Bump prometheus dependency to v2.21.0 (#8795)

* Bump prometheus dependency to v2.21.0

* Make golangci-lint happy

docs/LICENSE_OF_DEPENDENCIES.md

@@ -27,6 +27,7 @@ following works:
 - github.com/apache/thrift [Apache License 2.0](https://github.com/apache/thrift/blob/master/LICENSE)
 - github.com/aristanetworks/glog [Apache License 2.0](https://github.com/aristanetworks/glog/blob/master/LICENSE)
 - github.com/aristanetworks/goarista [Apache License 2.0](https://github.com/aristanetworks/goarista/blob/master/COPYING)
+- github.com/armon/go-metrics [MIT License](https://github.com/armon/go-metrics/blob/master/LICENSE)
 - github.com/aws/aws-sdk-go [Apache License 2.0](https://github.com/aws/aws-sdk-go/blob/master/LICENSE.txt)
 - github.com/aws/aws-sdk-go-v2 [Apache License 2.0](https://github.com/aws/aws-sdk-go-v2/blob/main/LICENSE.txt)
 - github.com/aws/aws-sdk-go-v2/config [Apache License 2.0](https://github.com/aws/aws-sdk-go-v2/blob/main/config/LICENSE.txt)
@@ -62,6 +63,7 @@ following works:
 - github.com/eapache/go-xerial-snappy [MIT License](https://github.com/eapache/go-xerial-snappy/blob/master/LICENSE)
 - github.com/eapache/queue [MIT License](https://github.com/eapache/queue/blob/master/LICENSE)
 - github.com/eclipse/paho.mqtt.golang [Eclipse Public License - v 1.0](https://github.com/eclipse/paho.mqtt.golang/blob/master/LICENSE)
+- github.com/fatih/color [MIT License](https://github.com/fatih/color/blob/master/LICENSE.md)
 - github.com/form3tech-oss/jwt-go [MIT License](https://github.com/form3tech-oss/jwt-go/blob/master/LICENSE)
 - github.com/ghodss/yaml [MIT License](https://github.com/ghodss/yaml/blob/master/LICENSE)
 - github.com/go-logfmt/logfmt [MIT License](https://github.com/go-logfmt/logfmt/blob/master/LICENSE)
@@ -94,10 +96,13 @@ following works:
 - github.com/grpc-ecosystem/grpc-gateway [BSD 3-Clause "New" or "Revised" License](https://github.com/grpc-ecosystem/grpc-gateway/blob/master/LICENSE.txt)
 - github.com/hailocab/go-hostpool [MIT License](https://github.com/hailocab/go-hostpool/blob/master/LICENSE)
 - github.com/harlow/kinesis-consumer [MIT License](https://github.com/harlow/kinesis-consumer/blob/master/MIT-LICENSE)
-- github.com/hashicorp/consul [Mozilla Public License 2.0](https://github.com/hashicorp/consul/blob/master/LICENSE)
+- github.com/hashicorp/consul/api [Mozilla Public License 2.0](https://github.com/hashicorp/consul/blob/master/LICENSE)
 - github.com/hashicorp/go-cleanhttp [Mozilla Public License 2.0](https://github.com/hashicorp/go-cleanhttp/blob/master/LICENSE)
+- github.com/hashicorp/go-hclog [Mozilla Public License 2.0](https://github.com/hashicorp/go-hclog/LICENSE)
+- github.com/hashicorp/go-immutable-radix [Mozilla Public License 2.0](https://github.com/hashicorp/go-immutable-radix/LICENSE)
 - github.com/hashicorp/go-rootcerts [Mozilla Public License 2.0](https://github.com/hashicorp/go-rootcerts/blob/master/LICENSE)
-- github.com/hashicorp/go-uuid [Mozilla Public License 2.0](https://github.com/hashicorp/go-uuid/LICENSE)
+- github.com/hashicorp/go-uuid [Mozilla Public License 2.0](https://github.com/hashicorp/go-uuid/blob/master/LICENSE)
+- github.com/hashicorp/golang-lru [Mozilla Public License 2.0](https://github.com/hashicorp/golang-lru/blob/master/LICENSE)
 - github.com/hashicorp/serf [Mozilla Public License 2.0](https://github.com/hashicorp/serf/blob/master/LICENSE)
 - github.com/influxdata/go-syslog [MIT License](https://github.com/influxdata/go-syslog/blob/develop/LICENSE)
 - github.com/influxdata/tail [MIT License](https://github.com/influxdata/tail/blob/master/LICENSE.txt)
@@ -117,6 +122,7 @@ following works:
 - github.com/konsorten/go-windows-terminal-sequences [MIT License](https://github.com/konsorten/go-windows-terminal-sequences/blob/master/LICENSE)
 - github.com/leodido/ragel-machinery [MIT License](https://github.com/leodido/ragel-machinery/blob/develop/LICENSE)
 - github.com/mailru/easyjson [MIT License](https://github.com/mailru/easyjson/blob/master/LICENSE)
+- github.com/mattn/go-colorable [MIT License](https://github.com/mattn/go-colorable/blob/master/LICENSE)
 - github.com/mattn/go-isatty [MIT License](https://github.com/mattn/go-isatty/blob/master/LICENSE)
 - github.com/matttproud/golang_protobuf_extensions [Apache License 2.0](https://github.com/matttproud/golang_protobuf_extensions/blob/master/LICENSE)
 - github.com/mdlayher/apcupsd [MIT License](https://github.com/mdlayher/apcupsd/blob/master/LICENSE.md)

go.mod

@@ -3,31 +3,29 @@ module github.com/influxdata/telegraf
 go 1.16
 
 require (
-	cloud.google.com/go v0.54.0
+	cloud.google.com/go v0.56.0
 	cloud.google.com/go/bigquery v1.4.0
 	cloud.google.com/go/pubsub v1.2.0
 	code.cloudfoundry.org/clock v1.0.0 // indirect
 	collectd.org v0.5.0
 	github.com/Azure/azure-event-hubs-go/v3 v3.2.0
 	github.com/Azure/azure-storage-queue-go v0.0.0-20181215014128-6ed74e755687
-	github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 // indirect
+	github.com/Azure/go-autorest/autorest v0.11.4
-	github.com/Azure/go-autorest/autorest v0.11.1
 	github.com/Azure/go-autorest/autorest/azure/auth v0.4.2
 	github.com/BurntSushi/toml v0.3.1
 	github.com/Mellanox/rdmamap v0.0.0-20191106181932-7c3c4763a6ee
 	github.com/Microsoft/ApplicationInsights-Go v0.4.2
-	github.com/Microsoft/go-winio v0.4.9 // indirect
 	github.com/Shopify/sarama v1.27.2
+	github.com/StackExchange/wmi v0.0.0-20210224194228-fe8f1750fd46 // indirect
 	github.com/aerospike/aerospike-client-go v1.27.0
-	github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4
+	github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d
-	github.com/aliyun/alibaba-cloud-sdk-go v1.61.785
+	github.com/aliyun/alibaba-cloud-sdk-go v1.61.1004
 	github.com/amir/raidman v0.0.0-20170415203553-1ccc43bfb9c9
-	github.com/antchfx/xmlquery v1.3.3
+	github.com/antchfx/xmlquery v1.3.5
 	github.com/antchfx/xpath v1.1.11
-	github.com/apache/thrift v0.12.0
+	github.com/apache/thrift v0.13.0
 	github.com/aristanetworks/glog v0.0.0-20191112221043-67e8567f59f3 // indirect
 	github.com/aristanetworks/goarista v0.0.0-20190325233358-a123909ec740
-	github.com/armon/go-metrics v0.3.0 // indirect
 	github.com/aws/aws-sdk-go v1.34.34
 	github.com/aws/aws-sdk-go-v2 v1.1.0
 	github.com/aws/aws-sdk-go-v2/config v1.1.0
@@ -39,7 +37,6 @@ require (
 	github.com/bmatcuk/doublestar/v3 v3.0.0
 	github.com/bmizerany/assert v0.0.0-20160611221934-b7ed37b82869
 	github.com/caio/go-tdigest v3.1.0+incompatible
-	github.com/cenkalti/backoff v2.0.0+incompatible // indirect
 	github.com/cisco-ie/nx-telemetry-proto v0.0.0-20190531143454-82441e232cf6
 	github.com/cockroachdb/apd v1.1.0 // indirect
 	github.com/containerd/containerd v1.4.1 // indirect
@@ -49,14 +46,11 @@ require (
 	github.com/denisenkom/go-mssqldb v0.0.0-20190707035753-2be1aa521ff4
 	github.com/dgrijalva/jwt-go/v4 v4.0.0-preview1
 	github.com/dimchansky/utfbom v1.1.0
-	github.com/docker/distribution v2.6.0-rc.1.0.20170726174610-edc3ab29cdff+incompatible // indirect
 	github.com/docker/docker v17.12.0-ce-rc1.0.20200916142827-bd33bbf0497b+incompatible
-	github.com/docker/go-connections v0.3.0 // indirect
-	github.com/docker/go-units v0.3.3 // indirect
 	github.com/docker/libnetwork v0.8.0-dev.2.0.20181012153825-d7b61745d166
 	github.com/eclipse/paho.mqtt.golang v1.3.0
 	github.com/ghodss/yaml v1.0.1-0.20190212211648-25d852aebe32
-	github.com/go-logfmt/logfmt v0.4.0
+	github.com/go-logfmt/logfmt v0.5.0
 	github.com/go-ping/ping v0.0.0-20210201095549-52eed920f98c
 	github.com/go-redis/redis v6.15.9+incompatible
 	github.com/go-sql-driver/mysql v1.5.0
@@ -71,16 +65,13 @@ require (
 	github.com/google/go-cmp v0.5.5
 	github.com/google/go-github/v32 v32.1.0
 	github.com/gopcua/opcua v0.1.13
-	github.com/gorilla/mux v1.6.2
+	github.com/gorilla/mux v1.7.3
 	github.com/gosnmp/gosnmp v1.30.0
 	github.com/grpc-ecosystem/grpc-gateway v1.16.0 // indirect
 	github.com/hailocab/go-hostpool v0.0.0-20160125115350-e80d13ce29ed // indirect
 	github.com/harlow/kinesis-consumer v0.3.1-0.20181230152818-2f58b136fee0
-	github.com/hashicorp/consul v1.2.1
+	github.com/hashicorp/consul/api v1.6.0
 	github.com/hashicorp/go-msgpack v0.5.5 // indirect
-	github.com/hashicorp/go-rootcerts v0.0.0-20160503143440-6bb64b370b90 // indirect
-	github.com/hashicorp/memberlist v0.1.5 // indirect
-	github.com/hashicorp/serf v0.8.1 // indirect
 	github.com/influxdata/go-syslog/v2 v2.0.1
 	github.com/influxdata/tail v1.0.1-0.20200707181643-03a791b270e4
 	github.com/influxdata/toml v0.0.0-20190415235208-270119a8ce65
@@ -92,13 +83,10 @@ require (
 	github.com/kardianos/service v1.0.0
 	github.com/karrick/godirwalk v1.16.1
 	github.com/kballard/go-shellquote v0.0.0-20180428030007-95032a82bc51
-	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/lib/pq v1.3.0 // indirect
 	github.com/matttproud/golang_protobuf_extensions v1.0.1
 	github.com/mdlayher/apcupsd v0.0.0-20200608131503-2bf01da7bf1b
-	github.com/miekg/dns v1.0.14
+	github.com/miekg/dns v1.1.31
-	github.com/mitchellh/go-testing-interface v1.0.0 // indirect
-	github.com/morikuni/aec v1.0.0 // indirect
 	github.com/multiplay/go-ts3 v1.0.0
 	github.com/naoina/go-stringutil v0.1.0 // indirect
 	github.com/nats-io/nats-server/v2 v2.1.4
@@ -106,26 +94,22 @@ require (
 	github.com/newrelic/newrelic-telemetry-sdk-go v0.5.1
 	github.com/nsqio/go-nsq v1.0.8
 	github.com/openconfig/gnmi v0.0.0-20180912164834-33a1865c3029
-	github.com/opencontainers/go-digest v1.0.0-rc1 // indirect
-	github.com/opencontainers/image-spec v1.0.1 // indirect
-	github.com/opentracing-contrib/go-observer v0.0.0-20170622124052-a52f23424492 // indirect
 	github.com/openzipkin/zipkin-go-opentracing v0.3.4
 	github.com/pkg/errors v0.9.1
-	github.com/prometheus/client_golang v1.5.1
+	github.com/prometheus/client_golang v1.7.1
 	github.com/prometheus/client_model v0.2.0
-	github.com/prometheus/common v0.9.1
+	github.com/prometheus/common v0.13.0
-	github.com/prometheus/procfs v0.0.8
+	github.com/prometheus/procfs v0.1.3
-	github.com/prometheus/prometheus v2.5.0+incompatible
+	github.com/prometheus/prometheus v1.8.2-0.20200911110723-e83ef207b6c2
 	github.com/riemann/riemann-go-client v0.5.0
 	github.com/safchain/ethtool v0.0.0-20200218184317-f459e2d13664
-	github.com/satori/go.uuid v1.2.1-0.20181028125025-b2ce2384e17b // indirect
 	github.com/sensu/sensu-go/api/core/v2 v2.6.0
 	github.com/shirou/gopsutil v3.20.11+incompatible
 	github.com/shopspring/decimal v0.0.0-20200105231215-408a2507e114 // indirect
 	github.com/signalfx/golib/v3 v3.3.0
 	github.com/sirupsen/logrus v1.6.0
 	github.com/soniah/gosnmp v1.25.0
-	github.com/streadway/amqp v0.0.0-20180528204448-e5adc2ada8b8
+	github.com/streadway/amqp v0.0.0-20190827072141-edfb9018d271
 	github.com/stretchr/testify v1.7.0
 	github.com/tbrandon/mbserver v0.0.0-20170611213546-993e1772cc62
 	github.com/tidwall/gjson v1.6.0
@@ -148,8 +132,8 @@ require (
 	golang.org/x/sys v0.0.0-20201119102817-f84b799fce68
 	golang.org/x/text v0.3.4
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20200205215550-e35592f146e4
-	google.golang.org/api v0.20.0
+	google.golang.org/api v0.29.0
-	google.golang.org/genproto v0.0.0-20200526211855-cb27e3aa2013
+	google.golang.org/genproto v0.0.0-20200815001618-f69a88009b70
 	google.golang.org/grpc v1.33.1
 	gopkg.in/djherbis/times.v1 v1.2.0
 	gopkg.in/fatih/pool.v2 v2.0.0 // indirect

plugins/parsers/prometheusremotewrite/parser_test.go

@@ -12,9 +12,9 @@ import (
 
 func TestParse(t *testing.T) {
 	prompbInput := prompb.WriteRequest{
-		Timeseries: []*prompb.TimeSeries{
+		Timeseries: []prompb.TimeSeries{
 			{
-				Labels: []*prompb.Label{
+				Labels: []prompb.Label{
 					{Name: "__name__", Value: "go_gc_duration_seconds"},
 					{Name: "quantile", Value: "0.99"},
 				},
@@ -23,7 +23,7 @@ func TestParse(t *testing.T) {
 				},
 			},
 			{
-				Labels: []*prompb.Label{
+				Labels: []prompb.Label{
 					{Name: "__name__", Value: "prometheus_target_interval_length_seconds"},
 					{Name: "job", Value: "prometheus"},
 				},
@@ -72,9 +72,9 @@ func TestParse(t *testing.T) {
 
 func TestDefaultTags(t *testing.T) {
 	prompbInput := prompb.WriteRequest{
-		Timeseries: []*prompb.TimeSeries{
+		Timeseries: []prompb.TimeSeries{
 			{
-				Labels: []*prompb.Label{
+				Labels: []prompb.Label{
 					{Name: "__name__", Value: "foo"},
 					{Name: "__eg__", Value: "bar"},
 				},
@@ -118,9 +118,9 @@ func TestMetricsWithTimestamp(t *testing.T) {
 	testTime := time.Date(2020, time.October, 4, 17, 0, 0, 0, time.UTC)
 	testTimeUnix := testTime.UnixNano() / int64(time.Millisecond)
 	prompbInput := prompb.WriteRequest{
-		Timeseries: []*prompb.TimeSeries{
+		Timeseries: []prompb.TimeSeries{
 			{
-				Labels: []*prompb.Label{
+				Labels: []prompb.Label{
 					{Name: "__name__", Value: "foo"},
 					{Name: "__eg__", Value: "bar"},
 				},

plugins/serializers/prometheusremotewrite/prometheusremotewrite.go

@@ -3,15 +3,16 @@ package prometheusremotewrite
 import (
 	"bytes"
 	"fmt"
-	"github.com/gogo/protobuf/proto"
-	"github.com/golang/snappy"
-	"github.com/influxdata/telegraf/plugins/serializers/prometheus"
 	"hash/fnv"
 	"sort"
 	"strconv"
 	"strings"
 	"time"
 
+	"github.com/gogo/protobuf/proto"
+	"github.com/golang/snappy"
+	"github.com/influxdata/telegraf/plugins/serializers/prometheus"
+
 	"github.com/influxdata/telegraf"
 	"github.com/prometheus/prometheus/prompb"
 )
@@ -54,11 +55,11 @@ func (s *Serializer) Serialize(metric telegraf.Metric) ([]byte, error) {
 
 func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 	var buf bytes.Buffer
-	var entries = make(map[MetricKey]*prompb.TimeSeries)
+	var entries = make(map[MetricKey]prompb.TimeSeries)
 	for _, metric := range metrics {
 		commonLabels := s.createLabels(metric)
 		var metrickey MetricKey
-		var promts *prompb.TimeSeries
+		var promts prompb.TimeSeries
 		for _, field := range metric.FieldList() {
 			metricName := prometheus.MetricName(metric.Name(), field.Key, metric.Type())
 			metricName, ok := prometheus.SanitizeMetricName(metricName)
@@ -88,9 +89,9 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 					if _, ok = entries[metrickeycount]; !ok {
 						entries[metrickeycount] = promtscount
 					}
-					labels := make([]*prompb.Label, len(commonLabels), len(commonLabels)+1)
+					labels := make([]prompb.Label, len(commonLabels), len(commonLabels)+1)
 					copy(labels, commonLabels)
-					labels = append(labels, &prompb.Label{
+					labels = append(labels, prompb.Label{
 						Name:  "le",
 						Value: "+Inf",
 					})
@@ -112,9 +113,9 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 						continue
 					}
 
-					labels = make([]*prompb.Label, len(commonLabels), len(commonLabels)+1)
+					labels = make([]prompb.Label, len(commonLabels), len(commonLabels)+1)
 					copy(labels, commonLabels)
-					labels = append(labels, &prompb.Label{
+					labels = append(labels, prompb.Label{
 						Name:  "le",
 						Value: fmt.Sprint(bound),
 					})
@@ -133,9 +134,9 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 					}
 
 					// if no bucket generate +Inf entry
-					labels := make([]*prompb.Label, len(commonLabels), len(commonLabels)+1)
+					labels := make([]prompb.Label, len(commonLabels), len(commonLabels)+1)
 					copy(labels, commonLabels)
-					labels = append(labels, &prompb.Label{
+					labels = append(labels, prompb.Label{
 						Name:  "le",
 						Value: "+Inf",
 					})
@@ -178,9 +179,9 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 						continue
 					}
 
-					labels := make([]*prompb.Label, len(commonLabels), len(commonLabels)+1)
+					labels := make([]prompb.Label, len(commonLabels), len(commonLabels)+1)
 					copy(labels, commonLabels)
-					labels = append(labels, &prompb.Label{
+					labels = append(labels, prompb.Label{
 						Name:  "quantile",
 						Value: fmt.Sprint(quantile),
 					})
@@ -203,8 +204,8 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 		}
 	}
 
-	var promTS = make([]*prompb.TimeSeries, len(entries))
+	var promTS = make([]prompb.TimeSeries, len(entries))
-	var i int64
+	var i int
 	for _, promts := range entries {
 		promTS[i] = promts
 		i++
@@ -244,7 +245,7 @@ func (s *Serializer) SerializeBatch(metrics []telegraf.Metric) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-func hasLabel(name string, labels []*prompb.Label) bool {
+func hasLabel(name string, labels []prompb.Label) bool {
 	for _, label := range labels {
 		if name == label.Name {
 			return true
@@ -253,8 +254,8 @@ func hasLabel(name string, labels []*prompb.Label) bool {
 	return false
 }
 
-func (s *Serializer) createLabels(metric telegraf.Metric) []*prompb.Label {
+func (s *Serializer) createLabels(metric telegraf.Metric) []prompb.Label {
-	labels := make([]*prompb.Label, 0, len(metric.TagList()))
+	labels := make([]prompb.Label, 0, len(metric.TagList()))
 	for _, tag := range metric.TagList() {
 		// Ignore special tags for histogram and summary types.
 		switch metric.Type() {
@@ -273,7 +274,7 @@ func (s *Serializer) createLabels(metric telegraf.Metric) []*prompb.Label {
 			continue
 		}
 
-		labels = append(labels, &prompb.Label{Name: name, Value: tag.Value})
+		labels = append(labels, prompb.Label{Name: name, Value: tag.Value})
 	}
 
 	if s.config.StringHandling != StringAsLabel {
@@ -298,7 +299,7 @@ func (s *Serializer) createLabels(metric telegraf.Metric) []*prompb.Label {
 			continue
 		}
 
-		labels = append(labels, &prompb.Label{Name: name, Value: value})
+		labels = append(labels, prompb.Label{Name: name, Value: value})
 		addedFieldLabel = true
 	}
 
@@ -311,7 +312,7 @@ func (s *Serializer) createLabels(metric telegraf.Metric) []*prompb.Label {
 	return labels
 }
 
-func MakeMetricKey(labels []*prompb.Label) MetricKey {
+func MakeMetricKey(labels []prompb.Label) MetricKey {
 	h := fnv.New64a()
 	for _, label := range labels {
 		h.Write([]byte(label.Name))
@@ -322,17 +323,17 @@ func MakeMetricKey(labels []*prompb.Label) MetricKey {
 	return MetricKey(h.Sum64())
 }
 
-func getPromTS(name string, labels []*prompb.Label, value float64, ts time.Time) (MetricKey, *prompb.TimeSeries) {
+func getPromTS(name string, labels []prompb.Label, value float64, ts time.Time) (MetricKey, prompb.TimeSeries) {
 	sample := []prompb.Sample{{
 		// Timestamp is int milliseconds for remote write.
 		Timestamp: ts.UnixNano() / int64(time.Millisecond),
 		Value:     value,
 	}}
-	labelscopy := make([]*prompb.Label, len(labels), len(labels)+1)
+	labelscopy := make([]prompb.Label, len(labels), len(labels)+1)
 	copy(labelscopy, labels)
-	labels = append(labelscopy, &prompb.Label{
+	labels = append(labelscopy, prompb.Label{
 		Name:  "__name__",
 		Value: name,
 	})
-	return MakeMetricKey(labels), &prompb.TimeSeries{Labels: labels, Samples: sample}
+	return MakeMetricKey(labels), prompb.TimeSeries{Labels: labels, Samples: sample}
 }

plugins/serializers/prometheusremotewrite/prometheusremotewrite_test.go

@@ -141,6 +141,7 @@ http_request_duration_seconds_bucket{le="0.5"} 129389
 			})
 			require.NoError(t, err)
 			data, err := s.Serialize(tt.metric)
+			require.NoError(t, err)
 			actual, err := prompbToText(data)
 			require.NoError(t, err)
 
@@ -647,7 +648,10 @@ func prompbToText(data []byte) ([]byte, error) {
 	}
 	samples := protoToSamples(&req)
 	for _, sample := range samples {
-		buf.Write([]byte(fmt.Sprintf("%s %s\n", sample.Metric.String(), sample.Value.String())))
+		_, err = buf.Write([]byte(fmt.Sprintf("%s %s\n", sample.Metric.String(), sample.Value.String())))
+		if err != nil {
+			return nil, err
+		}
 	}
 	if err != nil {
 		return nil, err