regexp filter: use modified package with optimisations

See https://github.com/grafana/regexp/tree/speedup#readme

Includes the following changes proposed upstream:
* [regexp: allow patterns with no alternates to be one-pass](https://go-review.googlesource.com/c/go/+/353711)
* [regexp: speed up onepass prefix check](https://go-review.googlesource.com/c/go/+/354909)
* [regexp: handle prefix string with fold-case](https://go-review.googlesource.com/c/go/+/358756)
* [regexp: avoid copying each instruction executed](https://go-review.googlesource.com/c/go/+/355789)
* [regexp: allow prefix string anchored at beginning](https://go-review.googlesource.com/c/go/+/377294)

CHANGELOG.md

@@ -52,6 +52,7 @@
 * [5077](https://github.com/grafana/loki/pull/5077) **trevorwhitney**: Change some default values for better out-of-the-box performance
 * [5204](https://github.com/grafana/loki/pull/5204) **trevorwhitney**: Default `max_outstanding_per_tenant` to `2048`
 * [5253](https://github.com/grafana/loki/pull/5253) **Juneezee**: refactor: use `T.TempDir` to create temporary test directory
+* [5315](https://github.com/grafana/loki/pull/5315) **bboreham**: filters: use faster regexp package
 
 # 2.4.1 (2021/11/07)
 

go.mod

@@ -288,6 +288,7 @@ require (
 	github.com/cloudflare/cloudflare-go v0.27.0
 	github.com/gofrs/flock v0.7.1 // indirect
 	github.com/gogo/status v1.1.0
+	github.com/grafana/regexp v0.0.0-20220202152701-6a046c4caf32
 	github.com/oklog/ulid v1.3.1
 )
 

go.sum

@@ -1039,6 +1039,8 @@ github.com/grafana/go-gelf v0.0.0-20211112153804-126646b86de8 h1:aEOagXOTqtN9gd4
 github.com/grafana/go-gelf v0.0.0-20211112153804-126646b86de8/go.mod h1:QAvS2C7TtQRhhv9Uf/sxD+BUhpkrPFm5jK/9MzUiDCY=
 github.com/grafana/gocql v0.0.0-20200605141915-ba5dc39ece85 h1:xLuzPoOzdfNb/RF/IENCw+oLVdZB4G21VPhkHBgwSHY=
 github.com/grafana/gocql v0.0.0-20200605141915-ba5dc39ece85/go.mod h1:crI9WX6p0IhrqB+DqIUHulRW853PaNFf7o4UprV//3I=
+github.com/grafana/regexp v0.0.0-20220202152701-6a046c4caf32 h1:M3wP8Hwic62qJsiydSgXtev03d4f92uN1I52nVjRgw0=
+github.com/grafana/regexp v0.0.0-20220202152701-6a046c4caf32/go.mod h1:M5qHK+eWfAv8VR/265dIuEpL3fNfeC21tXXp9itM24A=
 github.com/grafana/tail v0.0.0-20201004203643-7aa4e4a91f03 h1:fGgFrAraMB0BaPfYumu+iulfDXwHm+GFyHA4xEtBqI8=
 github.com/grafana/tail v0.0.0-20201004203643-7aa4e4a91f03/go.mod h1:GIMXMPB/lRAllP5rVDvcGif87ryO2hgD7tCtHMdHrho=
 github.com/gregjones/httpcache v0.0.0-20180305231024-9cad4c3443a7/go.mod h1:FecbI9+v66THATjSRHfNgh1IVFe/9kFxbXtjV0ctIMA=

pkg/logql/log/filter.go

@@ -3,11 +3,12 @@ package log
 import (
 	"bytes"
 	"fmt"
-	"regexp"
-	"regexp/syntax"
 	"unicode"
 	"unicode/utf8"
 
+	"github.com/grafana/regexp"
+	"github.com/grafana/regexp/syntax"
+
 	"github.com/prometheus/prometheus/model/labels"
 )
 

pkg/logql/log/fmt.go

@@ -3,12 +3,12 @@ package log
 import (
 	"bytes"
 	"fmt"
-	"regexp"
 	"strings"
 	"text/template"
 	"text/template/parse"
 
 	"github.com/Masterminds/sprig/v3"
+	"github.com/grafana/regexp"
 
 	"github.com/grafana/loki/pkg/logqlmodel"
 )

pkg/logql/log/parser.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"regexp"
 	"strings"
 	"unicode/utf8"
 
@@ -14,6 +13,7 @@ import (
 	"github.com/grafana/loki/pkg/logql/log/pattern"
 	"github.com/grafana/loki/pkg/logqlmodel"
 
+	"github.com/grafana/regexp"
 	jsoniter "github.com/json-iterator/go"
 	"github.com/prometheus/common/model"
 )