Better progress indication for OCI upload

[itowlson]

Although OCI upload should usually be reasonably quick, it can take some time if the app is large or if network conditions are causing problems. spinframework/spin#3139 reports a 63MB upload taking 15 minutes or longer before failing or having to be cancelled.

It would be useful to provide feedback to the user while a long upload is happening.

A challenge here is that we currently rely on the oci-distribution crate, which does not (as far as I can tell) provide a mechanism for giving progress feedback from within its push function. (The new version, oci-client, has the same limitation.) So we would need to either port the Client::push() code into Spin itself, or get upstream to accept a PR adding feedback support before we could work on this.

[bacongobbler]

FYI: new upstream location is fermyon/feedback#60

[bacongobbler]

In this specific situation it was due to a files argument including several large files, which meant the total app size was over 150MB. So it kinda starts to make sense why it may take so long to upload.

I think it'd be cool if we could show what files were being uploaded to the server along with a progress bar similar to docker push. But yeah I do agree this seems like something we'd have to contribute upstream. We could look at how the distribution client does this as that is what oci-distribution and the ORAS project are based on.

If I had to guess it'd be based on the offset value from the API:

https://github.com/distribution/distribution/blob/97495e53977ff5178fd5ca01608db1d71c9073d7/registry/handlers/hmac.go#L12-L25

Which is then consumed at the blobUploadHandler which IIRC handles the "smart blob upload" APIs.

https://github.com/distribution/distribution/blob/97495e53977ff5178fd5ca01608db1d71c9073d7/registry/handlers/blobupload.go#L52-L63

[vdice]

Spin has a dotted progress indicator for its registry push/pull commands which we could similarly use for a low-effort implementation here.