Put pdf letter validation failed message in S3 metadata

So it can be used to tell the user why the letter has failed validation

app/celery/letters_pdf_tasks.py

@@ -49,7 +49,6 @@ from app.models import (
     NOTIFICATION_VIRUS_SCAN_FAILED,
 )
 from app.cronitor import cronitor
-from json import JSONDecodeError
 
 
 @notify_celery.task(bind=True, name="create-letters-pdf", max_retries=15, default_retry_delay=300)
@@ -214,18 +213,16 @@ def process_virus_scan_passed(self, filename):
         billable_units = get_page_count(old_pdf)
     except PdfReadError:
         current_app.logger.exception(msg='Invalid PDF received for notification_id: {}'.format(notification.id))
-        _move_invalid_letter_and_update_status(notification, filename, scan_pdf_object)
+        _move_invalid_letter_and_update_status(
+            notification=notification, filename=filename, scan_pdf_object=scan_pdf_object
+        )
         return
 
     sanitise_response = _sanitise_precompiled_pdf(self, notification, old_pdf)
-    if not sanitise_response:
+    if sanitise_response["message"]:  # is response without message attribute possible now? I think not?
         new_pdf = None
     else:
-        sanitise_response = sanitise_response.json()
-        try:
-            new_pdf = base64.b64decode(sanitise_response["file"].encode())
-        except JSONDecodeError:
-            new_pdf = sanitise_response.content
+        new_pdf = base64.b64decode(sanitise_response["file"].encode())
 
         redaction_failed_message = sanitise_response.get("redaction_failed_message")
         if redaction_failed_message and not is_test_key:
@@ -241,7 +238,14 @@ def process_virus_scan_passed(self, filename):
 
     if not new_pdf:
         current_app.logger.info('Invalid precompiled pdf received {} ({})'.format(notification.id, filename))
-        _move_invalid_letter_and_update_status(notification, filename, scan_pdf_object)
+        _move_invalid_letter_and_update_status(
+            notification=notification,
+            filename=filename,
+            scan_pdf_object=scan_pdf_object,
+            message=sanitise_response["message"],
+            invalid_pages=sanitise_response.get("invalid_pages"),
+            page_count=sanitise_response.get("page_count")
+        )
         return
     else:
         current_app.logger.info(
@@ -270,9 +274,16 @@ def process_virus_scan_passed(self, filename):
         update_notification_status_by_id(notification.id, NOTIFICATION_TECHNICAL_FAILURE)
 
 
-def _move_invalid_letter_and_update_status(notification, filename, scan_pdf_object):
+def _move_invalid_letter_and_update_status(
+    *, notification, filename, scan_pdf_object, message=None, invalid_pages=None, page_count=None
+):
     try:
-        move_scan_to_invalid_pdf_bucket(filename)
+        move_scan_to_invalid_pdf_bucket(
+            source_filename=filename,
+            message=message,
+            invalid_pages=invalid_pages,
+            page_count=page_count
+        )
         scan_pdf_object.delete()
 
         update_letter_pdf_status(
@@ -311,17 +322,19 @@ def _sanitise_precompiled_pdf(self, notification, precompiled_pdf):
                      'Notification-ID': str(notification.id)}
         )
         response.raise_for_status()
-        return response
+        return response.json()
     except RequestException as ex:
         if ex.response is not None and ex.response.status_code == 400:
             message = "sanitise_precompiled_pdf validation error for notification: {}. ".format(notification.id)
             if "message" in response.json():
                 message += response.json()["message"]
+            if "invalid_pages" in response.json():
+                message += (" on pages: " + ", ".join(map(str, response.json()["invalid_pages"])))
 
             current_app.logger.info(
                 message
             )
-            return None
+            return response.json()
 
         try:
             current_app.logger.exception(

app/letters/utils.py

@@ -127,10 +127,21 @@ def move_error_pdf_to_scan_bucket(source_filename):
     _move_s3_object(scan_bucket, error_file, scan_bucket, source_filename)
 
 
-def move_scan_to_invalid_pdf_bucket(source_filename):
-    scan_bucket = current_app.config['LETTERS_SCAN_BUCKET_NAME']
-    invalid_pdf_bucket = current_app.config['INVALID_PDF_BUCKET_NAME']
-    _move_s3_object(scan_bucket, source_filename, invalid_pdf_bucket, source_filename)
+def move_scan_to_invalid_pdf_bucket(source_filename, message=None, invalid_pages=None, page_count=None):
+    metadata = {}
+    if message:
+        metadata["validation_failed_message"] = message
+    if invalid_pages:
+        metadata["invalid_pages"] = [str(p) for p in invalid_pages]
+    if page_count:
+        metadata["page_count"] = str(page_count)
+    _move_s3_object(
+        source_bucket=current_app.config['LETTERS_SCAN_BUCKET_NAME'],
+        source_filename=source_filename,
+        target_bucket=current_app.config['INVALID_PDF_BUCKET_NAME'],
+        target_filename=source_filename,
+        metadata=metadata
+    )
 
 
 def move_uploaded_pdf_to_letters_bucket(source_filename, upload_filename):
@@ -138,7 +149,7 @@ def move_uploaded_pdf_to_letters_bucket(source_filename, upload_filename):
         source_bucket=current_app.config['TRANSIENT_UPLOADED_LETTERS'],
         source_filename=source_filename,
         target_bucket=current_app.config['LETTERS_PDF_BUCKET_NAME'],
-        target_filename=upload_filename
+        target_filename=upload_filename,
     )
 
 
@@ -164,7 +175,7 @@ def get_letter_pdf(notification):
     return obj.get()["Body"].read()
 
 
-def _move_s3_object(source_bucket, source_filename, target_bucket, target_filename):
+def _move_s3_object(source_bucket, source_filename, target_bucket, target_filename, metadata=None):
     s3 = boto3.resource('s3')
     copy_source = {'Bucket': source_bucket, 'Key': source_filename}
 
@@ -174,7 +185,10 @@ def _move_s3_object(source_bucket, source_filename, target_bucket, target_filena
     # Tags are copied across but the expiration time is reset in the destination bucket
     # e.g. if a file has 5 days left to expire on a ONE_WEEK retention in the source bucket,
     # in the destination bucket the expiration time will be reset to 7 days left to expire
-    obj.copy(copy_source, ExtraArgs={'ServerSideEncryption': 'AES256'})
+    put_args = {'ServerSideEncryption': 'AES256'}
+    if metadata:
+        metadata = put_args['Metadata'] = metadata
+    obj.copy(copy_source, ExtraArgs=put_args)
 
     s3.Object(source_bucket, source_filename).delete()
 

tests/app/celery/test_letters_pdf_tasks.py

@@ -436,10 +436,9 @@ def test_process_letter_task_check_virus_scan_passed(
             json={
                 "file": base64.b64encode(b"new_pdf").decode("utf-8"),
                 "validation_passed": True,
-                "errors": {
-                    "content_outside_of_printable_area": [],
-                    "document_not_a4_size_portrait_orientation": [],
-                }
+                "message": "",
+                "invalid_pages": [],
+                "page_count": 1
             },
             status_code=200
         )
@@ -479,7 +478,16 @@ def test_process_letter_task_check_virus_scan_passed_when_sanitise_fails(
     sample_letter_notification.status = NOTIFICATION_PENDING_VIRUS_CHECK
     sample_letter_notification.key_type = key_type
     mock_move_s3 = mocker.patch('app.letters.utils._move_s3_object')
-    mock_sanitise = mocker.patch('app.celery.letters_pdf_tasks._sanitise_precompiled_pdf', return_value=None)
+    sanitise_response = {
+        "file": base64.b64encode(b"nyan").decode("utf-8"),
+        "validation_passed": False,
+        "message": "content-outside-printable-area",
+        "invalid_pages": [1],
+        "page_count": 1
+    }
+    mock_sanitise = mocker.patch(
+        'app.celery.letters_pdf_tasks._sanitise_precompiled_pdf', return_value=sanitise_response
+    )
     mock_get_page_count = mocker.patch('app.celery.letters_pdf_tasks.get_page_count', return_value=2)
 
     process_virus_scan_passed(filename)
@@ -492,8 +500,12 @@ def test_process_letter_task_check_virus_scan_passed_when_sanitise_fails(
         b'pdf_content'
     )
     mock_move_s3.assert_called_once_with(
-        source_bucket_name, filename,
-        target_bucket_name, filename
+        source_bucket=source_bucket_name, source_filename=filename,
+        target_bucket=target_bucket_name, target_filename=filename, metadata={
+            "validation_failed_message": "content-outside-printable-area",
+            "invalid_pages": ["1"],
+            "page_count": "1"
+        }
     )
 
     mock_get_page_count.assert_called_once_with(b'pdf_content')
@@ -533,10 +545,9 @@ def test_process_letter_task_check_virus_scan_passed_when_redaction_fails(
                 "file": base64.b64encode(b"new_pdf").decode("utf-8"),
                 "validation_passed": True,
                 "redaction_failed_message": "No matches for address block during redaction procedure",
-                "errors": {
-                    "content_outside_of_printable_area": [],
-                    "document_not_a4_size_portrait_orientation": []
-                }
+                "message": "",
+                "invalid_pages": "",
+                "page_count": 2
             },
             status_code=200
         )
@@ -582,8 +593,8 @@ def test_process_letter_task_check_virus_scan_passed_when_file_cannot_be_opened(
     mock_sanitise.assert_not_called()
     mock_get_page_count.assert_called_once_with(b'pdf_content')
     mock_move_s3.assert_called_once_with(
-        source_bucket_name, filename,
-        target_bucket_name, filename
+        source_bucket=source_bucket_name, source_filename=filename,
+        target_bucket=target_bucket_name, target_filename=filename, metadata={}
     )
     assert sample_letter_notification.status == NOTIFICATION_VALIDATION_FAILED
     assert sample_letter_notification.billable_units == 0
@@ -626,10 +637,9 @@ def test_process_virus_scan_passed_logs_error_and_sets_tech_failure_if_s3_error_
             json={
                 "file": base64.b64encode(b"new_pdf").decode("utf-8"),
                 "validation_passed": True,
-                "errors": {
-                    "content_outside_of_printable_area": [],
-                    "document_not_a4_size_portrait_orientation": [],
-                }
+                "message": "",
+                "invalid_pages": [],
+                "page_count": 1
             },
             status_code=200
         )
@@ -656,7 +666,11 @@ def test_move_invalid_letter_and_update_status_logs_error_and_sets_tech_failure_
                  side_effect=ClientError(error_response, 'operation_name'))
     mock_logger = mocker.patch('app.celery.tasks.current_app.logger.exception')
 
-    _move_invalid_letter_and_update_status(sample_letter_notification, 'filename', mocker.Mock())
+    _move_invalid_letter_and_update_status(
+        notification=sample_letter_notification,
+        filename='filename',
+        scan_pdf_object=mocker.Mock()
+    )
 
     assert sample_letter_notification.status == NOTIFICATION_TECHNICAL_FAILURE
     mock_logger.assert_called_once_with(
@@ -720,10 +734,9 @@ def test_sanitise_precompiled_pdf_returns_data_from_template_preview(rmock, samp
             json={
                 "file": base64.b64encode(b"new_pdf").decode("utf-8"),
                 "validation_passed": True,
-                "errors": {
-                    "content_outside_of_printable_area": [],
-                    "document_not_a4_size_portrait_orientation": [],
-                }
+                "message": "",
+                "invalid_pages": [],
+                "page_count": 1
             },
             status_code=200
         )
@@ -732,26 +745,26 @@ def test_sanitise_precompiled_pdf_returns_data_from_template_preview(rmock, samp
         assert rmock.called
         assert rmock.request_history[0].url == endpoint
 
-    assert base64.b64decode(response.json()["file"].encode()) == b"new_pdf"
+    assert base64.b64decode(response["file"].encode()) == b"new_pdf"
     assert rmock.last_request.text == 'old_pdf'
 
 
-def test_sanitise_precompiled_pdf_returns_none_on_validation_error(rmock, sample_letter_notification):
+def test_sanitise_precompiled_pdf_return_validation_error(rmock, sample_letter_notification):
     sample_letter_notification.status = NOTIFICATION_PENDING_VIRUS_CHECK
 
     endpoint = 'http://localhost:9999/precompiled/sanitise'
+    response_json = {
+        "file": base64.b64encode(b"nyan").decode("utf-8"),
+        "validation_passed": False,
+        "message": "content-outside-printable-area",
+        "invalid_pages": [1],
+        "page_count": 1
+    }
     with requests_mock.mock() as rmock:
         rmock.request(
             "POST",
             endpoint,
-            json={
-                "file": base64.b64encode(b"nyan").decode("utf-8"),
-                "validation_passed": False,
-                "errors": {
-                    "content_outside_of_printable_area": [1],
-                    "document_not_a4_size_portrait_orientation": [],
-                }
-            },
+            json=response_json,
             status_code=400
         )
         mock_celery = Mock(**{'retry.side_effect': Retry})
@@ -759,7 +772,7 @@ def test_sanitise_precompiled_pdf_returns_none_on_validation_error(rmock, sample
         assert rmock.called
         assert rmock.request_history[0].url == endpoint
 
-    assert response is None
+    assert response == response_json
 
 
 def test_sanitise_precompiled_pdf_passes_the_service_id_and_notification_id_to_template_preview(