Revert "Early Request Validation in Query Frontend (#10093)"

This reverts commit 3251e86.

CHANGELOG.md

@@ -78,7 +78,6 @@
 * [ENHANCEMENT] Distributor: allow a different limit for info series (series ending in `_info`) label count, via `-validation.max-label-names-per-info-series`. #10028
 * [ENHANCEMENT] Ingester: do not reuse labels, samples and histograms slices in the write request if there are more entries than 10x the pre-allocated size. This should help to reduce the in-use memory in case of few requests with a very large number of labels, samples or histograms. #10040
 * [ENHANCEMENT] Query-Frontend: prune `<subquery> and on() (vector(x)==y)` style queries and stop pruning `<subquery> < -Inf`. Triggered by https://github.com/prometheus/prometheus/pull/15245. #10026
-* [ENHANCEMENT] Query-Frontend: perform request format validation before processing the request. #10093
 * [BUGFIX] Fix issue where functions such as `rate()` over native histograms could return incorrect values if a float stale marker was present in the selected range. #9508
 * [BUGFIX] Fix issue where negation of native histograms (eg. `-some_native_histogram_series`) did nothing. #9508
 * [BUGFIX] Fix issue where `metric might not be a counter, name does not end in _total/_sum/_count/_bucket` annotation would be emitted even if `rate` or `increase` did not have enough samples to compute a result. #9508

pkg/frontend/querymiddleware/codec.go

@@ -8,7 +8,6 @@ package querymiddleware
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -33,7 +32,6 @@ import (
 	"golang.org/x/exp/slices"
 
 	apierror "github.com/grafana/mimir/pkg/api/error"
-	"github.com/grafana/mimir/pkg/cardinality"
 	"github.com/grafana/mimir/pkg/mimirpb"
 	"github.com/grafana/mimir/pkg/querier/api"
 	"github.com/grafana/mimir/pkg/querier/stats"
@@ -584,39 +582,6 @@ func DecodeLabelsSeriesQueryTimeParams(reqValues *url.Values) (start, end int64,
 	return start, end, err
 }
 
-// DecodeCardinalityQueryParams strictly handles validation for cardinality API endpoint parameters.
-// The current decoding of the cardinality requests is handled in the cardinality package
-// which is not yet compatible with the codec's approach of using interfaces
-// and multiple concrete proto implementations to represent different query types.
-func DecodeCardinalityQueryParams(r *http.Request) (any, error) {
-	var err error
-
-	reqValues, err := util.ParseRequestFormWithoutConsumingBody(r)
-	if err != nil {
-		return nil, apierror.New(apierror.TypeBadData, err.Error())
-	}
-
-	var parsedReq any
-	switch {
-	case strings.HasSuffix(r.URL.Path, cardinalityLabelNamesPathSuffix):
-		parsedReq, err = cardinality.DecodeLabelNamesRequestFromValues(reqValues)
-
-	case strings.HasSuffix(r.URL.Path, cardinalityLabelValuesPathSuffix):
-		parsedReq, err = cardinality.DecodeLabelValuesRequestFromValues(reqValues)
-
-	case strings.HasSuffix(r.URL.Path, cardinalityActiveSeriesPathSuffix):
-		parsedReq, err = cardinality.DecodeActiveSeriesRequestFromValues(reqValues)
-
-	default:
-		return nil, errors.New("unknown cardinality API endpoint")
-	}
-
-	if err != nil {
-		return nil, apierror.New(apierror.TypeBadData, err.Error())
-	}
-	return parsedReq, nil
-}
-
 func decodeQueryMinMaxTime(queryExpr parser.Expr, start, end, step int64, lookbackDelta time.Duration) (minTime, maxTime int64) {
 	evalStmt := &parser.EvalStmt{
 		Expr:          queryExpr,