Comment 6 for bug 1735284

Yes, I'd say Swift is definitely interested in being compatible here, it's mainly a matter of havine time to implement it. There have been some other S3-related features (like versioning) that saw more interest so got implemented first, as well as other Swift-related bugs and features.

That said, if you're interested, I think it'll be a reasonably small amount of work. (Famous last words...) Given the way Swift implements MPUs, we probably want to add a similar feature to SLO then have s3api handle the translation between S3 and Swift APIs. I'd start looking around https://github.com/openstack/swift/blob/2.25.0/swift/common/middleware/slo.py#L981-L982 for where to start changing SLO; s3api might need to do some query-parameter plumbing around https://github.com/openstack/swift/blob/2.25.0/swift/common/middleware/s3api/controllers/obj.py#L91 and some response header translation around https://github.com/openstack/swift/blob/2.25.0/swift/common/middleware/s3api/s3response.py#L114-L123

If you need help getting a dev environment up or figuring out what needs to change where, you can find a bunch of us devs in IRC on freenode in #openstack-swift. It's also cool if you don't want to do it, of course -- just might take longer to implement ;-)