Resume shards from first unmirrored file

mirror_worker.py

@@ -143,7 +143,24 @@ def main() -> None:
         if number % WORKER_COUNT == WORKER_INDEX
         and (item.get("Type") or item.get("type")) != "tree"
     ]
-    print(f"worker {WORKER_INDEX}/{WORKER_COUNT}: {len(selected)} files")
+    # Each shard is processed in deterministic manifest order.  Resume at its
+    # first absent path instead of walking tens of thousands of committed files
+    # after every hourly job restart.
+    shard_total = len(selected)
+    resume_at = next(
+        (
+            index
+            for index, item in enumerate(selected)
+            if (item.get("Path") or item.get("path") or item.get("Name")) not in uploaded
+        ),
+        len(selected),
+    )
+    print(
+        f"worker {WORKER_INDEX}/{WORKER_COUNT}: "
+        f"{resume_at}/{shard_total} complete; {shard_total - resume_at} remaining",
+        flush=True,
+    )
+    selected = selected[resume_at:]
     pending: list[tuple[str, Path]] = []
     pending_bytes = 0
 
@@ -157,12 +174,12 @@ def main() -> None:
         pending = []
         pending_bytes = 0
 
-    for number, item in enumerate(selected, start=1):
+    for number, item in enumerate(selected, start=resume_at + 1):
         path = item.get("Path") or item.get("path") or item.get("Name")
         if not path:
             continue
         if path in uploaded:
-            print(f"skip {number}/{len(selected)} {path}", flush=True)
+            print(f"skip {number}/{shard_total} {path}", flush=True)
             continue
         local = WORKDIR / path
         local.parent.mkdir(parents=True, exist_ok=True)
@@ -183,7 +200,7 @@ def main() -> None:
             uploaded.add(path)
             if len(pending) >= 200 or pending_bytes >= 5_000_000_000:
                 flush()
-            print(f"done {number}/{len(selected)} {path}", flush=True)
+            print(f"done {number}/{shard_total} {path}", flush=True)
         finally:
             # Staged files remain until their batch commit succeeds.
             if path not in uploaded: