Refactoring use_cache attribute on Worker classes

Closes #66 (closed)

arkindex_worker/worker/base.py

@@ -18,7 +18,12 @@ from tenacity import (
 
 from arkindex import ArkindexClient, options_from_env
 from arkindex_worker import logger
-from arkindex_worker.cache import create_tables, init_cache_db, merge_parents_cache
+from arkindex_worker.cache import (
+    create_tables,
+    init_cache_db,
+    merge_parents_cache,
+    retrieve_parents_cache_path,
+)
 
 
 def _is_500_error(exc):
@@ -137,12 +142,17 @@ class BaseWorker(object):
         self.secrets = {name: self.load_secret(name) for name in required_secrets}
 
         task_id = os.environ.get("PONOS_TASK")
-        task = None
+        paths = None
         if self.support_cache and self.args.database is not None:
             self.use_cache = True
         elif self.support_cache and task_id:
             task = self.request("RetrieveTaskFromAgent", id=task_id)
-            self.use_cache = len(task["parents"]) > 0
+            paths = retrieve_parents_cache_path(
+                task["parents"],
+                data_dir=os.environ.get("PONOS_DATA", "/data"),
+                chunk=os.environ.get("ARKINDEX_TASK_CHUNK"),
+            )
+            self.use_cache = len(paths) > 0
 
         if self.use_cache:
             if self.args.database is not None:
@@ -161,13 +171,8 @@ class BaseWorker(object):
             logger.debug("Cache is disabled")
 
         # Merging parents caches (if there are any) in the current task local cache, unless the database got overridden
-        if self.use_cache and self.args.database is None and task:
-            merge_parents_cache(
-                task["parents"],
-                self.cache_path,
-                data_dir=os.environ.get("PONOS_DATA", "/data"),
-                chunk=os.environ.get("ARKINDEX_TASK_CHUNK"),
-            )
+        if self.use_cache and self.args.database is None and paths is not None:
+            merge_parents_cache(paths, self.cache_path)
 
     def load_secret(self, name):
         """Load all secrets described in the worker configuration"""