Cherry-pick bugfix prometheus#12322 and create v2.43.1+stringlabels

* labels: respect Set after Del in Builder (prometheus#12322)

The implementations are not symmetric between `Set()` and `Del()`, so
we must be careful. Add tests for this, both in labels and in relabel
where the issue was reported.

Also make the slice implementation consistent re `slices.Contains`.

* Create v2.43.1 with bugfix

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Co-authored-by: Julius Volz <julius.volz@gmail.com>
Signed-off-by: Julien Pivotto <roidelapluie@o11y.eu>

CHANGELOG.md

@@ -1,5 +1,21 @@
 # Changelog
 
+## 2.43.1+stringlabels / 2023-05-04
+
+Special release build that incorporates performance improvements using
+the stringlabels Go tag. This release aims to provide a more efficient and
+faster solution for users managing large-scale deployments or facing performance
+issues with the default Prometheus binaries.
+
+The new labels data structure replaces the existing label/value storage with a
+single string, reducing heap size and improving performance in most cases. It
+enables Prometheus to use fewer system resources, particularly in
+memory-intensive environments.
+
+## 2.43.1 / 2023-05-03
+
+* [BUGFIX] Labels: `Set()` after `Del()` would be ignored, which broke some relabeling rules. #12322
+
 ## 2.43.0+stringlabels / 2023-03-21
 
 Special release build that incorporates performance improvements using

VERSION

@@ -1 +1 @@
-2.43.0+stringlabels
+2.43.1+stringlabels

model/labels/labels.go

@@ -531,16 +531,15 @@ func (b *Builder) Set(n, v string) *Builder {
 }
 
 func (b *Builder) Get(n string) string {
-	for _, d := range b.del {
-		if d == n {
-			return ""
-		}
-	}
+	// Del() removes entries from .add but Set() does not remove from .del, so check .add first.
 	for _, a := range b.add {
 		if a.Name == n {
 			return a.Value
 		}
 	}
+	if slices.Contains(b.del, n) {
+		return ""
+	}
 	return b.base.Get(n)
 }
 

model/labels/labels_string.go

@@ -587,14 +587,15 @@ func (b *Builder) Set(n, v string) *Builder {
 }
 
 func (b *Builder) Get(n string) string {
-	if slices.Contains(b.del, n) {
-		return ""
-	}
+	// Del() removes entries from .add but Set() does not remove from .del, so check .add first.
 	for _, a := range b.add {
 		if a.Name == n {
 			return a.Value
 		}
 	}
+	if slices.Contains(b.del, n) {
+		return ""
+	}
 	return b.base.Get(n)
 }
 

model/labels/labels_test.go

@@ -607,6 +607,13 @@ func TestBuilder(t *testing.T) {
 			require.Equal(t, tcase.want.BytesWithoutLabels(nil, "aaa", "bbb"), b.Labels(tcase.base).Bytes(nil))
 		})
 	}
+	t.Run("set_after_del", func(t *testing.T) {
+		b := NewBuilder(FromStrings("aaa", "111"))
+		b.Del("bbb")
+		b.Set("bbb", "222")
+		require.Equal(t, FromStrings("aaa", "111", "bbb", "222"), b.Labels(EmptyLabels()))
+		require.Equal(t, "222", b.Get("bbb"))
+	})
 }
 
 func TestScratchBuilder(t *testing.T) {

model/relabel/relabel_test.go

@@ -397,6 +397,34 @@ func TestRelabel(t *testing.T) {
 				"foo":              "bar",
 			}),
 		},
+		{ // From https://github.com/prometheus/prometheus/issues/12283
+			input: labels.FromMap(map[string]string{
+				"__meta_kubernetes_pod_container_port_name":         "foo",
+				"__meta_kubernetes_pod_annotation_XXX_metrics_port": "9091",
+			}),
+			relabel: []*Config{
+				{
+					Regex:  MustNewRegexp("^__meta_kubernetes_pod_container_port_name$"),
+					Action: LabelDrop,
+				},
+				{
+					SourceLabels: model.LabelNames{"__meta_kubernetes_pod_annotation_XXX_metrics_port"},
+					Regex:        MustNewRegexp("(.+)"),
+					Action:       Replace,
+					Replacement:  "metrics",
+					TargetLabel:  "__meta_kubernetes_pod_container_port_name",
+				},
+				{
+					SourceLabels: model.LabelNames{"__meta_kubernetes_pod_container_port_name"},
+					Regex:        MustNewRegexp("^metrics$"),
+					Action:       Keep,
+				},
+			},
+			output: labels.FromMap(map[string]string{
+				"__meta_kubernetes_pod_annotation_XXX_metrics_port": "9091",
+				"__meta_kubernetes_pod_container_port_name":         "metrics",
+			}),
+		},
 		{
 			input: labels.FromMap(map[string]string{
 				"a":  "foo",

web/ui/module/codemirror-promql/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@prometheus-io/codemirror-promql",
-  "version": "0.43.0",
+  "version": "0.43.1",
   "description": "a CodeMirror mode for the PromQL language",
   "types": "dist/esm/index.d.ts",
   "module": "dist/esm/index.js",
@@ -29,7 +29,7 @@
   },
   "homepage": "https://github.com/prometheus/prometheus/blob/main/web/ui/module/codemirror-promql/README.md",
   "dependencies": {
-    "@prometheus-io/lezer-promql": "0.43.0",
+    "@prometheus-io/lezer-promql": "0.43.1",
     "lru-cache": "^6.0.0"
   },
   "devDependencies": {

web/ui/module/lezer-promql/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@prometheus-io/lezer-promql",
-  "version": "0.43.0",
+  "version": "0.43.1",
   "description": "lezer-based PromQL grammar",
   "main": "dist/index.cjs",
   "type": "module",

web/ui/react-app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@prometheus-io/app",
-  "version": "0.43.0",
+  "version": "0.43.1",
   "private": true,
   "dependencies": {
     "@codemirror/autocomplete": "^6.4.0",
@@ -19,7 +19,7 @@
     "@lezer/common": "^1.0.2",
     "@nexucis/fuzzy": "^0.4.1",
     "@nexucis/kvsearch": "^0.8.1",
-    "@prometheus-io/codemirror-promql": "0.43.0",
+    "@prometheus-io/codemirror-promql": "0.43.1",
     "bootstrap": "^4.6.2",
     "css.escape": "^1.5.1",
     "downshift": "^7.2.0",