K8s: Ensure there is always a user in appcontext.User (#78247)

pkg/infra/appcontext/user.go

@@ -4,6 +4,10 @@ import (
 	"context"
 	"fmt"
 
+	k8suser "k8s.io/apiserver/pkg/authentication/user"
+	"k8s.io/apiserver/pkg/endpoints/request"
+
+	"github.com/grafana/grafana/pkg/models/roletype"
 	"github.com/grafana/grafana/pkg/services/contexthandler/ctxkey"
 	contextmodel "github.com/grafana/grafana/pkg/services/contexthandler/model"
 	grpccontext "github.com/grafana/grafana/pkg/services/grpcserver/context"
@@ -38,6 +42,26 @@ func User(ctx context.Context) (*user.SignedInUser, error) {
 		return c.SignedInUser, nil
 	}
 
+	// Find the kubernetes user info
+	k8sUserInfo, ok := request.UserFrom(ctx)
+	if ok {
+		for _, group := range k8sUserInfo.GetGroups() {
+			switch group {
+			case k8suser.APIServerUser:
+				fallthrough
+			case k8suser.SystemPrivilegedGroup:
+				return &user.SignedInUser{
+					UserID:         1,
+					OrgID:          1,
+					Name:           k8sUserInfo.GetName(),
+					Login:          k8sUserInfo.GetName(),
+					OrgRole:        roletype.RoleAdmin,
+					IsGrafanaAdmin: true,
+				}, nil
+			}
+		}
+	}
+
 	return nil, fmt.Errorf("a SignedInUser was not found in the context")
 }