Append to server.labels instead of overwriting; remove engine-role-label

Signed-off-by: JaySon-Huang <[email protected]>

Author: JaySon-Huang

contrib/tiflash-proxy

@@ -243,19 +243,22 @@ struct TiFlashProxyConfig
                 args_map["advertise-engine-addr"] = args_map["engine-addr"];
             args_map["engine-label"] = getProxyLabelByDisaggregatedMode(disaggregated_mode);
             // For tiflash write node, it should report a extra label with "key" == "engine-role-label"
+            String extra_label;
             if (disaggregated_mode == DisaggregatedMode::Storage)
-                args_map["engine-role-label"] = DISAGGREGATED_MODE_WRITE_ENGINE_ROLE;
+            {
+                extra_label = fmt::format("engine-role={}", DISAGGREGATED_MODE_WRITE_ENGINE_ROLE);
+            }
             else if (disaggregated_mode == DisaggregatedMode::Compute)
             {
                 // For compute node, explicitly add a label with `exclusive=no-data` to avoid Region
                 // being placed to the compute node.
                 // Related logic in pd-server:
                 // https://github.com/tikv/pd/blob/v8.5.0/pkg/schedule/placement/label_constraint.go#L69-L95
-                String new_labels = "exclusive=no-data";
-                if (args_map.contains("labels"))
-                    new_labels = fmt::format("{},{}", args_map["labels"], new_labels);
-                args_map["labels"] = new_labels;
+                extra_label = "exclusive=no-data";
             }
+            if (args_map.contains("labels"))
+                extra_label = fmt::format("{},{}", args_map["labels"], extra_label);
+            args_map["labels"] = extra_label;
 
 #if SERVERLESS_PROXY == 1
             if (config.has("blacklist_file"))