From 00e9eb243975371c166c6f0e6cc7de41d06e3962 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Tue, 16 Mar 2021 20:28:43 +0530
Subject: [PATCH 01/15] matchers support in sidecar

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus.go      |  2 +-
 pkg/store/prometheus_test.go | 26 ++++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index 7239c4b3ad..ce2b905db8 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -496,7 +496,7 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 		return &storepb.LabelValuesResponse{Values: []string{l}}, nil
 	}
 
-	vals, err := p.client.LabelValuesInGRPC(ctx, p.base, r.Label, nil, r.Start, r.End)
+	vals, err := p.client.LabelValuesInGRPC(ctx, p.base, r.Label, r.Matchers, r.Start, r.End)
 	if err != nil {
 		return nil, err
 	}
diff --git a/pkg/store/prometheus_test.go b/pkg/store/prometheus_test.go
index 4cda3ddafa..38cca22e5f 100644
--- a/pkg/store/prometheus_test.go
+++ b/pkg/store/prometheus_test.go
@@ -441,6 +441,32 @@ func TestPrometheusStore_LabelValues_e2e(t *testing.T) {
 	testutil.Ok(t, err)
 	testutil.Equals(t, []string(nil), resp.Warnings)
 	testutil.Equals(t, []string{}, resp.Values)
+
+	// check label value matcher
+	resp, err = proxy.LabelValues(ctx, &storepb.LabelValuesRequest{
+		Label: "a",
+		Start: timestamp.FromTime(minTime),
+		End:   timestamp.FromTime(maxTime),
+		Matchers: []storepb.LabelMatcher{
+			{Type: storepb.LabelMatcher_EQ, Name: "a", Value: "b"},
+		},
+	})
+	testutil.Ok(t, err)
+	testutil.Equals(t, []string(nil), resp.Warnings)
+	testutil.Equals(t, []string{"b"}, resp.Values)
+
+	// check another label value matcher
+	resp, err = proxy.LabelValues(ctx, &storepb.LabelValuesRequest{
+		Label: "a",
+		Start: timestamp.FromTime(minTime),
+		End:   timestamp.FromTime(maxTime),
+		Matchers: []storepb.LabelMatcher{
+			{Type: storepb.LabelMatcher_EQ, Name: "a", Value: "d"},
+		},
+	})
+	testutil.Ok(t, err)
+	testutil.Equals(t, []string(nil), resp.Warnings)
+	testutil.Equals(t, []string{}, resp.Values)
 }
 
 // Test to check external label values retrieve.

From 51a162d85ebb3a1c272a0129dd6b392b8240d425 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Fri, 19 Mar 2021 01:35:27 +0530
Subject: [PATCH 02/15] added and used buildinfo api

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 cmd/thanos/sidecar.go        | 50 +++++++++++++++++++++++++++++++++++-
 pkg/promclient/promclient.go | 28 ++++++++++++++++++++
 pkg/store/prometheus.go      | 34 ++++++++++++++++++++----
 pkg/store/prometheus_test.go | 17 ++++++------
 4 files changed, 115 insertions(+), 14 deletions(-)

diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index dd93addc85..8a8cd3057f 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -208,6 +208,33 @@ func runSidecar(
 			cancel()
 		})
 	}
+	{
+		ctx, cancel := context.WithCancel(context.Background())
+		g.Add(func() error {
+			// We retry infinitely until we reach and fetch BuildInfo from our Prometheus.
+			err := runutil.Retry(2*time.Second, ctx.Done(), func() error {
+				if err := m.BuildVersion(ctx); err != nil {
+					level.Warn(logger).Log(
+						"msg", "failed to fetch prometheur version. Is Prometheus running? Retrying",
+						"err", err,
+					)
+					return err
+				}
+
+				level.Info(logger).Log(
+					"msg", "successfully loaded prometheus version",
+					"prometheus_version", m.Version(),
+				)
+				return nil
+			})
+			if err != nil {
+				return errors.Wrap(err, "buildinfo query")
+			}
+			return nil
+		}, func(error) {
+			cancel()
+		})
+	}
 
 	{
 		t := exthttp.NewTransport()
@@ -215,7 +242,7 @@ func runSidecar(
 		t.MaxIdleConns = conf.connection.maxIdleConns
 		c := promclient.NewClient(&http.Client{Transport: tracing.HTTPTripperware(logger, t)}, logger, thanoshttp.ThanosUserAgent)
 
-		promStore, err := store.NewPrometheusStore(logger, reg, c, conf.prometheus.url, component.Sidecar, m.Labels, m.Timestamps)
+		promStore, err := store.NewPrometheusStore(logger, reg, c, conf.prometheus.url, component.Sidecar, m.Labels, m.Timestamps, m.Version)
 		if err != nil {
 			return errors.Wrap(err, "create Prometheus store")
 		}
@@ -348,6 +375,7 @@ type promMetadata struct {
 	mint   int64
 	maxt   int64
 	labels labels.Labels
+	promVersion string
 
 	limitMinTime thanosmodel.TimeOrDurationValue
 
@@ -393,6 +421,26 @@ func (s *promMetadata) Timestamps() (mint int64, maxt int64) {
 	return s.mint, s.maxt
 }
 
+func (s *promMetadata) BuildVersion(ctx context.Context) error {
+	ver, err := s.client.BuildInfo(ctx, s.promURL)
+	if err != nil {
+		return err
+	}
+
+	s.mtx.Lock()
+	defer s.mtx.Unlock()
+
+	s.promVersion = ver
+	return nil
+}
+
+func (s *promMetadata) Version() string {
+	s.mtx.Lock()
+	defer s.mtx.Unlock()
+
+	return s.promVersion
+}
+
 type sidecarConfig struct {
 	http         httpConfig
 	grpc         grpcConfig
diff --git a/pkg/promclient/promclient.go b/pkg/promclient/promclient.go
index 58fb296a03..0e29ccdf5d 100644
--- a/pkg/promclient/promclient.go
+++ b/pkg/promclient/promclient.go
@@ -607,6 +607,34 @@ func (c *Client) AlertmanagerAlerts(ctx context.Context, base *url.URL) ([]*mode
 	return v.Data, nil
 }
 
+// BuildInfo returns Prometheus version from /api/v1/status/buildinfo Prometheus endpoint.
+func (c *Client) BuildInfo(ctx context.Context, base *url.URL) (string, error) {
+	u := *base
+	u.Path = path.Join(u.Path, "/api/v1/status/buildinfo")
+
+	level.Debug(c.logger).Log("msg", "querying instant", "url", u.String())
+
+	span, ctx := tracing.StartSpan(ctx, "/prom_buildinfo HTTP[client]")
+	defer span.Finish()
+
+	body, _, err := c.req2xx(ctx, &u, http.MethodGet)
+	if err != nil {
+		return "", err
+	}
+
+	var b struct {
+		Data struct {
+			Version string `json:"version"`
+		} `json:"data"`
+	}
+
+	if err = json.Unmarshal(body, &b); err != nil {
+		return "", errors.Wrap(err, "unmarshal build info API response")
+	}
+
+	return b.Data.Version, nil
+}
+
 func formatTime(t time.Time) string {
 	return strconv.FormatFloat(float64(t.Unix())+float64(t.Nanosecond())/1e9, 'f', -1, 64)
 }
diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index ce2b905db8..82fd7eda59 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -50,6 +50,7 @@ type PrometheusStore struct {
 	component        component.StoreAPI
 	externalLabelsFn func() labels.Labels
 	timestamps       func() (mint int64, maxt int64)
+	promVersion		 func() string
 
 	remoteReadAcceptableResponses []prompb.ReadRequest_ResponseType
 
@@ -69,6 +70,7 @@ func NewPrometheusStore(
 	component component.StoreAPI,
 	externalLabelsFn func() labels.Labels,
 	timestamps func() (mint int64, maxt int64),
+	promVersion func() string,
 ) (*PrometheusStore, error) {
 	if logger == nil {
 		logger = log.NewNopLogger()
@@ -80,6 +82,7 @@ func NewPrometheusStore(
 		component:                     component,
 		externalLabelsFn:              externalLabelsFn,
 		timestamps:                    timestamps,
+		promVersion:				   promVersion,	
 		remoteReadAcceptableResponses: []prompb.ReadRequest_ResponseType{prompb.ReadRequest_STREAMED_XOR_CHUNKS, prompb.ReadRequest_SAMPLES},
 		buffers: sync.Pool{New: func() interface{} {
 			b := make([]byte, 0, initialBufSize)
@@ -496,10 +499,31 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 		return &storepb.LabelValuesResponse{Values: []string{l}}, nil
 	}
 
-	vals, err := p.client.LabelValuesInGRPC(ctx, p.base, r.Label, r.Matchers, r.Start, r.End)
-	if err != nil {
-		return nil, err
+	var (
+		vals     []string
+		sers 	 []map[string]string
+		err 	 error
+	)
+
+	version := p.promVersion()
+	if version > "2.24" {
+		vals, err = p.client.LabelValuesInGRPC(ctx, p.base, r.Label, r.Matchers, r.Start, r.End)
+		if err != nil {
+			return nil, err
+		}
+		sort.Strings(vals)
+	} else {
+		matchers, err := storepb.MatchersToPromMatchers(r.Matchers...)
+		if err != nil {
+			return nil, status.Error(codes.Internal, err.Error())
+		}
+		sers, err = p.client.SeriesInGRPC(ctx, p.base, matchers, r.Start, r.End)
+		if err != nil {
+			return nil, err
+		}
+		for _, s := range sers {
+			vals = append(vals, s[r.Label])
+		}
 	}
-	sort.Strings(vals)
-	return &storepb.LabelValuesResponse{Values: vals}, nil
+	return &storepb.LabelValuesResponse{Values: vals}, nil	
 }
diff --git a/pkg/store/prometheus_test.go b/pkg/store/prometheus_test.go
index 38cca22e5f..f963a4ed9a 100644
--- a/pkg/store/prometheus_test.go
+++ b/pkg/store/prometheus_test.go
@@ -64,7 +64,7 @@ func testPrometheusStoreSeriesE2e(t *testing.T, prefix string) {
 	limitMinT := int64(0)
 	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return limitMinT, -1 }) // Maxt does not matter.
+		func() (int64, int64) { return limitMinT, -1 }, nil) // Maxt does not matter.
 	testutil.Ok(t, err)
 
 	// Query all three samples except for the first one. Since we round up queried data
@@ -199,7 +199,7 @@ func TestPrometheusStore_SeriesLabels_e2e(t *testing.T) {
 
 	promStore, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return math.MinInt64/1000 + 62135596801, math.MaxInt64/1000 - 62135596801 })
+		func() (int64, int64) { return math.MinInt64/1000 + 62135596801, math.MaxInt64/1000 - 62135596801 }, nil)
 	testutil.Ok(t, err)
 
 	for _, tcase := range []struct {
@@ -375,7 +375,7 @@ func TestPrometheusStore_LabelNames_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil)
+	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil, nil)
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelNames(ctx, &storepb.LabelNamesRequest{
@@ -420,7 +420,8 @@ func TestPrometheusStore_LabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil)
+	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil, 
+		func() string {return "2.25"})
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{
@@ -492,7 +493,7 @@ func TestPrometheusStore_ExternalLabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil)
+	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil, nil)
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{
@@ -538,7 +539,7 @@ func TestPrometheusStore_Series_MatchExternalLabel_e2e(t *testing.T) {
 
 	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return 0, math.MaxInt64 })
+		func() (int64, int64) { return 0, math.MaxInt64 }, nil)
 	testutil.Ok(t, err)
 	srv := newStoreSeriesServer(ctx)
 
@@ -583,7 +584,7 @@ func TestPrometheusStore_Info(t *testing.T) {
 
 	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), nil, component.Sidecar,
 		func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-		func() (int64, int64) { return 123, 456 })
+		func() (int64, int64) { return 123, 456 }, nil)
 	testutil.Ok(t, err)
 
 	resp, err := proxy.Info(ctx, &storepb.InfoRequest{})
@@ -661,7 +662,7 @@ func TestPrometheusStore_Series_SplitSamplesIntoChunksWithMaxSizeOf120(t *testin
 
 		proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar,
 			func() labels.Labels { return labels.FromStrings("region", "eu-west") },
-			func() (int64, int64) { return 0, math.MaxInt64 })
+			func() (int64, int64) { return 0, math.MaxInt64 }, nil)
 		testutil.Ok(t, err)
 
 		// We build chunks only for SAMPLES method. Make sure we ask for SAMPLES only.

From f4096da200bdffad4d493bf238f700fdc9ac6887 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Fri, 19 Mar 2021 01:54:46 +0530
Subject: [PATCH 03/15] go formatting fix

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 cmd/thanos/sidecar.go        |  8 ++++----
 pkg/store/prometheus.go      | 12 ++++++------
 pkg/store/prometheus_test.go |  4 ++--
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index 8a8cd3057f..0d67cc89eb 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -371,10 +371,10 @@ func validatePrometheus(ctx context.Context, client *promclient.Client, logger l
 type promMetadata struct {
 	promURL *url.URL
 
-	mtx    sync.Mutex
-	mint   int64
-	maxt   int64
-	labels labels.Labels
+	mtx         sync.Mutex
+	mint        int64
+	maxt        int64
+	labels      labels.Labels
 	promVersion string
 
 	limitMinTime thanosmodel.TimeOrDurationValue
diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index 82fd7eda59..fbcff7037b 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -50,7 +50,7 @@ type PrometheusStore struct {
 	component        component.StoreAPI
 	externalLabelsFn func() labels.Labels
 	timestamps       func() (mint int64, maxt int64)
-	promVersion		 func() string
+	promVersion      func() string
 
 	remoteReadAcceptableResponses []prompb.ReadRequest_ResponseType
 
@@ -82,7 +82,7 @@ func NewPrometheusStore(
 		component:                     component,
 		externalLabelsFn:              externalLabelsFn,
 		timestamps:                    timestamps,
-		promVersion:				   promVersion,	
+		promVersion:                   promVersion,
 		remoteReadAcceptableResponses: []prompb.ReadRequest_ResponseType{prompb.ReadRequest_STREAMED_XOR_CHUNKS, prompb.ReadRequest_SAMPLES},
 		buffers: sync.Pool{New: func() interface{} {
 			b := make([]byte, 0, initialBufSize)
@@ -500,9 +500,9 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 	}
 
 	var (
-		vals     []string
-		sers 	 []map[string]string
-		err 	 error
+		vals []string
+		sers []map[string]string
+		err  error
 	)
 
 	version := p.promVersion()
@@ -525,5 +525,5 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 			vals = append(vals, s[r.Label])
 		}
 	}
-	return &storepb.LabelValuesResponse{Values: vals}, nil	
+	return &storepb.LabelValuesResponse{Values: vals}, nil
 }
diff --git a/pkg/store/prometheus_test.go b/pkg/store/prometheus_test.go
index f963a4ed9a..ce32b32c60 100644
--- a/pkg/store/prometheus_test.go
+++ b/pkg/store/prometheus_test.go
@@ -420,8 +420,8 @@ func TestPrometheusStore_LabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil, 
-		func() string {return "2.25"})
+	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil,
+		func() string { return "2.25" })
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{

From 6c2ec330a28cb67a51d992c242440e4b614936fa Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Sat, 27 Mar 2021 23:39:54 +0530
Subject: [PATCH 04/15] addressed minor changes

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 cmd/thanos/sidecar.go        | 4 ++--
 pkg/promclient/promclient.go | 8 ++++----
 pkg/store/prometheus.go      | 6 ++++--
 3 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index 7ac3dcc04f..e58e6779dd 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -212,7 +212,7 @@ func runSidecar(
 	{
 		ctx, cancel := context.WithCancel(context.Background())
 		g.Add(func() error {
-			// We retry infinitely until we reach and fetch BuildInfo from our Prometheus.
+			// We retry infinitely until we reach and fetch BuildVersion from our Prometheus.
 			err := runutil.Retry(2*time.Second, ctx.Done(), func() error {
 				if err := m.BuildVersion(ctx); err != nil {
 					level.Warn(logger).Log(
@@ -424,7 +424,7 @@ func (s *promMetadata) Timestamps() (mint int64, maxt int64) {
 }
 
 func (s *promMetadata) BuildVersion(ctx context.Context) error {
-	ver, err := s.client.BuildInfo(ctx, s.promURL)
+	ver, err := s.client.BuildVersion(ctx, s.promURL)
 	if err != nil {
 		return err
 	}
diff --git a/pkg/promclient/promclient.go b/pkg/promclient/promclient.go
index 6ea356b94d..c99cc49353 100644
--- a/pkg/promclient/promclient.go
+++ b/pkg/promclient/promclient.go
@@ -608,14 +608,14 @@ func (c *Client) AlertmanagerAlerts(ctx context.Context, base *url.URL) ([]*mode
 	return v.Data, nil
 }
 
-// BuildInfo returns Prometheus version from /api/v1/status/buildinfo Prometheus endpoint.
-func (c *Client) BuildInfo(ctx context.Context, base *url.URL) (string, error) {
+// BuildVersion returns Prometheus version from /api/v1/status/buildinfo Prometheus endpoint.
+func (c *Client) BuildVersion(ctx context.Context, base *url.URL) (string, error) {
 	u := *base
 	u.Path = path.Join(u.Path, "/api/v1/status/buildinfo")
 
-	level.Debug(c.logger).Log("msg", "querying instant", "url", u.String())
+	level.Debug(c.logger).Log("msg", "build version", "url", u.String())
 
-	span, ctx := tracing.StartSpan(ctx, "/prom_buildinfo HTTP[client]")
+	span, ctx := tracing.StartSpan(ctx, "/prom_buildversion HTTP[client]")
 	defer span.Finish()
 
 	body, _, err := c.req2xx(ctx, &u, http.MethodGet)
diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index fbcff7037b..37f7b369dd 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -511,7 +511,6 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 		if err != nil {
 			return nil, err
 		}
-		sort.Strings(vals)
 	} else {
 		matchers, err := storepb.MatchersToPromMatchers(r.Matchers...)
 		if err != nil {
@@ -522,8 +521,11 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 			return nil, err
 		}
 		for _, s := range sers {
-			vals = append(vals, s[r.Label])
+			if val, exists := s[r.Label]; exists {
+				vals = append(vals, val)
+			}
 		}
 	}
+	sort.Strings(vals)
 	return &storepb.LabelValuesResponse{Values: vals}, nil
 }

From a4073e4ba44d460a5a48858f39d301b376ab91ee Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Sat, 3 Apr 2021 23:36:54 +0530
Subject: [PATCH 05/15] using set to handle duplicate values

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 cmd/thanos/sidecar.go   | 2 +-
 pkg/store/prometheus.go | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index e58e6779dd..fd00fbe177 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -229,7 +229,7 @@ func runSidecar(
 				return nil
 			})
 			if err != nil {
-				return errors.Wrap(err, "buildinfo query")
+				return errors.Wrap(err, "failed to get prometheus version")
 			}
 			return nil
 		}, func(error) {
diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index 37f7b369dd..b1bf61e65e 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -520,11 +520,17 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 		if err != nil {
 			return nil, err
 		}
+
+		// using set to handle duplicate values.
+		labelValuesSet := make(map[string]struct{})
 		for _, s := range sers {
 			if val, exists := s[r.Label]; exists {
-				vals = append(vals, val)
+				labelValuesSet[val] = struct{}{}
 			}
 		}
+		for key := range labelValuesSet {
+			vals = append(vals, key)
+		}
 	}
 	sort.Strings(vals)
 	return &storepb.LabelValuesResponse{Values: vals}, nil

From fe5067a7eb1de04a2990ca0e86d23ca60c36f88b Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Wed, 14 Apr 2021 17:28:54 +0530
Subject: [PATCH 06/15] Logic correction

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus.go      | 42 +++++++++++++++++++++---------------
 pkg/store/prometheus_test.go |  5 ++++-
 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index b1bf61e65e..8d93499c5f 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -500,36 +500,44 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 	}
 
 	var (
-		vals []string
 		sers []map[string]string
 		err  error
 	)
 
+	vals := []string{}
 	version := p.promVersion()
+
 	if version > "2.24" {
 		vals, err = p.client.LabelValuesInGRPC(ctx, p.base, r.Label, r.Matchers, r.Start, r.End)
 		if err != nil {
 			return nil, err
 		}
 	} else {
-		matchers, err := storepb.MatchersToPromMatchers(r.Matchers...)
-		if err != nil {
-			return nil, status.Error(codes.Internal, err.Error())
-		}
-		sers, err = p.client.SeriesInGRPC(ctx, p.base, matchers, r.Start, r.End)
-		if err != nil {
-			return nil, err
-		}
+		if len(r.Matchers) == 0 {
+			vals, err = p.client.LabelValuesInGRPC(ctx, p.base, r.Label, nil, r.Start, r.End)
+			if err != nil {
+				return nil, err
+			}
+		} else {
+			matchers, err := storepb.MatchersToPromMatchers(r.Matchers...)
+			if err != nil {
+				return nil, status.Error(codes.Internal, err.Error())
+			}
+			sers, err = p.client.SeriesInGRPC(ctx, p.base, matchers, r.Start, r.End)
+			if err != nil {
+				return nil, err
+			}
 
-		// using set to handle duplicate values.
-		labelValuesSet := make(map[string]struct{})
-		for _, s := range sers {
-			if val, exists := s[r.Label]; exists {
-				labelValuesSet[val] = struct{}{}
+			// using set to handle duplicate values.
+			labelValuesSet := make(map[string]struct{})
+			for _, s := range sers {
+				if val, exists := s[r.Label]; exists {
+					labelValuesSet[val] = struct{}{}
+				}
+			}
+			for key := range labelValuesSet {
+				vals = append(vals, key)
 			}
-		}
-		for key := range labelValuesSet {
-			vals = append(vals, key)
 		}
 	}
 	sort.Strings(vals)
diff --git a/pkg/store/prometheus_test.go b/pkg/store/prometheus_test.go
index 94ae03436a..01d4c2240e 100644
--- a/pkg/store/prometheus_test.go
+++ b/pkg/store/prometheus_test.go
@@ -420,8 +420,11 @@ func TestPrometheusStore_LabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
+	version, err := promclient.NewDefaultClient().BuildVersion(ctx, u)
+	testutil.Ok(t, err)
+
 	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil,
-		func() string { return "2.25" })
+		func() string { return version })
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{

From 92c3234ca4bc9b824f476a6d3b7f5ac97a135e70 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Wed, 14 Apr 2021 18:00:13 +0530
Subject: [PATCH 07/15] test case update

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus_test.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkg/store/prometheus_test.go b/pkg/store/prometheus_test.go
index 01d4c2240e..c99d0375f5 100644
--- a/pkg/store/prometheus_test.go
+++ b/pkg/store/prometheus_test.go
@@ -496,7 +496,10 @@ func TestPrometheusStore_ExternalLabelValues_e2e(t *testing.T) {
 	u, err := url.Parse(fmt.Sprintf("http://%s", p.Addr()))
 	testutil.Ok(t, err)
 
-	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil, nil)
+	version, err := promclient.NewDefaultClient().BuildVersion(ctx, u)
+	testutil.Ok(t, err)
+
+	proxy, err := NewPrometheusStore(nil, nil, promclient.NewDefaultClient(), u, component.Sidecar, getExternalLabels, nil, func() string { return version })
 	testutil.Ok(t, err)
 
 	resp, err := proxy.LabelValues(ctx, &storepb.LabelValuesRequest{

From df6b6efa7680c65cd6f8715ae43357aff99eb528 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Wed, 14 Apr 2021 19:56:37 +0530
Subject: [PATCH 08/15] changes addressed

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus.go | 41 +++++++++++++++++------------------------
 1 file changed, 17 insertions(+), 24 deletions(-)

diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index 8d93499c5f..b828424940 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -507,38 +507,31 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 	vals := []string{}
 	version := p.promVersion()
 
-	if version > "2.24" {
+	if len(r.Matchers) == 0 || version > "2.24" {
 		vals, err = p.client.LabelValuesInGRPC(ctx, p.base, r.Label, r.Matchers, r.Start, r.End)
 		if err != nil {
 			return nil, err
 		}
 	} else {
-		if len(r.Matchers) == 0 {
-			vals, err = p.client.LabelValuesInGRPC(ctx, p.base, r.Label, nil, r.Start, r.End)
-			if err != nil {
-				return nil, err
-			}
-		} else {
-			matchers, err := storepb.MatchersToPromMatchers(r.Matchers...)
-			if err != nil {
-				return nil, status.Error(codes.Internal, err.Error())
-			}
-			sers, err = p.client.SeriesInGRPC(ctx, p.base, matchers, r.Start, r.End)
-			if err != nil {
-				return nil, err
-			}
+		matchers, err := storepb.MatchersToPromMatchers(r.Matchers...)
+		if err != nil {
+			return nil, status.Error(codes.Internal, err.Error())
+		}
+		sers, err = p.client.SeriesInGRPC(ctx, p.base, matchers, r.Start, r.End)
+		if err != nil {
+			return nil, err
+		}
 
-			// using set to handle duplicate values.
-			labelValuesSet := make(map[string]struct{})
-			for _, s := range sers {
-				if val, exists := s[r.Label]; exists {
-					labelValuesSet[val] = struct{}{}
-				}
-			}
-			for key := range labelValuesSet {
-				vals = append(vals, key)
+		// using set to handle duplicate values.
+		labelValuesSet := make(map[string]struct{})
+		for _, s := range sers {
+			if val, exists := s[r.Label]; exists {
+				labelValuesSet[val] = struct{}{}
 			}
 		}
+		for key := range labelValuesSet {
+			vals = append(vals, key)
+		}
 	}
 	sort.Strings(vals)
 	return &storepb.LabelValuesResponse{Values: vals}, nil

From aaf7906a83af5810d7d3f42d9ce490c8ad8f5729 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Sat, 17 Apr 2021 00:01:14 +0530
Subject: [PATCH 09/15] handling promVersion < 2.14

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 cmd/thanos/sidecar.go        | 3 +--
 pkg/promclient/promclient.go | 7 ++++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index fd00fbe177..156666fd95 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -216,7 +216,7 @@ func runSidecar(
 			err := runutil.Retry(2*time.Second, ctx.Done(), func() error {
 				if err := m.BuildVersion(ctx); err != nil {
 					level.Warn(logger).Log(
-						"msg", "failed to fetch prometheur version. Is Prometheus running? Retrying",
+						"msg", "failed to fetch prometheus version. Is Prometheus running? Retrying",
 						"err", err,
 					)
 					return err
@@ -224,7 +224,6 @@ func runSidecar(
 
 				level.Info(logger).Log(
 					"msg", "successfully loaded prometheus version",
-					"prometheus_version", m.Version(),
 				)
 				return nil
 			})
diff --git a/pkg/promclient/promclient.go b/pkg/promclient/promclient.go
index c99cc49353..4384b5d529 100644
--- a/pkg/promclient/promclient.go
+++ b/pkg/promclient/promclient.go
@@ -609,6 +609,7 @@ func (c *Client) AlertmanagerAlerts(ctx context.Context, base *url.URL) ([]*mode
 }
 
 // BuildVersion returns Prometheus version from /api/v1/status/buildinfo Prometheus endpoint.
+// For Prometheus versions < 2.14.0 it returns "0" as Prometheus version.
 func (c *Client) BuildVersion(ctx context.Context, base *url.URL) (string, error) {
 	u := *base
 	u.Path = path.Join(u.Path, "/api/v1/status/buildinfo")
@@ -618,8 +619,12 @@ func (c *Client) BuildVersion(ctx context.Context, base *url.URL) (string, error
 	span, ctx := tracing.StartSpan(ctx, "/prom_buildversion HTTP[client]")
 	defer span.Finish()
 
-	body, _, err := c.req2xx(ctx, &u, http.MethodGet)
+	// We get status code 404 for prometheus versions lower than 2.14.0
+	body, code, err := c.req2xx(ctx, &u, http.MethodGet)
 	if err != nil {
+		if code == http.StatusNotFound {
+			return "0", nil
+		}
 		return "", err
 	}
 

From ef797f682c7c53a369ca4a06aefc06e2ea0bae3d Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Sat, 24 Apr 2021 02:50:07 +0530
Subject: [PATCH 10/15] removed goroutine for promVersion

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 cmd/thanos/sidecar.go   | 50 +++++++++++++++++------------------------
 pkg/store/prometheus.go |  2 +-
 2 files changed, 22 insertions(+), 30 deletions(-)

diff --git a/cmd/thanos/sidecar.go b/cmd/thanos/sidecar.go
index 156666fd95..790ddc230c 100644
--- a/cmd/thanos/sidecar.go
+++ b/cmd/thanos/sidecar.go
@@ -145,15 +145,34 @@ func runSidecar(
 		g.Add(func() error {
 			// Only check Prometheus's flags when upload is enabled.
 			if uploads {
-				// Check prometheus's flags to ensure sane sidecar flags.
+				// Check prometheus's flags to ensure same sidecar flags.
 				if err := validatePrometheus(ctx, m.client, logger, conf.shipper.ignoreBlockSize, m); err != nil {
 					return errors.Wrap(err, "validate Prometheus flags")
 				}
 			}
 
+			// We retry infinitely until we reach and fetch BuildVersion from our Prometheus.
+			err := runutil.Retry(2*time.Second, ctx.Done(), func() error {
+				if err := m.BuildVersion(ctx); err != nil {
+					level.Warn(logger).Log(
+						"msg", "failed to fetch prometheus version. Is Prometheus running? Retrying",
+						"err", err,
+					)
+					return err
+				}
+
+				level.Info(logger).Log(
+					"msg", "successfully loaded prometheus version",
+				)
+				return nil
+			})
+			if err != nil {
+				return errors.Wrap(err, "failed to get prometheus version")
+			}
+
 			// Blocking query of external labels before joining as a Source Peer into gossip.
 			// We retry infinitely until we reach and fetch labels from our Prometheus.
-			err := runutil.Retry(2*time.Second, ctx.Done(), func() error {
+			err = runutil.Retry(2*time.Second, ctx.Done(), func() error {
 				if err := m.UpdateLabels(ctx); err != nil {
 					level.Warn(logger).Log(
 						"msg", "failed to fetch initial external labels. Is Prometheus running? Retrying",
@@ -209,33 +228,6 @@ func runSidecar(
 			cancel()
 		})
 	}
-	{
-		ctx, cancel := context.WithCancel(context.Background())
-		g.Add(func() error {
-			// We retry infinitely until we reach and fetch BuildVersion from our Prometheus.
-			err := runutil.Retry(2*time.Second, ctx.Done(), func() error {
-				if err := m.BuildVersion(ctx); err != nil {
-					level.Warn(logger).Log(
-						"msg", "failed to fetch prometheus version. Is Prometheus running? Retrying",
-						"err", err,
-					)
-					return err
-				}
-
-				level.Info(logger).Log(
-					"msg", "successfully loaded prometheus version",
-				)
-				return nil
-			})
-			if err != nil {
-				return errors.Wrap(err, "failed to get prometheus version")
-			}
-			return nil
-		}, func(error) {
-			cancel()
-		})
-	}
-
 	{
 		t := exthttp.NewTransport()
 		t.MaxIdleConnsPerHost = conf.connection.maxIdleConnsPerHost
diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index b828424940..abbc7cfee7 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -522,7 +522,7 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 			return nil, err
 		}
 
-		// using set to handle duplicate values.
+		// Using set to handle duplicate values.
 		labelValuesSet := make(map[string]struct{})
 		for _, s := range sers {
 			if val, exists := s[r.Label]; exists {

From fd708fe04877c8d4e404490a0e37130e27fcb89e Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Wed, 28 Apr 2021 00:11:21 +0530
Subject: [PATCH 11/15] using semver

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 go.mod                  |  1 +
 go.sum                  |  4 ++++
 pkg/store/prometheus.go | 17 +++++++++++++++--
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/go.mod b/go.mod
index 9f349b14f2..116899c53c 100644
--- a/go.mod
+++ b/go.mod
@@ -8,6 +8,7 @@ require (
 	github.com/NYTimes/gziphandler v1.1.1
 	github.com/alecthomas/units v0.0.0-20210208195552-ff826a37aa15
 	github.com/aliyun/aliyun-oss-go-sdk v2.0.4+incompatible
+	github.com/blang/semver/v4 v4.0.0
 	github.com/bradfitz/gomemcache v0.0.0-20190913173617-a41fca850d0b
 	github.com/cespare/xxhash v1.1.0
 	github.com/chromedp/cdproto v0.0.0-20200424080200-0de008e41fa0
diff --git a/go.sum b/go.sum
index d070c4160e..5adfef6f78 100644
--- a/go.sum
+++ b/go.sum
@@ -181,7 +181,11 @@ github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6r
 github.com/bgentry/speakeasy v0.1.0/go.mod h1:+zsyZBPWlz7T6j88CTgSN5bM796AkVf0kBD4zp0CCIs=
 github.com/bitly/go-hostpool v0.0.0-20171023180738-a3a6125de932/go.mod h1:NOuUCSz6Q9T7+igc/hlvDOUdtWKryOrtFyIVABv/p7k=
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
+github.com/blang/semver v3.5.0+incompatible h1:CGxCgetQ64DKk7rdZ++Vfnb1+ogGNnB17OJKJXD2Cfs=
 github.com/blang/semver v3.5.0+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
+github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdnnjpJbkM4JQ=
+github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
+github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
 github.com/bmizerany/assert v0.0.0-20160611221934-b7ed37b82869/go.mod h1:Ekp36dRnpXw/yCqJaO+ZrUyxD+3VXMFFr56k5XYrpB4=
 github.com/bmizerany/pat v0.0.0-20170815010413-6226ea591a40/go.mod h1:8rLXio+WjiTceGBHIoTvn60HIbs7Hm7bcHjyrSqYB9c=
 github.com/boltdb/bolt v1.3.1/go.mod h1:clJnj/oiGkjum5o1McbSZDSLxVThjynRyGBgiAx27Ps=
diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index abbc7cfee7..3ea7870cfe 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -17,6 +17,7 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/blang/semver/v4"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/gogo/protobuf/proto"
@@ -504,10 +505,22 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 		err  error
 	)
 
+	lvc := false // LabelValuesCall
 	vals := []string{}
-	version := p.promVersion()
+	v := p.promVersion()
 
-	if len(r.Matchers) == 0 || version > "2.24" {
+	version, err := semver.Parse(v)
+	if err == nil {
+		baseVer, err := semver.Make("2.24.0")
+		if err != nil {
+			return nil, err
+		}
+		if version.Compare(baseVer) == 1 {
+			lvc = true
+		}
+	}
+
+	if len(r.Matchers) == 0 || lvc {
 		vals, err = p.client.LabelValuesInGRPC(ctx, p.base, r.Label, r.Matchers, r.Start, r.End)
 		if err != nil {
 			return nil, err

From d874bc132a5006b6b5700df2c6f2948c7a137eac Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Wed, 28 Apr 2021 00:28:05 +0530
Subject: [PATCH 12/15] making linter happy1

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 go.sum | 1 -
 1 file changed, 1 deletion(-)

diff --git a/go.sum b/go.sum
index 5adfef6f78..6561def31a 100644
--- a/go.sum
+++ b/go.sum
@@ -183,7 +183,6 @@ github.com/bitly/go-hostpool v0.0.0-20171023180738-a3a6125de932/go.mod h1:NOuUCS
 github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJmJgSg28kpZDP6UIiPt0e0Oz0kqKNGyRaWEPv84=
 github.com/blang/semver v3.5.0+incompatible h1:CGxCgetQ64DKk7rdZ++Vfnb1+ogGNnB17OJKJXD2Cfs=
 github.com/blang/semver v3.5.0+incompatible/go.mod h1:kRBLl5iJ+tD4TcOOxsy/0fnwebNt5EWlYSAyrTnjyyk=
-github.com/blang/semver v3.5.1+incompatible h1:cQNTCjp13qL8KC3Nbxr/y2Bqb63oX6wdnnjpJbkM4JQ=
 github.com/blang/semver/v4 v4.0.0 h1:1PFHFE6yCCTv8C1TeyNNarDzntLi7wMI5i/pzqYIsAM=
 github.com/blang/semver/v4 v4.0.0/go.mod h1:IbckMUScFkM3pff0VJDNKRiT6TG/YpiHIM2yvyW5YoQ=
 github.com/bmizerany/assert v0.0.0-20160611221934-b7ed37b82869/go.mod h1:Ekp36dRnpXw/yCqJaO+ZrUyxD+3VXMFFr56k5XYrpB4=

From e59208c9162100c80cb02f5ccea7b4bea9d54915 Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Thu, 29 Apr 2021 19:43:53 +0530
Subject: [PATCH 13/15] small nits

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus.go | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index 3ea7870cfe..e726ba1be5 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -509,15 +509,11 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 	vals := []string{}
 	v := p.promVersion()
 
-	version, err := semver.Parse(v)
-	if err == nil {
-		baseVer, err := semver.Make("2.24.0")
-		if err != nil {
-			return nil, err
-		}
-		if version.Compare(baseVer) == 1 {
-			lvc = true
-		}
+	version, err1 := semver.Parse(v)
+	baseVer, err2 := semver.Make("2.24.0")
+
+	if err1 == nil && err2 == nil && version.Compare(baseVer) == 1 {
+		lvc = true
 	}
 
 	if len(r.Matchers) == 0 || lvc {

From 893e37cf7118a4ab6e9388810a5877c87afbef4d Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Fri, 30 Apr 2021 02:12:37 +0530
Subject: [PATCH 14/15] made baseVer global

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus.go | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index e726ba1be5..562335a157 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -58,6 +58,9 @@ type PrometheusStore struct {
 	framesRead prometheus.Histogram
 }
 
+// LabelValues call with matchers is supported for Prometheus versions >= 2.24.0
+var baseVer, _ = semver.Make("2.24.0")
+
 const initialBufSize = 32 * 1024 // 32KB seems like a good minimum starting size for sync pool size.
 
 // NewPrometheusStore returns a new PrometheusStore that uses the given HTTP client
@@ -509,10 +512,8 @@ func (p *PrometheusStore) LabelValues(ctx context.Context, r *storepb.LabelValue
 	vals := []string{}
 	v := p.promVersion()
 
-	version, err1 := semver.Parse(v)
-	baseVer, err2 := semver.Make("2.24.0")
-
-	if err1 == nil && err2 == nil && version.Compare(baseVer) == 1 {
+	version, err := semver.Parse(v)
+	if err == nil && version.GTE(baseVer) {
 		lvc = true
 	}
 

From 92570d0b3cca389aa9b269b27247b6659144afea Mon Sep 17 00:00:00 2001
From: Namanl2001 <namanlakhwani@gmail.com>
Date: Fri, 30 Apr 2021 02:23:31 +0530
Subject: [PATCH 15/15] linting correction

Signed-off-by: Namanl2001 <namanlakhwani@gmail.com>
---
 pkg/store/prometheus.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg/store/prometheus.go b/pkg/store/prometheus.go
index 562335a157..894cc34893 100644
--- a/pkg/store/prometheus.go
+++ b/pkg/store/prometheus.go
@@ -58,7 +58,7 @@ type PrometheusStore struct {
 	framesRead prometheus.Histogram
 }
 
-// LabelValues call with matchers is supported for Prometheus versions >= 2.24.0
+// LabelValues call with matchers is supported for Prometheus versions >= 2.24.0 .
 var baseVer, _ = semver.Make("2.24.0")
 
 const initialBufSize = 32 * 1024 // 32KB seems like a good minimum starting size for sync pool size.