Out-of-order Flag : Added option for sending out of order samples (#68)

* changed implementation of shuffleTimeStamps

Signed-off-by: Vanshikav123 <[email protected]>

* resolving conflicts and improve test

Signed-off-by: Vanshikav123 <[email protected]>

---------

Signed-off-by: Vanshikav123 <[email protected]>
Signed-off-by: Vanshika <[email protected]>

Author: Vanshikav123

Diff for: cmd/avalanche.go

@@ -56,6 +56,7 @@ var (
 	remoteTenant         = kingpin.Flag("remote-tenant", "Tenant ID to include in remote_write send").Default("0").String()
 	tlsClientInsecure    = kingpin.Flag("tls-client-insecure", "Skip certificate check on tls connection").Default("false").Bool()
 	remoteTenantHeader   = kingpin.Flag("remote-tenant-header", "Tenant ID to include in remote_write send. The default, is the default tenant header expected by Cortex.").Default("X-Scope-OrgID").String()
+	outOfOrder           = kingpin.Flag("out-of-order", "Enable out-of-order timestamps in remote write requests").Default("true").Bool()
 )
 
 func main() {
@@ -123,6 +124,7 @@ func main() {
 				InsecureSkipVerify: *tlsClientInsecure,
 			},
 			TenantHeader: *remoteTenantHeader,
+			OutOfOrder:   *outOfOrder,
 		}
 
 		// Collect Pprof during the write only if not collecting within a regular interval.
@@ -136,7 +138,7 @@ func main() {
 		)
 		if *remotePprofInterval > 0 {
 			if len(*remotePprofURLs) == 0 {
-				log.Fatal("remote profiling interval specified wihout any remote pprof urls")
+				log.Fatal("remote profiling interval specified without any remote pprof urls")
 			}
 			suffix := rand.Intn(1000)
 			go func() {
@@ -170,7 +172,7 @@ func main() {
 		return
 	}
 
-	fmt.Printf("Serving ur metrics at localhost:%v/metrics\n", *port)
+	fmt.Printf("Serving your metrics at localhost:%v/metrics\n", *port)
 	err = metrics.ServeMetrics(*port)
 	if err != nil {
 		log.Fatal(err)

Diff for: metrics/write.go

@@ -54,6 +54,7 @@ type ConfigWrite struct {
 	Tenant          string
 	TLSClientConfig tls.Config
 	TenantHeader    string
+	OutOfOrder      bool
 }
 
 // Client for the remote write requests.
@@ -108,7 +109,7 @@ func cloneRequest(r *http.Request) *http.Request {
 }
 
 func (c *Client) write() error {
-	tss, err := collectMetrics()
+	tss, err := collectMetrics(c.config.OutOfOrder)
 	if err != nil {
 		return err
 	}
@@ -140,7 +141,7 @@ func (c *Client) write() error {
 		select {
 		case <-c.config.UpdateNotify:
 			log.Println("updating remote write metrics")
-			tss, err = collectMetrics()
+			tss, err = collectMetrics(c.config.OutOfOrder)
 			if err != nil {
 				merr.Add(err)
 			}
@@ -193,14 +194,28 @@ func updateTimetamps(tss []prompb.TimeSeries) []prompb.TimeSeries {
 	return tss
 }
 
-func collectMetrics() ([]prompb.TimeSeries, error) {
+func collectMetrics(outOfOrder bool) ([]prompb.TimeSeries, error) {
 	metricsMux.Lock()
 	defer metricsMux.Unlock()
 	metricFamilies, err := promRegistry.Gather()
 	if err != nil {
 		return nil, err
 	}
-	return ToTimeSeriesSlice(metricFamilies), nil
+	tss := ToTimeSeriesSlice(metricFamilies)
+	if outOfOrder {
+		tss = shuffleTimestamps(tss)
+	}
+	return tss, nil
+}
+func shuffleTimestamps(tss []prompb.TimeSeries) []prompb.TimeSeries {
+	now := time.Now().UnixMilli()
+	offsets := []int64{0, -60 * 1000, -5 * 60 * 1000}
+
+	for i := range tss {
+		offset := offsets[i%len(offsets)]
+		tss[i].Samples[0].Timestamp = now + offset
+	}
+	return tss
 }
 
 // ToTimeSeriesSlice converts a slice of metricFamilies containing samples into a slice of TimeSeries

Diff for: metrics/write_test.go

@@ -0,0 +1,60 @@
+// Copyright 2022 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package metrics
+
+import (
+	"testing"
+	"time"
+
+	"github.com/prometheus/prometheus/prompb"
+)
+
+func TestShuffleTimestamps(t *testing.T) {
+	now := time.Now().UnixMilli()
+
+	tss := []prompb.TimeSeries{
+		{Samples: []prompb.Sample{{Timestamp: now}}},
+		{Samples: []prompb.Sample{{Timestamp: now}}},
+		{Samples: []prompb.Sample{{Timestamp: now}}},
+	}
+
+	shuffledTSS := shuffleTimestamps(tss)
+
+	offsets := []int64{0, -60 * 1000, -5 * 60 * 1000}
+	for _, ts := range shuffledTSS {
+		timestampValid := false
+		for _, offset := range offsets {
+			expectedTimestamp := now + offset
+			if ts.Samples[0].Timestamp == expectedTimestamp {
+				timestampValid = true
+				break
+			}
+		}
+		if !timestampValid {
+			t.Errorf("Timestamp %v is not in the expected offsets: %v", ts.Samples[0].Timestamp, offsets)
+		}
+	}
+
+	outOfOrder := false
+	for i := 1; i < len(shuffledTSS); i++ {
+		if shuffledTSS[i].Samples[0].Timestamp < shuffledTSS[i-1].Samples[0].Timestamp {
+			outOfOrder = true
+			break
+		}
+	}
+
+	if !outOfOrder {
+		t.Error("Timestamps are not out of order")
+	}
+}