docker / nerdctl inconsistent value type for Labels returned by container list --format json

[apostasie]

Description

docker returns Labels as a string with coma separated key=value, while nerdctl return them as an object.

I appreciate that nerdctl wants to mimic docker behavior as much as possible and I am usually on board with that, but in that case, I think Docker is just wrong and nerdctl should keep the current behavior, even at the cost of deviating.

I am opening the issue so that we can have a discussion on this and decide on a resolution.

My vote obviously is to just document it and not change the current behavior.

Thoughts?

Steps to reproduce the issue

1. docker container list --all --format json
2. sudo ./nerdctl container list --all --format json

Describe the results you received and expected

Docker returns:

{
  "Labels": "org.opencontainers.image.version=f40ece5,org.opencontainers.image.documentation=https://github.com/dubo-dubon-duponey/docker-dns/blob/master/README.md,org.opencontainers.image.ref.name=bookworm-2024-03-01,org.opencontainers.image.revision=f40ece567f4d6a0b1c8249f32ab0a82f5594efca,org.opencontainers.image.created=2024-03-27T12:15:26-0700,org.opencontainers.image.licenses=The MIT License (MIT),org.opencontainers.image.source=https://github.com/dubo-dubon-duponey/docker-dns/tree/master,org.opencontainers.image.vendor=dubodubonduponey,org.hadron.core.version=v0.1-dev,org.hadron.plan.tag=2024/04/02-17:19:16-5F6228B8-4152-4C7B-8D44-4E9293B1C59D,org.hadron.plan.sha=3c8d9485ffe7f0c91b837942b98be71d3d65a632029ae579143387eda499a137,org.opencontainers.image.authors=Dubo Dubon Duponey <[email protected]>,org.opencontainers.image.description=So image. Much DBDBDP. Such description.,org.opencontainers.image.title=A DBDBDP image,org.opencontainers.image.url=https://github.com/dubo-dubon-duponey/docker-dns,org.hadron.plan.description=some_plan_descriptor,org.hadron.plan.name=plan_name"
}

Nerdctl returns:

  "Labels": {
    "containerd.io/restart.loguri": "binary:///home/apo/nerdctl-patch?_NERDCTL_INTERNAL_LOGGING=%2Fvar%2Flib%2Fnerdctl%2F1935db59",
    "containerd.io/restart.policy": "always",
    "containerd.io/restart.status": "running",
    "io.containerd.image.config.stop-signal": "SIGTERM",
    "nerdctl/extraHosts": "null",
    "nerdctl/hostname": "airplay-oliphant.local",
    "nerdctl/ipc": "{\"mode\":\"private\"}",
    "nerdctl/log-uri": "binary:///home/apo/nerdctl-patch?_NERDCTL_INTERNAL_LOGGING=%2Fvar%2Flib%2Fnerdctl%2F1935db59",
    "nerdctl/mounts": "[{\"Type\":\"tmpfs\",\"Source\":\"tmpfs\",\"Destination\":\"/magnetar/cache\",\"Mode\":\"nodev,rw,uid=2000,gid=65534,noexec,nosuid,size=1000000000\",\"RW\":false,\"Propagation\":\"\"},{\"Type\":\"tmpfs\",\"Source\":\"tmpfs\",\"Destination\":\"/magnetar/runtime\",\"Mode\":\"nodev,rw,uid=2000,gid=65534,noexec,nosuid,size=1000000\",\"RW\":false,\"Propagation\":\"\"},{\"Type\":\"tmpfs\",\"Source\":\"tmpfs\",\"Destination\":\"/magnetar/state\",\"Mode\":\"nodev,rw,uid=2000,gid=65534,noexec,nosuid,size=1000000\",\"RW\":false,\"Propagation\":\"\"},{\"Type\":\"tmpfs\",\"Source\":\"tmpfs\",\"Destination\":\"/magnetar/state/avahi-daemon\",\"Mode\":\"nodev,rw,uid=101,gid=102,noexec,nosuid,size=1000000\",\"RW\":false,\"Propagation\":\"\"}]",
    "nerdctl/name": "airplay",
    "nerdctl/namespace": "default",
    "nerdctl/networks": "[\"hadron-mac-v6\"]",
    "nerdctl/platform": "linux/arm64/v8",
    "nerdctl/state-dir": "/var/lib/nerdctl/1935db59/containers/default/4b9798381227e513e01d08eb646ab336c6eb967e1a22f484b51e437d6a5c3cf0",
    "org.hadron.core.version": "v0.1-dev",
    "org.hadron.plan.description": "some_plan_descriptor",
    "org.hadron.plan.name": "plan_name",
    "org.hadron.plan.sha": "4c4179622ab1571d55d5eed32c5ac9bde46756197ba47d597f7f61e5d36ad742",
    "org.hadron.plan.tag": "2024/05/10-23:53:16-010DA0DA-FDA3-4C2A-A67D-35CB9FCB2F88"
  }

What version of nerdctl are you using?

1.7.6

Are you using a variant of nerdctl? (e.g., Rancher Desktop)

None

Host information

No response

[apostasie]

Interestingly, sudo /home/apo/nerdctl network list --format json does have the same behavior as docker (return serialized labels).

I would argue that we at least need to be consistent between commands.

[apostasie]

Also, more generally, the output of that command is varying a lot between docker and nerdctl ("State", "Status" have different syntax and some keys are present in one but not the other).

If consistency with Docker is required on this command, there is a lot of work to get it there.

[AkihiroSuda]

Thanks for reporting, it should follow Docker's behavior, although Docker seems weird in this case