feat(ruler): add labels support to rule groups

pkg/ruler/base/manager.go

@@ -301,6 +301,16 @@ func (*DefaultMultiTenantManager) ValidateRuleGroup(g rulefmt.RuleGroup) []error
 		return errs
 	}
 
+	for k, v := range g.Labels {
+		if !model.LabelName(k).IsValid() || k == model.MetricNameLabel {
+			errs = append(errs, errors.Errorf("invalid label name: %s", k))
+		}
+
+		if !model.LabelValue(v).IsValid() {
+			errs = append(errs, errors.Errorf("invalid label value: %s", v))
+		}
+	}
+
 	for i, r := range g.Rules {
 		ruleNode := rulefmt.RuleNode{
 			Record: yaml.Node{Value: r.Record},

pkg/ruler/compat.go

@@ -233,6 +233,16 @@ func ValidateGroups(grps ...rulefmt.RuleGroup) (errs []error) {
 			)
 		}
 
+		for k, v := range g.Labels {
+			if !model.LabelName(k).IsValid() || k == model.MetricNameLabel {
+				errs = append(errs, errors.Errorf("invalid label name: %s", k))
+			}
+
+			if !model.LabelValue(v).IsValid() {
+				errs = append(errs, errors.Errorf("invalid label value: %s", v))
+			}
+		}
+
 		set[g.Name] = struct{}{}
 
 		for _, r := range g.Rules {

pkg/ruler/rulespb/compat.go

@@ -19,6 +19,7 @@ func ToProto(user string, namespace string, rl rulefmt.RuleGroup) *RuleGroupDesc
 		Rules:     formattedRuleToProto(rl.Rules),
 		User:      user,
 		Limit:     int64(rl.Limit),
+		Labels:    logproto.FromLabelsToLabelAdapters(labels.FromMap(rl.Labels)),
 	}
 	return &rg
 }
@@ -46,6 +47,7 @@ func FromProto(rg *RuleGroupDesc) rulefmt.RuleGroup {
 		Interval: model.Duration(rg.Interval),
 		Rules:    make([]rulefmt.Rule, len(rg.GetRules())),
 		Limit:    int(rg.GetLimit()),
+		Labels:   logproto.FromLabelAdaptersToLabels(rg.Labels).Map(),
 	}
 
 	for i, rl := range rg.GetRules() {

pkg/ruler/rulespb/compat_test.go

@@ -0,0 +1,35 @@
+package rulespb
+
+import (
+	"testing"
+
+	"github.com/prometheus/prometheus/model/rulefmt"
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/loki/v3/pkg/logproto"
+)
+
+func TestRuleGroupRoundTripIncludesGroupLabels(t *testing.T) {
+	group := rulefmt.RuleGroup{
+		Name: "group",
+		Labels: map[string]string{
+			"foo":    "bar",
+			"shared": "group",
+		},
+		Rules: []rulefmt.Rule{{
+			Alert: "AlertName",
+			Expr:  "vector(1)",
+			Labels: map[string]string{
+				"shared": "rule",
+			},
+		}},
+	}
+
+	proto := ToProto("user", "namespace", group)
+	require.Equal(t, group.Labels, logproto.FromLabelAdaptersToLabels(proto.Labels).Map())
+	require.Equal(t, group.Rules[0].Labels, logproto.FromLabelAdaptersToLabels(proto.Rules[0].Labels).Map())
+
+	roundTrip := FromProto(proto)
+	require.Equal(t, group.Labels, roundTrip.Labels)
+	require.Equal(t, group.Rules[0].Labels, roundTrip.Rules[0].Labels)
+}