add featuregate for mtime configuration

pkg/stanza/fileconsumer/matcher/matcher.go

@@ -10,6 +10,14 @@ import (
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/fileconsumer/matcher/internal/filter"
 	"github.com/open-telemetry/opentelemetry-collector-contrib/pkg/stanza/fileconsumer/matcher/internal/finder"
+	"go.opentelemetry.io/collector/featuregate"
+)
+
+var allowOrderByMtime = featuregate.GlobalRegistry().MustRegister(
+	"filelog.allowOrderByMtime",
+	featuregate.StageAlpha,
+	featuregate.WithRegisterDescription("When enabled, allows usage of `ordering_criteria.mode` = `mtime`."),
+	featuregate.WithRegisterReferenceURL("https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/27812"),
 )
 
 const (
@@ -65,6 +73,10 @@ func New(c Criteria) (*Matcher, error) {
 	var f filter.Filter
 	switch c.OrderingCriteria.Method {
 	case methodMtime:
+		if !allowOrderByMtime.IsEnabled() {
+			return nil, fmt.Errorf("feature gate %q must be enabled to use mtime method", allowOrderByMtime.ID())
+		}
+
 		f = filter.NewMTimeFilter()
 	case methodRegex, "": // If no method is specified, defaults to regex
 		// regex type with no SortBy indicates no-op

pkg/stanza/fileconsumer/matcher/matcher_test.go

@@ -10,13 +10,15 @@ import (
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/collector/featuregate"
 )
 
 func TestNew(t *testing.T) {
 	cases := []struct {
-		name        string
-		criteria    Criteria
-		expectedErr string
+		name                    string
+		criteria                Criteria
+		expectedErr             string
+		disableMTimeFeaturegate bool
 	}{
 		{
 			name: "IncludeEmpty",
@@ -188,6 +190,17 @@ func TestNew(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "SortByMtimeDisabled",
+			criteria: Criteria{
+				Include: []string{"*.log"},
+				OrderingCriteria: OrderingCriteria{
+					Method: methodMtime,
+				},
+			},
+			disableMTimeFeaturegate: true,
+			expectedErr:             `feature gate "filelog.allowOrderByMtime" must be enabled to use mtime method`,
+		},
 		{
 			name: "InvalidMethod",
 			criteria: Criteria{
@@ -201,6 +214,10 @@ func TestNew(t *testing.T) {
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
+			if !tc.disableMTimeFeaturegate {
+				enableSortByMTimeFeature(t)
+			}
+
 			matcher, err := New(tc.criteria)
 			if tc.expectedErr != "" {
 				assert.EqualError(t, err, tc.expectedErr)
@@ -701,6 +718,7 @@ func TestMatcher(t *testing.T) {
 
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
+			enableSortByMTimeFeature(t)
 			cwd, err := os.Getwd()
 			require.NoError(t, err)
 			require.NoError(t, os.Chdir(t.TempDir()))
@@ -733,3 +751,12 @@ func TestMatcher(t *testing.T) {
 		})
 	}
 }
+
+func enableSortByMTimeFeature(t *testing.T) {
+	if !allowOrderByMtime.IsEnabled() {
+		require.NoError(t, featuregate.GlobalRegistry().Set(allowOrderByMtime.ID(), true))
+		t.Cleanup(func() {
+			require.NoError(t, featuregate.GlobalRegistry().Set(allowOrderByMtime.ID(), false))
+		})
+	}
+}