Implemented code review comments: md5 fallback and re.search

Author: jackiryan

bignbit/handle_big_result.py

@@ -93,8 +93,7 @@ def process(self) -> dict[str, Any]:
         nrt_filename_regex = dataset_config.get('nrtFilenameRegex')
         is_nrt = False
         if nrt_filename_regex:
-            nrt_match = re.match(nrt_filename_regex, granule_id)
-            if nrt_match:
+            if re.search(nrt_filename_regex, granule_id):
                 is_nrt = True
 
         try:
@@ -242,15 +241,27 @@ def process_harmony_results(harmony_job: dict[str, str], cmr_env: str) -> list[d
 
         response = s3_client.head_object(Bucket=bucket, Key=key,
                                          ExpectedBucketOwner=utils.get_aws_account_id())
-        # For single-part uploads, the S3 ETag is the MD5 hex digest of the object
         etag = response['ETag'].strip('"')
 
+        # For single-part uploads, the S3 ETag is the MD5 hex digest of the object.
+        # For multipart uploads, the ETag has a '-<partcount>' suffix and is not an MD5.
+        if re.fullmatch(r'[0-9a-fA-F]{32}', etag):
+            checksum = etag
+        else:
+            CUMULUS_LOGGER.warning(
+                'ETag {} for s3://{}/{} is not a valid MD5 digest; '
+                'falling back to streaming MD5 computation', etag, bucket, key
+            )
+            get_response = s3_client.get_object(Bucket=bucket, Key=key,
+                                                ExpectedBucketOwner=utils.get_aws_account_id())
+            checksum = hashlib.md5(get_response['Body'].read()).hexdigest()
+
         filename = key.split('/')[-1]
         file_dict = {
             'fileName': filename,
             'bucket': bucket,
             'key': key,
-            'checksum': etag,
+            'checksum': checksum,
             'checksumType': 'md5'
         }
         # Weird quirk where if we are working with a collection that doesn't define variables, the Harmony request

tests/test_handle_big_result.py

@@ -1,10 +1,12 @@
 """Unit tests for handle_big_result module"""
 import hashlib
+import io
 import json
 import xml.etree.ElementTree as ET
 from unittest.mock import MagicMock, patch
 import boto3
 import pytest
+from botocore.response import StreamingBody
 from moto import mock_s3, mock_sts
 
 import bignbit.utils
@@ -673,3 +675,35 @@ def test_process_harmony_results_all_variable_omitted(mock_get_harmony_client):
     assert 'variable' not in result[0]
     assert result[0]['output_crs'] == 'EPSG:4326'
     assert result[0]['fileName'] == 'result_image.png'
+
+
+@patch('bignbit.utils.get_harmony_client')
+@patch('bignbit.handle_big_result.boto3')
+def test_process_harmony_results_multipart_etag_fallback(mock_boto3, mock_get_harmony_client):
+    """When ETag has a multipart suffix, falls back to streaming the object to compute MD5."""
+    bignbit.utils.AWS_ACCOUNT_ID = '123456789012'
+
+    image_data = b'fake image data for multipart test'
+    expected_checksum = hashlib.md5(image_data).hexdigest()
+
+    bucket_name = 'test-harmony-bucket'
+    image_key = 'path/to/result_image.png'
+
+    mock_s3_instance = MagicMock()
+    mock_s3_instance.head_object.return_value = {'ETag': '"abcdef1234567890abcdef1234567890-5"'}
+    mock_s3_instance.get_object.return_value = {
+        'Body': StreamingBody(io.BytesIO(image_data), len(image_data))
+    }
+    mock_boto3.client.return_value = mock_s3_instance
+
+    mock_harmony_client = MagicMock()
+    mock_harmony_client.result_urls.return_value = iter([f's3://{bucket_name}/{image_key}'])
+    mock_get_harmony_client.return_value = mock_harmony_client
+
+    harmony_job = {'job': 'valid-job-id', 'variable': 'temperature', 'output_crs': 'EPSG:4326'}
+    result = process_harmony_results(harmony_job, 'UAT')
+
+    assert len(result) == 1
+    assert result[0]['checksumType'] == 'md5'
+    assert result[0]['checksum'] == expected_checksum
+    mock_s3_instance.get_object.assert_called_once()