Limit the default time window for label name and label value APIs

Signed-off-by: Kemal Akkoyun <kakkoyun@gmail.com>

CHANGELOG.md

@@ -13,7 +13,8 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 
 ### Added
 
-- [#3133](https://github.com/thanos-io/thanos/pull/3133) Query: Allow passing a `storeMatch[]` to Labels APIs. Also time range metadata based store filtering is supported on Labels APIs.
+- [#3133](https://github.com/thanos-io/thanos/pull/3133) Querier: Allow passing a `storeMatch[]` to Labels APIs. Also time range metadata based store filtering is supported on Labels APIs.
+- [#3147](https://github.com/thanos-io/thanos/pull/3147) Querier: Add `query.labels.lookback-delta` flag to specify the default lookback duration for retrieving labels through Labels APIs when time range parameters are not specified.
 
 ### Changed
 

cmd/thanos/query.go

@@ -23,6 +23,7 @@ import (
 	"github.com/prometheus/prometheus/discovery/targetgroup"
 	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/promql"
+
 	"github.com/thanos-io/thanos/pkg/extkingpin"
 
 	v1 "github.com/thanos-io/thanos/pkg/api/query"
@@ -80,6 +81,8 @@ func registerQuery(app *extkingpin.App) {
 
 	instantDefaultMaxSourceResolution := modelDuration(cmd.Flag("query.instant.default.max_source_resolution", "default value for max_source_resolution for instant queries. If not set, defaults to 0s only taking raw resolution into account. 1h can be a good value if you use instant queries over time ranges that incorporate times outside of your raw-retention.").Default("0s").Hidden())
 
+	defaultLabelLookbackDelta := cmd.Flag("query.labels.lookback-delta", "The default lookback duration for retrieving labels through Labels API when the range parameters are not specified.").Default("2h").Duration()
+
 	selectorLabels := cmd.Flag("selector-label", "Query selector labels that will be exposed in info endpoint (repeated).").
 		PlaceHolder("<name>=\"<value>\"").Strings()
 
@@ -192,6 +195,7 @@ func registerQuery(app *extkingpin.App) {
 			*dnsSDResolver,
 			time.Duration(*unhealthyStoreTimeout),
 			time.Duration(*instantDefaultMaxSourceResolution),
+			time.Duration(*defaultLabelLookbackDelta),
 			*strictStores,
 			component.Query,
 		)
@@ -240,6 +244,7 @@ func runQuery(
 	dnsSDResolver string,
 	unhealthyStoreTimeout time.Duration,
 	instantDefaultMaxSourceResolution time.Duration,
+	defaultLabelLookbackDelta time.Duration,
 	strictStores []string,
 	comp component.Component,
 ) error {
@@ -436,6 +441,7 @@ func runQuery(
 			queryReplicaLabels,
 			flagsMap,
 			instantDefaultMaxSourceResolution,
+			defaultLabelLookbackDelta,
 			maxConcurrentQueries,
 		)
 

docs/components/query.md

@@ -389,6 +389,10 @@ Flags:
                                  able to query without deduplication using
                                  'dedup=false' parameter. Data includes time
                                  series, recording rules, and alerting rules.
+      --query.labels.lookback-delta=2h
+                                 The default lookback duration for retrieving
+                                 labels through Labels API when the range
+                                 parameters are not specified.
       --selector-label=<name>="<value>" ...
                                  Query selector labels that will be exposed in
                                  info endpoint (repeated).

pkg/api/query/v1.go

@@ -73,10 +73,12 @@ type QueryAPI struct {
 	enableAutodownsampling     bool
 	enableQueryPartialResponse bool
 	enableRulePartialResponse  bool
-	replicaLabels              []string
 
-	storeSet                               *query.StoreSet
+	replicaLabels []string
+	storeSet      *query.StoreSet
+
 	defaultInstantQueryMaxSourceResolution time.Duration
+	defaultLabelLookbackDelta              time.Duration
 }
 
 // NewQueryAPI returns an initialized QueryAPI type.
@@ -93,6 +95,7 @@ func NewQueryAPI(
 	replicaLabels []string,
 	flagsMap map[string]string,
 	defaultInstantQueryMaxSourceResolution time.Duration,
+	defaultLabelLookbackDelta time.Duration,
 	maxConcurrentQueries int,
 ) *QueryAPI {
 	return &QueryAPI{
@@ -110,6 +113,7 @@ func NewQueryAPI(
 		replicaLabels:                          replicaLabels,
 		storeSet:                               storeSet,
 		defaultInstantQueryMaxSourceResolution: defaultInstantQueryMaxSourceResolution,
+		defaultLabelLookbackDelta:              defaultLabelLookbackDelta,
 	}
 }
 
@@ -423,11 +427,13 @@ func (qapi *QueryAPI) labelValues(r *http.Request) (interface{}, []error, *api.A
 		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: errors.Errorf("invalid label name: %q", name)}
 	}
 
-	start, err := parseTimeParam(r, "start", minTime)
+	// If start and end time not specified, we get the last 2h window by default.
+	now := time.Now()
+	start, err := parseTimeParam(r, "start", now.Add(-qapi.defaultLabelLookbackDelta))
 	if err != nil {
 		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
 	}
-	end, err := parseTimeParam(r, "end", maxTime)
+	end, err := parseTimeParam(r, "end", now)
 	if err != nil {
 		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
 	}
@@ -589,11 +595,13 @@ func parseDuration(s string) (time.Duration, error) {
 func (qapi *QueryAPI) labelNames(r *http.Request) (interface{}, []error, *api.ApiError) {
 	ctx := r.Context()
 
-	start, err := parseTimeParam(r, "start", minTime)
+	// If start and end time not specified, we get the last 2h window by default.
+	now := time.Now()
+	start, err := parseTimeParam(r, "start", now.Add(-qapi.defaultLabelLookbackDelta))
 	if err != nil {
 		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
 	}
-	end, err := parseTimeParam(r, "end", maxTime)
+	end, err := parseTimeParam(r, "end", now)
 	if err != nil {
 		return nil, nil, &api.ApiError{Typ: api.ErrorBadData, Err: err}
 	}