docker push support?

[k0ngk0ng]

Will this feature be supported?

[NotGlop]

Not planned yet, but if people really need it, i'll work on it (not planned soon though, or feel free to develop it in a PR and add the docker_push.py).

This could be tricky as this will need to:

• do some investigation on the upload of the image
• handle authentication to owned repositories

[kenwoodjw]

really need this feature

[NotGlop]

OK, I am working on the authentication part, I'll work on the push feature once authentication is finished.

[misuzu]

You can use https://github.com/containers/skopeo for pushing tar.gz images:
skopeo copy --insecure-policy docker-archive:/path/to/tar.gz docker://example-registry.com/image:latest

[NotGlop]

Facing an implementation issue, so I'm sharing it with you, if anyone has some knowledge about it.

Context:
The ID of a layer is the SHA256(layer.tar.gzip).
When imported into Docker (docker pull) the layer gets ungzipped of course, and when a tarball is created (docker save) the layer is kept ungzipped (actually the gzip is only useful for transitting through the internet, when pulling or pushing).

Issue:
The problem is that I cannot find a way to reproduce exactly the same gzip file from the ungzipped content (and it is necessary, to match the correct hash value referenced in the registry, to know where to push the layer).
For example, when downloading a layer from the Docker Hub, here is the header of the gzip content
1F 8B 08 00 00 00 00 00 00 FF.
If you are familiar with gzip format, then you see that there is no timestamp and no gzip flags.
Also, when looking at the data being compressed, the bytes are not the same than the gzip I create myself, so this doesn't only affect Gzip headers (which I can patch).

This is just two examples, but this tells me that the gzip libraries I have tested until then does not produce the same gzip file, which is an issue for pushing correct layers (because we need to match hashes of the registry)

Conclusion: if you know which implementation Docker registries use for their compression, please let me know. Also, different registries like Docker Hub, mcr.microsoft.com, quay.io and others may use a different implementation, so I need to do the test.

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Edit: Implementation found, now I need to convert it to Python code