feat: move detected field logic to query frontend

Squashed commit of the following:

commit 4d9af56
Author: Trevor Whitney <[email protected]>
Date:   Fri Sep 20 16:38:03 2024 -0600

    feat: move detected fields logic to QF

commit a23ea8b
Author: Trevor Whitney <[email protected]>
Date:   Fri Sep 20 14:37:35 2024 -0600

    fix: enforce query timeouts and limits

commit 2ef80ec
Author: Trevor Whitney <[email protected]>
Date:   Fri Sep 20 13:24:35 2024 -0600

    chore: no retries for detected_fields

commit c7a471d
Author: Trevor Whitney <[email protected]>
Date:   Fri Sep 20 13:05:33 2024 -0600

    feat: return empty result instead of error for failed detected fields queries

commit 7b3529a
Author: Trevor Whitney <[email protected]>
Date:   Fri Sep 20 09:39:33 2024 -0600

    fix: guard against failed ingester requests for detected fields

    (cherry picked from commit fbf9018)

pkg/querier/queryrange/detected_fields.go

@@ -0,0 +1,359 @@
+package queryrange
+
+import (
+	"context"
+	"net/http"
+	"slices"
+	"strconv"
+	"time"
+
+	"github.com/axiomhq/hyperloglog"
+	"github.com/dustin/go-humanize"
+	"github.com/grafana/dskit/httpgrpc"
+	"github.com/grafana/loki/pkg/push"
+	"github.com/grafana/loki/v3/pkg/logproto"
+	logql_log "github.com/grafana/loki/v3/pkg/logql/log"
+	"github.com/grafana/loki/v3/pkg/logql/syntax"
+	"github.com/grafana/loki/v3/pkg/logqlmodel"
+	"github.com/grafana/loki/v3/pkg/querier/plan"
+	base "github.com/grafana/loki/v3/pkg/querier/queryrange/queryrangebase"
+	"github.com/prometheus/prometheus/model/labels"
+)
+
+func NewDetectedFieldsHandler(
+	limitedHandler base.Handler,
+	logHandler base.Handler,
+	limits Limits,
+) base.Middleware {
+	return base.MiddlewareFunc(func(next base.Handler) base.Handler {
+		return base.HandlerFunc(
+			func(ctx context.Context, req base.Request) (base.Response, error) {
+				var resp base.Response
+				var err error
+				switch r := req.(type) {
+				case *DetectedFieldsRequest:
+					expr, err := syntax.ParseLogSelector(r.Query, true)
+					if err != nil {
+						return nil, httpgrpc.Errorf(http.StatusBadRequest, "%s", err.Error())
+					}
+
+					if err := validateMaxEntriesLimits(ctx, r.LineLimit, limits); err != nil {
+						return nil, httpgrpc.Errorf(http.StatusBadRequest, "%s", err.Error())
+					}
+
+					if err := validateMatchers(ctx, limits, expr.Matchers()); err != nil {
+						return nil, httpgrpc.Errorf(http.StatusBadRequest, "%s", err.Error())
+					}
+
+					lokiReq := &LokiRequest{
+						Query:     r.GetQuery(),
+						Step:      r.GetStep(),
+						StartTs:   r.GetStartTs(),
+						EndTs:     r.GetEndTs(),
+						Direction: logproto.BACKWARD,
+						Limit:     r.GetLineLimit(),
+						Path:      "/loki/api/v1/query_range",
+					}
+
+					lokiReq.Plan = &plan.QueryPlan{
+						AST: expr,
+					}
+
+					if !expr.HasFilter() {
+						resp, err = limitedHandler.Do(ctx, lokiReq)
+					}
+					resp, err = logHandler.Do(ctx, lokiReq)
+					if err != nil {
+						return nil, err
+					}
+
+					switch re := resp.(type) {
+					case *LokiResponse:
+						if re.Status != "success" {
+							return resp, nil
+						}
+
+						detectedFields := ParseDetectedFields(r.FieldLimit, re.Data.Result)
+
+						fields := make([]*logproto.DetectedField, len(detectedFields))
+						fieldCount := 0
+						for k, v := range detectedFields {
+							p := v.Parsers
+							if len(p) == 0 {
+								p = nil
+							}
+							fields[fieldCount] = &logproto.DetectedField{
+								Label:       k,
+								Type:        v.FieldType,
+								Cardinality: v.Estimate(),
+								Parsers:     p,
+							}
+
+							fieldCount++
+						}
+
+						return &DetectedFieldsResponse{
+							Response: &logproto.DetectedFieldsResponse{
+								Fields:     fields,
+								FieldLimit: r.GetFieldLimit(),
+							},
+							Headers: re.Headers,
+						}, nil
+					}
+				default:
+					resp, err = next.Do(ctx, req)
+				}
+
+				return resp, err
+			},
+		)
+	})
+}
+
+type ParsedFields struct {
+	Sketch    *hyperloglog.Sketch
+	FieldType logproto.DetectedFieldType
+	Parsers   []string
+}
+
+func newParsedFields(parsers []string) *ParsedFields {
+	return &ParsedFields{
+		Sketch:    hyperloglog.New(),
+		FieldType: logproto.DetectedFieldString,
+		Parsers:   parsers,
+	}
+}
+
+func newParsedLabels() *ParsedFields {
+	return &ParsedFields{
+		Sketch:    hyperloglog.New(),
+		FieldType: logproto.DetectedFieldString,
+	}
+}
+
+func (p *ParsedFields) Insert(value string) {
+	p.Sketch.Insert([]byte(value))
+}
+
+func (p *ParsedFields) Estimate() uint64 {
+	return p.Sketch.Estimate()
+}
+
+func (p *ParsedFields) Marshal() ([]byte, error) {
+	return p.Sketch.MarshalBinary()
+}
+
+func (p *ParsedFields) DetermineType(value string) {
+	p.FieldType = determineType(value)
+}
+
+func determineType(value string) logproto.DetectedFieldType {
+	if _, err := strconv.ParseInt(value, 10, 64); err == nil {
+		return logproto.DetectedFieldInt
+	}
+
+	if _, err := strconv.ParseFloat(value, 64); err == nil {
+		return logproto.DetectedFieldFloat
+	}
+
+	if _, err := strconv.ParseBool(value); err == nil {
+		return logproto.DetectedFieldBoolean
+	}
+
+	if _, err := time.ParseDuration(value); err == nil {
+		return logproto.DetectedFieldDuration
+	}
+
+	if _, err := humanize.ParseBytes(value); err == nil {
+		return logproto.DetectedFieldBytes
+	}
+
+	return logproto.DetectedFieldString
+}
+
+func ParseDetectedFields(limit uint32, streams logqlmodel.Streams) map[string]*ParsedFields {
+	detectedFields := make(map[string]*ParsedFields, limit)
+	fieldCount := uint32(0)
+	emtpyparsers := []string{}
+
+	for _, stream := range streams {
+		streamLbls, err := syntax.ParseLabels(stream.Labels)
+		if err != nil {
+			streamLbls = labels.EmptyLabels()
+		}
+
+		for _, entry := range stream.Entries {
+			structuredMetadata := getStructuredMetadata(entry)
+			for k, vals := range structuredMetadata {
+				df, ok := detectedFields[k]
+				if !ok && fieldCount < limit {
+					df = newParsedFields(emtpyparsers)
+					detectedFields[k] = df
+					fieldCount++
+				}
+
+				if df == nil {
+					continue
+				}
+
+				detectType := true
+				for _, v := range vals {
+					parsedFields := detectedFields[k]
+					if detectType {
+						// we don't want to determine the type for every line, so we assume the type in each stream will be the same, and re-detect the type for the next stream
+						parsedFields.DetermineType(v)
+						detectType = false
+					}
+
+					parsedFields.Insert(v)
+				}
+			}
+
+			streamLbls := logql_log.NewBaseLabelsBuilder().ForLabels(streamLbls, streamLbls.Hash())
+			parsedLabels, parsers := parseEntry(entry, streamLbls)
+			for k, vals := range parsedLabels {
+				df, ok := detectedFields[k]
+				if !ok && fieldCount < limit {
+					df = newParsedFields(parsers)
+					detectedFields[k] = df
+					fieldCount++
+				}
+
+				if df == nil {
+					continue
+				}
+
+				for _, parser := range parsers {
+					if !slices.Contains(df.Parsers, parser) {
+						df.Parsers = append(df.Parsers, parser)
+					}
+				}
+
+				detectType := true
+				for _, v := range vals {
+					parsedFields := detectedFields[k]
+					if detectType {
+						// we don't want to determine the type for every line, so we assume the type in each stream will be the same, and re-detect the type for the next stream
+						parsedFields.DetermineType(v)
+						detectType = false
+					}
+
+					parsedFields.Insert(v)
+				}
+			}
+		}
+	}
+
+	return detectedFields
+}
+
+func getStructuredMetadata(entry push.Entry) map[string][]string {
+	labels := map[string]map[string]struct{}{}
+	for _, lbl := range entry.StructuredMetadata {
+		if values, ok := labels[lbl.Name]; ok {
+			values[lbl.Value] = struct{}{}
+		} else {
+			labels[lbl.Name] = map[string]struct{}{lbl.Value: {}}
+		}
+	}
+
+	result := make(map[string][]string, len(labels))
+	for lbl, values := range labels {
+		vals := make([]string, 0, len(values))
+		for v := range values {
+			vals = append(vals, v)
+		}
+		result[lbl] = vals
+	}
+
+	return result
+}
+
+func parseEntry(entry push.Entry, lbls *logql_log.LabelsBuilder) (map[string][]string, []string) {
+	origParsed := getParsedLabels(entry)
+	parsed := make(map[string][]string, len(origParsed))
+
+	for lbl, values := range origParsed {
+		if lbl == logqlmodel.ErrorLabel || lbl == logqlmodel.ErrorDetailsLabel ||
+			lbl == logqlmodel.PreserveErrorLabel {
+			continue
+		}
+
+		parsed[lbl] = values
+	}
+
+	line := entry.Line
+	parser := "json"
+	jsonParser := logql_log.NewJSONParser()
+	_, jsonSuccess := jsonParser.Process(0, []byte(line), lbls)
+	if !jsonSuccess || lbls.HasErr() {
+		lbls.Reset()
+
+		logFmtParser := logql_log.NewLogfmtParser(false, false)
+		parser = "logfmt"
+		_, logfmtSuccess := logFmtParser.Process(0, []byte(line), lbls)
+		if !logfmtSuccess || lbls.HasErr() {
+			return parsed, nil
+		}
+	}
+
+	parsedLabels := map[string]map[string]struct{}{}
+	for lbl, values := range parsed {
+		if vals, ok := parsedLabels[lbl]; ok {
+			for _, value := range values {
+				vals[value] = struct{}{}
+			}
+		} else {
+			parsedLabels[lbl] = map[string]struct{}{}
+			for _, value := range values {
+				parsedLabels[lbl][value] = struct{}{}
+			}
+		}
+	}
+
+	lblsResult := lbls.LabelsResult().Parsed()
+	for _, lbl := range lblsResult {
+		if values, ok := parsedLabels[lbl.Name]; ok {
+			values[lbl.Value] = struct{}{}
+		} else {
+			parsedLabels[lbl.Name] = map[string]struct{}{lbl.Value: {}}
+		}
+	}
+
+	result := make(map[string][]string, len(parsedLabels))
+	for lbl, values := range parsedLabels {
+		if lbl == logqlmodel.ErrorLabel || lbl == logqlmodel.ErrorDetailsLabel ||
+			lbl == logqlmodel.PreserveErrorLabel {
+			continue
+		}
+		vals := make([]string, 0, len(values))
+		for v := range values {
+			vals = append(vals, v)
+		}
+		result[lbl] = vals
+	}
+
+	return result, []string{parser}
+}
+
+func getParsedLabels(entry push.Entry) map[string][]string {
+	labels := map[string]map[string]struct{}{}
+	for _, lbl := range entry.Parsed {
+		if values, ok := labels[lbl.Name]; ok {
+			values[lbl.Value] = struct{}{}
+		} else {
+			labels[lbl.Name] = map[string]struct{}{lbl.Value: {}}
+		}
+	}
+
+	result := make(map[string][]string, len(labels))
+	for lbl, values := range labels {
+		vals := make([]string, 0, len(values))
+		for v := range values {
+			vals = append(vals, v)
+		}
+		result[lbl] = vals
+	}
+
+	return result
+}