Rendering: Fix user information when using render key (#50879) (#51920)

* Rendering: Fix user information when using render key

* fix when render user ID is 0

* update fix

* improve fix

* add comment

(cherry picked from commit ca80865bf1)

Co-authored-by: Agnès Toulet <35176601+AgnesToulet@users.noreply.github.com>

pkg/services/contexthandler/contexthandler.go

@@ -445,7 +445,7 @@ func (h *ContextHandler) initContextWithRenderAuth(reqContext *models.ReqContext
 		return false
 	}
 
-	_, span := h.tracer.Start(reqContext.Req.Context(), "initContextWithRenderAuth")
+	ctx, span := h.tracer.Start(reqContext.Req.Context(), "initContextWithRenderAuth")
 	defer span.End()
 
 	renderUser, exists := h.RenderService.GetRenderUser(reqContext.Req.Context(), key)
@@ -454,12 +454,21 @@ func (h *ContextHandler) initContextWithRenderAuth(reqContext *models.ReqContext
 		return true
 	}
 
-	reqContext.IsSignedIn = true
 	reqContext.SignedInUser = &models.SignedInUser{
 		OrgId:   renderUser.OrgID,
 		UserId:  renderUser.UserID,
 		OrgRole: models.RoleType(renderUser.OrgRole),
 	}
+
+	// UserID can be 0 for background tasks and, in this case, there is no user info to retrieve
+	if renderUser.UserID != 0 {
+		query := models.GetSignedInUserQuery{UserId: renderUser.UserID, OrgId: renderUser.OrgID}
+		if err := h.SQLStore.GetSignedInUserWithCacheCtx(ctx, &query); err == nil {
+			reqContext.SignedInUser = query.Result
+		}
+	}
+
+	reqContext.IsSignedIn = true
 	reqContext.IsRenderCall = true
 	reqContext.LastSeenAt = time.Now()
 	return true