Migrating File Directories to Amazon S3

We’ve recently been looking into containerising our expression engine installs with Docker and had some good success so far. However the main solution we need to solve is moving all our Expression Engine file upload directories into cloud storage so that each container can reference the same assets, and be run independently.

We’ve looked at plugins like Treasury and Assets. Treasury hasn’t had any updates for a while and AWS S3 has recently depreciated S3 API access with SigV2 requests. Any new S3 buckets made now use SigV4 which neither Treasury or Assets support yet.

In the event they do support it soon, we still have an issue that we need to convert all our file field types to ‘Asset Fields’. This seems reasonably straightforward, but it’s not possible to convert a file field in a grid field type!

Some of our sites are 10+ years old and have huge numbers of channel entries and this would be impossible to perform manually. The only real solution I can think of currently is not using S3 and mounting the file directories in AWS EFS storage or other cloud disk volumes, but EFS is more costly and slower than S3, so we’d prefer not to.

Has anyone been in a similar situation? How did you resolve this? I’m sure we could edit the field types in the database, but we don’t want to introduce any possible instability across our sites.