refactor

WDL/runtime/cache.py

@@ -214,7 +214,7 @@ def put_download(
     ) -> str:
         """
         Move the downloaded file to the cache location & return the new path; or if the uri isn't
-        cacheable, return the given path.
+        cacheable, memoize the association and return the given path.
         """
         if directory:
             uri = uri.rstrip("/")
@@ -243,23 +243,35 @@ def put_download(
                     if directory and os.path.isdir(p):
                         rmtree_atomic(p)
                     os.renames(filename, p)
+                    self.flock(p)
                     # the renames() op should be atomic, because the download operation should have
                     # been run under the cache directory (download.py:run_cached)
                     logger.info(_("stored in download cache", uri=uri, cache_path=p))
                     ans = p
         if not p:
-            with self._lock:
-                (self._workflow_directory_downloads if directory else self._workflow_downloads)[
-                    uri
-                ] = ans
-        self.flock(ans)
+            self.memo_download(uri, filename, directory=directory)
         return ans
 
     def download_cacheable(self, uri: str, directory: bool = False) -> Optional[str]:
         if not self._cfg["download_cache"].get_bool("put"):
             return None
         return self.download_path(uri, directory=directory)
 
+    def memo_download(
+        self,
+        uri: str,
+        filename: str,
+        directory: bool = False,
+    ) -> None:
+        """
+        Memoize (for the lifetime of self) that filename is a local copy of uri; flock it as well.
+        """
+        with self._lock:
+            memo = self._workflow_directory_downloads if directory else self._workflow_downloads
+            if uri not in memo:
+                memo[uri] = filename
+                self.flock(filename)
+
     def flock(self, filename: str, exclusive: bool = False) -> None:
         self._flocker.flock(filename, update_atime=True, exclusive=exclusive)