drop noop marker in favor of comma-ok

Signed-off-by: Siavash Safi <siavash@cloudflare.com>

Author: siavashs

api/v2/api.go

@@ -487,7 +487,7 @@ func (api *API) alertFilter(parent context.Context, matchers []*labels.Matcher,
 
 		// Set alert's current status based on its label set.
 		// The inhibitor and silencer write to m via the context.
-		ctx = marker.WithAlertMarker(ctx, m)
+		ctx = marker.WithContext(ctx, m)
 		api.setAlertStatus(ctx, a.Labels)
 
 		// Get alert's current status after seeing if it is suppressed.

dispatch/dispatch.go

@@ -687,7 +687,7 @@ func (ag *aggrGroup) run(nf notifyFunc) {
 			ctx = notify.WithRouteID(ctx, ag.routeID)
 			ctx = notify.WithFlushID(ctx, ag.flushIdx)
 			ctx = notify.WithGroupMatchers(ctx, ag.matchers)
-			ctx = marker.WithAlertMarker(ctx, ag.marker)
+			ctx = marker.WithContext(ctx, ag.marker)
 
 			ag.flushIdx++
 

inhibit/inhibit.go

@@ -193,7 +193,15 @@ func (ih *Inhibitor) Mutes(ctx context.Context, lset model.LabelSet) bool {
 	)
 	defer span.End()
 
-	m := marker.GetAlertMarker(ctx)
+	var inhibitedBy []string
+	defer func() {
+		// Get the marker from context and set the inhibited alerts on it if any.
+		m, ok := marker.FromContext(ctx)
+		if ok {
+			m.SetInhibited(fp, inhibitedBy)
+		}
+	}()
+
 	now := time.Now()
 	for _, r := range ih.rules {
 		if !r.TargetMatchers.Matches(lset) {
@@ -208,7 +216,7 @@ func (ih *Inhibitor) Mutes(ctx context.Context, lset model.LabelSet) bool {
 		// If we are here, the target side matches. If the source side matches, too, we
 		// need to exclude inhibiting alerts for which the same is true.
 		if inhibitedByFP, eq := r.hasEqual(lset, r.SourceMatchers.Matches(lset), now); eq {
-			m.SetInhibited(fp, []string{inhibitedByFP.String()})
+			inhibitedBy = append(inhibitedBy, inhibitedByFP.String())
 			span.AddEvent("alert inhibited",
 				trace.WithAttributes(
 					attribute.String("alerting.inhibit_rule.source.fingerprint", inhibitedByFP.String()),
@@ -223,7 +231,6 @@ func (ih *Inhibitor) Mutes(ctx context.Context, lset model.LabelSet) bool {
 			return true
 		}
 	}
-	m.SetInhibited(fp, nil)
 	span.AddEvent("alert not inhibited")
 
 	return false

inhibit/inhibit_test.go

@@ -39,7 +39,7 @@ var nopLogger = promslog.NewNopLogger()
 func checkMutes(t *testing.T, ih *Inhibitor, target model.LabelSet, wantMuted bool, msgAndArgs ...any) {
 	t.Helper()
 	m := marker.NewAlertMarker()
-	ctx := marker.WithAlertMarker(context.Background(), m)
+	ctx := marker.WithContext(context.Background(), m)
 	got := ih.Mutes(ctx, target)
 	require.Equal(t, wantMuted, got, msgAndArgs...)
 	fp := target.Fingerprint()

marker/alert_test.go

@@ -116,15 +116,15 @@ func TestAlertMarkerContext(t *testing.T) {
 	ctx := t.Context()
 
 	// No marker in context — should return no-op marker.
-	got := GetAlertMarker(ctx)
-	require.NotNil(t, got)
-	// No-op marker returns unknown for any fingerprint.
-	require.Equal(t, alert.AlertStateUnprocessed, got.Status(model.Fingerprint(1)).State)
+	got, ok := FromContext(ctx)
+	require.False(t, ok)
+	require.Nil(t, got)
 
 	// Set marker in context.
 	gm := NewAlertMarker()
-	ctx = WithAlertMarker(ctx, gm)
-	got = GetAlertMarker(ctx)
+	ctx = WithContext(ctx, gm)
+	got, ok = FromContext(ctx)
+	require.True(t, ok)
 	require.NotNil(t, got)
 
 	// Writing through the context-extracted marker should be visible.

marker/context.go

@@ -0,0 +1,40 @@
+// Copyright The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package marker
+
+import (
+	"context"
+)
+
+// markerKey defines a custom type with which a context is populated to
+// avoid accidental collisions.
+type markerKey int
+
+const (
+	keyAlertMarker markerKey = iota
+)
+
+// WithContext returns a copy of ctx carrying the given
+// AlertMarker. Inhibitor and Silencer extract it from the context to
+// write per-group alert status.
+func WithContext(ctx context.Context, m AlertMarker) context.Context {
+	return context.WithValue(ctx, keyAlertMarker, m)
+}
+
+// FromContext extracts the AlertMarker from the context if present,
+// otherwise returns a no-op marker.
+func FromContext(ctx context.Context) (AlertMarker, bool) {
+	m, ok := ctx.Value(keyAlertMarker).(AlertMarker)
+	return m, ok
+}

marker/util.go

@@ -108,7 +108,7 @@ func TestMuteStageWithSilences(t *testing.T) {
 
 	reg := prometheus.NewRegistry()
 	alertMarker := marker.NewAlertMarker()
-	ctx := marker.WithAlertMarker(context.Background(), alertMarker)
+	ctx := marker.WithContext(context.Background(), alertMarker)
 	silencer := silence.NewSilencer(silences, promslog.NewNopLogger(), eventrecorder.NopRecorder())
 	metrics := NewMetrics(reg, featurecontrol.NoopFlags{})
 	stage := NewMuteStage(silencer, metrics)

notify/mute_test.go

@@ -176,7 +176,10 @@ func (s *Silencer) Mutes(ctx context.Context, lset model.LabelSet) bool {
 	var markedSilences []string
 	defer func() {
 		// Get the marker from context and set the silences on it if any.
-		marker.GetAlertMarker(ctx).SetSilenced(fp, markedSilences)
+		m, ok := marker.FromContext(ctx)
+		if ok {
+			m.SetSilenced(fp, markedSilences)
+		}
 	}()
 
 	// Get the cached entry for this fingerprint.

silence/silence.go

@@ -2287,7 +2287,7 @@ func TestSilencer(t *testing.T) {
 	s := NewSilencer(ss, promslog.NewNopLogger(), eventrecorder.NopRecorder())
 
 	m := marker.NewAlertMarker()
-	ctx := marker.WithAlertMarker(t.Context(), m)
+	ctx := marker.WithContext(t.Context(), m)
 
 	require.False(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert not silenced without any silences")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, false, "expected marker not silenced without any silences")
@@ -2302,7 +2302,7 @@ func TestSilencer(t *testing.T) {
 	require.NoError(t, ss.Set(t.Context(), sil1))
 
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.False(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert not silenced by non-matching silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, false, "expected marker not silenced by non-matching silence")
 
@@ -2317,7 +2317,7 @@ func TestSilencer(t *testing.T) {
 	require.NotEmpty(t, sil2.Id)
 
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.True(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert silenced by matching silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, true, "expected marker silenced by matching silence")
 
@@ -2326,7 +2326,7 @@ func TestSilencer(t *testing.T) {
 	now = ss.nowUTC()
 
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.False(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert not silenced by expired silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, false, "expected marker not silenced by expired silence")
 
@@ -2342,7 +2342,7 @@ func TestSilencer(t *testing.T) {
 	require.NoError(t, err)
 
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.False(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert not silenced by future silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, false, "expected marker not silenced by future silence")
 
@@ -2352,7 +2352,7 @@ func TestSilencer(t *testing.T) {
 
 	// Exposes issue #2426.
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.True(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert silenced by activated silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, true, "expected marker silenced by activated silence")
 
@@ -2367,7 +2367,7 @@ func TestSilencer(t *testing.T) {
 
 	// Note that issue #2426 doesn't apply anymore because we added a new silence.
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.True(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert still silenced by activated silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, true, "expected marker still silenced by activated silence")
 
@@ -2376,7 +2376,7 @@ func TestSilencer(t *testing.T) {
 
 	// Another variant of issue #2426 (overlapping silences).
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.True(t, s.Mutes(ctx, model.LabelSet{"foo": "bar"}), "expected alert silenced by activated second silence")
 	checkMutes(t, m, model.LabelSet{"foo": "bar"}, true, "expected marker silenced by activated second silence")
 }
@@ -2406,7 +2406,7 @@ func TestSilencerPostDeleteEvictsCache(t *testing.T) {
 
 	// Mutes populates the cache.
 	m := marker.NewAlertMarker()
-	ctx := marker.WithAlertMarker(t.Context(), m)
+	ctx := marker.WithContext(t.Context(), m)
 	require.True(t, s.Mutes(ctx, lset))
 	checkMutes(t, m, lset, true, "expected marker silenced after initial Mutes")
 	entry := s.cache.get(fp)
@@ -2420,7 +2420,7 @@ func TestSilencerPostDeleteEvictsCache(t *testing.T) {
 
 	// Mutes re-evaluates from scratch (cache miss) and still finds the silence.
 	m = marker.NewAlertMarker()
-	ctx = marker.WithAlertMarker(t.Context(), m)
+	ctx = marker.WithContext(t.Context(), m)
 	require.True(t, s.Mutes(ctx, lset), "expected alert still silenced after cache eviction")
 	checkMutes(t, m, lset, true, "expected marker silenced after cache eviction")
 	entry = s.cache.get(fp)