TimeSampler {
+func NewTimeSampler(interval int64) *TimeSampler {
 	return &TimeSampler{
 		interval:                    interval,
 		contextResolver:             newContextResolver(),
 		metricsByTimestamp:          map[int64]metrics.ContextMetrics{},
-		defaultHostname:             defaultHostname,
 		counterLastSampledByContext: map[ckey.ContextKey]float64{},
 	}
 }
diff --git a/pkg/aggregator/time_sampler_test.go b/pkg/aggregator/time_sampler_test.go
index b212f3e7bbd145..eed83fe40b9cef 100644
--- a/pkg/aggregator/time_sampler_test.go
+++ b/pkg/aggregator/time_sampler_test.go
@@ -6,15 +6,12 @@
 package aggregator
 
 import (
-	// stdlib
 	"sort"
 	"testing"
 
-	// 3p
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	// project
 	"github.com/DataDog/datadog-agent/pkg/aggregator/ckey"
 	"github.com/DataDog/datadog-agent/pkg/metrics"
 )
@@ -37,7 +34,7 @@ func (os OrderedSeries) Swap(i, j int) {
 
 // TimeSampler
 func TestCalculateBucketStart(t *testing.T) {
-	sampler := NewTimeSampler(10, "")
+	sampler := NewTimeSampler(10)
 
 	assert.Equal(t, int64(123450), sampler.calculateBucketStart(123456.5))
 	assert.Equal(t, int64(123460), sampler.calculateBucketStart(123460.5))
@@ -45,7 +42,7 @@ func TestCalculateBucketStart(t *testing.T) {
 }
 
 func TestBucketSampling(t *testing.T) {
-	sampler := NewTimeSampler(10, "")
+	sampler := NewTimeSampler(10)
 
 	mSample := metrics.MetricSample{
 		Name:       "my.metric.name",
@@ -76,7 +73,7 @@ func TestBucketSampling(t *testing.T) {
 }
 
 func TestContextSampling(t *testing.T) {
-	sampler := NewTimeSampler(10, "default-hostname")
+	sampler := NewTimeSampler(10)
 
 	mSample1 := metrics.MetricSample{
 		Name:       "my.metric.name1",
@@ -142,7 +139,7 @@ func TestContextSampling(t *testing.T) {
 }
 
 func TestCounterExpirySeconds(t *testing.T) {
-	sampler := NewTimeSampler(10, "default-hostname")
+	sampler := NewTimeSampler(10)
 
 	sampleCounter1 := &metrics.MetricSample{
 		Name:       "my.counter1",
@@ -267,107 +264,3 @@ func TestCounterExpirySeconds(t *testing.T) {
 	assert.Equal(t, 0, len(sampler.counterLastSampledByContext))
 	assert.Equal(t, 0, len(sampler.contextResolver.contextsByKey))
 }
-
-//func TestOne(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestFormatter(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestCounterNormalization(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestHistogramNormalization(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestCounter(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestSampledCounter(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestGauge(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestSets(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestStringSets(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestRate(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestRateErrors(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestGaugeSampleRate(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestHistogram(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestSampledHistogram(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestBatchSubmission(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestMonokeyBatchingNoTags(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestMonokeyBatchingWithTags(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestMonokeyBatchingWithTagsWithSampling(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestBadPacketsThrowErrors(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestMetricsExpiry(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestDiagnosticStats(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestHistogramCounter(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestEventTags(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestServiceCheckBasic(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestServiceCheckTags(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}
-//
-//func TestRecentPointThreshold(t *testing.T) {
-//	assert.Equal(t, 1, 1)
-//}

From e5bba7e3c79a7ae78388d25b7f60f7b1421012d9 Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Tue, 18 Sep 2018 17:34:40 +0200
Subject: [PATCH 03/14] improve testing

---
 pkg/aggregator/aggregator_test.go |  7 +++++++
 pkg/aggregator/sender_test.go     | 22 ++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/pkg/aggregator/aggregator_test.go b/pkg/aggregator/aggregator_test.go
index 5dd8812d26430a..33e239fe593828 100644
--- a/pkg/aggregator/aggregator_test.go
+++ b/pkg/aggregator/aggregator_test.go
@@ -132,6 +132,13 @@ func TestSetHostname(t *testing.T) {
 	resetAggregator()
 	agg := InitAggregator(nil, "hostname")
 	assert.Equal(t, "hostname", agg.hostname)
+	sender, err := GetSender(checkID1)
+	require.NoError(t, err)
+	checkSender, ok := sender.(*checkSender)
+	require.True(t, ok)
+	assert.Equal(t, "hostname", checkSender.defaultHostname)
+
 	agg.SetHostname("different-hostname")
 	assert.Equal(t, "different-hostname", agg.hostname)
+	assert.Equal(t, "different-hostname", checkSender.defaultHostname)
 }
diff --git a/pkg/aggregator/sender_test.go b/pkg/aggregator/sender_test.go
index c190d9ae99633a..0e55da2567a0f3 100644
--- a/pkg/aggregator/sender_test.go
+++ b/pkg/aggregator/sender_test.go
@@ -264,3 +264,25 @@ func TestCheckSenderHostname(t *testing.T) {
 		})
 	}
 }
+
+func TestChangeAllSendersDefaultHostname(t *testing.T) {
+	senderMetricSampleChan := make(chan senderMetricSample, 10)
+	serviceCheckChan := make(chan metrics.ServiceCheck, 10)
+	eventChan := make(chan metrics.Event, 10)
+	checkSender := newCheckSender(checkID1, "hostname1", senderMetricSampleChan, serviceCheckChan, eventChan)
+	SetSender(checkSender, checkID1)
+
+	checkSender.Gauge("my.metric", 1.0, "", nil)
+	gaugeSenderSample := <-senderMetricSampleChan
+	assert.Equal(t, "hostname1", gaugeSenderSample.metricSample.Host)
+
+	changeAllSendersDefaultHostname("hostname2")
+	checkSender.Gauge("my.metric", 1.0, "", nil)
+	gaugeSenderSample = <-senderMetricSampleChan
+	assert.Equal(t, "hostname2", gaugeSenderSample.metricSample.Host)
+
+	changeAllSendersDefaultHostname("hostname1")
+	checkSender.Gauge("my.metric", 1.0, "", nil)
+	gaugeSenderSample = <-senderMetricSampleChan
+	assert.Equal(t, "hostname1", gaugeSenderSample.metricSample.Host)
+}

From 3419582fd7fb6c0f7ae5fe88afa34c888f369e6b Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 19 Sep 2018 12:03:09 +0200
Subject: [PATCH 04/14] fix hostname passing in checksampler

---
 pkg/aggregator/check_sampler.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkg/aggregator/check_sampler.go b/pkg/aggregator/check_sampler.go
index 39ce305a26b98c..0933e6cc16815f 100644
--- a/pkg/aggregator/check_sampler.go
+++ b/pkg/aggregator/check_sampler.go
@@ -56,6 +56,7 @@ func (cs *CheckSampler) commit(timestamp float64) {
 		}
 		serie.Name = context.Name + serie.NameSuffix
 		serie.Tags = context.Tags
+		serie.Host = context.Host
 		serie.SourceTypeName = checksSourceTypeName // this source type is required for metrics coming from the checks
 
 		cs.series = append(cs.series, serie)

From 9251008d0ab33036de6d1310bf40da3c1ccb531c Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 19 Sep 2018 14:42:59 +0200
Subject: [PATCH 05/14] improve testing

---
 pkg/aggregator/sender.go      |  6 +++---
 pkg/aggregator/sender_test.go | 16 ++++++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/pkg/aggregator/sender.go b/pkg/aggregator/sender.go
index c913a726499a03..cd5682d3c1893c 100644
--- a/pkg/aggregator/sender.go
+++ b/pkg/aggregator/sender.go
@@ -203,7 +203,7 @@ func (s *checkSender) sendMetricSample(metric string, value float64, hostname st
 		Timestamp:  timeNowNano(),
 	}
 
-	if !s.disableDefaultHostname && metricSample.Host == "" {
+	if hostname == "" && !s.disableDefaultHostname {
 		metricSample.Host = s.defaultHostname
 	}
 
@@ -271,7 +271,7 @@ func (s *checkSender) ServiceCheck(checkName string, status metrics.ServiceCheck
 		Message:   message,
 	}
 
-	if !s.disableDefaultHostname && serviceCheck.Host == "" {
+	if hostname == "" && !s.disableDefaultHostname {
 		serviceCheck.Host = s.defaultHostname
 	}
 
@@ -286,7 +286,7 @@ func (s *checkSender) ServiceCheck(checkName string, status metrics.ServiceCheck
 func (s *checkSender) Event(e metrics.Event) {
 	log.Trace("Event submitted: ", e.Title, " for hostname: ", e.Host, " tags: ", e.Tags)
 
-	if !s.disableDefaultHostname && e.Host == "" {
+	if e.Host == "" && !s.disableDefaultHostname {
 		e.Host = s.defaultHostname
 	}
 
diff --git a/pkg/aggregator/sender_test.go b/pkg/aggregator/sender_test.go
index 0e55da2567a0f3..8ffd4ce3dc344c 100644
--- a/pkg/aggregator/sender_test.go
+++ b/pkg/aggregator/sender_test.go
@@ -14,6 +14,7 @@ import (
 	// 3p
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	"github.com/DataDog/datadog-agent/pkg/collector/check"
 	"github.com/DataDog/datadog-agent/pkg/metrics"
@@ -119,6 +120,21 @@ func TestGetAndSetSender(t *testing.T) {
 
 }
 
+func TestGetSenderDefaultHostname(t *testing.T) {
+	resetAggregator()
+	InitAggregator(nil, "testhostname")
+
+	sender, err := GetSender(checkID1)
+	require.NoError(t, err)
+
+	checksender, ok := sender.(*checkSender)
+	require.True(t, ok)
+
+	assert.Equal(t, "testhostname", checksender.defaultHostname)
+	assert.Equal(t, false, checksender.disableDefaultHostname)
+
+}
+
 func TestCheckSenderInterface(t *testing.T) {
 	senderMetricSampleChan := make(chan senderMetricSample, 10)
 	serviceCheckChan := make(chan metrics.ServiceCheck, 10)

From 30377f3db19b3145cb92d47827b2d03e300e2c91 Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 19 Sep 2018 14:50:37 +0200
Subject: [PATCH 06/14] use agent hostname in the startup event

---
 pkg/aggregator/aggregator.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/pkg/aggregator/aggregator.go b/pkg/aggregator/aggregator.go
index 242fd921e06a4e..2b14fa24f6535f 100644
--- a/pkg/aggregator/aggregator.go
+++ b/pkg/aggregator/aggregator.go
@@ -227,6 +227,7 @@ func (agg *BufferedAggregator) AddAgentStartupEvent(agentVersion string) {
 	event := metrics.Event{
 		Text:           fmt.Sprintf("Version %s", agentVersion),
 		SourceTypeName: "System",
+		Host:           agg.hostname,
 		EventType:      "Agent Startup",
 	}
 	agg.eventIn <- event

From 50b4434b8f03c8e985b5255cda19dea151e2c259 Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 19 Sep 2018 16:02:26 +0200
Subject: [PATCH 07/14] handle empty host: tag for dsd events and service
 checks

---
 pkg/dogstatsd/parser.go      | 31 ++++++++++++++++++++++------
 pkg/dogstatsd/parser_test.go | 40 ++++++++++++++++++++++++++++++------
 2 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/pkg/dogstatsd/parser.go b/pkg/dogstatsd/parser.go
index 7330d85f899aa8..db7abb9cb0ae6e 100644
--- a/pkg/dogstatsd/parser.go
+++ b/pkg/dogstatsd/parser.go
@@ -100,7 +100,6 @@ func parseServiceCheckMessage(message []byte, defaultHostname string) (*metrics.
 
 	service := metrics.ServiceCheck{
 		CheckName: string(rawName),
-		Host:      defaultHostname,
 	}
 
 	if status, err := strconv.Atoi(string(rawStatus)); err != nil {
@@ -111,6 +110,11 @@ func parseServiceCheckMessage(message []byte, defaultHostname string) (*metrics.
 		service.Status = serviceStatus
 	}
 
+	// Handle hostname, with a priority to the h: field, then the host:
+	// tag and finally the defaultHostname value
+	var hostFromField string
+	hostFromTags := defaultHostname
+
 	// Metadata
 	for {
 		var rawMetadataField []byte
@@ -127,9 +131,9 @@ func parseServiceCheckMessage(message []byte, defaultHostname string) (*metrics.
 			}
 			service.Ts = ts
 		} else if bytes.HasPrefix(rawMetadataField, []byte("h:")) {
-			service.Host = string(rawMetadataField[2:])
+			hostFromField = string(rawMetadataField[2:])
 		} else if bytes.HasPrefix(rawMetadataField, []byte("#")) {
-			service.Tags, _ = parseTags(rawMetadataField[1:], false, "")
+			service.Tags, hostFromTags = parseTags(rawMetadataField[1:], true, defaultHostname)
 		} else if bytes.HasPrefix(rawMetadataField, []byte("m:")) {
 			service.Message = string(rawMetadataField[2:])
 		} else {
@@ -137,6 +141,11 @@ func parseServiceCheckMessage(message []byte, defaultHostname string) (*metrics.
 		}
 	}
 
+	if hostFromField != "" {
+		service.Host = hostFromField
+	} else {
+		service.Host = hostFromTags
+	}
 	return &service, nil
 }
 
@@ -187,11 +196,15 @@ func parseEventMessage(message []byte, defaultHostname string) (*metrics.Event,
 	event := metrics.Event{
 		Priority:  metrics.EventPriorityNormal,
 		AlertType: metrics.EventAlertTypeInfo,
-		Host:      defaultHostname,
 		Title:     string(rawTitle),
 		Text:      string(bytes.Replace(rawText, []byte("\\n"), []byte("\n"), -1)),
 	}
 
+	// Handle hostname, with a priority to the h: field, then the host:
+	// tag and finally the defaultHostname value
+	var hostFromField string
+	hostFromTags := defaultHostname
+
 	// Metadata
 	if len(message) > 1 {
 		rawMetadataFields := bytes.Split(message[1:], []byte("|"))
@@ -212,7 +225,7 @@ func parseEventMessage(message []byte, defaultHostname string) (*metrics.Event,
 				}
 				event.Priority = priority
 			} else if bytes.HasPrefix(rawMetadataFields[i], []byte("h:")) {
-				event.Host = string(rawMetadataFields[i][2:])
+				hostFromField = string(rawMetadataFields[i][2:])
 			} else if bytes.HasPrefix(rawMetadataFields[i], []byte("t:")) {
 				t, err := metrics.GetAlertTypeFromString(string(rawMetadataFields[i][2:]))
 				if err != nil {
@@ -225,13 +238,19 @@ func parseEventMessage(message []byte, defaultHostname string) (*metrics.Event,
 			} else if bytes.HasPrefix(rawMetadataFields[i], []byte("s:")) {
 				event.SourceTypeName = string(rawMetadataFields[i][2:])
 			} else if bytes.HasPrefix(rawMetadataFields[i], []byte("#")) {
-				event.Tags, _ = parseTags(rawMetadataFields[i][1:], false, "")
+				event.Tags, hostFromTags = parseTags(rawMetadataFields[i][1:], true, defaultHostname)
+
 			} else {
 				log.Warnf("unknown metadata type: '%s'", rawMetadataFields[i])
 			}
 		}
 	}
 
+	if hostFromField != "" {
+		event.Host = hostFromField
+	} else {
+		event.Host = hostFromTags
+	}
 	return &event, nil
 }
 
diff --git a/pkg/dogstatsd/parser_test.go b/pkg/dogstatsd/parser_test.go
index 5ef793042244ad..7ae32e57fea2ad 100644
--- a/pkg/dogstatsd/parser_test.go
+++ b/pkg/dogstatsd/parser_test.go
@@ -382,8 +382,20 @@ func TestServiceCheckMetadataHostname(t *testing.T) {
 	assert.Equal(t, []string(nil), sc.Tags)
 }
 
-func TestServiceCheckMetadataEmptyHostname(t *testing.T) {
-	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|h:"), "default-hostname")
+func TestServiceCheckMetadataHostnameInTag(t *testing.T) {
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|#host:localhost"), "default-hostname")
+
+	require.Nil(t, err)
+	assert.Equal(t, "agent.up", sc.CheckName)
+	assert.Equal(t, "localhost", sc.Host)
+	assert.Equal(t, int64(0), sc.Ts)
+	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
+	assert.Equal(t, "", sc.Message)
+	assert.Equal(t, []string{}, sc.Tags)
+}
+
+func TestServiceCheckMetadataEmptyHostTag(t *testing.T) {
+	sc, err := parseServiceCheckMessage([]byte("_sc|agent.up|0|#host:,other:tag"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "agent.up", sc.CheckName)
@@ -391,7 +403,7 @@ func TestServiceCheckMetadataEmptyHostname(t *testing.T) {
 	assert.Equal(t, int64(0), sc.Ts)
 	assert.Equal(t, metrics.ServiceCheckOK, sc.Status)
 	assert.Equal(t, "", sc.Message)
-	assert.Equal(t, []string(nil), sc.Tags)
+	assert.Equal(t, []string{"other:tag"}, sc.Tags)
 }
 
 func TestServiceCheckMetadataTags(t *testing.T) {
@@ -601,8 +613,24 @@ func TestEventMetadataHostname(t *testing.T) {
 	assert.Equal(t, "", e.EventType)
 }
 
-func TestEventMetadataEmptyHostname(t *testing.T) {
-	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|h:"), "default-hostname")
+func TestEventMetadataHostnameInTag(t *testing.T) {
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|#host:localhost"), "default-hostname")
+
+	require.Nil(t, err)
+	assert.Equal(t, "test title", e.Title)
+	assert.Equal(t, "test text", e.Text)
+	assert.Equal(t, int64(0), e.Ts)
+	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
+	assert.Equal(t, "localhost", e.Host)
+	assert.Equal(t, []string{}, e.Tags)
+	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
+	assert.Equal(t, "", e.AggregationKey)
+	assert.Equal(t, "", e.SourceTypeName)
+	assert.Equal(t, "", e.EventType)
+}
+
+func TestEventMetadataEmptyHostTag(t *testing.T) {
+	e, err := parseEventMessage([]byte("_e{10,9}:test title|test text|#host:,other:tag"), "default-hostname")
 
 	require.Nil(t, err)
 	assert.Equal(t, "test title", e.Title)
@@ -610,7 +638,7 @@ func TestEventMetadataEmptyHostname(t *testing.T) {
 	assert.Equal(t, int64(0), e.Ts)
 	assert.Equal(t, metrics.EventPriorityNormal, e.Priority)
 	assert.Equal(t, "", e.Host)
-	assert.Equal(t, []string(nil), e.Tags)
+	assert.Equal(t, []string{"other:tag"}, e.Tags)
 	assert.Equal(t, metrics.EventAlertTypeInfo, e.AlertType)
 	assert.Equal(t, "", e.AggregationKey)
 	assert.Equal(t, "", e.SourceTypeName)

From 7b7afe95ea452ca1dc2ea6061573337c157a426d Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 19 Sep 2018 16:04:23 +0200
Subject: [PATCH 08/14] reno

---
 .../notes/dogstatsd-empty-hostname-fefa16f74994210f.yaml      | 4 ++++
 1 file changed, 4 insertions(+)
 create mode 100644 releasenotes/notes/dogstatsd-empty-hostname-fefa16f74994210f.yaml

diff --git a/releasenotes/notes/dogstatsd-empty-hostname-fefa16f74994210f.yaml b/releasenotes/notes/dogstatsd-empty-hostname-fefa16f74994210f.yaml
new file mode 100644
index 00000000000000..b706dc4e0e32b5
--- /dev/null
+++ b/releasenotes/notes/dogstatsd-empty-hostname-fefa16f74994210f.yaml
@@ -0,0 +1,4 @@
+---
+enhancements:
+  - Dogstatsd supports removing the hostname on events and services checks
+    as it did with metrics, by adding an empty ``host:`` tag

From 32b29bb94f6c8b367d62c671366a7ddbaa8e8de8 Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 26 Sep 2018 15:30:59 +0200
Subject: [PATCH 09/14] clear cci cache

---
 .circleci/config.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 477dab8036fb3c..ff2308a9e40dc2 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -27,8 +27,8 @@ templates:
           # The first match will be used. Doing that so new branches
           # use master's cache but don't pollute it back.
           - v2-godeps-{{ .Branch }}-{{ .Revision }}
-          - v2-godeps-{{ .Branch }}-
-          - v2-godeps-master-
+          #- v2-godeps-{{ .Branch }}-
+          #- v2-godeps-master-
     - run: &enter_venv
         name: add virtualenv to bashrc
         command: echo "source /go/src/github.com/DataDog/datadog-agent/venv/bin/activate" >> $BASH_ENV

From 2287e6c4a548c89422c6b3fefc1d60aa34302fbc Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Wed, 26 Sep 2018 15:43:09 +0200
Subject: [PATCH 10/14] Revert "clear cci cache"

This reverts commit a99fc330ad7ae60c18ab21071428008fe3747b2b.
---
 .circleci/config.yml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index ff2308a9e40dc2..477dab8036fb3c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -27,8 +27,8 @@ templates:
           # The first match will be used. Doing that so new branches
           # use master's cache but don't pollute it back.
           - v2-godeps-{{ .Branch }}-{{ .Revision }}
-          #- v2-godeps-{{ .Branch }}-
-          #- v2-godeps-master-
+          - v2-godeps-{{ .Branch }}-
+          - v2-godeps-master-
     - run: &enter_venv
         name: add virtualenv to bashrc
         command: echo "source /go/src/github.com/DataDog/datadog-agent/venv/bin/activate" >> $BASH_ENV

From 3eafdaaddc358c91647ad60a89d5b174d55cf90d Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Thu, 27 Sep 2018 10:14:48 +0200
Subject: [PATCH 11/14] add end-to-end testing for check and dsd hostnames

---
 test/e2e/argo-workflows/agent.yaml            | 216 ++++++++++++++++--
 test/e2e/containers/dsd_sender/Dockerfile     |   7 +
 test/e2e/containers/dsd_sender/Makefile       |   9 +
 test/e2e/containers/dsd_sender/sender.py      |  22 ++
 .../scripts/run-instance/22-argo-submit.sh    |  10 +-
 5 files changed, 245 insertions(+), 19 deletions(-)
 create mode 100644 test/e2e/containers/dsd_sender/Dockerfile
 create mode 100644 test/e2e/containers/dsd_sender/Makefile
 create mode 100644 test/e2e/containers/dsd_sender/sender.py

diff --git a/test/e2e/argo-workflows/agent.yaml b/test/e2e/argo-workflows/agent.yaml
index 7c55d709b25f5d..0ed9663da39e97 100644
--- a/test/e2e/argo-workflows/agent.yaml
+++ b/test/e2e/argo-workflows/agent.yaml
@@ -96,6 +96,39 @@ spec:
                     memory: "64Mi"
                     cpu: "400m"
 
+    - name: dsd-hostname
+      value: |
+        apiVersion: extensions/v1beta1
+        kind: Deployment
+        metadata:
+          name: dsd-hostname
+          namespace: default
+        spec:
+          replicas: 1
+          template:
+            metadata:
+              labels:
+                app: dsd-hostname
+            spec:
+              containers:
+              - name: sender
+                image: datadog/docker-library:e2e-dsd-sender_latest
+                resources:
+                  requests:
+                    memory: "32Mi"
+                    cpu: "100m"
+                  limits:
+                    memory: "32Mi"
+                    cpu: "100m"
+                volumeMounts:
+                - name: dogstatsd
+                  mountPath: /var/run/dogstatsd
+                  readOnly: true
+              volumes:
+              - hostPath:
+                  path: /var/run/dogstatsd
+                name: dogstatsd
+
     - name: agent-service-account
       value: |
         kind: ServiceAccount
@@ -183,6 +216,9 @@ spec:
               polling: true
             leader_election: true
             kubernetes_metadata_tag_update_freq: 20
+            dogstatsd_socket: /var/run/dogstatsd/dsd.socket
+            # Hardcode a hostname to test dogstatsd hostname injection
+            hostname: e2e-test
 
           kubelet.yaml: |
             init_config:
@@ -207,7 +243,6 @@ spec:
             instances:
             - {}
 
-
     - name: agent-daemonset
       value: |
         apiVersion: extensions/v1beta1
@@ -280,7 +315,9 @@ spec:
                 - name: dockersocket
                   mountPath: /var/run/docker.sock
                   readOnly: true
-
+                - name: dogstatsd
+                  mountPath: /var/run/dogstatsd
+                  readOnly: false
               volumes:
               - name: datadog-config
                 configMap:
@@ -294,6 +331,9 @@ spec:
               - hostPath:
                   path: /var/run/docker.sock
                 name: dockersocket
+              - hostPath:
+                  path: /var/run/dogstatsd
+                name: dogstatsd
 
     - name: fake-datadog-service
       value: |
@@ -464,6 +504,7 @@ spec:
     inputs:
       parameters:
       - name: cpu-stress
+      - name: dsd-hostname
       - name: redis-service
       - name: redis-deployment
       - name: agent-configmap
@@ -500,6 +541,19 @@ spec:
         withItems:
         - "{{inputs.parameters.redis-deployment}}"
 
+      - name: kube-state-metrics-setup
+        template: manifest
+        arguments:
+          parameters:
+          - name: action
+            value: "apply"
+          - name: manifest
+            value: "{{item}}"
+        withItems:
+        - "{{inputs.parameters.kube-state-metrics-rbac}}"
+        - "{{inputs.parameters.kube-state-metrics-deployment}}"
+        - "{{inputs.parameters.kube-state-metrics-service}}"
+
       - name: cpu-stress-setup
         template: manifest
         arguments:
@@ -511,10 +565,7 @@ spec:
         withItems:
         - "{{inputs.parameters.cpu-stress}}"
 
-    - - name: fake-dd-reset
-        template: fake-dd-reset
-
-    - - name: agent-setup
+      - name: dsd-hostname
         template: manifest
         arguments:
           parameters:
@@ -523,13 +574,12 @@ spec:
           - name: manifest
             value: "{{item}}"
         withItems:
-        - "{{inputs.parameters.agent-configmap}}"
-        - "{{inputs.parameters.agent-service-account}}"
-        - "{{inputs.parameters.agent-cluster-role}}"
-        - "{{inputs.parameters.agent-cluster-role-binding}}"
-        - "{{inputs.parameters.agent-daemonset}}"
+        - "{{inputs.parameters.dsd-hostname}}"
+
+    - - name: fake-dd-reset
+        template: fake-dd-reset
 
-    - - name: kube-state-metrics-setup
+    - - name: agent-setup
         template: manifest
         arguments:
           parameters:
@@ -538,9 +588,11 @@ spec:
           - name: manifest
             value: "{{item}}"
         withItems:
-        - "{{inputs.parameters.kube-state-metrics-rbac}}"
-        - "{{inputs.parameters.kube-state-metrics-deployment}}"
-        - "{{inputs.parameters.kube-state-metrics-service}}"
+        - "{{inputs.parameters.agent-configmap}}"
+        - "{{inputs.parameters.agent-service-account}}"
+        - "{{inputs.parameters.agent-cluster-role}}"
+        - "{{inputs.parameters.agent-cluster-role-binding}}"
+        - "{{inputs.parameters.agent-daemonset}}"
 
     - - name: health
         template: datadog-agent-health
@@ -569,6 +621,12 @@ spec:
       - name: find-metrics-cpu-system
         template: find-metrics-cpu-system
 
+      - name: find-dogstatsd-hostname
+        template: find-dogstatsd-hostname
+
+      - name: find-checks-hostname
+        template: find-checks-hostname
+
     - - name: redis-service-setup
         template: manifest
         arguments:
@@ -615,6 +673,7 @@ spec:
       - name: redis-service
       - name: redis-deployment
       - name: cpu-stress
+      - name: dsd-hostname
       - name: agent-configmap
       - name: agent-service-account
       - name: agent-cluster-role
@@ -638,6 +697,7 @@ spec:
         - "{{inputs.parameters.redis-service}}"
         - "{{inputs.parameters.redis-deployment}}"
         - "{{inputs.parameters.cpu-stress}}"
+        - "{{inputs.parameters.dsd-hostname}}"
         - "{{inputs.parameters.agent-configmap}}"
         - "{{inputs.parameters.agent-service-account}}"
         - "{{inputs.parameters.agent-cluster-role}}"
@@ -847,6 +907,132 @@ spec:
           sleep(2000);
         }
 
+  - name: find-dogstatsd-hostname
+    activeDeadlineSeconds: 200
+    script:
+      image: mongo:3.6.3
+      command: [mongo, "fake-datadog.default.svc.cluster.local/datadog"]
+      source: |
+        while (1) {
+          sleep(2000);
+
+          // Gauges
+          var nb = db.series.find({
+            metric: "dsd.hostname.e2e",
+            host: "e2e-test",
+            tags: {$all: ["case:nominal"]}
+          }).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e metric with nominal hostname");
+            continue;
+          }
+          var nb = db.series.find({
+            metric: "dsd.hostname.e2e",
+            host: "forced",
+            tags: {$all: ["case:forced"]}
+          }).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e metric with forced hostname");
+            continue;
+          }
+          var nb = db.series.find({
+            metric: "dsd.hostname.e2e",
+            host: "",
+            tags: {$all: ["case:empty"]}
+          }).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e metric with empty hostname");
+            continue;
+          }
+
+          // Service checks
+          var nb = db.check_run.find({
+            check: "dsd.hostname.e2e",
+            host_name: "e2e-test",
+            tags: {$all: ["case:nominal"]}
+          }).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e servicecheck with nominal hostname");
+            continue;
+          }
+          var nb = db.check_run.find({
+            check: "dsd.hostname.e2e",
+            host_name: "forced",
+            tags: {$all: ["case:forced"]}
+          }).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e servicecheck with forced hostname");
+            continue;
+          }
+          var nb = db.check_run.find({
+            check: "dsd.hostname.e2e",
+            host_name: "",
+            tags: {$all: ["case:empty"]}
+          }).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e servicecheck with empty hostname");
+            continue;
+          }
+
+          // Events
+          var nb = db.intake.find({
+            "events.api": { $elemMatch: {
+              msg_title: "dsd.hostname.e2e",
+              host: "e2e-test",
+              tags: {$all: ["case:nominal"]}
+          }}}).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e event with nominal hostname");
+            continue;
+          }
+          var nb = db.intake.find({
+            "events.api": { $elemMatch: {
+              msg_title: "dsd.hostname.e2e",
+              host: "forced",
+              tags: {$all: ["case:forced"]}
+          }}}).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e event with forced hostname");
+            continue;
+          }
+          var nb = db.intake.find({
+            "events.api": { $elemMatch: {
+              msg_title: "dsd.hostname.e2e",
+              host: "",
+              tags: {$all: ["case:empty"]}
+          }}}).count();
+          if (nb == 0) {
+            print("no dsd.hostname.e2e event with empty hostname");
+            continue;
+          }
+
+          print("All good");
+          break;
+        }
+
+  - name: find-checks-hostname
+    activeDeadlineSeconds: 200
+    script:
+      image: mongo:3.6.3
+      command: [mongo, "fake-datadog.default.svc.cluster.local/datadog"]
+      source: |
+        while (1) {
+          sleep(2000);
+
+          // Gauges
+          var nb = db.series.find({
+            metric: "system.cpu.user",
+            host: "e2e-test"
+          }).count();
+          if (nb == 0) {
+            print("no system.cpu.user metric with nominal hostname");
+            continue;
+          }
+
+          print("All good");
+          break;
+        }
+
   - name: find-metrics-cpu-system
     activeDeadlineSeconds: 200
     script:
diff --git a/test/e2e/containers/dsd_sender/Dockerfile b/test/e2e/containers/dsd_sender/Dockerfile
new file mode 100644
index 00000000000000..1b6a5ae33c311d
--- /dev/null
+++ b/test/e2e/containers/dsd_sender/Dockerfile
@@ -0,0 +1,7 @@
+FROM datadog/docker-library:python_2_7-alpine3_6
+
+RUN pip install datadog
+
+COPY sender.py /sender.py
+
+CMD [ "python", "/sender.py" ]
diff --git a/test/e2e/containers/dsd_sender/Makefile b/test/e2e/containers/dsd_sender/Makefile
new file mode 100644
index 00000000000000..bfdc5e51e02727
--- /dev/null
+++ b/test/e2e/containers/dsd_sender/Makefile
@@ -0,0 +1,9 @@
+TAG?=latest
+
+default: build push
+
+build:
+	docker build --force-rm -t datadog/docker-library:e2e-dsd-sender_$(TAG) .
+
+push:
+	docker push datadog/docker-library:e2e-dsd-sender_$(TAG)
diff --git a/test/e2e/containers/dsd_sender/sender.py b/test/e2e/containers/dsd_sender/sender.py
new file mode 100644
index 00000000000000..4e3736ea393de1
--- /dev/null
+++ b/test/e2e/containers/dsd_sender/sender.py
@@ -0,0 +1,22 @@
+import datadog
+import time
+
+client = datadog.dogstatsd.base.DogStatsd(socket_path="/var/run/dogstatsd/dsd.socket")
+
+while True:
+    # Nominal case, dsd will inject its hostname
+    client.gauge('dsd.hostname.e2e', 1, tags=["case:nominal"])
+    client.service_check('dsd.hostname.e2e', 0, tags=["case:nominal"])
+    client.event('dsd.hostname.e2e', 'text', tags=["case:nominal"])
+
+    # Force the hostname value
+    client.gauge('dsd.hostname.e2e', 1, tags=["case:forced", "host:forced"])
+    client.service_check('dsd.hostname.e2e', 0, tags=["case:forced"], hostname="forced")
+    client.event('dsd.hostname.e2e', 'text', tags=["case:forced"], hostname="forced")
+
+    # Force an empty hostname
+    client.gauge('dsd.hostname.e2e', 1, tags=["case:empty", "host:"])
+    client.service_check('dsd.hostname.e2e', 0, tags=["case:empty", "host:"])
+    client.event('dsd.hostname.e2e', 'text', tags=["case:empty", "host:"])
+
+    time.sleep(10)
diff --git a/test/e2e/scripts/run-instance/22-argo-submit.sh b/test/e2e/scripts/run-instance/22-argo-submit.sh
index e4b0eb2b090f3e..9127734dfff0e9 100755
--- a/test/e2e/scripts/run-instance/22-argo-submit.sh
+++ b/test/e2e/scripts/run-instance/22-argo-submit.sh
@@ -78,9 +78,6 @@ spec:
         - name: datadog-config
           mountPath: /etc/datadog-agent/conf.d/network.d/conf.yaml.default
           subPath: network.yaml
-        - name: datadog-config
-          mountPath: /etc/datadog-agent/conf.d/docker.d/conf.yaml.default
-          subPath: docker.yaml
         - name: proc
           mountPath: /host/proc
           readOnly: true
@@ -90,7 +87,9 @@ spec:
         - name: dockersocket
           mountPath: /var/run/docker.sock
           readOnly: true
-
+        - name: dogstatsd
+          mountPath: /var/run/dogstatsd
+          readOnly: false
       volumes:
       - name: datadog-config
         configMap:
@@ -104,6 +103,9 @@ spec:
       - hostPath:
           path: /var/run/docker.sock
         name: dockersocket
+      - hostPath:
+          path: /var/run/dogstatsd
+        name: dogstatsd
 ---
 EOF
 )

From 9bc084dd967c973aa2e6583db4071934067a0ede Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Thu, 27 Sep 2018 15:14:52 +0200
Subject: [PATCH 12/14] rename checkSender internal member

---
 pkg/aggregator/sender.go      | 24 ++++++++++++------------
 pkg/aggregator/sender_test.go | 34 +++++++++++++++++-----------------
 2 files changed, 29 insertions(+), 29 deletions(-)

diff --git a/pkg/aggregator/sender.go b/pkg/aggregator/sender.go
index cd5682d3c1893c..9f4153241a065c 100644
--- a/pkg/aggregator/sender.go
+++ b/pkg/aggregator/sender.go
@@ -53,14 +53,14 @@ type RawSender interface {
 
 // checkSender implements Sender
 type checkSender struct {
-	id                     check.ID
-	defaultHostname        string
-	disableDefaultHostname bool
-	metricStats            metricStats
-	priormetricStats       metricStats
-	smsOut                 chan<- senderMetricSample
-	serviceCheckOut        chan<- metrics.ServiceCheck
-	eventOut               chan<- metrics.Event
+	id                      check.ID
+	defaultHostname         string
+	defaultHostnameDisabled bool
+	metricStats             metricStats
+	priormetricStats        metricStats
+	smsOut                  chan<- senderMetricSample
+	serviceCheckOut         chan<- metrics.ServiceCheck
+	eventOut                chan<- metrics.Event
 }
 
 type senderMetricSample struct {
@@ -149,7 +149,7 @@ func changeAllSendersDefaultHostname(hostname string) {
 // DisableDefaultHostname allows check to override the default hostname that will be injected
 // when no hostname is specified at submission (for metrics, events and service checks).
 func (s *checkSender) DisableDefaultHostname(disable bool) {
-	s.disableDefaultHostname = disable
+	s.defaultHostnameDisabled = disable
 }
 
 // Commit commits the metric samples that were added during a check run
@@ -203,7 +203,7 @@ func (s *checkSender) sendMetricSample(metric string, value float64, hostname st
 		Timestamp:  timeNowNano(),
 	}
 
-	if hostname == "" && !s.disableDefaultHostname {
+	if hostname == "" && !s.defaultHostnameDisabled {
 		metricSample.Host = s.defaultHostname
 	}
 
@@ -271,7 +271,7 @@ func (s *checkSender) ServiceCheck(checkName string, status metrics.ServiceCheck
 		Message:   message,
 	}
 
-	if hostname == "" && !s.disableDefaultHostname {
+	if hostname == "" && !s.defaultHostnameDisabled {
 		serviceCheck.Host = s.defaultHostname
 	}
 
@@ -286,7 +286,7 @@ func (s *checkSender) ServiceCheck(checkName string, status metrics.ServiceCheck
 func (s *checkSender) Event(e metrics.Event) {
 	log.Trace("Event submitted: ", e.Title, " for hostname: ", e.Host, " tags: ", e.Tags)
 
-	if e.Host == "" && !s.disableDefaultHostname {
+	if e.Host == "" && !s.defaultHostnameDisabled {
 		e.Host = s.defaultHostname
 	}
 
diff --git a/pkg/aggregator/sender_test.go b/pkg/aggregator/sender_test.go
index 8ffd4ce3dc344c..7bd2ce02248ef2 100644
--- a/pkg/aggregator/sender_test.go
+++ b/pkg/aggregator/sender_test.go
@@ -131,7 +131,7 @@ func TestGetSenderDefaultHostname(t *testing.T) {
 	require.True(t, ok)
 
 	assert.Equal(t, "testhostname", checksender.defaultHostname)
-	assert.Equal(t, false, checksender.disableDefaultHostname)
+	assert.Equal(t, false, checksender.defaultHostnameDisabled)
 
 }
 
@@ -211,29 +211,29 @@ func TestCheckSenderHostname(t *testing.T) {
 	defaultHostname := "default-host"
 
 	for nb, tc := range []struct {
-		disableDefaultHostname bool
-		submittedHostname      string
-		expectedHostname       string
+		defaultHostnameDisabled bool
+		submittedHostname       string
+		expectedHostname        string
 	}{
 		{
-			disableDefaultHostname: false,
-			submittedHostname:      "",
-			expectedHostname:       defaultHostname,
+			defaultHostnameDisabled: false,
+			submittedHostname:       "",
+			expectedHostname:        defaultHostname,
 		},
 		{
-			disableDefaultHostname: false,
-			submittedHostname:      "custom",
-			expectedHostname:       "custom",
+			defaultHostnameDisabled: false,
+			submittedHostname:       "custom",
+			expectedHostname:        "custom",
 		},
 		{
-			disableDefaultHostname: true,
-			submittedHostname:      "",
-			expectedHostname:       "",
+			defaultHostnameDisabled: true,
+			submittedHostname:       "",
+			expectedHostname:        "",
 		},
 		{
-			disableDefaultHostname: true,
-			submittedHostname:      "custom",
-			expectedHostname:       "custom",
+			defaultHostnameDisabled: true,
+			submittedHostname:       "custom",
+			expectedHostname:        "custom",
 		},
 	} {
 		t.Run(fmt.Sprintf("case %d: %q -> %q", nb, tc.submittedHostname, tc.expectedHostname), func(t *testing.T) {
@@ -241,7 +241,7 @@ func TestCheckSenderHostname(t *testing.T) {
 			serviceCheckChan := make(chan metrics.ServiceCheck, 10)
 			eventChan := make(chan metrics.Event, 10)
 			checkSender := newCheckSender(checkID1, defaultHostname, senderMetricSampleChan, serviceCheckChan, eventChan)
-			checkSender.DisableDefaultHostname(tc.disableDefaultHostname)
+			checkSender.DisableDefaultHostname(tc.defaultHostnameDisabled)
 
 			checkSender.Gauge("my.metric", 1.0, tc.submittedHostname, []string{"foo", "bar"})
 			checkSender.Commit()

From e795c7f24e595cbcecafe2c87385ad77acc991cf Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Thu, 27 Sep 2018 18:30:57 +0200
Subject: [PATCH 13/14] fix docker e2e

---
 test/e2e/scripts/run-instance/22-argo-submit.sh | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/test/e2e/scripts/run-instance/22-argo-submit.sh b/test/e2e/scripts/run-instance/22-argo-submit.sh
index 9127734dfff0e9..ed8122d1681ff6 100755
--- a/test/e2e/scripts/run-instance/22-argo-submit.sh
+++ b/test/e2e/scripts/run-instance/22-argo-submit.sh
@@ -78,6 +78,9 @@ spec:
         - name: datadog-config
           mountPath: /etc/datadog-agent/conf.d/network.d/conf.yaml.default
           subPath: network.yaml
+        - name: datadog-config
+          mountPath: /etc/datadog-agent/conf.d/docker.d/conf.yaml.default
+          subPath: docker.yaml
         - name: proc
           mountPath: /host/proc
           readOnly: true
@@ -90,6 +93,7 @@ spec:
         - name: dogstatsd
           mountPath: /var/run/dogstatsd
           readOnly: false
+
       volumes:
       - name: datadog-config
         configMap:

From 5d5bda4b74e4103c9ba3ad0f5facb5996e038170 Mon Sep 17 00:00:00 2001
From: Xavier Vello <xavier.vello@datadoghq.com>
Date: Fri, 28 Sep 2018 11:59:15 +0200
Subject: [PATCH 14/14] empty lines

---
 pkg/aggregator/sender_test.go | 2 --
 1 file changed, 2 deletions(-)

diff --git a/pkg/aggregator/sender_test.go b/pkg/aggregator/sender_test.go
index 7bd2ce02248ef2..6e8ef5e18362d6 100644
--- a/pkg/aggregator/sender_test.go
+++ b/pkg/aggregator/sender_test.go
@@ -117,7 +117,6 @@ func TestGetAndSetSender(t *testing.T) {
 	sender, err := GetSender(checkID1)
 	assert.Nil(t, err)
 	assert.Equal(t, testCheckSender, sender)
-
 }
 
 func TestGetSenderDefaultHostname(t *testing.T) {
@@ -132,7 +131,6 @@ func TestGetSenderDefaultHostname(t *testing.T) {
 
 	assert.Equal(t, "testhostname", checksender.defaultHostname)
 	assert.Equal(t, false, checksender.defaultHostnameDisabled)
-
 }
 
 func TestCheckSenderInterface(t *testing.T) {