podman-image-scp: Load images without the use of a temporary file.

[gordonmessmer]

This PR fixes #21239

This change requires changes to the containers-common repo, and I will send that PR shortly. To support CI, those changes are included in a separate commit which I will remove before this PR is merged.

Does this PR introduce a user-facing change?

None

[gordonmessmer]

I've opened containers/common#1831 for the ssh library changes that this PR requires.

[rhatdan]

@cdoern PTAL

[cdoern]

@gordonmessmer can you squash into one commit?

[cdoern]

looks good once you squash into one commit. I think this is a requirement for this repo. I do wonder if there is a limit to the stdin size podman image load can read. If not, then this is a good solution.

[gordonmessmer]

I can squash if that's the right thing to do, but I notice that some of the CI builds fail and the error suggests that those builds aren't using the files in vendor/github.com/containers/common/pkg/ssh from my PR.

I'm not sure where that workflow is defined... Is it replacing those files with http://github.com/containers/common/pkg/ssh ? My PR against that repo seems like it's acceptable, but the CI builds there are also failing for unclear reasons (the unmodified "main" branch doesn't pass, and the error doesn't seem to be related to my changes.)

If you want these squashed, and can merge them despite the CI failures, just say so and I'll squash them. Otherwise, I'll wait on getting things sorted out in the containers/common repo.

[rhatdan]

No the changes to common have to be merged their first and then we can vendor them into this PR. Keeping the PR for the common/vendor separate from the podman changes is correct.

[gordonmessmer]

I'll remove 9232edca218e043fa52568930f54166a660ea3d9 later today, now that the supporting changes have been merged in containers/common. Does the main branch require work to import those changes, before we can test this one in CI?

[gordonmessmer]

Manual tests of this change are successful. I've dropped the commit that modified vendor/ (which didn't work anyway), and rebased to the current main branch.

[packit-as-a-service]

Ephemeral COPR build failed. @containers/packit-build please check.

[rhatdan]

Did you forget to add a file to your PR?

[gordonmessmer]

You said that you needed to "vendor them into this PR" after the supporting changes were merged into https://github.com/containers/common/

[gordonmessmer]

Just to check that I understand the process for this PR: I think that this PR is waiting on a release of containers-common v 0.58, at some point in the future. Once that's released, it can be vendored in to the podman main branch. And after that, this PR can be rebased, and tests should pass.

Does that sound right?

[rhatdan]

No the vendoring should have already happened, you do not need to wait for a release. Should rebase now and then re-push. If the latest code has not been vendored from common yet, then we can vendor it in now.

[edsantiago]

@gordonmessmer yes, exactly. The only thing missing from your synopsis is a notification mechanism to let you know when the vendoring has happened. We have no automated mechanism for this, and most of the developers on our team are fallible humans. We will try to remember to ping you when c-c is vendored, but it would help us greatly if you check in periodically -- perhaps with a github web search, or by doing periodic git pulls on your repo and grep -F 'containers/common v0.58' go.mod. Thank you for understanding.

Oops, never mind. Listen to Dan, not me.

[gordonmessmer]

OK, rebased. "Build for fedora-39" completes successfully, and I can locally build podman without patching the vendor dir.

[gordonmessmer]

Tests look good, and I recalled that @cdoern had asked:

I do wonder if there is a limit to the stdin size podman image load can read. If not, then this is a good solution.

So I used the modified podman to copy a large image:

$ ./bin/podman --ssh=native image scp freeipa-server:almalinux-9 local::freeipa-server
Copying ...
Writing manifest to image destination
Loaded image: docker.io/freeipa/freeipa-server:almalinux-9

# podman image ls
REPOSITORY                        TAG          IMAGE ID      CREATED       SIZE
localhost/freeipa-server          latest       a4dde2e0aa50  15 hours ago  1.03 GB
docker.io/freeipa/freeipa-server  almalinux-9  a4dde2e0aa50  15 hours ago  1.03 GB

[rhatdan]

Thanks @gordonmessmer
/lgtm
/approve

[openshift-ci]

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[gordonmessmer]

Thanks, @rhatdan (and everyone who helped review both PRs.)