Image download

[ghost]

Please describe the change you are making

This change fixes #7 and adds the ability to download VM images.

This PR is based on #5

[Gal-Zaidman]

I looked at client_disk and client_disk_download for now.
I think that a lot of the code here can be shared with the
https://github.com/oVirt/go-ovirt-client/blob/main/client_disk_uploadimage.go

There are large parts that are basically the same between the paths, and I think that both paths (upload and download) can improve one another if they will share the same code.
I also liked that on the upload path we are removing the disk in case of failure but in download we didn't handle that...
Plus I don't see that we waited for the disk to be OK or for the job to finish

[ghost]

@Gal-Zaidman I did the refactor, please check again.

[Gal-Zaidman]

It's a reoccurring theme here that whenever you use the retry function,
the actual operation is inside the anonymous function which is sent to the retry function.
Like here[1]

I think you can refactor the code a bit and try to remove as many of those anonymous functions as you can, and splite it, especially the large once.
For example the waitForImageTransferReady is implemented completely within the anonymous function, I see a couple of problems with that:

• Makes it much harder to understand and review especially for large functions which are most of them.
• Could lead to code duplication since you will probably not look for what you need inside an anonymous function.
• Less function documentation.

It can be split into "isImageTransferReady" which is the anonymous function and "waitForImageTransferReady" which is the retry part.

[1] https://github.com/oVirt/go-ovirt-client/pull/9/files?file-filters%5B%5D=.go#diff-d1c06aacde3ad46e36b19977671b2eb7945ec63ae785916f5b1d1ba911624f2bR179

[Gal-Zaidman]

I tried to do the best I can, please when you make changes commit them on a SEPARATE commit so I can understand what has change easily.

Other than that, great job 😃