Reuse cluster_conf in backup_restore_on_cluster

Author: Felixoid

tests/integration/test_backup_restore_on_cluster/concurrency_helper.py

@@ -1,32 +1,39 @@
 from pathlib import Path
-from typing import Callable, List
+from typing import List
 
 from helpers.cluster import ClickHouseCluster, ClickHouseInstance
 
 
 def generate_cluster_def(file: str, num_nodes: int) -> str:
+    # For multiple workers, it has race and sometimes errors out,
+    # so we generate it once and reuse
     path = (
         Path(__file__).parent / f"_gen/cluster_{Path(file).stem}_{num_nodes}_nodes.xml"
     )
-    path.parent.mkdir(parents=True, exist_ok=True)
     replicas = "\n".join(
         f"""                <replica>
                     <host>node{i}</host>
                     <port>9000</port>
                 </replica>"""
         for i in range(num_nodes)
     )
-    path.write_text(
-        encoding="utf-8",
-        data=f"""<clickhouse>
+    config = f"""<clickhouse>
     <remote_servers>
         <cluster>
             <shard>
 {replicas}
             </shard>
         </cluster>
     </remote_servers>
-</clickhouse>""",
+</clickhouse>"""
+    if path.is_file():
+        existing = path.read_text(encoding="utf-8")
+        if existing == config:
+            return str(path.absolute())
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(
+        encoding="utf-8",
+        data=config,
     )
     return str(path.absolute())