Allow overwrite on upload retry in remote uploader downloader

composer/loggers/remote_uploader_downloader.py

@@ -673,8 +673,8 @@ def _upload_worker(
 
         # defining as a function-in-function to use decorator notation with num_attempts as an argument
         @retry(ObjectStoreTransientError, num_attempts=num_attempts)
-        def upload_file():
-            if not overwrite:
+        def upload_file(retry_index: int = 0):
+            if retry_index == 0 and not overwrite:
                 try:
                     remote_backend.get_object_size(remote_file_name)
                 except FileNotFoundError:

composer/utils/retrying.py

@@ -7,6 +7,7 @@
 
 import collections.abc
 import functools
+import inspect
 import logging
 import random
 import time
@@ -46,18 +47,16 @@ def retry(  # type: ignore
 
     Attempts are spaced out with ``initial_backoff + 2**num_attempts + random.random() * max_jitter`` seconds.
 
+    Optionally, the decorated function can specify `retry_index` as an argument to receive the current attempt number.
+
     Example:
     .. testcode::
 
         from composer.utils import retry
 
-        num_tries = 0
-
         @retry(RuntimeError, num_attempts=3, initial_backoff=0.1)
-        def flaky_function():
-            global num_tries
-            if num_tries < 2:
-                num_tries += 1
+        def flaky_function(retry_index: int):
+            if retry_index < 2:
                 raise RuntimeError("Called too soon!")
             return "Third time's a charm."
 
@@ -84,9 +83,12 @@ def wrapped_func(func: TCallable) -> TCallable:
 
         @functools.wraps(func)
         def new_func(*args: Any, **kwargs: Any):
+            retry_index_param = 'retry_index'
             i = 0
             while True:
                 try:
+                    if retry_index_param in inspect.signature(func).parameters:
+                        kwargs[retry_index_param] = i
                     return func(*args, **kwargs)
                 except exc_class as e:
                     log.debug(f'Attempt {i} failed. Exception type: {type(e)}, message: {str(e)}.')

tests/loggers/test_remote_uploader_downloader.py

@@ -15,7 +15,7 @@
 
 from composer.core import Event, State
 from composer.loggers import Logger, RemoteUploaderDownloader
-from composer.utils.object_store.object_store import ObjectStore
+from composer.utils.object_store.object_store import ObjectStore, ObjectStoreTransientError
 
 
 class DummyObjectStore(ObjectStore):
@@ -190,6 +190,64 @@ def test_remote_uploader_downloader_no_overwrite(
     )
 
 
+def test_allow_overwrite_on_retry(tmp_path: pathlib.Path, dummy_state: State):
+    file_path = tmp_path / 'samples' / 'sample'
+    os.makedirs(tmp_path / 'samples')
+    with open(file_path, 'w') as f:
+        f.write('sample')
+
+    # Dummy object store that fails the first two uploads
+    # This tests that the remote uploader downloader allows overwriting a partially uploaded file on a retry.
+    class RetryDummyObjectStore(DummyObjectStore):
+
+        def __init__(
+            self,
+            dir: Optional[pathlib.Path] = None,
+            always_fail: bool = False,
+            **kwargs: Dict[str, Any],
+        ) -> None:
+            self._retry = 0
+            super().__init__(dir, always_fail, **kwargs)
+
+        def upload_object(
+            self,
+            object_name: str,
+            filename: Union[str, pathlib.Path],
+            callback: Optional[Callable[[int, int], None]] = None,
+        ) -> None:
+            if self._retry < 2:
+                self._retry += 1  # Takes two retries to upload the file
+                raise ObjectStoreTransientError('Retry this')
+            self._retry += 1
+            return super().upload_object(object_name, filename, callback)
+
+        def get_object_size(self, object_name: str) -> int:
+            if self._retry > 0:
+                return 1  # The 0th upload resulted in a partial upload
+            return super().get_object_size(object_name)
+
+    fork_context = multiprocessing.get_context('fork')
+    with patch('composer.loggers.remote_uploader_downloader.S3ObjectStore', RetryDummyObjectStore):
+        with patch('composer.loggers.remote_uploader_downloader.multiprocessing.get_context', lambda _: fork_context):
+            remote_uploader_downloader = RemoteUploaderDownloader(
+                bucket_uri=f"s3://{tmp_path}/'object_store_backend",
+                backend_kwargs={
+                    'dir': tmp_path / 'object_store_backend',
+                },
+                num_concurrent_uploads=4,
+                upload_staging_folder=str(tmp_path / 'staging_folder'),
+                use_procs=True,
+                num_attempts=3,
+            )
+            logger = Logger(dummy_state, destinations=[remote_uploader_downloader])
+
+            remote_uploader_downloader.run_event(Event.INIT, dummy_state, logger)
+            remote_file_name = 'remote_file_name'
+            remote_uploader_downloader.upload_file(dummy_state, remote_file_name, file_path, overwrite=False)
+            remote_uploader_downloader.close(dummy_state, logger=logger)
+            remote_uploader_downloader.post_close()
+
+
 @pytest.mark.parametrize('use_procs', [True, False])
 def test_race_with_overwrite(tmp_path: pathlib.Path, use_procs: bool, dummy_state: State):
     # Test a race condition with the object store logger where multiple files with the same name are logged in rapid succession