Merge branch 'main' into sparsehistogram

cmd/promtool/main.go

@@ -353,8 +353,10 @@ func checkConfig(agentMode bool, filename string) ([]string, error) {
 	}
 
 	for _, scfg := range cfg.ScrapeConfigs {
-		if err := checkFileExists(scfg.HTTPClientConfig.BearerTokenFile); err != nil {
+		if scfg.HTTPClientConfig.Authorization != nil {
-			return nil, errors.Wrapf(err, "error checking bearer token file %q", scfg.HTTPClientConfig.BearerTokenFile)
+			if err := checkFileExists(scfg.HTTPClientConfig.Authorization.CredentialsFile); err != nil {
+				return nil, errors.Wrapf(err, "error checking authorization credentials or bearer token file %q", scfg.HTTPClientConfig.Authorization.CredentialsFile)
+			}
 		}
 
 		if err := checkTLSConfig(scfg.HTTPClientConfig.TLSConfig); err != nil {

cmd/promtool/main_test.go

@@ -203,3 +203,33 @@ func TestCheckTargetConfig(t *testing.T) {
 		})
 	}
 }
+
+func TestAuthorizationConfig(t *testing.T) {
+	cases := []struct {
+		name string
+		file string
+		err  string
+	}{
+		{
+			name: "authorization_credentials_file.bad",
+			file: "authorization_credentials_file.bad.yml",
+			err:  "error checking authorization credentials or bearer token file",
+		},
+		{
+			name: "authorization_credentials_file.good",
+			file: "authorization_credentials_file.good.yml",
+			err:  "",
+		},
+	}
+
+	for _, test := range cases {
+		t.Run(test.name, func(t *testing.T) {
+			_, err := checkConfig(false, "testdata/"+test.file)
+			if test.err != "" {
+				require.Contains(t, err.Error(), test.err, "Expected error to contain %q, got %q", test.err, err.Error())
+				return
+			}
+			require.NoError(t, err)
+		})
+	}
+}

cmd/promtool/testdata/authorization_credentials_file.bad.yml

@@ -0,0 +1,4 @@
+scrape_configs:
+  - job_name: test
+    authorization:
+      credentials_file: "/random/file/which/does/not/exist.yml"

cmd/promtool/testdata/authorization_credentials_file.good.yml

@@ -0,0 +1,4 @@
+scrape_configs:
+  - job_name: test
+    authorization:
+      credentials_file: "."

go.mod

@@ -3,13 +3,13 @@ module github.com/prometheus/prometheus
 go 1.14
 
 require (
-	github.com/Azure/azure-sdk-for-go v58.3.0+incompatible
+	github.com/Azure/azure-sdk-for-go v59.4.0+incompatible
 	github.com/Azure/go-autorest/autorest v0.11.22
 	github.com/Azure/go-autorest/autorest/adal v0.9.17
 	github.com/Azure/go-autorest/autorest/to v0.4.0 // indirect
 	github.com/Azure/go-autorest/autorest/validation v0.3.1 // indirect
 	github.com/alecthomas/units v0.0.0-20210927113745-59d0afb8317a
-	github.com/aws/aws-sdk-go v1.42.10
+	github.com/aws/aws-sdk-go v1.42.15
 	github.com/cespare/xxhash/v2 v2.1.2
 	github.com/containerd/containerd v1.5.7 // indirect
 	github.com/dennwc/varint v1.0.0
@@ -23,7 +23,7 @@ require (
 	github.com/fsnotify/fsnotify v1.5.1
 	github.com/go-kit/log v0.2.0
 	github.com/go-logfmt/logfmt v0.5.1
-	github.com/go-openapi/strfmt v0.21.0
+	github.com/go-openapi/strfmt v0.21.1
 	github.com/go-zookeeper/zk v1.0.2
 	github.com/gogo/protobuf v1.3.2
 	github.com/golang/snappy v0.0.4

go.sum

@@ -51,8 +51,8 @@ collectd.org v0.3.0/go.mod h1:A/8DzQBkF6abtvrT2j/AU/4tiBgJWYyh0y/oB/4MlWE=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/Azure/azure-sdk-for-go v16.2.1+incompatible/go.mod h1:9XXNKU+eRnpl9moKnB4QOLf1HestfXbmab5FXxiDBjc=
 github.com/Azure/azure-sdk-for-go v41.3.0+incompatible/go.mod h1:9XXNKU+eRnpl9moKnB4QOLf1HestfXbmab5FXxiDBjc=
-github.com/Azure/azure-sdk-for-go v58.3.0+incompatible h1:lb9OWePNuJMiibdxg9XvdbiOldR0Yifge37L4LoOxIs=
+github.com/Azure/azure-sdk-for-go v59.4.0+incompatible h1:gDA8odnngdNd3KYHL2NoK1j9vpWBgEnFSjKKLpkC8Aw=
-github.com/Azure/azure-sdk-for-go v58.3.0+incompatible/go.mod h1:9XXNKU+eRnpl9moKnB4QOLf1HestfXbmab5FXxiDBjc=
+github.com/Azure/azure-sdk-for-go v59.4.0+incompatible/go.mod h1:9XXNKU+eRnpl9moKnB4QOLf1HestfXbmab5FXxiDBjc=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78/go.mod h1:LmzpDX56iTiv29bbRTIsUNlaFfuhWRQBWjQdVyAevI8=
 github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1 h1:UQHMgLO+TxOElx5B5HZ4hJQsoJ/PvUvKRhJHDQXO8P8=
 github.com/Azure/go-ansiterm v0.0.0-20210617225240-d185dfc1b5a1/go.mod h1:xomTg63KZ2rFqZQzSB4Vz2SUXa1BpHTVz9L5PTmPC4E=
@@ -187,8 +187,8 @@ github.com/aws/aws-sdk-go v1.30.12/go.mod h1:5zCpMtNQVjRREroY7sYe8lOMRSxkhG6MZve
 github.com/aws/aws-sdk-go v1.34.28/go.mod h1:H7NKnBqNVzoTJpGfLrQkkD+ytBA93eiDYi/+8rV9s48=
 github.com/aws/aws-sdk-go v1.38.35/go.mod h1:hcU610XS61/+aQV88ixoOzUoG7v3b31pl2zKMmprdro=
 github.com/aws/aws-sdk-go v1.40.11/go.mod h1:585smgzpB/KqRA+K3y/NL/oYRqQvpNJYvLm+LY1U59Q=
-github.com/aws/aws-sdk-go v1.42.10 h1:PW9G/hnsuKttbFtOcgNKD0vQrp4yfNrtACA+X0p9mjM=
+github.com/aws/aws-sdk-go v1.42.15 h1:RcUChuF7KzrrTqx9LAzJbLBX00LkUY7cH9T1VdxNdqk=
-github.com/aws/aws-sdk-go v1.42.10/go.mod h1:585smgzpB/KqRA+K3y/NL/oYRqQvpNJYvLm+LY1U59Q=
+github.com/aws/aws-sdk-go v1.42.15/go.mod h1:585smgzpB/KqRA+K3y/NL/oYRqQvpNJYvLm+LY1U59Q=
 github.com/aws/aws-sdk-go-v2 v0.18.0/go.mod h1:JWVYvqSMppoMJC0x5wdwiImzgXTI9FuZwxzkQq9wy+g=
 github.com/benbjohnson/immutable v0.2.1/go.mod h1:uc6OHo6PN2++n98KHLxW8ef4W42ylHiQSENghE1ezxI=
 github.com/benbjohnson/tmpl v1.0.0/go.mod h1:igT620JFIi44B6awvU9IsDhR77IXWtFigTLil/RPdps=
@@ -547,8 +547,8 @@ github.com/go-openapi/strfmt v0.19.5/go.mod h1:eftuHTlB/dI8Uq8JJOyRlieZf+WkkxUuk
 github.com/go-openapi/strfmt v0.19.11/go.mod h1:UukAYgTaQfqJuAFlNxxMWNvMYiwiXtLsF2VwmoFtbtc=
 github.com/go-openapi/strfmt v0.20.0/go.mod h1:UukAYgTaQfqJuAFlNxxMWNvMYiwiXtLsF2VwmoFtbtc=
 github.com/go-openapi/strfmt v0.20.1/go.mod h1:43urheQI9dNtE5lTZQfuFJvjYJKPrxicATpEfZwHUNk=
-github.com/go-openapi/strfmt v0.21.0 h1:hX2qEZKmYks+t0hKeb4VTJpUm2UYsdL3+DCid5swxIs=
+github.com/go-openapi/strfmt v0.21.1 h1:G6s2t5V5kGCHLVbSdZ/6lI8Wm4OzoPFkc3/cjAsKQrM=
-github.com/go-openapi/strfmt v0.21.0/go.mod h1:ZRQ409bWMj+SOgXofQAGTIo2Ebu72Gs+WaRADcS5iNg=
+github.com/go-openapi/strfmt v0.21.1/go.mod h1:I/XVKeLc5+MM5oPNN7P6urMOpuLXEcNrCX/rPGuWb0k=
 github.com/go-openapi/swag v0.0.0-20160704191624-1d0bd113de87/go.mod h1:DXUve3Dpr1UfpPtxFw+EFuQ41HhCWZfha5jSVRG7C7I=
 github.com/go-openapi/swag v0.17.0/go.mod h1:AByQ+nYG6gQg71GINrmuDXCPWdL640yX49/kXLo40Tg=
 github.com/go-openapi/swag v0.18.0/go.mod h1:AByQ+nYG6gQg71GINrmuDXCPWdL640yX49/kXLo40Tg=
@@ -1351,8 +1351,8 @@ go.mongodb.org/mongo-driver v1.4.3/go.mod h1:WcMNYLx/IlOxLe6JRJiv2uXuCz6zBLndR4S
 go.mongodb.org/mongo-driver v1.4.4/go.mod h1:WcMNYLx/IlOxLe6JRJiv2uXuCz6zBLndR4SoGjYphSc=
 go.mongodb.org/mongo-driver v1.4.6/go.mod h1:WcMNYLx/IlOxLe6JRJiv2uXuCz6zBLndR4SoGjYphSc=
 go.mongodb.org/mongo-driver v1.5.1/go.mod h1:gRXCHX4Jo7J0IJ1oDQyUxF7jfy19UfxniMS4xxMmUqw=
-go.mongodb.org/mongo-driver v1.7.3 h1:G4l/eYY9VrQAK/AUgkV0koQKzQnyddnWxrd/Etf0jIs=
+go.mongodb.org/mongo-driver v1.7.5 h1:ny3p0reEpgsR2cfA5cjgwFZg3Cv/ofFh/8jbhGtz9VI=
-go.mongodb.org/mongo-driver v1.7.3/go.mod h1:NqaYOwnXWr5Pm7AOpO5QFxKJ503nbMse/R79oO62zWg=
+go.mongodb.org/mongo-driver v1.7.5/go.mod h1:VXEWRZ6URJIkUq2SCAyapmhH0ZLRBP+FT4xhp5Zvxng=
 go.mozilla.org/pkcs7 v0.0.0-20200128120323-432b2356ecb1/go.mod h1:SNgMg+EgDFwmvSmLRTNKC5fegJjB7v23qTQ0XLGUNHk=
 go.opencensus.io v0.20.1/go.mod h1:6WKK9ahsWS3RSO+PY9ZHZUfv2irvY6gN279GOPZjmmk=
 go.opencensus.io v0.20.2/go.mod h1:6WKK9ahsWS3RSO+PY9ZHZUfv2irvY6gN279GOPZjmmk=

tsdb/agent/db.go

@@ -16,9 +16,11 @@ package agent
 import (
 	"context"
 	"fmt"
+	"math"
 	"path/filepath"
 	"sync"
 	"time"
+	"unicode/utf8"
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
@@ -94,6 +96,8 @@ type dbMetrics struct {
 	numActiveSeries             prometheus.Gauge
 	numWALSeriesPendingDeletion prometheus.Gauge
 	totalAppendedSamples        prometheus.Counter
+	totalAppendedExemplars      prometheus.Counter
+	totalOutOfOrderSamples      prometheus.Counter
 	walTruncateDuration         prometheus.Summary
 	walCorruptionsTotal         prometheus.Counter
 	walTotalReplayDuration      prometheus.Gauge
@@ -120,6 +124,16 @@ func newDBMetrics(r prometheus.Registerer) *dbMetrics {
 		Help: "Total number of samples appended to the storage",
 	})
 
+	m.totalAppendedExemplars = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "prometheus_agent_exemplars_appended_total",
+		Help: "Total number of exemplars appended to the storage",
+	})
+
+	m.totalOutOfOrderSamples = prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "prometheus_agent_out_of_order_samples_total",
+		Help: "Total number of out of order samples ingestion failed attempts.",
+	})
+
 	m.walTruncateDuration = prometheus.NewSummary(prometheus.SummaryOpts{
 		Name: "prometheus_agent_truncate_duration_seconds",
 		Help: "Duration of WAL truncation.",
@@ -160,6 +174,8 @@ func newDBMetrics(r prometheus.Registerer) *dbMetrics {
 			m.numActiveSeries,
 			m.numWALSeriesPendingDeletion,
 			m.totalAppendedSamples,
+			m.totalAppendedExemplars,
+			m.totalOutOfOrderSamples,
 			m.walTruncateDuration,
 			m.walCorruptionsTotal,
 			m.walTotalReplayDuration,
@@ -181,6 +197,15 @@ func (m *dbMetrics) Unregister() {
 		m.numActiveSeries,
 		m.numWALSeriesPendingDeletion,
 		m.totalAppendedSamples,
+		m.totalAppendedExemplars,
+		m.totalOutOfOrderSamples,
+		m.walTruncateDuration,
+		m.walCorruptionsTotal,
+		m.walTotalReplayDuration,
+		m.checkpointDeleteFail,
+		m.checkpointDeleteTotal,
+		m.checkpointCreationFail,
+		m.checkpointCreationTotal,
 	}
 	for _, c := range cs {
 		m.r.Unregister(c)
@@ -261,6 +286,7 @@ func Open(l log.Logger, reg prometheus.Registerer, rs *remote.Storage, dir strin
 			DB:               db,
 			pendingSeries:    make([]record.RefSeries, 0, 100),
 			pendingSamples:   make([]record.RefSample, 0, 100),
+			pendingExamplars: make([]record.RefExemplar, 0, 10),
 		}
 	}
 
@@ -412,11 +438,8 @@ func (db *DB) loadWAL(r *wal.Reader, multiRef map[chunks.HeadSeriesRef]chunks.He
 					return
 				}
 				decoded <- samples
-			case record.Tombstones:
+			case record.Tombstones, record.Exemplars:
-				// We don't care about tombstones
+				// We don't care about tombstones or exemplars during replay.
-				continue
-			case record.Exemplars:
-				// We don't care about exemplars
 				continue
 			default:
 				errCh <- &wal.CorruptionErr{
@@ -668,23 +691,19 @@ type appender struct {
 
 	pendingSeries    []record.RefSeries
 	pendingSamples   []record.RefSample
+	pendingExamplars []record.RefExemplar
+
+	// Pointers to the series referenced by each element of pendingSamples.
+	// Series lock is not held on elements.
+	sampleSeries []*memSeries
 }
 
 func (a *appender) Append(ref storage.SeriesRef, l labels.Labels, t int64, v float64) (storage.SeriesRef, error) {
-	if ref == 0 {
+	// series references and chunk references are identical for agent mode.
-		r, err := a.Add(l, t, v)
+	headRef := chunks.HeadSeriesRef(ref)
-		return storage.SeriesRef(r), err
-	}
-	return ref, a.AddFast(chunks.HeadSeriesRef(ref), t, v)
-}
-
-func (a *appender) Add(l labels.Labels, t int64, v float64) (chunks.HeadSeriesRef, error) {
-	hash := l.Hash()
-	series := a.series.GetByHash(hash, l)
-	if series != nil {
-		return series.ref, a.AddFast(series.ref, t, v)
-	}
 
+	series := a.series.GetByID(headRef)
+	if series == nil {
 		// Ensure no empty or duplicate labels have gotten through. This mirrors the
 		// equivalent validation code in the TSDB's headAppender.
 		l = l.WithoutEmpty()
@@ -696,52 +715,88 @@ func (a *appender) Add(l labels.Labels, t int64, v float64) (chunks.HeadSeriesRe
 			return 0, errors.Wrap(tsdb.ErrInvalidSample, fmt.Sprintf(`label name "%s" is not unique`, lbl))
 		}
 
-	ref := chunks.HeadSeriesRef(a.nextRef.Inc())
+		var created bool
-	series = &memSeries{ref: ref, lset: l, lastTs: t}
+		series, created = a.getOrCreate(l)
-
+		if created {
 			a.pendingSeries = append(a.pendingSeries, record.RefSeries{
-		Ref:    ref,
+				Ref:    series.ref,
 				Labels: l,
 			})
-	a.pendingSamples = append(a.pendingSamples, record.RefSample{
-		Ref: ref,
-		T:   t,
-		V:   v,
-	})
-
-	a.series.Set(hash, series)
 
 			a.metrics.numActiveSeries.Inc()
-	a.metrics.totalAppendedSamples.Inc()
-
-	return series.ref, nil
-}
-
-func (a *appender) AddFast(ref chunks.HeadSeriesRef, t int64, v float64) error {
-	series := a.series.GetByID(ref)
-	if series == nil {
-		return storage.ErrNotFound
 		}
+	}
+
 	series.Lock()
 	defer series.Unlock()
 
-	// Update last recorded timestamp. Used by Storage.gc to determine if a
+	if t < series.lastTs {
-	// series is dead.
+		a.metrics.totalOutOfOrderSamples.Inc()
-	series.lastTs = t
+		return 0, storage.ErrOutOfOrderSample
+	}
 
+	// NOTE: always modify pendingSamples and sampleSeries together
 	a.pendingSamples = append(a.pendingSamples, record.RefSample{
-		Ref: ref,
+		Ref: series.ref,
 		T:   t,
 		V:   v,
 	})
+	a.sampleSeries = append(a.sampleSeries, series)
 
 	a.metrics.totalAppendedSamples.Inc()
-	return nil
+	return storage.SeriesRef(series.ref), nil
+}
+
+func (a *appender) getOrCreate(l labels.Labels) (series *memSeries, created bool) {
+	hash := l.Hash()
+
+	series = a.series.GetByHash(hash, l)
+	if series != nil {
+		return series, false
+	}
+
+	ref := chunks.HeadSeriesRef(a.nextRef.Inc())
+	series = &memSeries{ref: ref, lset: l, lastTs: math.MinInt64}
+	a.series.Set(hash, series)
+	return series, true
 }
 
 func (a *appender) AppendExemplar(ref storage.SeriesRef, l labels.Labels, e exemplar.Exemplar) (storage.SeriesRef, error) {
-	// remote_write doesn't support exemplars yet, so do nothing here.
+	// series references and chunk references are identical for agent mode.
-	return 0, nil
+	headRef := chunks.HeadSeriesRef(ref)
+
+	s := a.series.GetByID(headRef)
+	if s == nil {
+		return 0, fmt.Errorf("unknown series ref when trying to add exemplar: %d", ref)
+	}
+
+	// Ensure no empty labels have gotten through.
+	e.Labels = e.Labels.WithoutEmpty()
+
+	if lbl, dup := e.Labels.HasDuplicateLabelNames(); dup {
+		return 0, errors.Wrap(tsdb.ErrInvalidExemplar, fmt.Sprintf(`label name "%s" is not unique`, lbl))
+	}
+
+	// Exemplar label length does not include chars involved in text rendering such as quotes
+	// equals sign, or commas. See definition of const ExemplarMaxLabelLength.
+	labelSetLen := 0
+	for _, l := range e.Labels {
+		labelSetLen += utf8.RuneCountInString(l.Name)
+		labelSetLen += utf8.RuneCountInString(l.Value)
+
+		if labelSetLen > exemplar.ExemplarMaxLabelSetLength {
+			return 0, storage.ErrExemplarLabelLength
+		}
+	}
+
+	a.pendingExamplars = append(a.pendingExamplars, record.RefExemplar{
+		Ref:    s.ref,
+		T:      e.Ts,
+		V:      e.Value,
+		Labels: e.Labels,
+	})
+
+	return storage.SeriesRef(s.ref), nil
 }
 
 func (a *appender) AppendHistogram(ref storage.SeriesRef, l labels.Labels, t int64, h *histogram.Histogram) (storage.SeriesRef, error) {
@@ -773,6 +828,22 @@ func (a *appender) Commit() error {
 		buf = buf[:0]
 	}
 
+	if len(a.pendingExamplars) > 0 {
+		buf = encoder.Exemplars(a.pendingExamplars, buf)
+		if err := a.wal.Log(buf); err != nil {
+			return err
+		}
+		buf = buf[:0]
+	}
+
+	var series *memSeries
+	for i, s := range a.pendingSamples {
+		series = a.sampleSeries[i]
+		if !series.updateTimestamp(s.T) {
+			a.metrics.totalOutOfOrderSamples.Inc()
+		}
+	}
+
 	//nolint:staticcheck
 	a.bufPool.Put(buf)
 	return a.Rollback()
@@ -781,6 +852,8 @@ func (a *appender) Commit() error {
 func (a *appender) Rollback() error {
 	a.pendingSeries = a.pendingSeries[:0]
 	a.pendingSamples = a.pendingSamples[:0]
+	a.pendingExamplars = a.pendingExamplars[:0]
+	a.sampleSeries = a.sampleSeries[:0]
 	a.appenderPool.Put(a)
 	return nil
 }

tsdb/agent/db_test.go

@@ -15,8 +15,8 @@ package agent
 
 import (
 	"context"
+	"path/filepath"
 	"strconv"
-	"sync"
 	"testing"
 	"time"
 
@@ -26,25 +26,70 @@ import (
 	dto "github.com/prometheus/client_model/go"
 	"github.com/stretchr/testify/require"
 
+	"github.com/prometheus/prometheus/model/exemplar"
 	"github.com/prometheus/prometheus/model/labels"
+	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/storage/remote"
+	"github.com/prometheus/prometheus/tsdb"
 	"github.com/prometheus/prometheus/tsdb/record"
 	"github.com/prometheus/prometheus/tsdb/tsdbutil"
 	"github.com/prometheus/prometheus/tsdb/wal"
 	"github.com/prometheus/prometheus/util/testutil"
 )
 
-func TestUnsupported(t *testing.T) {
+func TestDB_InvalidSeries(t *testing.T) {
-	promAgentDir := t.TempDir()
+	s := createTestAgentDB(t, nil, DefaultOptions())
+	defer s.Close()
 
-	opts := DefaultOptions()
+	app := s.Appender(context.Background())
-	logger := log.NewNopLogger()
 
-	s, err := Open(logger, prometheus.NewRegistry(), nil, promAgentDir, opts)
+	t.Run("Samples", func(t *testing.T) {
+		_, err := app.Append(0, labels.Labels{}, 0, 0)
+		require.ErrorIs(t, err, tsdb.ErrInvalidSample, "should reject empty labels")
+
+		_, err = app.Append(0, labels.Labels{{Name: "a", Value: "1"}, {Name: "a", Value: "2"}}, 0, 0)
+		require.ErrorIs(t, err, tsdb.ErrInvalidSample, "should reject duplicate labels")
+	})
+
+	t.Run("Exemplars", func(t *testing.T) {
+		sRef, err := app.Append(0, labels.Labels{{Name: "a", Value: "1"}}, 0, 0)
+		require.NoError(t, err, "should not reject valid series")
+
+		_, err = app.AppendExemplar(0, nil, exemplar.Exemplar{})
+		require.EqualError(t, err, "unknown series ref when trying to add exemplar: 0")
+
+		e := exemplar.Exemplar{Labels: labels.Labels{{Name: "a", Value: "1"}, {Name: "a", Value: "2"}}}
+		_, err = app.AppendExemplar(sRef, nil, e)
+		require.ErrorIs(t, err, tsdb.ErrInvalidExemplar, "should reject duplicate labels")
+
+		e = exemplar.Exemplar{Labels: labels.Labels{{Name: "a_somewhat_long_trace_id", Value: "nYJSNtFrFTY37VR7mHzEE/LIDt7cdAQcuOzFajgmLDAdBSRHYPDzrxhMA4zz7el8naI/AoXFv9/e/G0vcETcIoNUi3OieeLfaIRQci2oa"}}}
+		_, err = app.AppendExemplar(sRef, nil, e)
+		require.ErrorIs(t, err, storage.ErrExemplarLabelLength, "should reject too long label length")
+
+		// Inverse check
+		e = exemplar.Exemplar{Labels: labels.Labels{{Name: "a", Value: "1"}}, Value: 20, Ts: 10, HasTs: true}
+		_, err = app.AppendExemplar(sRef, nil, e)
+		require.NoError(t, err, "should not reject valid exemplars")
+	})
+}
+
+func createTestAgentDB(t *testing.T, reg prometheus.Registerer, opts *Options) *DB {
+	t.Helper()
+
+	dbDir := t.TempDir()
+	rs := remote.NewStorage(log.NewNopLogger(), reg, startTime, dbDir, time.Second*30, nil)
+	t.Cleanup(func() {
+		require.NoError(t, rs.Close())
+	})
+
+	db, err := Open(log.NewNopLogger(), reg, rs, dbDir, opts)
 	require.NoError(t, err)
-	defer func() {
+	return db
-		require.NoError(t, s.Close())
+}
-	}()
+
+func TestUnsupportedFunctions(t *testing.T) {
+	s := createTestAgentDB(t, nil, DefaultOptions())
+	defer s.Close()
 
 	t.Run("Querier", func(t *testing.T) {
 		_, err := s.Querier(context.TODO(), 0, 0)
@@ -68,93 +113,74 @@ func TestCommit(t *testing.T) {
 		numSeries     = 8
 	)
 
-	promAgentDir := t.TempDir()
+	s := createTestAgentDB(t, nil, DefaultOptions())
+	app := s.Appender(context.TODO())
 
 	lbls := labelsForTest(t.Name(), numSeries)
-	opts := DefaultOptions()
-	logger := log.NewNopLogger()
-	reg := prometheus.NewRegistry()
-	remoteStorage := remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func(rs *remote.Storage) {
-		require.NoError(t, rs.Close())
-	}(remoteStorage)
-
-	s, err := Open(logger, reg, remoteStorage, promAgentDir, opts)
-	require.NoError(t, err)
-
-	a := s.Appender(context.TODO())
-
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
 		for i := 0; i < numDatapoints; i++ {
 			sample := tsdbutil.GenerateSamples(0, 1)
-			_, err := a.Append(0, lset, sample[0].T(), sample[0].V())
+			ref, err := app.Append(0, lset, sample[0].T(), sample[0].V())
+			require.NoError(t, err)
+
+			e := exemplar.Exemplar{
+				Labels: lset,
+				Ts:     sample[0].T(),
+				Value:  sample[0].V(),
+				HasTs:  true,
+			}
+			_, err = app.AppendExemplar(ref, lset, e)
 			require.NoError(t, err)
 		}
 	}
 
-	require.NoError(t, a.Commit())
+	require.NoError(t, app.Commit())
 	require.NoError(t, s.Close())
 
-	// Read records from WAL and check for expected count of series and samples.
+	sr, err := wal.NewSegmentsReader(s.wal.Dir())
-	walSeriesCount := 0
-	walSamplesCount := 0
-
-	reg = prometheus.NewRegistry()
-	remoteStorage = remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func() {
-		require.NoError(t, remoteStorage.Close())
-	}()
-
-	s1, err := Open(logger, nil, remoteStorage, promAgentDir, opts)
-	require.NoError(t, err)
-	defer func() {
-		require.NoError(t, s1.Close())
-	}()
-
-	var dec record.Decoder
-
-	if err == nil {
-		sr, err := wal.NewSegmentsReader(s1.wal.Dir())
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, sr.Close())
 	}()
 
-		r := wal.NewReader(sr)
+	// Read records from WAL and check for expected count of series, samples, and exemplars.
-		seriesPool := sync.Pool{
+	var (
-			New: func() interface{} {
+		r   = wal.NewReader(sr)
-				return []record.RefSeries{}
+		dec record.Decoder
-			},
-		}
-		samplesPool := sync.Pool{
-			New: func() interface{} {
-				return []record.RefSample{}
-			},
-		}
 
+		walSeriesCount, walSamplesCount, walExemplarsCount int
+	)
 	for r.Next() {
 		rec := r.Record()
 		switch dec.Type(rec) {
 		case record.Series:
-				series := seriesPool.Get().([]record.RefSeries)[:0]
+			var series []record.RefSeries
-				series, _ = dec.Series(rec, series)
+			series, err = dec.Series(rec, series)
+			require.NoError(t, err)
 			walSeriesCount += len(series)
+
 		case record.Samples:
-				samples := samplesPool.Get().([]record.RefSample)[:0]
+			var samples []record.RefSample
-				samples, _ = dec.Samples(rec, samples)
+			samples, err = dec.Samples(rec, samples)
+			require.NoError(t, err)
 			walSamplesCount += len(samples)
+
+		case record.Exemplars:
+			var exemplars []record.RefExemplar
+			exemplars, err = dec.Exemplars(rec, exemplars)
+			require.NoError(t, err)
+			walExemplarsCount += len(exemplars)
+
 		default:
 		}
 	}
-	}
 
-	// Retrieved series count from WAL should match the count of series been added to the WAL.
+	// Check that the WAL contained the same number of commited series/samples/exemplars.
-	require.Equal(t, walSeriesCount, numSeries)
+	require.Equal(t, numSeries, walSeriesCount, "unexpected number of series")
-
+	require.Equal(t, numSeries*numDatapoints, walSamplesCount, "unexpected number of samples")
-	// Retrieved samples count from WAL should match the count of samples been added to the WAL.
+	require.Equal(t, numSeries*numDatapoints, walExemplarsCount, "unexpected number of exemplars")
-	require.Equal(t, walSamplesCount, numSeries*numDatapoints)
 }
 
 func TestRollback(t *testing.T) {
@@ -163,93 +189,68 @@ func TestRollback(t *testing.T) {
 		numSeries     = 8
 	)
 
-	promAgentDir := t.TempDir()
+	s := createTestAgentDB(t, nil, DefaultOptions())
+	app := s.Appender(context.TODO())
 
 	lbls := labelsForTest(t.Name(), numSeries)
-	opts := DefaultOptions()
-	logger := log.NewNopLogger()
-	reg := prometheus.NewRegistry()
-	remoteStorage := remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func(rs *remote.Storage) {
-		require.NoError(t, rs.Close())
-	}(remoteStorage)
-
-	s, err := Open(logger, reg, remoteStorage, promAgentDir, opts)
-	require.NoError(t, err)
-
-	a := s.Appender(context.TODO())
-
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
 		for i := 0; i < numDatapoints; i++ {
 			sample := tsdbutil.GenerateSamples(0, 1)
-			_, err := a.Append(0, lset, sample[0].T(), sample[0].V())
+			_, err := app.Append(0, lset, sample[0].T(), sample[0].V())
 			require.NoError(t, err)
 		}
 	}
 
-	require.NoError(t, a.Rollback())
+	// Do a rollback, which should clear uncommitted data. A followup call to
+	// commit should persist nothing to the WAL.
+	require.NoError(t, app.Rollback())
+	require.NoError(t, app.Commit())
 	require.NoError(t, s.Close())
 
-	// Read records from WAL and check for expected count of series and samples.
+	sr, err := wal.NewSegmentsReader(s.wal.Dir())
-	walSeriesCount := 0
-	walSamplesCount := 0
-
-	reg = prometheus.NewRegistry()
-	remoteStorage = remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func() {
-		require.NoError(t, remoteStorage.Close())
-	}()
-
-	s1, err := Open(logger, nil, remoteStorage, promAgentDir, opts)
-	require.NoError(t, err)
-	defer func() {
-		require.NoError(t, s1.Close())
-	}()
-
-	var dec record.Decoder
-
-	if err == nil {
-		sr, err := wal.NewSegmentsReader(s1.wal.Dir())
 	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, sr.Close())
 	}()
 
-		r := wal.NewReader(sr)
+	// Read records from WAL and check for expected count of series and samples.
-		seriesPool := sync.Pool{
+	var (
-			New: func() interface{} {
+		r   = wal.NewReader(sr)
-				return []record.RefSeries{}
+		dec record.Decoder
-			},
-		}
-		samplesPool := sync.Pool{
-			New: func() interface{} {
-				return []record.RefSample{}
-			},
-		}
 
+		walSeriesCount, walSamplesCount, walExemplarsCount int
+	)
 	for r.Next() {
 		rec := r.Record()
 		switch dec.Type(rec) {
 		case record.Series:
-				series := seriesPool.Get().([]record.RefSeries)[:0]
+			var series []record.RefSeries
-				series, _ = dec.Series(rec, series)
+			series, err = dec.Series(rec, series)
+			require.NoError(t, err)
 			walSeriesCount += len(series)
+
 		case record.Samples:
-				samples := samplesPool.Get().([]record.RefSample)[:0]
+			var samples []record.RefSample
-				samples, _ = dec.Samples(rec, samples)
+			samples, err = dec.Samples(rec, samples)
+			require.NoError(t, err)
 			walSamplesCount += len(samples)
+
+		case record.Exemplars:
+			var exemplars []record.RefExemplar
+			exemplars, err = dec.Exemplars(rec, exemplars)
+			require.NoError(t, err)
+			walExemplarsCount += len(exemplars)
+
 		default:
 		}
 	}
-	}
 
-	// Retrieved series count from WAL should be zero.
+	// Check that the rollback ensured nothing got stored.
-	require.Equal(t, walSeriesCount, 0)
+	require.Equal(t, 0, walSeriesCount, "series should not have been written to WAL")
-
+	require.Equal(t, 0, walSamplesCount, "samples should not have been written to WAL")
-	// Retrieved samples count from WAL should be zero.
+	require.Equal(t, 0, walExemplarsCount, "exemplars should not have been written to WAL")
-	require.Equal(t, walSamplesCount, 0)
 }
 
 func TestFullTruncateWAL(t *testing.T) {
@@ -259,34 +260,25 @@ func TestFullTruncateWAL(t *testing.T) {
 		lastTs        = 500
 	)
 
-	promAgentDir := t.TempDir()
+	reg := prometheus.NewRegistry()
-
-	lbls := labelsForTest(t.Name(), numSeries)
 	opts := DefaultOptions()
 	opts.TruncateFrequency = time.Minute * 2
-	logger := log.NewNopLogger()
-	reg := prometheus.NewRegistry()
-	remoteStorage := remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func() {
-		require.NoError(t, remoteStorage.Close())
-	}()
 
-	s, err := Open(logger, reg, remoteStorage, promAgentDir, opts)
+	s := createTestAgentDB(t, reg, opts)
-	require.NoError(t, err)
 	defer func() {
 		require.NoError(t, s.Close())
 	}()
+	app := s.Appender(context.TODO())
 
-	a := s.Appender(context.TODO())
+	lbls := labelsForTest(t.Name(), numSeries)
-
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
 		for i := 0; i < numDatapoints; i++ {
-			_, err := a.Append(0, lset, int64(lastTs), 0)
+			_, err := app.Append(0, lset, int64(lastTs), 0)
 			require.NoError(t, err)
 		}
-		require.NoError(t, a.Commit())
+		require.NoError(t, app.Commit())
 	}
 
 	// Truncate WAL with mint to GC all the samples.
@@ -302,52 +294,40 @@ func TestPartialTruncateWAL(t *testing.T) {
 		numSeries     = 800
 	)
 
-	promAgentDir := t.TempDir()
-
 	opts := DefaultOptions()
 	opts.TruncateFrequency = time.Minute * 2
-	logger := log.NewNopLogger()
-	reg := prometheus.NewRegistry()
-	remoteStorage := remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func() {
-		require.NoError(t, remoteStorage.Close())
-	}()
 
-	s, err := Open(logger, reg, remoteStorage, promAgentDir, opts)
+	reg := prometheus.NewRegistry()
-	require.NoError(t, err)
+	s := createTestAgentDB(t, reg, opts)
 	defer func() {
 		require.NoError(t, s.Close())
 	}()
-
+	app := s.Appender(context.TODO())
-	a := s.Appender(context.TODO())
-
-	var lastTs int64
 
 	// Create first batch of 800 series with 1000 data-points with a fixed lastTs as 500.
-	lastTs = 500
+	var lastTs int64 = 500
 	lbls := labelsForTest(t.Name()+"batch-1", numSeries)
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
 		for i := 0; i < numDatapoints; i++ {
-			_, err := a.Append(0, lset, lastTs, 0)
+			_, err := app.Append(0, lset, lastTs, 0)
 			require.NoError(t, err)
 		}
-		require.NoError(t, a.Commit())
+		require.NoError(t, app.Commit())
 	}
 
 	// Create second batch of 800 series with 1000 data-points with a fixed lastTs as 600.
 	lastTs = 600
-
 	lbls = labelsForTest(t.Name()+"batch-2", numSeries)
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
 		for i := 0; i < numDatapoints; i++ {
-			_, err := a.Append(0, lset, lastTs, 0)
+			_, err := app.Append(0, lset, lastTs, 0)
 			require.NoError(t, err)
 		}
-		require.NoError(t, a.Commit())
+		require.NoError(t, app.Commit())
 	}
 
 	// Truncate WAL with mint to GC only the first batch of 800 series and retaining 2nd batch of 800 series.
@@ -364,53 +344,41 @@ func TestWALReplay(t *testing.T) {
 		lastTs        = 500
 	)
 
-	promAgentDir := t.TempDir()
+	s := createTestAgentDB(t, nil, DefaultOptions())
+	app := s.Appender(context.TODO())
 
 	lbls := labelsForTest(t.Name(), numSeries)
-	opts := DefaultOptions()
-
-	logger := log.NewNopLogger()
-	reg := prometheus.NewRegistry()
-	remoteStorage := remote.NewStorage(log.With(logger, "component", "remote"), reg, startTime, promAgentDir, time.Second*30, nil)
-	defer func() {
-		require.NoError(t, remoteStorage.Close())
-	}()
-
-	s, err := Open(logger, reg, remoteStorage, promAgentDir, opts)
-	require.NoError(t, err)
-
-	a := s.Appender(context.TODO())
-
 	for _, l := range lbls {
 		lset := labels.New(l...)
 
 		for i := 0; i < numDatapoints; i++ {
-			_, err := a.Append(0, lset, lastTs, 0)
+			_, err := app.Append(0, lset, lastTs, 0)
 			require.NoError(t, err)
 		}
 	}
 
-	require.NoError(t, a.Commit())
+	require.NoError(t, app.Commit())
 	require.NoError(t, s.Close())
 
-	restartOpts := DefaultOptions()
+	// Hack: s.wal.Dir() is the /wal subdirectory of the original storage path.
-	restartLogger := log.NewNopLogger()
+	// We need the original directory so we can recreate the storage for replay.
-	restartReg := prometheus.NewRegistry()
+	storageDir := filepath.Dir(s.wal.Dir())
 
-	// Open a new DB with the same WAL to check that series from the previous DB
+	reg := prometheus.NewRegistry()
-	// get replayed.
+	replayStorage, err := Open(s.logger, reg, nil, storageDir, s.opts)
-	replayDB, err := Open(restartLogger, restartReg, nil, promAgentDir, restartOpts)
+	if err != nil {
-	require.NoError(t, err)
+		t.Fatalf("unable to create storage for the agent: %v", err)
+	}
 	defer func() {
-		require.NoError(t, replayDB.Close())
+		require.NoError(t, replayStorage.Close())
 	}()
 
 	// Check if all the series are retrieved back from the WAL.
-	m := gatherFamily(t, restartReg, "prometheus_agent_active_series")
+	m := gatherFamily(t, reg, "prometheus_agent_active_series")
 	require.Equal(t, float64(numSeries), m.Metric[0].Gauge.GetValue(), "agent wal replay mismatch of active series count")
 
 	// Check if lastTs of the samples retrieved from the WAL is retained.
-	metrics := replayDB.series.series
+	metrics := replayStorage.series.series
 	for i := 0; i < len(metrics); i++ {
 		mp := metrics[i]
 		for _, v := range mp {

tsdb/agent/series.go

@@ -26,9 +26,24 @@ type memSeries struct {
 
 	ref  chunks.HeadSeriesRef
 	lset labels.Labels
+
+	// Last recorded timestamp. Used by Storage.gc to determine if a series is
+	// stale.
 	lastTs int64
 }
 
+// updateTimestamp obtains the lock on s and will attempt to update lastTs.
+// fails if newTs < lastTs.
+func (m *memSeries) updateTimestamp(newTs int64) bool {
+	m.Lock()
+	defer m.Unlock()
+	if newTs >= m.lastTs {
+		m.lastTs = newTs
+		return true
+	}
+	return false
+}
+
 // seriesHashmap is a simple hashmap for memSeries by their label set.
 // It is built on top of a regular hashmap and holds a slice of series to
 // resolve hash collisions. Its methods require the hash to be submitted

web/ui/module/codemirror-promql/package.json

@@ -46,7 +46,7 @@
     "@types/chai": "^4.2.22",
     "@types/lru-cache": "^5.1.0",
     "@types/mocha": "^9.0.0",
-    "@types/node": "^16.11.9",
+    "@types/node": "^16.11.10",
     "@typescript-eslint/eslint-plugin": "^5.3.1",
     "@typescript-eslint/parser": "^5.3.1",
     "chai": "^4.2.0",

web/ui/package-lock.json

@@ -32,7 +32,7 @@
         "@types/chai": "^4.2.22",
         "@types/lru-cache": "^5.1.0",
         "@types/mocha": "^9.0.0",
-        "@types/node": "^16.11.9",
+        "@types/node": "^16.11.10",
         "@typescript-eslint/eslint-plugin": "^5.3.1",
         "@typescript-eslint/parser": "^5.3.1",
         "chai": "^4.2.0",
@@ -1775,9 +1775,9 @@
       "license": "MIT"
     },
     "node_modules/@types/node": {
-      "version": "16.11.9",
+      "version": "16.11.10",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-16.11.9.tgz",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-16.11.10.tgz",
-      "integrity": "sha512-MKmdASMf3LtPzwLyRrFjtFFZ48cMf8jmX5VRYrDQiJa8Ybu5VAmkqBWqKU8fdCwD8ysw4mQ9nrEHvzg6gunR7A==",
+      "integrity": "sha512-3aRnHa1KlOEEhJ6+CvyHKK5vE9BcLGjtUpwvqYLRvYNQKMfabu3BwfJaA/SLW8dxe28LsNDjtHwePTuzn3gmOA==",
       "dev": true
     },
     "node_modules/@types/prop-types": {
@@ -7252,7 +7252,7 @@
         "@types/flot": "0.0.32",
         "@types/jest": "^27.0.3",
         "@types/jquery": "^3.5.9",
-        "@types/node": "^16.11.9",
+        "@types/node": "^16.11.10",
         "@types/react": "^17.0.36",
         "@types/react-copy-to-clipboard": "^5.0.2",
         "@types/react-dom": "^17.0.11",
@@ -27808,9 +27808,9 @@
       "dev": true
     },
     "@types/node": {
-      "version": "16.11.9",
+      "version": "16.11.10",
-      "resolved": "https://registry.npmjs.org/@types/node/-/node-16.11.9.tgz",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-16.11.10.tgz",
-      "integrity": "sha512-MKmdASMf3LtPzwLyRrFjtFFZ48cMf8jmX5VRYrDQiJa8Ybu5VAmkqBWqKU8fdCwD8ysw4mQ9nrEHvzg6gunR7A==",
+      "integrity": "sha512-3aRnHa1KlOEEhJ6+CvyHKK5vE9BcLGjtUpwvqYLRvYNQKMfabu3BwfJaA/SLW8dxe28LsNDjtHwePTuzn3gmOA==",
       "dev": true
     },
     "@types/prop-types": {
@@ -28413,7 +28413,7 @@
         "@types/chai": "^4.2.22",
         "@types/lru-cache": "^5.1.0",
         "@types/mocha": "^9.0.0",
-        "@types/node": "^16.11.9",
+        "@types/node": "^16.11.10",
         "@typescript-eslint/eslint-plugin": "^5.3.1",
         "@typescript-eslint/parser": "^5.3.1",
         "chai": "^4.2.0",
@@ -29645,7 +29645,7 @@
         "@types/flot": "0.0.32",
         "@types/jest": "^27.0.3",
         "@types/jquery": "^3.5.9",
-        "@types/node": "^16.11.9",
+        "@types/node": "^16.11.10",
         "@types/react": "^17.0.36",
         "@types/react-copy-to-clipboard": "^5.0.2",
         "@types/react-dom": "^17.0.11",

web/ui/react-app/package.json

@@ -69,7 +69,7 @@
     "@types/flot": "0.0.32",
     "@types/jest": "^27.0.3",
     "@types/jquery": "^3.5.9",
-    "@types/node": "^16.11.9",
+    "@types/node": "^16.11.10",
     "@types/react": "^17.0.36",
     "@types/react-copy-to-clipboard": "^5.0.2",
     "@types/react-dom": "^17.0.11",

web/ui/react-app/public/index.html

@@ -15,10 +15,11 @@
         It will render a "Consoles" link in the navbar when it is non-empty.
       - PROMETHEUS_AGENT_MODE is replaced by a boolean indicating if Prometheus is running in agent mode.
         It true, it will disable querying capacities in the UI and generally adapt the UI to the agent mode.
+        It has to be represented as a string, because booleans can be mangled to !1 in production builds.
     -->
     <script>
       const GLOBAL_CONSOLES_LINK='CONSOLES_LINK_PLACEHOLDER';
-      const GLOBAL_PROMETHEUS_AGENT_MODE=PROMETHEUS_AGENT_MODE_PLACEHOLDER;
+      const GLOBAL_AGENT_MODE='AGENT_MODE_PLACEHOLDER';
     </script>
 
     <!--

web/ui/react-app/src/App.test.tsx

@@ -5,6 +5,7 @@ import Navigation from './Navbar';
 import { Container } from 'reactstrap';
 import { Route } from 'react-router-dom';
 import {
+  AgentPage,
   AlertsPage,
   ConfigPage,
   FlagsPage,
@@ -24,6 +25,7 @@ describe('App', () => {
   });
   it('routes', () => {
     [
+      AgentPage,
       AlertsPage,
       ConfigPage,
       FlagsPage,
@@ -37,7 +39,7 @@ describe('App', () => {
       const c = app.find(component);
       expect(c).toHaveLength(1);
     });
-    expect(app.find(Route)).toHaveLength(9);
+    expect(app.find(Route)).toHaveLength(10);
     expect(app.find(Container)).toHaveLength(1);
   });
 });

web/ui/react-app/src/App.tsx

@@ -4,6 +4,7 @@ import { Container } from 'reactstrap';
 
 import { BrowserRouter as Router, Redirect, Switch, Route } from 'react-router-dom';
 import {
+  AgentPage,
   AlertsPage,
   ConfigPage,
   FlagsPage,
@@ -22,14 +23,16 @@ import useMedia from './hooks/useMedia';
 
 interface AppProps {
   consolesLink: string | null;
+  agentMode: boolean;
 }
 
-const App: FC<AppProps> = ({ consolesLink }) => {
+const App: FC<AppProps> = ({ consolesLink, agentMode }) => {
   // This dynamically/generically determines the pathPrefix by stripping the first known
   // endpoint suffix from the window location path. It works out of the box for both direct
   // hosting and reverse proxy deployments with no additional configurations required.
   let basePath = window.location.pathname;
   const paths = [
+    '/agent',
     '/graph',
     '/alerts',
     '/status',
@@ -70,14 +73,17 @@ const App: FC<AppProps> = ({ consolesLink }) => {
       <Theme />
       <PathPrefixContext.Provider value={basePath}>
         <Router basename={basePath}>
-          <Navigation consolesLink={consolesLink} />
+          <Navigation consolesLink={consolesLink} agentMode={agentMode} />
           <Container fluid style={{ paddingTop: 70 }}>
             <Switch>
-              <Redirect exact from="/" to={`graph`} />
+              <Redirect exact from="/" to={agentMode ? '/agent' : '/graph'} />
               {/*
               NOTE: Any route added here needs to also be added to the list of
               React-handled router paths ("reactRouterPaths") in /web/web.go.
             */}
+              <Route path="/agent">
+                <AgentPage />
+              </Route>
               <Route path="/graph">
                 <PanelListPage />
               </Route>

web/ui/react-app/src/Navbar.tsx

@@ -17,17 +17,18 @@ import { ThemeToggle } from './Theme';
 
 interface NavbarProps {
   consolesLink: string | null;
+  agentMode: boolean;
 }
 
-const Navigation: FC<NavbarProps> = ({ consolesLink }) => {
+const Navigation: FC<NavbarProps> = ({ consolesLink, agentMode }) => {
   const [isOpen, setIsOpen] = useState(false);
   const toggle = () => setIsOpen(!isOpen);
   const pathPrefix = usePathPrefix();
   return (
     <Navbar className="mb-3" dark color="dark" expand="md" fixed="top">
       <NavbarToggler onClick={toggle} className="mr-2" />
-      <Link className="pt-0 navbar-brand" to="/graph">
+      <Link className="pt-0 navbar-brand" to={agentMode ? '/agent' : '/graph'}>
-        Prometheus
+        Prometheus{agentMode && ' Agent'}
       </Link>
       <Collapse isOpen={isOpen} navbar style={{ justifyContent: 'space-between' }}>
         <Nav className="ml-0" navbar>
@@ -36,6 +37,8 @@ const Navigation: FC<NavbarProps> = ({ consolesLink }) => {
               <NavLink href={consolesLink}>Consoles</NavLink>
             </NavItem>
           )}
+          {!agentMode && (
+            <>
               <NavItem>
                 <NavLink tag={Link} to="/alerts">
                   Alerts
@@ -46,6 +49,8 @@ const Navigation: FC<NavbarProps> = ({ consolesLink }) => {
                   Graph
                 </NavLink>
               </NavItem>
+            </>
+          )}
           <UncontrolledDropdown nav inNavbar>
             <DropdownToggle nav caret>
               Status
@@ -54,18 +59,22 @@ const Navigation: FC<NavbarProps> = ({ consolesLink }) => {
               <DropdownItem tag={Link} to="/status">
                 Runtime & Build Information
               </DropdownItem>
+              {!agentMode && (
                 <DropdownItem tag={Link} to="/tsdb-status">
                   TSDB Status
                 </DropdownItem>
+              )}
               <DropdownItem tag={Link} to="/flags">
                 Command-Line Flags
               </DropdownItem>
               <DropdownItem tag={Link} to="/config">
                 Configuration
               </DropdownItem>
+              {!agentMode && (
                 <DropdownItem tag={Link} to="/rules">
                   Rules
                 </DropdownItem>
+              )}
               <DropdownItem tag={Link} to="/targets">
                 Targets
               </DropdownItem>
@@ -77,9 +86,11 @@ const Navigation: FC<NavbarProps> = ({ consolesLink }) => {
           <NavItem>
             <NavLink href="https://prometheus.io/docs/prometheus/latest/getting_started/">Help</NavLink>
           </NavItem>
+          {!agentMode && (
             <NavItem>
               <NavLink href={`${pathPrefix}/classic/graph${window.location.search}`}>Classic UI</NavLink>
             </NavItem>
+          )}
         </Nav>
       </Collapse>
       <ThemeToggle />

web/ui/react-app/src/index.tsx

@@ -10,8 +10,10 @@ import { isPresent } from './utils';
 
 // Declared/defined in public/index.html, value replaced by Prometheus when serving bundle.
 declare const GLOBAL_CONSOLES_LINK: string;
+declare const GLOBAL_AGENT_MODE: string;
 
 let consolesLink: string | null = GLOBAL_CONSOLES_LINK;
+const agentMode: string | null = GLOBAL_AGENT_MODE;
 
 if (
   GLOBAL_CONSOLES_LINK === 'CONSOLES_LINK_PLACEHOLDER' ||
@@ -21,4 +23,4 @@ if (
   consolesLink = null;
 }
 
-ReactDOM.render(<App consolesLink={consolesLink} />, document.getElementById('root'));
+ReactDOM.render(<App consolesLink={consolesLink} agentMode={agentMode === 'true'} />, document.getElementById('root'));

web/ui/react-app/src/pages/agent/Agent.tsx

@@ -0,0 +1,16 @@
+import React, { FC } from 'react';
+
+const Agent: FC = () => {
+  return (
+    <>
+      <h2>Prometheus Agent</h2>
+      <p>
+        This Prometheus instance is running in <strong>agent mode</strong>. In this mode, Prometheus is only used to scrape
+        discovered targets and forward them to remote write endpoints.
+      </p>
+      <p>Some features are not available in this mode, such as querying and alerting.</p>
+    </>
+  );
+};
+
+export default Agent;

web/ui/react-app/src/pages/index.ts

@@ -1,3 +1,4 @@
+import Agent from './agent/Agent';
 import Alerts from './alerts/Alerts';
 import Config from './config/Config';
 import Flags from './flags/Flags';
@@ -9,6 +10,7 @@ import PanelList from './graph/PanelList';
 import TSDBStatus from './tsdbStatus/TSDBStatus';
 import { withStartingIndicator } from '../components/withStartingIndicator';
 
+const AgentPage = withStartingIndicator(Agent);
 const AlertsPage = withStartingIndicator(Alerts);
 const ConfigPage = withStartingIndicator(Config);
 const FlagsPage = withStartingIndicator(Flags);
@@ -21,6 +23,7 @@ const PanelListPage = withStartingIndicator(PanelList);
 
 // prettier-ignore
 export {
+  AgentPage,
   AlertsPage,
   ConfigPage,
   FlagsPage,

web/ui/react-app/src/pages/targets/EndpointLink.test.tsx

@@ -1,6 +1,6 @@
 import React from 'react';
 import { shallow, mount } from 'enzyme';
-import { Badge, Alert } from 'reactstrap';
+import { Badge } from 'reactstrap';
 import EndpointLink from './EndpointLink';
 
 describe('EndpointLink', () => {
@@ -29,11 +29,24 @@ describe('EndpointLink', () => {
     const targetLabel = badges.filterWhere((badge) => badge.children().text() === 'target="http://some-service"');
     expect(targetLabel.length).toEqual(1);
   });
-
+  // In cases of IPv6 addresses with a Zone ID, URL may not be parseable.
-  it('renders an alert if url is invalid', () => {
+  // See https://github.com/prometheus/prometheus/issues/9760
-    const endpointLink = shallow(<EndpointLink endpoint={'afdsacas'} globalUrl={'afdsacas'} />);
+  it('renders an anchor for IPv6 link with zone ID including labels for query params', () => {
-    const err = endpointLink.find(Alert);
+    const endpoint =
-    expect(err.render().text()).toEqual('Error: Invalid URL: afdsacas');
+      'http://[fe80::f1ee:adeb:371d:983%eth1]:9100/stats/prometheus?module=http_2xx&target=http://some-service';
+    const globalURL =
+      'http://[fe80::f1ee:adeb:371d:983%eth1]:9100/stats/prometheus?module=http_2xx&target=http://some-service';
+    const endpointLink = shallow(<EndpointLink endpoint={endpoint} globalUrl={globalURL} />);
+    const anchor = endpointLink.find('a');
+    const badges = endpointLink.find(Badge);
+    expect(anchor.prop('href')).toEqual(globalURL);
+    expect(anchor.children().text()).toEqual('http://[fe80::f1ee:adeb:371d:983%eth1]:9100/stats/prometheus');
+    expect(endpointLink.find('br')).toHaveLength(1);
+    expect(badges).toHaveLength(2);
+    const moduleLabel = badges.filterWhere((badge) => badge.children().text() === 'module="http_2xx"');
+    expect(moduleLabel.length).toEqual(1);
+    const targetLabel = badges.filterWhere((badge) => badge.children().text() === 'target="http://some-service"');
+    expect(targetLabel.length).toEqual(1);
   });
 
   it('handles params with multiple values correctly', () => {

web/ui/react-app/src/pages/targets/EndpointLink.tsx

@@ -1,5 +1,5 @@
 import React, { FC } from 'react';
-import { Badge, Alert } from 'reactstrap';
+import { Badge } from 'reactstrap';
 
 export interface EndpointLinkProps {
   endpoint: string;
@@ -8,23 +8,28 @@ export interface EndpointLinkProps {
 
 const EndpointLink: FC<EndpointLinkProps> = ({ endpoint, globalUrl }) => {
   let url: URL;
+  let search = '';
+  let invalidURL = false;
   try {
     url = new URL(endpoint);
   } catch (err: unknown) {
-    const error = err as Error;
+    // In cases of IPv6 addresses with a Zone ID, URL may not be parseable.
-    return (
+    // See https://github.com/prometheus/prometheus/issues/9760
-      <Alert color="danger">
+    // In this case, we attempt to prepare a synthetic URL with the
-        <strong>Error:</strong> {error.message}
+    // same query parameters, for rendering purposes.
-      </Alert>
+    invalidURL = true;
-    );
+    if (endpoint.indexOf('?') > -1) {
+      search = endpoint.substring(endpoint.indexOf('?'));
+    }
+    url = new URL('http://0.0.0.0' + search);
   }
 
   const { host, pathname, protocol, searchParams }: URL = url;
   const params = Array.from(searchParams.entries());
-
+  const displayLink = invalidURL ? endpoint.replace(search, '') : `${protocol}//${host}${pathname}`;
   return (
     <>
-      <a href={globalUrl}>{`${protocol}//${host}${pathname}`}</a>
+      <a href={globalUrl}>{displayLink}</a>
       {params.length > 0 ? <br /> : null}
       {params.map(([labelName, labelValue]: [string, string]) => {
         return (

web/web.go

@@ -71,18 +71,27 @@ import (
 
 // Paths that are handled by the React / Reach router that should all be served the main React app's index.html.
 var reactRouterPaths = []string{
-	"/alerts",
 	"/config",
 	"/flags",
-	"/graph",
-	"/rules",
 	"/service-discovery",
 	"/status",
 	"/targets",
-	"/tsdb-status",
 	"/starting",
 }
 
+// Paths that are handled by the React router when the Agent mode is set.
+var reactRouterAgentPaths = []string{
+	"/agent",
+}
+
+// Paths that are handled by the React router when the Agent mode is not set.
+var reactRouterServerPaths = []string{
+	"/alerts",
+	"/graph",
+	"/rules",
+	"/tsdb-status",
+}
+
 // withStackTrace logs the stack trace in case the request panics. The function
 // will re-raise the error which will then be handled by the net/http package.
 // It is needed because the go-kit log package doesn't manage properly the
@@ -346,10 +355,15 @@ func New(logger log.Logger, o *Options) *Handler {
 		router = router.WithPrefix(o.RoutePrefix)
 	}
 
+	homePage := "/graph"
+	if o.IsAgent {
+		homePage = "/agent"
+	}
+
 	readyf := h.testReady
 
 	router.Get("/", func(w http.ResponseWriter, r *http.Request) {
-		http.Redirect(w, r, path.Join(o.ExternalURL.Path, "/graph"), http.StatusFound)
+		http.Redirect(w, r, path.Join(o.ExternalURL.Path, homePage), http.StatusFound)
 	})
 	router.Get("/classic/", func(w http.ResponseWriter, r *http.Request) {
 		http.Redirect(w, r, path.Join(o.ExternalURL.Path, "/classic/graph"), http.StatusFound)
@@ -409,7 +423,7 @@ func New(logger log.Logger, o *Options) *Handler {
 		}
 		replacedIdx := bytes.ReplaceAll(idx, []byte("CONSOLES_LINK_PLACEHOLDER"), []byte(h.consolesPath()))
 		replacedIdx = bytes.ReplaceAll(replacedIdx, []byte("TITLE_PLACEHOLDER"), []byte(h.options.PageTitle))
-		replacedIdx = bytes.ReplaceAll(replacedIdx, []byte("PROMETHEUS_AGENT_MODE_PLACEHOLDER"), []byte(strconv.FormatBool(h.options.IsAgent)))
+		replacedIdx = bytes.ReplaceAll(replacedIdx, []byte("AGENT_MODE_PLACEHOLDER"), []byte(strconv.FormatBool(h.options.IsAgent)))
 		w.Write(replacedIdx)
 	}
 
@@ -418,6 +432,16 @@ func New(logger log.Logger, o *Options) *Handler {
 		router.Get(p, serveReactApp)
 	}
 
+	if h.options.IsAgent {
+		for _, p := range reactRouterAgentPaths {
+			router.Get(p, serveReactApp)
+		}
+	} else {
+		for _, p := range reactRouterServerPaths {
+			router.Get(p, serveReactApp)
+		}
+	}
+
 	// The favicon and manifest are bundled as part of the React app, but we want to serve
 	// them on the root.
 	for _, p := range []string{"/favicon.ico", "/manifest.json"} {

web/web_test.go

@@ -585,6 +585,8 @@ func TestAgentAPIEndPoints(t *testing.T) {
 		"/query",
 		"/query_range",
 		"/query_exemplars",
+		"/graph",
+		"/rules",
 	} {
 		w := httptest.NewRecorder()
 		req, err := http.NewRequest("GET", baseURL+u, nil)
@@ -595,6 +597,7 @@ func TestAgentAPIEndPoints(t *testing.T) {
 
 	// Test for available endpoints in the Agent mode.
 	for _, u := range []string{
+		"/agent",
 		"/targets",
 		"/status",
 	} {