support max-chunk-length for push imge

[harris2012]

Description

considering someone is pushing a very large image like 2G.

Without the max-chunk-length.
any little network failure will let him patch whole image from 0%.

With the max-chunk-length.
He can patch the image every 30M. When networkle failure at 40%, he will continue to retry from 40%.

distribution-spec support the POST/PATCH/PUT method to push chunked image. if docker-cli support this, will be very useful.

[laurazard]

Hi @harris2012, thanks for the report.

The Docker CLI is only a client for the Docker Engine (moby/moby), so this ticket is better suited for that repository. If the engine implements support for this feature, we'll make it available in the CLI.

Other than that though, there's an open issue in distribution/distribution to implement support for setting max chunk length when pushing – distribution/distribution#4144. While the impetus there is to support registries hinting the client as to what max chunk length to use, we'd likely want to see that discussion/implementation resolved before implementing support for this in the engine. There's ongoing discussion related to this in distribution-spec (here's a proposal – opencontainers/distribution-spec#485).

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I'll close this for now, but feel free to open a ticket related to this in moby/moby if you'd like to continue the discussion.