From 2dc48c0b98bbd092f4d1198533d91e627e99b2ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?G=C3=A1bor=20Farkas?= <gabor.farkas@gmail.com>
Date: Mon, 10 Nov 2025 15:48:59 +0100
Subject: [PATCH] datasources: querier: add mode-info (#113592)

* datasources: querier: add mode-info

* fixed unit test
---
 pkg/registry/apis/query/client/instance_provider.go | 4 ++++
 pkg/registry/apis/query/clientapi/clientapi.go      | 1 +
 pkg/registry/apis/query/query.go                    | 2 ++
 pkg/registry/apis/query/query_test.go               | 4 ++++
 4 files changed, 11 insertions(+)

diff --git a/pkg/registry/apis/query/client/instance_provider.go b/pkg/registry/apis/query/client/instance_provider.go
index e48e2e9a084..9a8e6138b65 100644
--- a/pkg/registry/apis/query/client/instance_provider.go
+++ b/pkg/registry/apis/query/client/instance_provider.go
@@ -52,6 +52,10 @@ func (s *singleTenantInstanceProvider) GetInstance(_ context.Context, logger log
 	}, nil
 }
 
+func (s *singleTenantInstanceProvider) GetMode() string {
+	return "st"
+}
+
 func (s *singleTenantInstance) GetSettings() clientapi.InstanceConfigurationSettings {
 	return s.instanceConf
 }
diff --git a/pkg/registry/apis/query/clientapi/clientapi.go b/pkg/registry/apis/query/clientapi/clientapi.go
index 5d44045f77f..0248ebab8ac 100644
--- a/pkg/registry/apis/query/clientapi/clientapi.go
+++ b/pkg/registry/apis/query/clientapi/clientapi.go
@@ -39,4 +39,5 @@ type Instance interface {
 
 type InstanceProvider interface {
 	GetInstance(ctx context.Context, logger log.Logger, headers map[string]string) (Instance, error)
+	GetMode() string
 }
diff --git a/pkg/registry/apis/query/query.go b/pkg/registry/apis/query/query.go
index 30a1ae6b567..987251bcdb0 100644
--- a/pkg/registry/apis/query/query.go
+++ b/pkg/registry/apis/query/query.go
@@ -122,6 +122,8 @@ func (r *queryREST) Connect(connectCtx context.Context, name string, _ runtime.O
 	b := r.builder
 
 	return http.HandlerFunc(func(w http.ResponseWriter, httpreq *http.Request) {
+		w.Header().Set("X-Ds-Querier", b.instanceProvider.GetMode())
+
 		ctx, span := b.tracer.Start(httpreq.Context(), "QueryService.Query")
 		defer span.End()
 		ctx = request.WithNamespace(ctx, request.NamespaceValue(connectCtx))
diff --git a/pkg/registry/apis/query/query_test.go b/pkg/registry/apis/query/query_test.go
index 53ee003882b..b23c78d55bc 100644
--- a/pkg/registry/apis/query/query_test.go
+++ b/pkg/registry/apis/query/query_test.go
@@ -274,6 +274,10 @@ func (m mockClient) GetInstance(ctx context.Context, logger log.Logger, headers
 	return mclient, nil
 }
 
+func (m mockClient) GetMode() string {
+	return "testing"
+}
+
 func (m mockClient) ReportMetrics() {
 }