Show progress bar when downloading or pushing content from/to a registry

[FeynmanZhou]

What is the version of your ORAS CLI

v1.0.0-RC.2

What would you like to be added?

Per the discussion at ORAS slack channel, @vsoch suggests design and provide a progress bar when downloading content from the remote registry.

Why is this needed for ORAS?

It would be helpful to show the progress bar in ORAS CLI commands such as oras blob fetch, especially when downloading a big layer or blob. Sometimes, the file transfer might be stuck but users are not aware of the progress. If ORAS output displays no output for a while, it will look broken. A good spinner or progress bar/indicator can make a CLI appear to be easier to use. It’s also good to show the estimated time remaining, or even just have an animated component, to reassure them that you’re still working on it.

Similarly, we could also add a progress bar to the push scenario. This would be a UX improvement.

Are you willing to submit PRs to contribute to this feature?

• Yes, I am willing to implement it.

[shizhMSFT]

Although we don't have a progress bar implemented for oras yet, it is possible with jq and pv. Here's an example:

$ blob_ref=ghcr.io/oras-project/oras@sha256:74529e03eae02d1fff5c05e9a6ec2089e1f5ae96421169c29a7c165346e042e4
$ size=$(oras blob fetch --descriptor $blob_ref | jq -r .size)
$ oras blob fetch $blob_ref --output - | pv -s $size > layer.bin
1.58MiB 0:00:03 [1.47MiB/s] [================================>                                ] 45% ETA 0:00:03

[sbdtu5498]

How about using https://github.com/schollz/progressbar rather than depending on external utility. I have done the basic changes for the issue. Should we also implement the same for blob push as well. I will make the PR, just let me know.

[amands98]

I am interested in working on this. // @sajayantony @FeynmanZhou @qweeah

[qweeah]

@amands98 Sorry for not updated the status but I have already worked on this, I have two PoC in my own fork, please check
https://github.com/qweeah/oras/releases/tag/v1.2.0-spinner
https://github.com/qweeah/oras/releases/tag/v1.2.0-bar

[qweeah]

How about using https://github.com/schollz/progressbar rather than depending on external utility. I have done the basic changes for the issue. Should we also implement the same for blob push as well. I will make the PR, just let me know.

It contains <1.0 dependencies which we want to avoid.