From 619046cae7f685a4fff2dcf938e563108e3c983a Mon Sep 17 00:00:00 2001
From: Christopher Adams <christopher.r.adams@gmail.com>
Date: Sun, 26 Jun 2022 15:01:19 -0400
Subject: [PATCH] Returned ETag for uploaded entities

- If 'ETag' is present in service response, return it inside a metadata
  dictionary for both `tasks.CompleteMultipartUploadTask` and
  `upload.PutObjectTask`.
- This change will allow integrations which rely on these call sites to
  access the ETag.
---
 s3transfer/tasks.py       | 8 +++++++-
 s3transfer/upload.py      | 9 ++++++++-
 tests/unit/test_tasks.py  | 9 ++++++---
 tests/unit/test_upload.py | 7 +++++--
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/s3transfer/tasks.py b/s3transfer/tasks.py
index 1bad9812..3c161c8b 100644
--- a/s3transfer/tasks.py
+++ b/s3transfer/tasks.py
@@ -377,11 +377,17 @@ def _main(self, client, bucket, key, upload_id, parts, extra_args):
             ``UploadPartTask.main()``.
         :param extra_args:  A dictionary of any extra arguments that may be
             used in completing the multipart transfer.
+        :returns: A dictionary representing metadata information about the
+            upload, such as the ETag for the uploaded entity.
         """
-        client.complete_multipart_upload(
+        response = client.complete_multipart_upload(
             Bucket=bucket,
             Key=key,
             UploadId=upload_id,
             MultipartUpload={'Parts': parts},
             **extra_args,
         )
+        metadata = dict()
+        if 'ETag' in response:
+            metadata['ETag'] = response['ETag']
+        return metadata
diff --git a/s3transfer/upload.py b/s3transfer/upload.py
index 0c99bd7b..62f2c252 100644
--- a/s3transfer/upload.py
+++ b/s3transfer/upload.py
@@ -753,9 +753,16 @@ def _main(self, client, fileobj, bucket, key, extra_args):
         :param key: The name of the key to upload to
         :param extra_args: A dictionary of any extra arguments that may be
             used in the upload.
+        :returns: A dictionary representing metadata information about the
+            upload, such as the ETag for the uploaded entity.
         """
         with fileobj as body:
-            client.put_object(Bucket=bucket, Key=key, Body=body, **extra_args)
+            response = client.put_object(Bucket=bucket, Key=key, Body=body,
+                **extra_args)
+            metadata = dict()
+            if 'ETag' in response:
+                metadata['ETag'] = response['ETag']
+            return metadata
 
 
 class UploadPartTask(Task):
diff --git a/tests/unit/test_tasks.py b/tests/unit/test_tasks.py
index 9759e8fb..84df092e 100644
--- a/tests/unit/test_tasks.py
+++ b/tests/unit/test_tasks.py
@@ -779,7 +779,8 @@ def test_main(self):
 class TestCompleteMultipartUploadTask(BaseMultipartTaskTest):
     def test_main(self):
         upload_id = 'my-id'
-        parts = [{'ETag': 'etag', 'PartNumber': 0}]
+        parts = [{'ETag': 'part-etag', 'PartNumber': 0}]
+        etag = 'uploaded-etag'
         task = self.get_task(
             CompleteMultipartUploadTask,
             main_kwargs={
@@ -793,7 +794,7 @@ def test_main(self):
         )
         self.stubber.add_response(
             method='complete_multipart_upload',
-            service_response={},
+            service_response={'ETag': etag},
             expected_params={
                 'Bucket': self.bucket,
                 'Key': self.key,
@@ -801,7 +802,9 @@ def test_main(self):
                 'MultipartUpload': {'Parts': parts},
             },
         )
-        task()
+        task_response = task()
+        self.assertIn("ETag", task_response)
+        self.assertEqual(task_response["ETag"], etag)
         self.stubber.assert_no_pending_responses()
 
     def test_includes_extra_args(self):
diff --git a/tests/unit/test_upload.py b/tests/unit/test_upload.py
index 4c523011..123d395b 100644
--- a/tests/unit/test_upload.py
+++ b/tests/unit/test_upload.py
@@ -631,6 +631,7 @@ def test_submits_tag_for_multipart_fileobj(self):
 class TestPutObjectTask(BaseUploadTest):
     def test_main(self):
         extra_args = {'Metadata': {'foo': 'bar'}}
+        etag = 'uploaded-etag'
         with open(self.filename, 'rb') as fileobj:
             task = self.get_task(
                 PutObjectTask,
@@ -644,7 +645,7 @@ def test_main(self):
             )
             self.stubber.add_response(
                 method='put_object',
-                service_response={},
+                service_response={'ETag': etag},
                 expected_params={
                     'Body': ANY,
                     'Bucket': self.bucket,
@@ -652,7 +653,9 @@ def test_main(self):
                     'Metadata': {'foo': 'bar'},
                 },
             )
-            task()
+            task_response = task()
+            self.assertIn("ETag", task_response)
+            self.assertEqual(task_response["ETag"], etag)
             self.stubber.assert_no_pending_responses()
             self.assertEqual(self.sent_bodies, [self.content])