Loki: Series API will return all series with no match or empty matcher (#2254)

* Allow series queries with no match or an empty {} matcher which will return all series for the provided timeframe.

* fix test

* fix lint

pkg/ingester/ingester_test.go

@@ -105,12 +105,26 @@ func TestIngester(t *testing.T) {
 
 	// Series
 
-	// empty matchers
-	_, err = i.Series(ctx, &logproto.SeriesRequest{
+	// empty matcher return all series
+	resp, err := i.Series(ctx, &logproto.SeriesRequest{
 		Start: time.Unix(0, 0),
 		End:   time.Unix(1, 0),
 	})
-	require.Error(t, err)
+	require.Nil(t, err)
+	require.ElementsMatch(t, []logproto.SeriesIdentifier{
+		{
+			Labels: map[string]string{
+				"foo": "bar",
+				"bar": "baz1",
+			},
+		},
+		{
+			Labels: map[string]string{
+				"foo": "bar",
+				"bar": "baz2",
+			},
+		},
+	}, resp.GetSeries())
 
 	// wrong matchers fmt
 	_, err = i.Series(ctx, &logproto.SeriesRequest{
@@ -129,7 +143,7 @@ func TestIngester(t *testing.T) {
 	require.Error(t, err)
 
 	// foo=bar
-	resp, err := i.Series(ctx, &logproto.SeriesRequest{
+	resp, err = i.Series(ctx, &logproto.SeriesRequest{
 		Start:  time.Unix(0, 0),
 		End:    time.Unix(1, 0),
 		Groups: []string{`{foo="bar"}`},

pkg/ingester/instance.go

@@ -249,33 +249,64 @@ func (i *instance) Series(_ context.Context, req *logproto.SeriesRequest) (*logp
 		return nil, err
 	}
 
-	dedupedSeries := make(map[uint64]logproto.SeriesIdentifier)
-	for _, matchers := range groups {
-		err = i.forMatchingStreams(matchers, func(stream *stream) error {
-			// exit early when this stream was added by an earlier group
-			key := stream.labels.Hash()
-			if _, found := dedupedSeries[key]; found {
-				return nil
-			}
+	var series []logproto.SeriesIdentifier
 
-			dedupedSeries[key] = logproto.SeriesIdentifier{
+	// If no matchers were supplied we include all streams.
+	if len(groups) == 0 {
+		series = make([]logproto.SeriesIdentifier, 0, len(i.streams))
+		err = i.forAllStreams(func(stream *stream) error {
+			series = append(series, logproto.SeriesIdentifier{
 				Labels: stream.labels.Map(),
-			}
+			})
 			return nil
 		})
-
 		if err != nil {
 			return nil, err
 		}
-	}
-	series := make([]logproto.SeriesIdentifier, 0, len(dedupedSeries))
-	for _, v := range dedupedSeries {
-		series = append(series, v)
+	} else {
+		dedupedSeries := make(map[uint64]logproto.SeriesIdentifier)
+		for _, matchers := range groups {
+			err = i.forMatchingStreams(matchers, func(stream *stream) error {
+				// exit early when this stream was added by an earlier group
+				key := stream.labels.Hash()
+				if _, found := dedupedSeries[key]; found {
+					return nil
+				}
+
+				dedupedSeries[key] = logproto.SeriesIdentifier{
+					Labels: stream.labels.Map(),
+				}
+				return nil
+			})
+			if err != nil {
+				return nil, err
+			}
+		}
+		series = make([]logproto.SeriesIdentifier, 0, len(dedupedSeries))
+		for _, v := range dedupedSeries {
+			series = append(series, v)
 
+		}
 	}
+
 	return &logproto.SeriesResponse{Series: series}, nil
 }
 
+// forAllStreams will execute a function for all streams in the instance.
+// It uses a function in order to enable generic stream access without accidentally leaking streams under the mutex.
+func (i *instance) forAllStreams(fn func(*stream) error) error {
+	i.streamsMtx.RLock()
+	defer i.streamsMtx.RUnlock()
+
+	for _, stream := range i.streams {
+		err := fn(stream)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // forMatchingStreams will execute a function for each stream that satisfies a set of requirements (time range, matchers, etc).
 // It uses a function in order to enable generic stream access without accidentally leaking streams under the mutex.
 func (i *instance) forMatchingStreams(

pkg/loghttp/params.go

@@ -79,10 +79,6 @@ func interval(r *http.Request) (time.Duration, error) {
 
 // Match extracts and parses multiple matcher groups from a slice of strings
 func Match(xs []string) ([][]*labels.Matcher, error) {
-	if len(xs) == 0 {
-		return nil, errors.New("0 matcher groups supplied")
-	}
-
 	groups := make([][]*labels.Matcher, 0, len(xs))
 	for _, x := range xs {
 		ms, err := logql.ParseMatchers(x)

pkg/loghttp/params_test.go

@@ -234,7 +234,8 @@ func Test_match(t *testing.T) {
 		wantErr bool
 	}{
 		{"malformed", []string{`{a="1`}, nil, true},
-		{"errors on nil input", nil, nil, true},
+		{"empty on nil input", nil, [][]*labels.Matcher{}, false},
+		{"empty on empty input", []string{}, [][]*labels.Matcher{}, false},
 		{
 			"single",
 			[]string{`{a="1"}`},

pkg/loghttp/series.go

@@ -3,6 +3,7 @@ package loghttp
 import (
 	"net/http"
 	"sort"
+	"strings"
 
 	"github.com/grafana/loki/pkg/logproto"
 )
@@ -25,6 +26,17 @@ func ParseSeriesQuery(r *http.Request) (*logproto.SeriesRequest, error) {
 	deduped := union(xs, ys)
 	sort.Strings(deduped)
 
+	// Special case to allow for an empty label matcher `{}` in a Series query,
+	// we support either not specifying the `match` query parameter at all or specifying it with a single `{}`
+	// empty label matcher, we treat the latter case here as if no `match` was supplied at all.
+	if len(deduped) == 1 {
+		matcher := deduped[0]
+		matcher = strings.Replace(matcher, " ", "", -1)
+		if matcher == "{}" {
+			deduped = deduped[:0]
+		}
+	}
+
 	// ensure matchers are valid before fanning out to ingesters/store as well as returning valuable parsing errors
 	// instead of 500s
 	_, err = Match(deduped)

pkg/loghttp/series_test.go

@@ -19,9 +19,32 @@ func TestParseSeriesQuery(t *testing.T) {
 	}{
 		{
 			"no match",
-			withForm(url.Values{}),
-			true,
-			nil,
+			withForm(url.Values{
+				"start": []string{"1000"},
+				"end":   []string{"2000"},
+			}),
+			false,
+			mkSeriesRequest(t, "1000", "2000", []string{}),
+		},
+		{
+			"empty matcher",
+			withForm(url.Values{
+				"start": []string{"1000"},
+				"end":   []string{"2000"},
+				"match": []string{"{}"},
+			}),
+			false,
+			mkSeriesRequest(t, "1000", "2000", []string{}),
+		},
+		{
+			"empty matcher with whitespace",
+			withForm(url.Values{
+				"start": []string{"1000"},
+				"end":   []string{"2000"},
+				"match": []string{" { }"},
+			}),
+			false,
+			mkSeriesRequest(t, "1000", "2000", []string{}),
 		},
 		{
 			"malformed",
@@ -80,6 +103,7 @@ func withForm(form url.Values) *http.Request {
 	return &http.Request{Form: form}
 }
 
+// nolint
 func mkSeriesRequest(t *testing.T, from, to string, matches []string) *logproto.SeriesRequest {
 	start, end, err := bounds(withForm(url.Values{
 		"start": []string{from},

pkg/querier/querier.go

@@ -461,26 +461,43 @@ func (q *Querier) seriesForMatchers(
 ) ([]logproto.SeriesIdentifier, error) {
 
 	var results []logproto.SeriesIdentifier
-	for _, group := range groups {
-		ids, err := q.store.GetSeries(ctx, logql.SelectParams{
-			QueryRequest: &logproto.QueryRequest{
-				Selector:  group,
-				Limit:     1,
-				Start:     from,
-				End:       through,
-				Direction: logproto.FORWARD,
-			},
-		})
+	// If no matchers were specified for the series query,
+	// we send a query with an empty matcher which will match every series.
+	if len(groups) == 0 {
+		var err error
+		results, err = q.seriesForMatcher(ctx, from, through, "")
 		if err != nil {
 			return nil, err
 		}
-
-		results = append(results, ids...)
-
+	} else {
+		for _, group := range groups {
+			ids, err := q.seriesForMatcher(ctx, from, through, group)
+			if err != nil {
+				return nil, err
+			}
+			results = append(results, ids...)
+		}
 	}
 	return results, nil
 }
 
+// seriesForMatcher fetches series from the store for a given matcher
+func (q *Querier) seriesForMatcher(ctx context.Context, from, through time.Time, matcher string) ([]logproto.SeriesIdentifier, error) {
+	ids, err := q.store.GetSeries(ctx, logql.SelectParams{
+		QueryRequest: &logproto.QueryRequest{
+			Selector:  matcher,
+			Limit:     1,
+			Start:     from,
+			End:       through,
+			Direction: logproto.FORWARD,
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+	return ids, nil
+}
+
 func (q *Querier) validateQueryRequest(ctx context.Context, req *logproto.QueryRequest) error {
 	userID, err := user.ExtractOrgID(ctx)
 	if err != nil {

pkg/storage/store.go

@@ -148,9 +148,24 @@ func (s *store) lazyChunks(ctx context.Context, matchers []*labels.Matcher, from
 }
 
 func (s *store) GetSeries(ctx context.Context, req logql.SelectParams) ([]logproto.SeriesIdentifier, error) {
-	matchers, _, from, through, err := decodeReq(req)
-	if err != nil {
-		return nil, err
+	var from, through model.Time
+	var matchers []*labels.Matcher
+
+	// The Loki parser doesn't allow for an empty label matcher but for the Series API
+	// we allow this to select all series in the time range.
+	if req.Selector == "" {
+		from, through = util.RoundToMilliseconds(req.Start, req.End)
+		nameLabelMatcher, err := labels.NewMatcher(labels.MatchEqual, labels.MetricName, "logs")
+		if err != nil {
+			return nil, err
+		}
+		matchers = []*labels.Matcher{nameLabelMatcher}
+	} else {
+		var err error
+		matchers, _, from, through, err = decodeReq(req)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	lazyChunks, err := s.lazyChunks(ctx, matchers, from, through)