Revert "storage/remote: remote write 2.0 content negotiation"

cmd/promtool/metrics.go

@@ -116,7 +116,7 @@ func parseAndPushMetrics(client *remote.Client, data []byte, labels map[string]s
 
 	// Encode the request body into snappy encoding.
 	compressed := snappy.Encode(nil, raw)
-	err = client.Store(context.Background(), compressed, 0, remote.Version1, "snappy")
+	err = client.Store(context.Background(), compressed, 0)
 	if err != nil {
 		fmt.Fprintln(os.Stderr, "  FAILED:", err)
 		return false

storage/remote/client.go

@@ -17,7 +17,6 @@ import (
 	"bufio"
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"math/rand"
@@ -47,22 +46,6 @@ const maxErrMsgLen = 1024
 
 var UserAgent = fmt.Sprintf("Prometheus/%s", version.Version)
 
-// If we send a Remote Write 2.0 request to a Remote Write endpoint that only understands
-// Remote Write 1.0 it will respond with an error. We need to handle these errors
-// accordingly. Any 5xx errors will just need to be retried as they are considered
-// transient/recoverable errors. A 4xx error will need to be passed back to the queue
-// manager in order to be re-encoded in a suitable format.
-
-// A Remote Write 2.0 request sent to, for example, a Prometheus 2.50 receiver (which does
-// not understand Remote Write 2.0) will result in an HTTP 400 status code from the receiver.
-var ErrStatusBadRequest = errors.New("HTTP StatusBadRequest") // 400
-
-// A Remote Write 2.0 request sent to a remote write receiver may (depending on receiver version)
-// result in an HTTP 406 status code to indicate that it does not accept the protocol or
-// encoding of that request and that the sender should retry with a more suitable protocol
-// version or encoding.
-var ErrStatusNotAcceptable = errors.New("HTTP StatusNotAcceptable") // 406
-
 var (
 	remoteReadQueriesTotal = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
@@ -102,7 +85,7 @@ func init() {
 type Client struct {
 	remoteName string                   // Used to differentiate clients in metrics.
 	urlString  string                   // url.String()
-	lastRWHeader string
+	rwFormat   config.RemoteWriteFormat // For write clients, ignored for read clients.
 	Client     *http.Client
 	timeout    time.Duration
 
@@ -184,6 +167,7 @@ func NewWriteClient(name string, conf *ClientConfig) (WriteClient, error) {
 	httpClient.Transport = otelhttp.NewTransport(t)
 
 	return &Client{
+		rwFormat:         conf.RemoteWriteFormat,
 		remoteName:       name,
 		urlString:        conf.URL.String(),
 		Client:           httpClient,
@@ -215,58 +199,9 @@ type RecoverableError struct {
 	retryAfter model.Duration
 }
 
-// Attempt a HEAD request against a remote write endpoint to see what it supports.
-func (c *Client) probeRemoteVersions(ctx context.Context) error {
-	// We assume we are in Version2 mode otherwise we shouldn't be calling this.
-
-	httpReq, err := http.NewRequest("HEAD", c.urlString, nil)
-	if err != nil {
-		// Errors from NewRequest are from unparsable URLs, so are not
-		// recoverable.
-		return err
-	}
-
-	// Set the version header to be nice.
-	httpReq.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion20HeaderValue)
-	httpReq.Header.Set("User-Agent", UserAgent)
-
-	ctx, cancel := context.WithTimeout(ctx, c.timeout)
-	defer cancel()
-
-	httpResp, err := c.Client.Do(httpReq.WithContext(ctx))
-	if err != nil {
-		// We don't attempt a retry here.
-		return err
-	}
-
-	// See if we got a header anyway.
-	promHeader := httpResp.Header.Get(RemoteWriteVersionHeader)
-
-	// Only update lastRWHeader if the X-Prometheus-Remote-Write header is not blank.
-	if promHeader != "" {
-		c.lastRWHeader = promHeader
-	}
-
-	// Check for an error.
-	if httpResp.StatusCode != 200 {
-		if httpResp.StatusCode == 405 {
-			// If we get a 405 (MethodNotAllowed) error then it means the endpoint doesn't
-			// understand Remote Write 2.0, so we allow the lastRWHeader to be overwritten
-			// even if it is blank.
-			// This will make subsequent sends use RemoteWrite 1.0 until the endpoint gives
-			// a response that confirms it can speak 2.0.
-			c.lastRWHeader = promHeader
-		}
-		return fmt.Errorf(httpResp.Status)
-	}
-
-	// All ok, return no error.
-	return nil
-}
-
 // Store sends a batch of samples to the HTTP endpoint, the request is the proto marshalled
 // and encoded bytes from codec.go.
-func (c *Client) Store(ctx context.Context, req []byte, attempt int, rwFormat config.RemoteWriteFormat, compression string) error {
+func (c *Client) Store(ctx context.Context, req []byte, attempt int) error {
 	httpReq, err := http.NewRequest("POST", c.urlString, bytes.NewReader(req))
 	if err != nil {
 		// Errors from NewRequest are from unparsable URLs, so are not
@@ -274,15 +209,15 @@ func (c *Client) Store(ctx context.Context, req []byte, attempt int, rwFormat co
 		return err
 	}
 
-	httpReq.Header.Add("Content-Encoding", compression)
+	httpReq.Header.Add("Content-Encoding", "snappy")
 	httpReq.Header.Set("Content-Type", "application/x-protobuf")
 	httpReq.Header.Set("User-Agent", UserAgent)
 
-	if rwFormat == Version1 {
+	if c.rwFormat == Version1 {
 		httpReq.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion1HeaderValue)
 	} else {
-		// Set the right header if we're using v2.0 remote write protocol.
+		// Set the right header if we're using v1.1 remote write protocol
-		httpReq.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion20HeaderValue)
+		httpReq.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion2HeaderValue)
 	}
 
 	if attempt > 0 {
@@ -306,12 +241,7 @@ func (c *Client) Store(ctx context.Context, req []byte, attempt int, rwFormat co
 		httpResp.Body.Close()
 	}()
 
-	// See if we got a X-Prometheus-Remote-Write header in the response.
+	// TODO-RW11: Here is where we need to handle version downgrade on error
-	if promHeader := httpResp.Header.Get(RemoteWriteVersionHeader); promHeader != "" {
-		// Only update lastRWHeader if the X-Prometheus-Remote-Write header is not blank.
-		// (It's blank if it wasn't present, we don't care about that distinction.)
-		c.lastRWHeader = promHeader
-	}
 
 	if httpResp.StatusCode/100 != 2 {
 		scanner := bufio.NewScanner(io.LimitReader(httpResp.Body, maxErrMsgLen))
@@ -319,23 +249,8 @@ func (c *Client) Store(ctx context.Context, req []byte, attempt int, rwFormat co
 		if scanner.Scan() {
 			line = scanner.Text()
 		}
-		switch httpResp.StatusCode {
-		case 400:
-			// Return an unrecoverable error to indicate the 400.
-			// This then gets passed up the chain so we can react to it properly.
-			// TODO(alexg) Do we want to include the first line of the message?
-			return ErrStatusBadRequest
-		case 406:
-			// Return an unrecoverable error to indicate the 406.
-			// This then gets passed up the chain so we can react to it properly.
-			// TODO(alexg) Do we want to include the first line of the message?
-			// TODO(alexg) Do we want to combine these two errors as one, with the statuscode and first line of message in the error?
-			return ErrStatusNotAcceptable
-		default:
-			// We want to end up returning a non-specific error.
 		err = fmt.Errorf("server returned HTTP status %s: %s", httpResp.Status, line)
 	}
-	}
 	if httpResp.StatusCode/100 == 5 ||
 		(c.retryOnRateLimit && httpResp.StatusCode == http.StatusTooManyRequests) {
 		return RecoverableError{err, retryAfterDuration(httpResp.Header.Get("Retry-After"))}
@@ -369,10 +284,6 @@ func (c Client) Endpoint() string {
 	return c.urlString
 }
 
-func (c *Client) GetLastRWHeader() string {
-	return c.lastRWHeader
-}
-
 // Read reads from a remote endpoint.
 func (c *Client) Read(ctx context.Context, query *prompb.Query) (*prompb.QueryResult, error) {
 	c.readQueries.Inc()
@@ -455,11 +366,7 @@ func NewTestClient(name, url string) WriteClient {
 	return &TestClient{name: name, url: url}
 }
 
-func (c *TestClient) probeRemoteVersions(_ context.Context) error {
+func (c *TestClient) Store(_ context.Context, req []byte, _ int) error {
-	return nil
-}
-
-func (c *TestClient) Store(_ context.Context, req []byte, _ int, _ config.RemoteWriteFormat, _ string) error {
 	r := rand.Intn(200-100) + 100
 	time.Sleep(time.Duration(r) * time.Millisecond)
 	return nil
@@ -472,7 +379,3 @@ func (c *TestClient) Name() string {
 func (c *TestClient) Endpoint() string {
 	return c.url
 }
-
-func (c *TestClient) GetLastRWHeader() string {
-	return "2.0;snappy,0.1.0"
-}

storage/remote/client_test.go

@@ -73,7 +73,7 @@ func TestStoreHTTPErrorHandling(t *testing.T) {
 		c, err := NewWriteClient(hash, conf)
 		require.NoError(t, err)
 
-		err = c.Store(context.Background(), []byte{}, 0, Version1, "snappy")
+		err = c.Store(context.Background(), []byte{}, 0)
 		if test.err != nil {
 			require.EqualError(t, err, test.err.Error())
 		} else {
@@ -133,7 +133,7 @@ func TestClientRetryAfter(t *testing.T) {
 			c := getClient(getClientConfig(serverURL, tc.retryOnRateLimit))
 
 			var recErr RecoverableError
-			err = c.Store(context.Background(), []byte{}, 0, Version1, "snappy")
+			err = c.Store(context.Background(), []byte{}, 0)
 			require.Equal(t, tc.expectedRecoverable, errors.As(err, &recErr), "Mismatch in expected recoverable error status.")
 			if tc.expectedRecoverable {
 				require.Equal(t, tc.expectedRetryAfter, recErr.retryAfter)
@@ -203,7 +203,7 @@ func TestClientHeaders(t *testing.T) {
 	c, err := NewWriteClient("c", conf)
 	require.NoError(t, err)
 
-	err = c.Store(context.Background(), []byte{}, 0, Version1, "snappy")
+	err = c.Store(context.Background(), []byte{}, 0)
 	require.NoError(t, err)
 
 	require.True(t, called, "The remote server wasn't called")

storage/remote/codec_test.go

@@ -559,7 +559,7 @@ func TestMetricTypeToMetricTypeProto(t *testing.T) {
 }
 
 func TestDecodeWriteRequest(t *testing.T) {
-	buf, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil, "snappy")
+	buf, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil)
 	require.NoError(t, err)
 
 	actual, err := DecodeWriteRequest(bytes.NewReader(buf))
@@ -568,7 +568,7 @@ func TestDecodeWriteRequest(t *testing.T) {
 }
 
 func TestDecodeMinWriteRequest(t *testing.T) {
-	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil, "snappy")
+	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil)
 	require.NoError(t, err)
 
 	actual, err := DecodeMinimizedWriteRequestStr(bytes.NewReader(buf))

storage/remote/queue_manager.go

@@ -16,10 +16,8 @@ package remote
 import (
 	"context"
 	"errors"
-	"fmt"
 	"math"
 	"strconv"
-	"strings"
 	"sync"
 	"time"
 
@@ -389,20 +387,16 @@ func (m *queueManagerMetrics) unregister() {
 // external timeseries database.
 type WriteClient interface {
 	// Store stores the given samples in the remote storage.
-	Store(ctx context.Context, req []byte, retryAttempt int, rwFormat config.RemoteWriteFormat, compression string) error
+	Store(ctx context.Context, req []byte, retryAttempt int) error
 	// Name uniquely identifies the remote storage.
 	Name() string
 	// Endpoint is the remote read or write endpoint for the storage client.
 	Endpoint() string
-	// Get the protocol versions supported by the endpoint.
-	probeRemoteVersions(ctx context.Context) error
-	// Get the last RW header received from the endpoint.
-	GetLastRWHeader() string
 }
 
 const (
 	Version1 config.RemoteWriteFormat = iota // 1.0, 0.1, etc.
-	Version2                                 // symbols are indices into an array of strings.
+	Version2                                 // symbols are indices into an array of strings
 )
 
 // QueueManager manages a queue of samples to be sent to the Storage
@@ -422,6 +416,7 @@ type QueueManager struct {
 	sendNativeHistograms bool
 	watcher              *wlog.Watcher
 	metadataWatcher      *MetadataWatcher
+	// experimental feature, new remote write proto format
 	rwFormat config.RemoteWriteFormat
 
 	clientMtx   sync.RWMutex
@@ -495,6 +490,8 @@ func NewQueueManager(
 		storeClient:          client,
 		sendExemplars:        enableExemplarRemoteWrite,
 		sendNativeHistograms: enableNativeHistogramRemoteWrite,
+		// TODO: we should eventually set the format via content negotiation,
+		// so this field would be the desired format, maybe with a fallback?
 		rwFormat: rwFormat,
 
 		seriesLabels:         make(map[chunks.HeadSeriesRef]labels.Labels),
@@ -575,11 +572,7 @@ func (t *QueueManager) AppendWatcherMetadata(ctx context.Context, metadata []scr
 
 func (t *QueueManager) sendMetadataWithBackoff(ctx context.Context, metadata []prompb.MetricMetadata, pBuf *proto.Buffer) error {
 	// Build the WriteRequest with no samples.
-
+	req, _, _, err := buildWriteRequest(t.logger, nil, metadata, pBuf, nil, nil)
-	// Get compression to use from content negotiation based on last header seen (defaults to snappy).
-	compression, _ := negotiateRWProto(t.rwFormat, t.storeClient.GetLastRWHeader())
-
-	req, _, _, err := buildWriteRequest(t.logger, nil, metadata, pBuf, nil, nil, compression)
 	if err != nil {
 		return err
 	}
@@ -602,7 +595,7 @@ func (t *QueueManager) sendMetadataWithBackoff(ctx context.Context, metadata []p
 		}
 
 		begin := time.Now()
-		err := t.storeClient.Store(ctx, req, try, Version1, compression)
+		err := t.storeClient.Store(ctx, req, try)
 		t.metrics.sentBatchDuration.Observe(time.Since(begin).Seconds())
 
 		if err != nil {
@@ -1498,40 +1491,6 @@ func (q *queue) newBatch(capacity int) []timeSeries {
 	return make([]timeSeries, 0, capacity)
 }
 
-func negotiateRWProto(rwFormat config.RemoteWriteFormat, lastHeaderSeen string) (string, config.RemoteWriteFormat) {
-	if rwFormat == Version1 {
-		// If we're only handling Version1 then all we can do is that with snappy compression.
-		return "snappy", Version1
-	}
-	if rwFormat != Version2 {
-		// If we get here then someone has added a new RemoteWriteFormat value but hasn't
-		// fixed this function to handle it. Panic!
-		panic(fmt.Sprintf("Unhandled RemoteWriteFormat %q", rwFormat))
-	}
-	if lastHeaderSeen == "" {
-		// We haven't had a valid header, so we just default to "0.1.0/snappy".
-		return "snappy", Version1
-	}
-	// We can currently handle:
-	// "2.0;snappy"
-	// "0.1.0" - implicit compression of snappy
-	// lastHeaderSeen should contain a list of tuples.
-	// If we find a match to something we can handle then we can return that.
-	for _, tuple := range strings.Split(lastHeaderSeen, ",") {
-		// Remove spaces from the tuple.
-		curr := strings.ReplaceAll(tuple, " ", "")
-		switch curr {
-		case "2.0;snappy":
-			return "snappy", Version2
-		case "0.1.0":
-			return "snappy", Version1
-		}
-	}
-
-	// Otherwise we have to default to "0.1.0".
-	return "snappy", Version1
-}
-
 func (s *shards) runShard(ctx context.Context, shardID int, queue *queue) {
 	defer func() {
 		if s.running.Dec() == 0 {
@@ -1582,26 +1541,6 @@ func (s *shards) runShard(ctx context.Context, shardID int, queue *queue) {
 	}
 	defer stop()
 
-	attemptBatchSend := func(batch []timeSeries, rwFormat config.RemoteWriteFormat, compression string, timer bool) error {
-		switch rwFormat {
-		case Version1:
-			nPendingSamples, nPendingExemplars, nPendingHistograms := populateTimeSeries(batch, pendingData, s.qm.sendExemplars, s.qm.sendNativeHistograms)
-			n := nPendingSamples + nPendingExemplars + nPendingHistograms
-			if timer {
-				level.Debug(s.qm.logger).Log("msg", "runShard timer ticked, sending buffered data", "samples", nPendingSamples,
-					"exemplars", nPendingExemplars, "shard", shardNum, "histograms", nPendingHistograms)
-			}
-			return s.sendSamples(ctx, pendingData[:n], nPendingSamples, nPendingExemplars, nPendingHistograms, pBuf, &buf, compression)
-		case Version2:
-			nPendingSamples, nPendingExemplars, nPendingHistograms, nPendingMetadata := populateV2TimeSeries(&symbolTable, batch, pendingMinStrData, s.qm.sendExemplars, s.qm.sendNativeHistograms)
-			n := nPendingSamples + nPendingExemplars + nPendingHistograms
-			err := s.sendV2Samples(ctx, pendingMinStrData[:n], symbolTable.LabelsStrings(), nPendingSamples, nPendingExemplars, nPendingHistograms, nPendingMetadata, &pBufRaw, &buf, compression)
-			symbolTable.clear()
-			return err
-		}
-		return nil
-	}
-
 	for {
 		select {
 		case <-ctx.Done():
@@ -1625,20 +1564,16 @@ func (s *shards) runShard(ctx context.Context, shardID int, queue *queue) {
 			if !ok {
 				return
 			}
-			// Resend logic on 406.
+			switch s.qm.rwFormat {
-			// ErrStatusNotAcceptable is a new error defined in client.go.
+			case Version1:
-
+				nPendingSamples, nPendingExemplars, nPendingHistograms := populateTimeSeries(batch, pendingData, s.qm.sendExemplars, s.qm.sendNativeHistograms)
-			// Work out what version to send based on the last header seen and the QM's rwFormat setting.
+				n := nPendingSamples + nPendingExemplars + nPendingHistograms
-			// TODO(alexg) - see comments below about retry/renegotiate design.
+				s.sendSamples(ctx, pendingData[:n], nPendingSamples, nPendingExemplars, nPendingHistograms, pBuf, &buf)
-			for attemptNos := 1; attemptNos <= 3; attemptNos++ {
+			case Version2:
-				lastHeaderSeen := s.qm.storeClient.GetLastRWHeader()
+				nPendingSamples, nPendingExemplars, nPendingHistograms, nPendingMetadata := populateV2TimeSeries(&symbolTable, batch, pendingMinStrData, s.qm.sendExemplars, s.qm.sendNativeHistograms)
-				compression, rwFormat := negotiateRWProto(s.qm.rwFormat, lastHeaderSeen)
+				n := nPendingSamples + nPendingExemplars + nPendingHistograms
-				sendErr := attemptBatchSend(batch, rwFormat, compression, false)
+				s.sendV2Samples(ctx, pendingMinStrData[:n], symbolTable.LabelsStrings(), nPendingSamples, nPendingExemplars, nPendingHistograms, nPendingMetadata, &pBufRaw, &buf)
-				if sendErr == nil || !(errors.Is(sendErr, ErrStatusNotAcceptable) || errors.Is(sendErr, ErrStatusBadRequest)) {
+				symbolTable.clear()
-					// It wasn't an error, or wasn't a 406 or 400 so we can just stop trying.
-					break
-				}
-				// If we get either of the two errors (406, 400) we loop and re-negotiate.
 			}
 
 			queue.ReturnForReuse(batch)
@@ -1649,23 +1584,19 @@ func (s *shards) runShard(ctx context.Context, shardID int, queue *queue) {
 		case <-timer.C:
 			batch := queue.Batch()
 			if len(batch) > 0 {
-				for attemptNos := 1; attemptNos <= 3; attemptNos++ {
+				switch s.qm.rwFormat {
-					// Work out what version to send based on the last header seen and the QM's rwFormat setting.
+				case Version1:
-					lastHeaderSeen := s.qm.storeClient.GetLastRWHeader()
+					nPendingSamples, nPendingExemplars, nPendingHistograms := populateTimeSeries(batch, pendingData, s.qm.sendExemplars, s.qm.sendNativeHistograms)
-					compression, rwFormat := negotiateRWProto(s.qm.rwFormat, lastHeaderSeen)
+					n := nPendingSamples + nPendingExemplars + nPendingHistograms
-					sendErr := attemptBatchSend(batch, rwFormat, compression, true)
+					s.sendSamples(ctx, pendingData[:n], nPendingSamples, nPendingExemplars, nPendingHistograms, pBuf, &buf)
-					if sendErr == nil || !(errors.Is(sendErr, ErrStatusNotAcceptable) || errors.Is(sendErr, ErrStatusBadRequest)) {
+					level.Debug(s.qm.logger).Log("msg", "runShard timer ticked, sending buffered data", "samples", nPendingSamples,
-						// It wasn't an error, or wasn't a 406 or 400 so we can just stop trying.
+						"exemplars", nPendingExemplars, "shard", shardNum, "histograms", nPendingHistograms)
-						break
+				case Version2:
+					nPendingSamples, nPendingExemplars, nPendingHistograms, nPendingMetadata := populateV2TimeSeries(&symbolTable, batch, pendingMinStrData, s.qm.sendExemplars, s.qm.sendNativeHistograms)
+					n := nPendingSamples + nPendingExemplars + nPendingHistograms
+					s.sendV2Samples(ctx, pendingMinStrData[:n], symbolTable.LabelsStrings(), nPendingSamples, nPendingExemplars, nPendingHistograms, nPendingMetadata, &pBufRaw, &buf)
+					symbolTable.clear()
 				}
-					// If we get either of the two errors (406, 400) we loop and re-negotiate.
-				}
-				// TODO(alexg) - the question here is whether we use the 3rd attempt to ensure we
-				// Consider a server that erroneously reports it can handle "0.2.0/snappy" even in the 406/400 errors when that data is sent in that format
-				// Q: Do we always try downgrading to 1.0 at least once?
-				// Q: Do we limit our attempts to only try a particular protocol/encoding tuple once?
-				// Q: Is 3 a suitable limit?
-				// TODO(alexg) - add retry/renegotiate metrics here
 			}
 			queue.ReturnForReuse(batch)
 			timer.Reset(time.Duration(s.qm.cfg.BatchSendDeadline))
@@ -1714,22 +1645,16 @@ func populateTimeSeries(batch []timeSeries, pendingData []prompb.TimeSeries, sen
 	return nPendingSamples, nPendingExemplars, nPendingHistograms
 }
 
-func (s *shards) sendSamples(ctx context.Context, samples []prompb.TimeSeries, sampleCount, exemplarCount, histogramCount int, pBuf *proto.Buffer, buf *[]byte, compression string) error {
+func (s *shards) sendSamples(ctx context.Context, samples []prompb.TimeSeries, sampleCount, exemplarCount, histogramCount int, pBuf *proto.Buffer, buf *[]byte) {
 	begin := time.Now()
-	err := s.sendSamplesWithBackoff(ctx, samples, sampleCount, exemplarCount, histogramCount, 0, pBuf, buf, compression)
+	err := s.sendSamplesWithBackoff(ctx, samples, sampleCount, exemplarCount, histogramCount, 0, pBuf, buf)
 	s.updateMetrics(ctx, err, sampleCount, exemplarCount, histogramCount, 0, time.Since(begin))
-
-	// Return the error in case it is a 406 and we need to reformat the data.
-	return err
 }
 
-func (s *shards) sendV2Samples(ctx context.Context, samples []writev2.TimeSeries, labels []string, sampleCount, exemplarCount, histogramCount, metadataCount int, pBuf, buf *[]byte, compression string) error {
+func (s *shards) sendV2Samples(ctx context.Context, samples []writev2.TimeSeries, labels []string, sampleCount, exemplarCount, histogramCount, metadataCount int, pBuf, buf *[]byte) {
 	begin := time.Now()
-	err := s.sendV2SamplesWithBackoff(ctx, samples, labels, sampleCount, exemplarCount, histogramCount, metadataCount, pBuf, buf, compression)
+	err := s.sendV2SamplesWithBackoff(ctx, samples, labels, sampleCount, exemplarCount, histogramCount, metadataCount, pBuf, buf)
 	s.updateMetrics(ctx, err, sampleCount, exemplarCount, histogramCount, metadataCount, time.Since(begin))
-
-	// Return the error in case it is a 406 and we need to reformat the data.
-	return err
 }
 
 func (s *shards) updateMetrics(ctx context.Context, err error, sampleCount, exemplarCount, histogramCount, metadataCount int, duration time.Duration) {
@@ -1756,9 +1681,9 @@ func (s *shards) updateMetrics(ctx context.Context, err error, sampleCount, exem
 }
 
 // sendSamples to the remote storage with backoff for recoverable errors.
-func (s *shards) sendSamplesWithBackoff(ctx context.Context, samples []prompb.TimeSeries, sampleCount, exemplarCount, histogramCount, metadataCount int, pBuf *proto.Buffer, buf *[]byte, compression string) error {
+func (s *shards) sendSamplesWithBackoff(ctx context.Context, samples []prompb.TimeSeries, sampleCount, exemplarCount, histogramCount, metadataCount int, pBuf *proto.Buffer, buf *[]byte) error {
 	// Build the WriteRequest with no metadata.
-	req, highest, lowest, err := buildWriteRequest(s.qm.logger, samples, nil, pBuf, buf, nil, compression)
+	req, highest, lowest, err := buildWriteRequest(s.qm.logger, samples, nil, pBuf, buf, nil)
 	s.qm.buildRequestLimitTimestamp.Store(lowest)
 	if err != nil {
 		// Failing to build the write request is non-recoverable, since it will
@@ -1784,7 +1709,6 @@ func (s *shards) sendSamplesWithBackoff(ctx context.Context, samples []prompb.Ti
 				pBuf,
 				buf,
 				isTimeSeriesOldFilter(s.qm.metrics, currentTime, time.Duration(s.qm.cfg.SampleAgeLimit)),
-				compression,
 			)
 			s.qm.buildRequestLimitTimestamp.Store(lowest)
 			if err != nil {
@@ -1816,7 +1740,7 @@ func (s *shards) sendSamplesWithBackoff(ctx context.Context, samples []prompb.Ti
 		s.qm.metrics.exemplarsTotal.Add(float64(exemplarCount))
 		s.qm.metrics.histogramsTotal.Add(float64(histogramCount))
 		s.qm.metrics.metadataTotal.Add(float64(metadataCount))
-		err := s.qm.client().Store(ctx, *buf, try, Version1, compression)
+		err := s.qm.client().Store(ctx, *buf, try)
 		s.qm.metrics.sentBatchDuration.Observe(time.Since(begin).Seconds())
 
 		if err != nil {
@@ -1847,9 +1771,9 @@ func (s *shards) sendSamplesWithBackoff(ctx context.Context, samples []prompb.Ti
 }
 
 // sendV2Samples to the remote storage with backoff for recoverable errors.
-func (s *shards) sendV2SamplesWithBackoff(ctx context.Context, samples []writev2.TimeSeries, labels []string, sampleCount, exemplarCount, histogramCount, metadataCount int, pBuf, buf *[]byte, compression string) error {
+func (s *shards) sendV2SamplesWithBackoff(ctx context.Context, samples []writev2.TimeSeries, labels []string, sampleCount, exemplarCount, histogramCount, metadataCount int, pBuf, buf *[]byte) error {
 	// Build the WriteRequest with no metadata.
-	req, highest, lowest, err := buildV2WriteRequest(s.qm.logger, samples, labels, pBuf, buf, nil, compression)
+	req, highest, lowest, err := buildV2WriteRequest(s.qm.logger, samples, labels, pBuf, buf, nil)
 	s.qm.buildRequestLimitTimestamp.Store(lowest)
 	if err != nil {
 		// Failing to build the write request is non-recoverable, since it will
@@ -1875,7 +1799,6 @@ func (s *shards) sendV2SamplesWithBackoff(ctx context.Context, samples []writev2
 				pBuf,
 				buf,
 				isV2TimeSeriesOldFilter(s.qm.metrics, currentTime, time.Duration(s.qm.cfg.SampleAgeLimit)),
-				compression,
 			)
 			s.qm.buildRequestLimitTimestamp.Store(lowest)
 			if err != nil {
@@ -1907,7 +1830,7 @@ func (s *shards) sendV2SamplesWithBackoff(ctx context.Context, samples []writev2
 		s.qm.metrics.exemplarsTotal.Add(float64(exemplarCount))
 		s.qm.metrics.histogramsTotal.Add(float64(histogramCount))
 		s.qm.metrics.metadataTotal.Add(float64(metadataCount))
-		err := s.qm.client().Store(ctx, *buf, try, Version2, compression)
+		err := s.qm.client().Store(ctx, *buf, try)
 		s.qm.metrics.sentBatchDuration.Observe(time.Since(begin).Seconds())
 
 		if err != nil {
@@ -2094,23 +2017,7 @@ func buildTimeSeries(timeSeries []prompb.TimeSeries, filter func(prompb.TimeSeri
 	return highest, lowest, timeSeries, droppedSamples, droppedExemplars, droppedHistograms
 }
 
-func compressPayload(tmpbuf *[]byte, inp []byte, compression string) ([]byte, error) {
+func buildWriteRequest(logger log.Logger, timeSeries []prompb.TimeSeries, metadata []prompb.MetricMetadata, pBuf *proto.Buffer, buf *[]byte, filter func(prompb.TimeSeries) bool) ([]byte, int64, int64, error) {
-	var compressed []byte
-
-	switch compression {
-	case "snappy":
-		compressed = snappy.Encode(*tmpbuf, inp)
-		if n := snappy.MaxEncodedLen(len(inp)); n > len(*tmpbuf) {
-			// grow the buffer for the next time
-			*tmpbuf = make([]byte, n)
-		}
-		return compressed, nil
-	default:
-		return compressed, fmt.Errorf("Unknown compression scheme [%s]", compression)
-	}
-}
-
-func buildWriteRequest(logger log.Logger, timeSeries []prompb.TimeSeries, metadata []prompb.MetricMetadata, pBuf *proto.Buffer, buf *[]byte, filter func(prompb.TimeSeries) bool, compression string) ([]byte, int64, int64, error) {
 	highest, lowest, timeSeries,
 		droppedSamples, droppedExemplars, droppedHistograms := buildTimeSeries(timeSeries, filter)
 
@@ -2140,14 +2047,11 @@ func buildWriteRequest(logger log.Logger, timeSeries []prompb.TimeSeries, metada
 	} else {
 		buf = &[]byte{}
 	}
-
+	compressed := snappy.Encode(*buf, pBuf.Bytes())
-	var compressed []byte
+	if n := snappy.MaxEncodedLen(len(pBuf.Bytes())); n > len(*buf) {
-
+		// grow the buffer for the next time
-	compressed, err = compressPayload(buf, pBuf.Bytes(), compression)
+		*buf = make([]byte, n)
-	if err != nil {
-		return nil, highest, lowest, err
 	}
-
 	return compressed, highest, lowest, nil
 }
 
@@ -2183,7 +2087,7 @@ func (r *rwSymbolTable) clear() {
 	}
 }
 
-func buildV2WriteRequest(logger log.Logger, samples []writev2.TimeSeries, labels []string, pBuf, buf *[]byte, filter func(writev2.TimeSeries) bool, compression string) ([]byte, int64, int64, error) {
+func buildV2WriteRequest(logger log.Logger, samples []writev2.TimeSeries, labels []string, pBuf, buf *[]byte, filter func(writev2.TimeSeries) bool) ([]byte, int64, int64, error) {
 	highest, lowest, timeSeries, droppedSamples, droppedExemplars, droppedHistograms := buildV2TimeSeries(samples, filter)
 
 	if droppedSamples > 0 || droppedExemplars > 0 || droppedHistograms > 0 {
@@ -2213,11 +2117,10 @@ func buildV2WriteRequest(logger log.Logger, samples []writev2.TimeSeries, labels
 		buf = &[]byte{}
 	}
 
-	var compressed []byte
+	compressed := snappy.Encode(*buf, data)
-
+	if n := snappy.MaxEncodedLen(len(data)); n > len(*buf) {
-	compressed, err = compressPayload(buf, data, compression)
+		// grow the buffer for the next time
-	if err != nil {
+		*buf = make([]byte, n)
-		return nil, highest, lowest, err
 	}
 
 	return compressed, highest, lowest, nil

storage/remote/queue_manager_test.go

@@ -63,146 +63,6 @@ func newHighestTimestampMetric() *maxTimestamp {
 	}
 }
 
-type contentNegotiationStep struct {
-	lastRWHeader  string
-	compression   string
-	behaviour     error // or nil
-	attemptString string
-}
-
-func TestContentNegotiation(t *testing.T) {
-	testcases := []struct {
-		name       string
-		success    bool
-		qmRwFormat config.RemoteWriteFormat
-		rwFormat   config.RemoteWriteFormat
-		steps      []contentNegotiationStep
-	}{
-		// Test a simple case where the v2 request we send is processed first time.
-		{
-			success: true, name: "v2 happy path", qmRwFormat: Version2, rwFormat: Version2, steps: []contentNegotiationStep{
-				{lastRWHeader: "2.0;snappy,0.1.0", compression: "snappy", behaviour: nil, attemptString: "0,1,snappy,ok"},
-			},
-		},
-		// Test a simple case where the v1 request we send is processed first time.
-		{
-			success: true, name: "v1 happy path", qmRwFormat: Version1, rwFormat: Version1, steps: []contentNegotiationStep{
-				{lastRWHeader: "0.1.0", compression: "snappy", behaviour: nil, attemptString: "0,0,snappy,ok"},
-			},
-		},
-		// Test a case where the v1 request has a temporary delay but goes through on retry.
-		// There is no content re-negotiation between first and retry attempts.
-		{
-			success: true, name: "v1 happy path with one 5xx retry", qmRwFormat: Version1, rwFormat: Version1, steps: []contentNegotiationStep{
-				{lastRWHeader: "0.1.0", compression: "snappy", behaviour: RecoverableError{fmt.Errorf("Pretend 500"), 1}, attemptString: "0,0,snappy,Pretend 500"},
-				{lastRWHeader: "0.1.0", compression: "snappy", behaviour: nil, attemptString: "1,0,snappy,ok"},
-			},
-		},
-		// Repeat the above test but with v2. The request has a temporary delay but goes through on retry.
-		// There is no content re-negotiation between first and retry attempts.
-		{
-			success: true, name: "v2 happy path with one 5xx retry", qmRwFormat: Version2, rwFormat: Version2, steps: []contentNegotiationStep{
-				{lastRWHeader: "2.0;snappy,0.1.0", compression: "snappy", behaviour: RecoverableError{fmt.Errorf("Pretend 500"), 1}, attemptString: "0,1,snappy,Pretend 500"},
-				{lastRWHeader: "2.0;snappy,0.1.0", compression: "snappy", behaviour: nil, attemptString: "1,1,snappy,ok"},
-			},
-		},
-		// Now test where the server suddenly stops speaking 2.0 and we need to downgrade.
-		{
-			success: true, name: "v2 request to v2 server that has downgraded via 406", qmRwFormat: Version2, rwFormat: Version2, steps: []contentNegotiationStep{
-				{lastRWHeader: "2.0;snappy,0.1.0", compression: "snappy", behaviour: ErrStatusNotAcceptable, attemptString: "0,1,snappy,HTTP StatusNotAcceptable"},
-				{lastRWHeader: "0.1.0", compression: "snappy", behaviour: nil, attemptString: "0,0,snappy,ok"},
-			},
-		},
-		// Now test where the server suddenly stops speaking 2.0 and we need to downgrade because it returns a 400.
-		{
-			success: true, name: "v2 request to v2 server that has downgraded via 400", qmRwFormat: Version2, rwFormat: Version2, steps: []contentNegotiationStep{
-				{lastRWHeader: "2.0;snappy,0.1.0", compression: "snappy", behaviour: ErrStatusBadRequest, attemptString: "0,1,snappy,HTTP StatusBadRequest"},
-				{lastRWHeader: "0.1.0", compression: "snappy", behaviour: nil, attemptString: "0,0,snappy,ok"},
-			},
-		},
-		// Now test where the server flip flops between "2.0;snappy" and "0.1.0" only.
-		{
-			success: false, name: "flip flopping", qmRwFormat: Version2, rwFormat: Version2, steps: []contentNegotiationStep{
-				{lastRWHeader: "2.0;snappy", compression: "snappy", behaviour: ErrStatusNotAcceptable, attemptString: "0,1,snappy,HTTP StatusNotAcceptable"},
-				{lastRWHeader: "0.1.0", compression: "snappy", behaviour: ErrStatusNotAcceptable, attemptString: "0,0,snappy,HTTP StatusNotAcceptable"},
-				{lastRWHeader: "2.0;snappy", compression: "snappy", behaviour: ErrStatusNotAcceptable, attemptString: "0,1,snappy,HTTP StatusNotAcceptable"},
-				// There's no 4th attempt as we do a maximum of 3 sending attempts (not counting retries).
-			},
-		},
-	}
-
-	queueConfig := config.DefaultQueueConfig
-	queueConfig.BatchSendDeadline = model.Duration(100 * time.Millisecond)
-	queueConfig.MaxShards = 1
-
-	// We need to set URL's so that metric creation doesn't panic.
-	writeConfig := baseRemoteWriteConfig("http://test-storage.com")
-	writeConfig.QueueConfig = queueConfig
-
-	conf := &config.Config{
-		GlobalConfig: config.DefaultGlobalConfig,
-		RemoteWriteConfigs: []*config.RemoteWriteConfig{
-			writeConfig,
-		},
-	}
-
-	for _, tc := range testcases {
-		t.Run(tc.name, func(t *testing.T) {
-			dir := t.TempDir()
-			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, true)
-			defer s.Close()
-
-			var (
-				series   []record.RefSeries
-				metadata []record.RefMetadata
-				samples  []record.RefSample
-			)
-
-			// Generates same series in both cases.
-			samples, series = createTimeseries(1, 1)
-			metadata = createSeriesMetadata(series)
-
-			// Apply new config.
-			queueConfig.Capacity = len(samples)
-			queueConfig.MaxSamplesPerSend = len(samples)
-			// For now we only ever have a single rw config in this test.
-			conf.RemoteWriteConfigs[0].ProtocolVersion = tc.qmRwFormat
-			require.NoError(t, s.ApplyConfig(conf))
-			hash, err := toHash(writeConfig)
-			require.NoError(t, err)
-			qm := s.rws.queues[hash]
-
-			c := NewTestWriteClient(tc.rwFormat)
-			c.setSteps(tc.steps) // set expected behaviour.
-			qm.SetClient(c)
-
-			qm.StoreSeries(series, 0)
-			qm.StoreMetadata(metadata)
-
-			// Did we expect some data back?
-			if tc.success {
-				c.expectSamples(samples, series)
-			}
-			qm.Append(samples)
-
-			if !tc.success {
-				// We just need to sleep for a bit to give it time to run.
-				time.Sleep(2 * time.Second)
-				// But we still need to check for data with no delay to avoid race.
-				c.waitForExpectedData(t, 0*time.Second)
-			} else {
-				// We expected data so wait for it.
-				c.waitForExpectedData(t, 5*time.Second)
-			}
-
-			require.Equal(t, len(c.sendAttempts), len(tc.steps))
-			for i, s := range c.sendAttempts {
-				require.Equal(t, s, tc.steps[i].attemptString)
-			}
-		})
-	}
-}
-
 func TestSampleDelivery(t *testing.T) {
 	testcases := []struct {
 		name            string
@@ -218,7 +78,7 @@ func TestSampleDelivery(t *testing.T) {
 		{samples: false, exemplars: false, histograms: true, floatHistograms: false, name: "histograms only"},
 		{samples: false, exemplars: false, histograms: false, floatHistograms: true, name: "float histograms only"},
 
-		// TODO(alexg): update some portion of this test to check for the 2.0 metadata
+		// TODO: update some portion of this test to check for the 2.0 metadata
 		{samples: true, exemplars: false, histograms: false, floatHistograms: false, name: "samples only", rwFormat: Version2},
 		{samples: true, exemplars: true, histograms: true, floatHistograms: true, name: "samples, exemplars, and histograms", rwFormat: Version2},
 		{samples: false, exemplars: true, histograms: false, floatHistograms: false, name: "exemplars only", rwFormat: Version2},
@@ -280,6 +140,8 @@ func TestSampleDelivery(t *testing.T) {
 			// Apply new config.
 			queueConfig.Capacity = len(samples)
 			queueConfig.MaxSamplesPerSend = len(samples) / 2
+			// For now we only ever have a single rw config in this test.
+			conf.RemoteWriteConfigs[0].ProtocolVersion = tc.rwFormat
 			require.NoError(t, s.ApplyConfig(conf))
 			hash, err := toHash(writeConfig)
 			require.NoError(t, err)
@@ -371,7 +233,7 @@ func (c *perRequestWriteClient) expectedData(t testing.TB) {
 	}
 }
 
-func (c *perRequestWriteClient) Store(ctx context.Context, req []byte, r int, rwFormat config.RemoteWriteFormat, compression string) error {
+func (c *perRequestWriteClient) Store(ctx context.Context, req []byte, r int) error {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 	defer func() { c.i++ }()
@@ -379,7 +241,7 @@ func (c *perRequestWriteClient) Store(ctx context.Context, req []byte, r int, rw
 		return nil
 	}
 
-	if err := c.TestWriteClient.Store(ctx, req, r, rwFormat, compression); err != nil {
+	if err := c.TestWriteClient.Store(ctx, req, r); err != nil {
 		return err
 	}
 
@@ -409,7 +271,7 @@ func (c *perRequestWriteClient) Store(ctx context.Context, req []byte, r int, rw
 	}
 	c.requests[c.i].expectSamples(c.expectedRequestSamples[expReqSampleToUse], c.expectedSeries)
 	c.expectedRequestSamples = append(c.expectedRequestSamples[:expReqSampleToUse], c.expectedRequestSamples[expReqSampleToUse+1:]...)
-	return c.requests[c.i].Store(ctx, req, r, rwFormat, compression)
+	return c.requests[c.i].Store(ctx, req, r)
 }
 
 func testDefaultQueueConfig() config.QueueConfig {
@@ -500,7 +362,7 @@ func TestMetadataDelivery(t *testing.T) {
 	mcfg := config.DefaultMetadataConfig
 
 	metrics := newQueueManagerMetrics(nil, "", "")
-	m := NewQueueManager(metrics, nil, nil, nil, dir, newEWMARate(ewmaWeight, shardUpdateDuration), cfg, mcfg, labels.EmptyLabels(), nil, c, defaultFlushDeadline, newPool(), newHighestTimestampMetric(), nil, false, false, Version1)
+	m := NewQueueManager(metrics, nil, nil, nil, dir, newEWMARate(ewmaWeight, shardUpdateDuration), cfg, mcfg, labels.EmptyLabels(), nil, c, defaultFlushDeadline, newPool(), newHighestTimestampMetric(), nil, false, false, 0)
 	m.Start()
 	defer m.Stop()
 
@@ -1108,10 +970,6 @@ type TestWriteClient struct {
 	mtx                     sync.Mutex
 	buf                     []byte
 	rwFormat                config.RemoteWriteFormat
-	sendAttempts            []string
-	steps                   []contentNegotiationStep
-	currstep                int
-	retry                   bool
 }
 
 func NewTestWriteClient(rwFormat config.RemoteWriteFormat) *TestWriteClient {
@@ -1123,12 +981,6 @@ func NewTestWriteClient(rwFormat config.RemoteWriteFormat) *TestWriteClient {
 	}
 }
 
-func (c *TestWriteClient) setSteps(steps []contentNegotiationStep) {
-	c.steps = steps
-	c.currstep = -1 // incremented by GetLastRWHeader()
-	c.retry = false
-}
-
 func (c *TestWriteClient) expectSamples(ss []record.RefSample, series []record.RefSeries) {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
@@ -1235,7 +1087,7 @@ func (c *TestWriteClient) waitForExpectedData(tb testing.TB, timeout time.Durati
 	}
 }
 
-func (c *TestWriteClient) Store(_ context.Context, req []byte, attemptNos int, rwFormat config.RemoteWriteFormat, compression string) error {
+func (c *TestWriteClient) Store(_ context.Context, req []byte, _ int) error {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 	// nil buffers are ok for snappy, ignore cast error.
@@ -1248,23 +1100,8 @@ func (c *TestWriteClient) Store(_ context.Context, req []byte, attemptNos int, r
 		return err
 	}
 
-	attemptString := fmt.Sprintf("%d,%d,%s", attemptNos, rwFormat, compression)
-
-	if attemptNos > 0 {
-		// If this is a second attempt then we need to bump to the next step otherwise we loop.
-		c.currstep++
-	}
-
-	// Check if we've been told to return something for this config.
-	if len(c.steps) > 0 {
-		if err = c.steps[c.currstep].behaviour; err != nil {
-			c.sendAttempts = append(c.sendAttempts, attemptString+","+fmt.Sprintf("%s", err))
-			return err
-		}
-	}
-
 	var reqProto *prompb.WriteRequest
-	switch rwFormat {
+	switch c.rwFormat {
 	case Version1:
 		reqProto = &prompb.WriteRequest{}
 		err = proto.Unmarshal(reqBuf, reqProto)
@@ -1277,7 +1114,6 @@ func (c *TestWriteClient) Store(_ context.Context, req []byte, attemptNos int, r
 	}
 
 	if err != nil {
-		c.sendAttempts = append(c.sendAttempts, attemptString+","+fmt.Sprintf("%s", err))
 		return err
 	}
 
@@ -1303,7 +1139,6 @@ func (c *TestWriteClient) Store(_ context.Context, req []byte, attemptNos int, r
 	}
 
 	c.writesReceived++
-	c.sendAttempts = append(c.sendAttempts, attemptString+",ok")
 	return nil
 }
 
@@ -1315,20 +1150,6 @@ func (c *TestWriteClient) Endpoint() string {
 	return "http://test-remote.com/1234"
 }
 
-func (c *TestWriteClient) probeRemoteVersions(_ context.Context) error {
-	return nil
-}
-
-func (c *TestWriteClient) GetLastRWHeader() string {
-	c.mtx.Lock()
-	defer c.mtx.Unlock()
-	c.currstep++
-	if len(c.steps) > 0 {
-		return c.steps[c.currstep].lastRWHeader
-	}
-	return "2.0;snappy,0.1.0"
-}
-
 // TestBlockingWriteClient is a queue_manager WriteClient which will block
 // on any calls to Store(), until the request's Context is cancelled, at which
 // point the `numCalls` property will contain a count of how many times Store()
@@ -1341,7 +1162,7 @@ func NewTestBlockedWriteClient() *TestBlockingWriteClient {
 	return &TestBlockingWriteClient{}
 }
 
-func (c *TestBlockingWriteClient) Store(ctx context.Context, _ []byte, _ int, _ config.RemoteWriteFormat, _ string) error {
+func (c *TestBlockingWriteClient) Store(ctx context.Context, _ []byte, _ int) error {
 	c.numCalls.Inc()
 	<-ctx.Done()
 	return nil
@@ -1359,27 +1180,13 @@ func (c *TestBlockingWriteClient) Endpoint() string {
 	return "http://test-remote-blocking.com/1234"
 }
 
-func (c *TestBlockingWriteClient) probeRemoteVersions(_ context.Context) error {
-	return nil
-}
-
-func (c *TestBlockingWriteClient) GetLastRWHeader() string {
-	return "2.0;snappy,0.1.0"
-}
-
 // For benchmarking the send and not the receive side.
 type NopWriteClient struct{}
 
 func NewNopWriteClient() *NopWriteClient                           { return &NopWriteClient{} }
-func (c *NopWriteClient) Store(context.Context, []byte, int, config.RemoteWriteFormat, string) error {
+func (c *NopWriteClient) Store(context.Context, []byte, int) error { return nil }
-	return nil
-}
 func (c *NopWriteClient) Name() string                             { return "nopwriteclient" }
 func (c *NopWriteClient) Endpoint() string                         { return "http://test-remote.com/1234" }
-func (c *NopWriteClient) probeRemoteVersions(_ context.Context) error {
-	return nil
-}
-func (c *NopWriteClient) GetLastRWHeader() string { return "2.0;snappy,0.1.0" }
 
 // Extra labels to make a more realistic workload - taken from Kubernetes' embedded cAdvisor metrics.
 var extraLabels []labels.Label = []labels.Label{
@@ -1970,14 +1777,14 @@ func BenchmarkBuildWriteRequest(b *testing.B) {
 		// Warmup buffers
 		for i := 0; i < 10; i++ {
 			populateTimeSeries(batch, seriesBuff, true, true)
-			buildWriteRequest(noopLogger, seriesBuff, nil, pBuf, &buff, nil, "snappy")
+			buildWriteRequest(noopLogger, seriesBuff, nil, pBuf, &buff, nil)
 		}
 
 		b.ResetTimer()
 		totalSize := 0
 		for i := 0; i < b.N; i++ {
 			populateTimeSeries(batch, seriesBuff, true, true)
-			req, _, _, err := buildWriteRequest(noopLogger, seriesBuff, nil, pBuf, &buff, nil, "snappy")
+			req, _, _, err := buildWriteRequest(noopLogger, seriesBuff, nil, pBuf, &buff, nil)
 			if err != nil {
 				b.Fatal(err)
 			}
@@ -2026,7 +1833,7 @@ func BenchmarkBuildMinimizedWriteRequest(b *testing.B) {
 		// Warmup buffers
 		for i := 0; i < 10; i++ {
 			populateV2TimeSeries(&symbolTable, tc.batch, seriesBuff, true, true)
-			buildV2WriteRequest(noopLogger, seriesBuff, symbolTable.LabelsStrings(), &pBuf, &buff, nil, "snappy")
+			buildV2WriteRequest(noopLogger, seriesBuff, symbolTable.LabelsStrings(), &pBuf, &buff, nil)
 		}
 
 		b.Run(fmt.Sprintf("%d-instances", len(tc.batch)), func(b *testing.B) {
@@ -2034,7 +1841,7 @@ func BenchmarkBuildMinimizedWriteRequest(b *testing.B) {
 			for j := 0; j < b.N; j++ {
 				populateV2TimeSeries(&symbolTable, tc.batch, seriesBuff, true, true)
 				b.ResetTimer()
-				req, _, _, err := buildV2WriteRequest(noopLogger, seriesBuff, symbolTable.LabelsStrings(), &pBuf, &buff, nil, "snappy")
+				req, _, _, err := buildV2WriteRequest(noopLogger, seriesBuff, symbolTable.LabelsStrings(), &pBuf, &buff, nil)
 				if err != nil {
 					b.Fatal(err)
 				}
@@ -2052,7 +1859,7 @@ func TestDropOldTimeSeries(t *testing.T) {
 	nSamples := config.DefaultQueueConfig.Capacity * size
 	samples, newSamples, series := createTimeseriesWithOldSamples(nSamples, nSeries)
 
-	// TODO(alexg): test with new version
+	// TODO: test with new version
 	c := NewTestWriteClient(Version1)
 	c.expectSamples(newSamples, series)
 

storage/remote/write.go

@@ -192,21 +192,6 @@ func (rws *WriteStorage) ApplyConfig(conf *config.Config) error {
 			continue
 		}
 
-		// Work out what protocol and compression to use for this endpoint.
-		// Default to Remote Write Version1.
-		rwFormat := Version1
-		switch rwConf.ProtocolVersion {
-		case Version1:
-			// We use the standard value as there's no negotiation to be had.
-		case Version2:
-			rwFormat = Version2
-			// If this newer remote write format is enabled then we need to probe the remote server
-			// to work out the desired protocol version and compressions.
-			// The value of the header is kept in the client so no need to see it here.
-			_ = c.probeRemoteVersions(context.Background())
-			// We ignore any error here, at some point we may choose to log it.
-		}
-
 		// Redacted to remove any passwords in the URL (that are
 		// technically accepted but not recommended) since this is
 		// only used for metric labels.
@@ -229,7 +214,7 @@ func (rws *WriteStorage) ApplyConfig(conf *config.Config) error {
 			rws.scraper,
 			rwConf.SendExemplars,
 			rwConf.SendNativeHistograms,
-			rwFormat,
+			rwConf.ProtocolVersion,
 		)
 		// Keep track of which queues are new so we know which to start.
 		newHashes = append(newHashes, hash)

storage/remote/write_handler.go

@@ -17,16 +17,11 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"io"
 	"net/http"
-	"strings"
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
 
-	"github.com/gogo/protobuf/proto"
-	"github.com/golang/snappy"
-
 	"github.com/prometheus/client_golang/prometheus"
 
 	"github.com/prometheus/prometheus/config"
@@ -41,74 +36,18 @@ import (
 const (
 	RemoteWriteVersionHeader       = "X-Prometheus-Remote-Write-Version"
 	RemoteWriteVersion1HeaderValue = "0.1.0"
-	RemoteWriteVersion20HeaderValue = "2.0"
+	RemoteWriteVersion2HeaderValue = "2.0"
 )
 
-func rwHeaderNameValues(rwFormat config.RemoteWriteFormat) map[string]string {
-	// Return the correct remote write header name/values based on provided rwFormat.
-	ret := make(map[string]string, 1)
-
-	switch rwFormat {
-	case Version1:
-		ret[RemoteWriteVersionHeader] = RemoteWriteVersion1HeaderValue
-	case Version2:
-		// We need to add the supported protocol definitions in order:
-		tuples := make([]string, 0, 2)
-		// Add "2.0;snappy".
-		tuples = append(tuples, RemoteWriteVersion20HeaderValue+";snappy")
-		// Add default "0.1.0".
-		tuples = append(tuples, RemoteWriteVersion1HeaderValue)
-		ret[RemoteWriteVersionHeader] = strings.Join(tuples, ",")
-	}
-	return ret
-}
-
-type writeHeadHandler struct {
-	logger log.Logger
-
-	remoteWrite20HeadRequests prometheus.Counter
-
-	// Experimental feature, new remote write proto format.
-	// The handler will accept the new format, but it can still accept the old one.
-	rwFormat config.RemoteWriteFormat
-}
-
-func NewWriteHeadHandler(logger log.Logger, reg prometheus.Registerer, rwFormat config.RemoteWriteFormat) http.Handler {
-	h := &writeHeadHandler{
-		logger:   logger,
-		rwFormat: rwFormat,
-		remoteWrite20HeadRequests: prometheus.NewCounter(prometheus.CounterOpts{
-			Namespace: "prometheus",
-			Subsystem: "api",
-			Name:      "remote_write_20_head_requests",
-			Help:      "The number of remote write 2.0 head requests.",
-		}),
-	}
-	if reg != nil {
-		reg.MustRegister(h.remoteWrite20HeadRequests)
-	}
-	return h
-}
-
-func (h *writeHeadHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	// Send a response to the HEAD request based on the format supported.
-
-	// Add appropriate header values for the specific rwFormat.
-	for hName, hValue := range rwHeaderNameValues(h.rwFormat) {
-		w.Header().Set(hName, hValue)
-	}
-
-	w.WriteHeader(http.StatusOK)
-}
-
 type writeHandler struct {
 	logger     log.Logger
 	appendable storage.Appendable
 
 	samplesWithInvalidLabelsTotal prometheus.Counter
 
-	// Experimental feature, new remote write proto format.
+	// Experimental feature, new remote write proto format
-	// The handler will accept the new format, but it can still accept the old one.
+	// The handler will accept the new format, but it can still accept the old one
+	// TODO: this should eventually be via content negotiation?
 	rwFormat config.RemoteWriteFormat
 }
 
@@ -134,81 +73,29 @@ func NewWriteHandler(logger log.Logger, reg prometheus.Registerer, appendable st
 
 func (h *writeHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	var err error
+	var req *prompb.WriteRequest
+	var reqMinStr *writev2.WriteRequest
 
-	// Set the header(s) in the response based on the rwFormat the server supports.
+	// TODO: this should eventually be done via content negotiation/looking at the header
-	for hName, hValue := range rwHeaderNameValues(h.rwFormat) {
+	switch h.rwFormat {
-		w.Header().Set(hName, hValue)
+	case Version1:
+		req, err = DecodeWriteRequest(r.Body)
+	case Version2:
+		reqMinStr, err = DecodeMinimizedWriteRequestStr(r.Body)
 	}
 
-	// Parse the headers to work out how to handle this.
-	contentEncoding := r.Header.Get("Content-Encoding")
-	protoVer := r.Header.Get(RemoteWriteVersionHeader)
-
-	switch protoVer {
-	case "":
-		// No header provided, assume 0.1.0 as everything that relies on later.
-		protoVer = RemoteWriteVersion1HeaderValue
-	case RemoteWriteVersion1HeaderValue, RemoteWriteVersion20HeaderValue:
-		// We know this header, woo.
-	default:
-		// We have a version in the header but it is not one we recognise.
-		level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", "Unknown remote write version in headers", "ver", protoVer)
-		// Return a 406 so that the client can choose a more appropriate protocol to use.
-		http.Error(w, "Unknown remote write version in headers", http.StatusNotAcceptable)
-		return
-	}
-
-	// Deal with 0.1.0 clients that forget to send Content-Encoding.
-	if protoVer == RemoteWriteVersion1HeaderValue && contentEncoding == "" {
-		contentEncoding = "snappy"
-	}
-
-	// Read the request body.
-	body, err := io.ReadAll(r.Body)
 	if err != nil {
 		level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", err.Error())
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
 
-	// Deal with contentEncoding first.
+	// TODO: this should eventually be done detecting the format version above
-	var decompressed []byte
+	switch h.rwFormat {
-
+	case Version1:
-	switch contentEncoding {
+		err = h.write(r.Context(), req)
-	case "snappy":
+	case Version2:
-		decompressed, err = snappy.Decode(nil, body)
+		err = h.writeMinStr(r.Context(), reqMinStr)
-		if err != nil {
-			level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", err.Error())
-			http.Error(w, err.Error(), http.StatusBadRequest)
-			return
-		}
-	default:
-		level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", "Unsupported Content-Encoding", "contentEncoding", contentEncoding)
-		// Return a 406 so that the client can choose a more appropriate protocol to use.
-		http.Error(w, "Unsupported Content-Encoding", http.StatusNotAcceptable)
-		return
-	}
-
-	// Now we have a decompressed buffer we can unmarshal it.
-	// At this point we are happy with the version but need to check the encoding.
-	switch protoVer {
-	case RemoteWriteVersion1HeaderValue:
-		var req prompb.WriteRequest
-		if err := proto.Unmarshal(decompressed, &req); err != nil {
-			level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", err.Error())
-			http.Error(w, err.Error(), http.StatusBadRequest)
-			return
-		}
-		err = h.write(r.Context(), &req)
-	case RemoteWriteVersion20HeaderValue:
-		// 2.0 request.
-		var reqMinStr writev2.WriteRequest
-		if err := proto.Unmarshal(decompressed, &reqMinStr); err != nil {
-			level.Error(h.logger).Log("msg", "Error decoding remote write request", "err", err.Error())
-			http.Error(w, err.Error(), http.StatusBadRequest)
-			return
-		}
-		err = h.writeMinStr(r.Context(), &reqMinStr)
 	}
 
 	switch {

storage/remote/write_handler_test.go

@@ -39,94 +39,15 @@ import (
 	"github.com/prometheus/prometheus/util/testutil"
 )
 
-func TestRemoteWriteHeadHandler(t *testing.T) {
-	handler := NewWriteHeadHandler(log.NewNopLogger(), nil, Version2)
-
-	req, err := http.NewRequest(http.MethodHead, "", nil)
-	require.NoError(t, err)
-
-	recorder := httptest.NewRecorder()
-	handler.ServeHTTP(recorder, req)
-
-	resp := recorder.Result()
-	require.Equal(t, http.StatusOK, resp.StatusCode)
-
-	// Check header is expected value.
-	protHeader := resp.Header.Get(RemoteWriteVersionHeader)
-	require.Equal(t, "2.0;snappy,0.1.0", protHeader)
-}
-
-func TestRemoteWriteHandlerMinimizedMissingContentEncoding(t *testing.T) {
-	// Send a v2 request without a "Content-Encoding:" header -> 406.
-	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil, "snappy")
-	require.NoError(t, err)
-
-	req, err := http.NewRequest("", "", bytes.NewReader(buf))
-	req.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion20HeaderValue)
-	// Do not provide "Content-Encoding: snappy" header.
-	// req.Header.Set("Content-Encoding", "snappy")
-	require.NoError(t, err)
-
-	appendable := &mockAppendable{}
-	handler := NewWriteHandler(log.NewNopLogger(), nil, appendable, Version2)
-
-	recorder := httptest.NewRecorder()
-	handler.ServeHTTP(recorder, req)
-
-	resp := recorder.Result()
-	// Should give us a 406.
-	require.Equal(t, http.StatusNotAcceptable, resp.StatusCode)
-}
-
-func TestRemoteWriteHandlerInvalidCompression(t *testing.T) {
-	// Send a v2 request without an unhandled compression scheme -> 406.
-	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil, "snappy")
-	require.NoError(t, err)
-
-	req, err := http.NewRequest("", "", bytes.NewReader(buf))
-	req.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion20HeaderValue)
-	req.Header.Set("Content-Encoding", "zstd")
-	require.NoError(t, err)
-
-	appendable := &mockAppendable{}
-	handler := NewWriteHandler(log.NewNopLogger(), nil, appendable, Version2)
-
-	recorder := httptest.NewRecorder()
-	handler.ServeHTTP(recorder, req)
-
-	resp := recorder.Result()
-	// Expect a 406.
-	require.Equal(t, http.StatusNotAcceptable, resp.StatusCode)
-}
-
-func TestRemoteWriteHandlerInvalidVersion(t *testing.T) {
-	// Send a protocol version number that isn't recognised/supported -> 406.
-	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil, "snappy")
-	require.NoError(t, err)
-
-	req, err := http.NewRequest("", "", bytes.NewReader(buf))
-	req.Header.Set(RemoteWriteVersionHeader, "3.0")
-	require.NoError(t, err)
-
-	appendable := &mockAppendable{}
-	handler := NewWriteHandler(log.NewNopLogger(), nil, appendable, Version2)
-
-	recorder := httptest.NewRecorder()
-	handler.ServeHTTP(recorder, req)
-
-	resp := recorder.Result()
-	// Expect a 406.
-	require.Equal(t, http.StatusNotAcceptable, resp.StatusCode)
-}
-
 func TestRemoteWriteHandler(t *testing.T) {
-	buf, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil, "snappy")
+	buf, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil)
 	require.NoError(t, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
 	require.NoError(t, err)
 
 	appendable := &mockAppendable{}
+	// TODO: test with other proto format(s)
 	handler := NewWriteHandler(log.NewNopLogger(), nil, appendable, Version1)
 
 	recorder := httptest.NewRecorder()
@@ -135,10 +56,6 @@ func TestRemoteWriteHandler(t *testing.T) {
 	resp := recorder.Result()
 	require.Equal(t, http.StatusNoContent, resp.StatusCode)
 
-	// Check header is expected value.
-	protHeader := resp.Header.Get(RemoteWriteVersionHeader)
-	require.Equal(t, "0.1.0", protHeader)
-
 	i := 0
 	j := 0
 	k := 0
@@ -170,17 +87,16 @@ func TestRemoteWriteHandler(t *testing.T) {
 }
 
 func TestRemoteWriteHandlerMinimizedFormat(t *testing.T) {
-	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil, "snappy")
+	buf, _, _, err := buildV2WriteRequest(log.NewNopLogger(), writeRequestMinimizedFixture.Timeseries, writeRequestMinimizedFixture.Symbols, nil, nil, nil)
 	require.NoError(t, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
-	req.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion20HeaderValue)
+	req.Header.Set(RemoteWriteVersionHeader, RemoteWriteVersion2HeaderValue)
-	// Must provide "Content-Encoding: snappy" header.
-	req.Header.Set("Content-Encoding", "snappy")
 	require.NoError(t, err)
 
 	appendable := &mockAppendable{}
-	handler := NewWriteHandler(log.NewNopLogger(), nil, appendable, Version2)
+	// TODO: test with other proto format(s)
+	handler := NewWriteHandler(nil, nil, appendable, Version2)
 
 	recorder := httptest.NewRecorder()
 	handler.ServeHTTP(recorder, req)
@@ -188,10 +104,6 @@ func TestRemoteWriteHandlerMinimizedFormat(t *testing.T) {
 	resp := recorder.Result()
 	require.Equal(t, http.StatusNoContent, resp.StatusCode)
 
-	// Check header is expected value.
-	protHeader := resp.Header.Get(RemoteWriteVersionHeader)
-	require.Equal(t, "2.0;snappy,0.1.0", protHeader)
-
 	i := 0
 	j := 0
 	k := 0
@@ -230,7 +142,7 @@ func TestOutOfOrderSample(t *testing.T) {
 	buf, _, _, err := buildWriteRequest(nil, []prompb.TimeSeries{{
 		Labels:  []prompb.Label{{Name: "__name__", Value: "test_metric"}},
 		Samples: []prompb.Sample{{Value: 1, Timestamp: 0}},
-	}}, nil, nil, nil, nil, "snappy")
+	}}, nil, nil, nil, nil)
 	require.NoError(t, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
@@ -256,7 +168,7 @@ func TestOutOfOrderExemplar(t *testing.T) {
 	buf, _, _, err := buildWriteRequest(nil, []prompb.TimeSeries{{
 		Labels:    []prompb.Label{{Name: "__name__", Value: "test_metric"}},
 		Exemplars: []prompb.Exemplar{{Labels: []prompb.Label{{Name: "foo", Value: "bar"}}, Value: 1, Timestamp: 0}},
-	}}, nil, nil, nil, nil, "snappy")
+	}}, nil, nil, nil, nil)
 	require.NoError(t, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
@@ -280,7 +192,7 @@ func TestOutOfOrderHistogram(t *testing.T) {
 	buf, _, _, err := buildWriteRequest(nil, []prompb.TimeSeries{{
 		Labels:     []prompb.Label{{Name: "__name__", Value: "test_metric"}},
 		Histograms: []prompb.Histogram{HistogramToHistogramProto(0, &testHistogram), FloatHistogramToHistogramProto(1, testHistogram.ToFloat(nil))},
-	}}, nil, nil, nil, nil, "snappy")
+	}}, nil, nil, nil, nil)
 	require.NoError(t, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
@@ -310,7 +222,7 @@ func BenchmarkRemoteWritehandler(b *testing.B) {
 				{Name: "test_label_name_" + num, Value: labelValue + num},
 			},
 			Histograms: []prompb.Histogram{HistogramToHistogramProto(0, &testHistogram)},
-		}}, nil, nil, nil, nil, "snappy")
+		}}, nil, nil, nil, nil)
 		require.NoError(b, err)
 		req, err := http.NewRequest("", "", bytes.NewReader(buf))
 		require.NoError(b, err)
@@ -329,7 +241,7 @@ func BenchmarkRemoteWritehandler(b *testing.B) {
 }
 
 func TestCommitErr(t *testing.T) {
-	buf, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil, "snappy")
+	buf, _, _, err := buildWriteRequest(nil, writeRequestFixture.Timeseries, nil, nil, nil, nil)
 	require.NoError(t, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
@@ -368,7 +280,7 @@ func BenchmarkRemoteWriteOOOSamples(b *testing.B) {
 	// TODO: test with other proto format(s)
 	handler := NewWriteHandler(log.NewNopLogger(), nil, db.Head(), Version1)
 
-	buf, _, _, err := buildWriteRequest(nil, genSeriesWithSample(1000, 200*time.Minute.Milliseconds()), nil, nil, nil, nil, "snappy")
+	buf, _, _, err := buildWriteRequest(nil, genSeriesWithSample(1000, 200*time.Minute.Milliseconds()), nil, nil, nil, nil)
 	require.NoError(b, err)
 
 	req, err := http.NewRequest("", "", bytes.NewReader(buf))
@@ -381,7 +293,7 @@ func BenchmarkRemoteWriteOOOSamples(b *testing.B) {
 
 	var bufRequests [][]byte
 	for i := 0; i < 100; i++ {
-		buf, _, _, err = buildWriteRequest(nil, genSeriesWithSample(1000, int64(80+i)*time.Minute.Milliseconds()), nil, nil, nil, nil, "snappy")
+		buf, _, _, err = buildWriteRequest(nil, genSeriesWithSample(1000, int64(80+i)*time.Minute.Milliseconds()), nil, nil, nil, nil)
 		require.NoError(b, err)
 		bufRequests = append(bufRequests, buf)
 	}

web/api/v1/api.go

@@ -217,7 +217,6 @@ type API struct {
 	isAgent       bool
 	statsRenderer StatsRenderer
 
-	remoteWriteHeadHandler http.Handler
 	remoteWriteHandler http.Handler
 	remoteReadHandler  http.Handler
 	otlpWriteHandler   http.Handler
@@ -297,20 +296,7 @@ func NewAPI(
 	}
 
 	if rwEnabled {
-		// TODO(alexg) - Two phase rwFormat rollout needs to create handlers with flag for advertising.
-		// For rollout we do two phases:
-		// 0. (Before) no flags set
-		// 1. (During) support new protocols but don't advertise
-		// <wait until all servers have rolled out and now support RW2.0>
-		// 2. (After) support new protocols and advertise
-		//
-		// For rollback the two phases are:
-		// 0. (Before) support new protocols and advertise
-		// 1. (During) support new protocols but don't advertise
-		// <wait a suitable period for all sending clients to be aware that receiving servers no longer support 2.0>
-		// 2. (After) no flags set
 		a.remoteWriteHandler = remote.NewWriteHandler(logger, registerer, ap, rwFormat)
-		a.remoteWriteHeadHandler = remote.NewWriteHeadHandler(logger, registerer, rwFormat)
 	}
 	if otlpEnabled {
 		a.otlpWriteHandler = remote.NewOTLPWriteHandler(logger, ap)
@@ -407,7 +393,6 @@ func (api *API) Register(r *route.Router) {
 	r.Get("/status/walreplay", api.serveWALReplayStatus)
 	r.Post("/read", api.ready(api.remoteRead))
 	r.Post("/write", api.ready(api.remoteWrite))
-	r.Head("/write", api.remoteWriteHead)
 	r.Post("/otlp/v1/metrics", api.ready(api.otlpWrite))
 
 	r.Get("/alerts", wrapAgent(api.alerts))
@@ -1631,14 +1616,6 @@ func (api *API) remoteRead(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
-func (api *API) remoteWriteHead(w http.ResponseWriter, r *http.Request) {
-	if api.remoteWriteHeadHandler != nil {
-		api.remoteWriteHeadHandler.ServeHTTP(w, r)
-	} else {
-		http.Error(w, "remote write receiver needs to be enabled with --web.enable-remote-write-receiver", http.StatusNotFound)
-	}
-}
-
 func (api *API) remoteWrite(w http.ResponseWriter, r *http.Request) {
 	if api.remoteWriteHandler != nil {
 		api.remoteWriteHandler.ServeHTTP(w, r)

web/api/v1/api_test.go

@@ -337,48 +337,6 @@ var sampleFlagMap = map[string]string{
 	"flag2": "value2",
 }
 
-func TestHeadEndpoint(t *testing.T) {
-	for _, tc := range []struct {
-		name                string
-		rwFormat            config.RemoteWriteFormat
-		expectedStatusCode  int
-		expectedHeaderValue string
-	}{
-		{
-			name:                "HEAD Version 1",
-			rwFormat:            remote.Version1,
-			expectedStatusCode:  http.StatusOK,
-			expectedHeaderValue: "0.1.0",
-		},
-		{
-			name:                "HEAD Version 2",
-			rwFormat:            remote.Version2,
-			expectedStatusCode:  http.StatusOK,
-			expectedHeaderValue: "2.0;snappy,0.1.0",
-		},
-	} {
-		r := route.New()
-		api := &API{
-			remoteWriteHeadHandler: remote.NewWriteHeadHandler(log.NewNopLogger(), nil, tc.rwFormat),
-			ready:                  func(f http.HandlerFunc) http.HandlerFunc { return f },
-		}
-		api.Register(r)
-
-		s := httptest.NewServer(r)
-		defer s.Close()
-
-		req, err := http.NewRequest("HEAD", s.URL+"/write", nil)
-		require.NoError(t, err, "Error creating HEAD request")
-		client := &http.Client{}
-		resp, err := client.Do(req)
-		require.NoError(t, err, "Error executing HEAD request")
-		require.Equal(t, tc.expectedStatusCode, resp.StatusCode)
-
-		promHeader := resp.Header.Get(remote.RemoteWriteVersionHeader)
-		require.Equal(t, tc.expectedHeaderValue, promHeader)
-	}
-}
-
 func TestEndpoints(t *testing.T) {
 	storage := promql.LoadedStorage(t, `
 		load 1m