prw2: Split PRW2.0 from metadata-wal-records feature (#16030)

Rationales:

* metadata-wal-records might be deprecated and replaced going forward: https://github.com/prometheus/prometheus/issues/15911
* PRW 2.0 works without metadata just fine (although it sends untyped metrics as expected).

Signed-off-by: bwplotka <bwplotka@gmail.com>

cmd/prometheus/main.go

@@ -231,7 +231,7 @@ func (c *flagConfig) setFeatureListOptions(logger *slog.Logger) error {
 				logger.Info("Experimental additional scrape metrics enabled")
 			case "metadata-wal-records":
 				c.scrape.AppendMetadata = true
-				logger.Info("Experimental metadata records in WAL enabled, required for remote write 2.0")
+				logger.Info("Experimental metadata records in WAL enabled")
 			case "promql-per-step-stats":
 				c.enablePerStepStats = true
 				logger.Info("Experimental per-step statistics reporting")
@@ -699,7 +699,7 @@ func main() {
 	var (
 		localStorage  = &readyStorage{stats: tsdb.NewDBStats()}
 		scraper       = &readyScrapeManager{}
-		remoteStorage = remote.NewStorage(logger.With("component", "remote"), prometheus.DefaultRegisterer, localStorage.StartTime, localStoragePath, time.Duration(cfg.RemoteFlushDeadline), scraper, cfg.scrape.AppendMetadata)
+		remoteStorage = remote.NewStorage(logger.With("component", "remote"), prometheus.DefaultRegisterer, localStorage.StartTime, localStoragePath, time.Duration(cfg.RemoteFlushDeadline), scraper)
 		fanoutStorage = storage.NewFanout(logger, localStorage, remoteStorage)
 	)
 

docs/feature_flags.md

@@ -114,8 +114,7 @@ Fall back to serving the old (Prometheus 2.x) web UI instead of the new UI. The
 When enabled, Prometheus will store metadata in-memory and keep track of
 metadata changes as WAL records on a per-series basis.
 
-This must be used if
-you are also using remote write 2.0 as it will only gather metadata from the WAL.
+This must be used if you would like to send metadata using the new remote write 2.0.
 
 ## Delay compaction start time
 

storage/remote/queue_manager_test.go

@@ -135,7 +135,7 @@ func TestBasicContentNegotiation(t *testing.T) {
 	} {
 		t.Run(tc.name, func(t *testing.T) {
 			dir := t.TempDir()
-			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, true)
+			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 			defer s.Close()
 
 			var (
@@ -243,7 +243,7 @@ func TestSampleDelivery(t *testing.T) {
 	} {
 		t.Run(fmt.Sprintf("%s-%s", tc.protoMsg, tc.name), func(t *testing.T) {
 			dir := t.TempDir()
-			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, true)
+			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 			defer s.Close()
 
 			var (
@@ -362,7 +362,7 @@ func TestMetadataDelivery(t *testing.T) {
 
 func TestWALMetadataDelivery(t *testing.T) {
 	dir := t.TempDir()
-	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, true)
+	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 	defer s.Close()
 
 	cfg := config.DefaultQueueConfig

storage/remote/read_test.go

@@ -93,7 +93,7 @@ func TestNoDuplicateReadConfigs(t *testing.T) {
 
 	for _, tc := range cases {
 		t.Run("", func(t *testing.T) {
-			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, false)
+			s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 			conf := &config.Config{
 				GlobalConfig:      config.DefaultGlobalConfig,
 				RemoteReadConfigs: tc.cfgs,

storage/remote/storage.go

@@ -64,7 +64,7 @@ type Storage struct {
 }
 
 // NewStorage returns a remote.Storage.
-func NewStorage(l *slog.Logger, reg prometheus.Registerer, stCallback startTimeCallback, walDir string, flushDeadline time.Duration, sm ReadyScrapeManager, metadataInWAL bool) *Storage {
+func NewStorage(l *slog.Logger, reg prometheus.Registerer, stCallback startTimeCallback, walDir string, flushDeadline time.Duration, sm ReadyScrapeManager) *Storage {
 	if l == nil {
 		l = promslog.NewNopLogger()
 	}
@@ -76,7 +76,7 @@ func NewStorage(l *slog.Logger, reg prometheus.Registerer, stCallback startTimeC
 		deduper:                deduper,
 		localStartTimeCallback: stCallback,
 	}
-	s.rws = NewWriteStorage(s.logger, reg, walDir, flushDeadline, sm, metadataInWAL)
+	s.rws = NewWriteStorage(s.logger, reg, walDir, flushDeadline, sm)
 	return s
 }
 

storage/remote/storage_test.go

@@ -29,7 +29,7 @@ import (
 func TestStorageLifecycle(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 	conf := &config.Config{
 		GlobalConfig: config.DefaultGlobalConfig,
 		RemoteWriteConfigs: []*config.RemoteWriteConfig{
@@ -56,7 +56,7 @@ func TestStorageLifecycle(t *testing.T) {
 func TestUpdateRemoteReadConfigs(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 
 	conf := &config.Config{
 		GlobalConfig: config.GlobalConfig{},
@@ -77,7 +77,7 @@ func TestUpdateRemoteReadConfigs(t *testing.T) {
 func TestFilterExternalLabels(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 
 	conf := &config.Config{
 		GlobalConfig: config.GlobalConfig{
@@ -102,7 +102,7 @@ func TestFilterExternalLabels(t *testing.T) {
 func TestIgnoreExternalLabels(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewStorage(nil, nil, nil, dir, defaultFlushDeadline, nil)
 
 	conf := &config.Config{
 		GlobalConfig: config.GlobalConfig{
@@ -154,7 +154,7 @@ func baseRemoteReadConfig(host string) *config.RemoteReadConfig {
 // ApplyConfig runs concurrently with Notify
 // See https://github.com/prometheus/prometheus/issues/12747
 func TestWriteStorageApplyConfigsDuringCommit(t *testing.T) {
-	s := NewStorage(nil, nil, nil, t.TempDir(), defaultFlushDeadline, nil, false)
+	s := NewStorage(nil, nil, nil, t.TempDir(), defaultFlushDeadline, nil)
 
 	var wg sync.WaitGroup
 	wg.Add(2000)

storage/remote/write.go

@@ -15,7 +15,6 @@ package remote
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"log/slog"
 	"math"
@@ -67,7 +66,6 @@ type WriteStorage struct {
 	externalLabels    labels.Labels
 	dir               string
 	queues            map[string]*QueueManager
-	metadataInWAL     bool
 	samplesIn         *ewmaRate
 	flushDeadline     time.Duration
 	interner          *pool
@@ -79,7 +77,7 @@ type WriteStorage struct {
 }
 
 // NewWriteStorage creates and runs a WriteStorage.
-func NewWriteStorage(logger *slog.Logger, reg prometheus.Registerer, dir string, flushDeadline time.Duration, sm ReadyScrapeManager, metadataInWal bool) *WriteStorage {
+func NewWriteStorage(logger *slog.Logger, reg prometheus.Registerer, dir string, flushDeadline time.Duration, sm ReadyScrapeManager) *WriteStorage {
 	if logger == nil {
 		logger = promslog.NewNopLogger()
 	}
@@ -95,7 +93,6 @@ func NewWriteStorage(logger *slog.Logger, reg prometheus.Registerer, dir string,
 		interner:          newPool(),
 		scraper:           sm,
 		quit:              make(chan struct{}),
-		metadataInWAL:     metadataInWal,
 		highestTimestamp: &maxTimestamp{
 			Gauge: prometheus.NewGauge(prometheus.GaugeOpts{
 				Namespace: namespace,
@@ -149,9 +146,6 @@ func (rws *WriteStorage) ApplyConfig(conf *config.Config) error {
 	newQueues := make(map[string]*QueueManager)
 	newHashes := []string{}
 	for _, rwConf := range conf.RemoteWriteConfigs {
-		if rwConf.ProtobufMessage == config.RemoteWriteProtoMsgV2 && !rws.metadataInWAL {
-			return errors.New("invalid remote write configuration, if you are using remote write version 2.0 the `--enable-feature=metadata-wal-records` feature flag must be enabled")
-		}
 		hash, err := toHash(rwConf)
 		if err != nil {
 			return err

storage/remote/write_test.go

@@ -117,7 +117,7 @@ func TestWriteStorageApplyConfig_NoDuplicateWriteConfigs(t *testing.T) {
 		},
 	} {
 		t.Run("", func(t *testing.T) {
-			s := NewWriteStorage(nil, nil, dir, time.Millisecond, nil, false)
+			s := NewWriteStorage(nil, nil, dir, time.Millisecond, nil)
 			conf := &config.Config{
 				GlobalConfig:       config.DefaultGlobalConfig,
 				RemoteWriteConfigs: tc.cfgs,
@@ -143,7 +143,7 @@ func TestWriteStorageApplyConfig_RestartOnNameChange(t *testing.T) {
 	hash, err := toHash(cfg)
 	require.NoError(t, err)
 
-	s := NewWriteStorage(nil, nil, dir, time.Millisecond, nil, false)
+	s := NewWriteStorage(nil, nil, dir, time.Millisecond, nil)
 
 	conf := &config.Config{
 		GlobalConfig:       config.DefaultGlobalConfig,
@@ -165,7 +165,7 @@ func TestWriteStorageApplyConfig_RestartOnNameChange(t *testing.T) {
 func TestWriteStorageApplyConfig_UpdateWithRegisterer(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewWriteStorage(nil, prometheus.NewRegistry(), dir, time.Millisecond, nil, false)
+	s := NewWriteStorage(nil, prometheus.NewRegistry(), dir, time.Millisecond, nil)
 	c1 := &config.RemoteWriteConfig{
 		Name: "named",
 		URL: &common_config.URL{
@@ -206,7 +206,7 @@ func TestWriteStorageApplyConfig_UpdateWithRegisterer(t *testing.T) {
 func TestWriteStorageApplyConfig_Lifecycle(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewWriteStorage(nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewWriteStorage(nil, nil, dir, defaultFlushDeadline, nil)
 	conf := &config.Config{
 		GlobalConfig: config.DefaultGlobalConfig,
 		RemoteWriteConfigs: []*config.RemoteWriteConfig{
@@ -222,7 +222,7 @@ func TestWriteStorageApplyConfig_Lifecycle(t *testing.T) {
 func TestWriteStorageApplyConfig_UpdateExternalLabels(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewWriteStorage(nil, prometheus.NewRegistry(), dir, time.Second, nil, false)
+	s := NewWriteStorage(nil, prometheus.NewRegistry(), dir, time.Second, nil)
 
 	externalLabels := labels.FromStrings("external", "true")
 	conf := &config.Config{
@@ -250,7 +250,7 @@ func TestWriteStorageApplyConfig_UpdateExternalLabels(t *testing.T) {
 func TestWriteStorageApplyConfig_Idempotent(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewWriteStorage(nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewWriteStorage(nil, nil, dir, defaultFlushDeadline, nil)
 	conf := &config.Config{
 		GlobalConfig: config.GlobalConfig{},
 		RemoteWriteConfigs: []*config.RemoteWriteConfig{
@@ -274,7 +274,7 @@ func TestWriteStorageApplyConfig_Idempotent(t *testing.T) {
 func TestWriteStorageApplyConfig_PartialUpdate(t *testing.T) {
 	dir := t.TempDir()
 
-	s := NewWriteStorage(nil, nil, dir, defaultFlushDeadline, nil, false)
+	s := NewWriteStorage(nil, nil, dir, defaultFlushDeadline, nil)
 
 	c0 := &config.RemoteWriteConfig{
 		RemoteTimeout: model.Duration(10 * time.Second),

tsdb/agent/db_test.go

@@ -91,7 +91,7 @@ func createTestAgentDB(t testing.TB, reg prometheus.Registerer, opts *Options) *
 	t.Helper()
 
 	dbDir := t.TempDir()
-	rs := remote.NewStorage(promslog.NewNopLogger(), reg, startTime, dbDir, time.Second*30, nil, false)
+	rs := remote.NewStorage(promslog.NewNopLogger(), reg, startTime, dbDir, time.Second*30, nil)
 	t.Cleanup(func() {
 		require.NoError(t, rs.Close())
 	})
@@ -737,7 +737,7 @@ func TestLockfile(t *testing.T) {
 	tsdbutil.TestDirLockerUsage(t, func(t *testing.T, data string, createLock bool) (*tsdbutil.DirLocker, testutil.Closer) {
 		logger := promslog.NewNopLogger()
 		reg := prometheus.NewRegistry()
-		rs := remote.NewStorage(logger, reg, startTime, data, time.Second*30, nil, false)
+		rs := remote.NewStorage(logger, reg, startTime, data, time.Second*30, nil)
 		t.Cleanup(func() {
 			require.NoError(t, rs.Close())
 		})
@@ -757,7 +757,7 @@ func TestLockfile(t *testing.T) {
 
 func Test_ExistingWAL_NextRef(t *testing.T) {
 	dbDir := t.TempDir()
-	rs := remote.NewStorage(promslog.NewNopLogger(), nil, startTime, dbDir, time.Second*30, nil, false)
+	rs := remote.NewStorage(promslog.NewNopLogger(), nil, startTime, dbDir, time.Second*30, nil)
 	defer func() {
 		require.NoError(t, rs.Close())
 	}()

web/api/v1/api_test.go

@@ -495,7 +495,7 @@ func TestEndpoints(t *testing.T) {
 
 		remote := remote.NewStorage(promslog.New(&promslogConfig), prometheus.DefaultRegisterer, func() (int64, error) {
 			return 0, nil
-		}, dbDir, 1*time.Second, nil, false)
+		}, dbDir, 1*time.Second, nil)
 
 		err = remote.ApplyConfig(&config.Config{
 			RemoteReadConfigs: []*config.RemoteReadConfig{