Store info about files as S3 metadata

Storing things in the session is proving buggy – we still have one user
(that we know about) where the session data isn’t getting written, so
they’re blocked from uploading a file.

Since all the info we’re storing in the session is about the file, it
makes sense to store it with the file.

This commit only does the writing of the metadata, once we’re sure this
is working we can do subsequent work to read it back, and remove
reliance on the session.

app/main/s3_client.py

@@ -15,6 +15,17 @@ def get_s3_object(bucket_name, filename):
     return s3.Object(bucket_name, filename)
 
 
+def get_csv_location(service_id, upload_id):
+    return (
+        current_app.config['CSV_UPLOAD_BUCKET_NAME'],
+        FILE_LOCATION_STRUCTURE.format(service_id, upload_id),
+    )
+
+
+def get_csv_upload(service_id, upload_id):
+    return get_s3_object(*get_csv_location(service_id, upload_id))
+
+
 def delete_s3_object(filename):
     bucket_name = current_app.config['LOGO_UPLOAD_BUCKET_NAME']
     get_s3_object(bucket_name, filename).delete()
@@ -39,20 +50,20 @@ def get_temp_truncated_filename(filename, user_id):
 
 def s3upload(service_id, filedata, region):
     upload_id = str(uuid.uuid4())
-    upload_file_name = FILE_LOCATION_STRUCTURE.format(service_id, upload_id)
-    utils_s3upload(filedata=filedata['data'],
-                   region=region,
-                   bucket_name=current_app.config['CSV_UPLOAD_BUCKET_NAME'],
-                   file_location=upload_file_name)
+    bucket_name, file_location = get_csv_location(service_id, upload_id)
+    utils_s3upload(
+        filedata=filedata['data'],
+        region=region,
+        bucket_name=bucket_name,
+        file_location=file_location,
+    )
     return upload_id
 
 
 def s3download(service_id, upload_id):
     contents = ''
     try:
-        bucket_name = current_app.config['CSV_UPLOAD_BUCKET_NAME']
-        upload_file_name = FILE_LOCATION_STRUCTURE.format(service_id, upload_id)
-        key = get_s3_object(bucket_name, upload_file_name)
+        key = get_csv_upload(service_id, upload_id)
         contents = key.get()['Body'].read().decode('utf-8')
     except botocore.exceptions.ClientError as e:
         current_app.logger.error("Unable to download s3 file {}".format(
@@ -121,3 +132,16 @@ def delete_temp_file(filename):
         raise ValueError('Not a temp file: {}'.format(filename))
 
     delete_s3_object(filename)
+
+
+def set_metadata_on_csv_upload(service_id, upload_id, **kwargs):
+    get_csv_upload(
+        service_id, upload_id
+    ).copy_from(
+        CopySource='{}/{}'.format(*get_csv_location(service_id, upload_id)),
+        ServerSideEncryption='AES256',
+        Metadata={
+            key: str(value) for key, value in kwargs.items()
+        },
+        MetadataDirective='REPLACE',
+    )

app/main/views/send.py

@@ -38,7 +38,7 @@ from app.main.forms import (
     SetSenderForm,
     get_placeholder_form_instance,
 )
-from app.main.s3_client import s3download, s3upload
+from app.main.s3_client import s3download, s3upload, set_metadata_on_csv_upload
 from app.template_previews import TemplatePreview, get_page_count_for_letter
 from app.utils import (
     Spreadsheet,
@@ -549,6 +549,13 @@ def _check_messages(service_id, template_id, upload_id, preview_row, letters_as_
         session['file_uploads'][upload_id]['notification_count'] = len(recipients)
         session['file_uploads'][upload_id]['template_id'] = str(template_id)
         session['file_uploads'][upload_id]['valid'] = True
+        set_metadata_on_csv_upload(
+            service_id,
+            upload_id,
+            notification_count=len(recipients),
+            template_id=str(template_id),
+            valid=True,
+        )
     else:
         session['file_uploads'].pop(upload_id)