Failed to rerun this script when the first running interrupted by a network problem

[mika-cn]

This script can't continue to download the target file when the request fails.

Traceback (most recent call last):
  File "docker_pull.py", line 93, in <module>
    os.mkdir(imgdir)
FileExistsError: [Errno 17] File exists: 'tmp_imagename_latest'

[mika-cn]

Range requests are supported.

This endpoint should support aggressive HTTP caching for image layers. Support for Etags, modification dates and other cache control headers should be included. To allow for incremental downloads, Range requests should be supported, as well.

[mika-cn]

I walked around it by commented out layer download code and print each layer's URL. Download these URLs using wget -c [URL] -O targetPath. It works. If it returns a forbidden response (there's a token like parameter in URL that expired) then i rerun the script to get the latest URLs and try the download again.

After all layers had downloaded. I moved the image folder to another machine, then I used gunzip to decompress each layer.

Finally, compress the entire image folder (using tar command) and run docker load -i image-folder.tar.

Done!

[NotGlop]

Not sure to understand the issue. Which image are you trying to download ?

As the error says, it failed to rerun the script because the temporary folder has been previously created.
File exists: 'tmp_imagename_latest'
So please delete it and rerun script.

Of course, I should catch the exception when the download gets interrupted, to perform some cleanup, if this is what you want ?

[mika-cn]

@NotGlop

Network connections sometimes are slow and unstable. It means the request may failed due to a network problem especially when you download a large file. This can be resolved with several Range requests (continue the download from where it left off).

In this script, it downloads several files. It shouldn't cleanup the downloaded files when any download fails. In my case, there are 4 layers had downloaded and the last one failed. Ideally, when we rerun this script, it should lean that the first 4 layers have downloaded and continue download the 5th layer.