podman version --json should include .Client.Platform.Name

[felipecrs]

Issue Description

I am trying to use podman's docker CLI compatibility, but some scripts I have rely on the output of docker version --json to decide whether the version of docker is good enough or not.

podman version should include the client name, so that scripts can detect when the client is podmand and decide what to do in such case, like for example, checking the minimum supported version of podman.

Steps to reproduce the issue

$ docker version --format '{{.Client | json}}' | jq .
{
  "Platform": {
    "Name": "Docker Engine - Community"
  },
  "Version": "24.0.7",
  "ApiVersion": "1.43",
  "DefaultAPIVersion": "1.43",
  "GitCommit": "afdd53b",
  "GoVersion": "go1.20.10",
  "Os": "linux",
  "Arch": "amd64",
  "BuildTime": "Thu Oct 26 09:08:01 2023",
  "Context": "default"
}

$ podman version --format '{{.Client | json}}' | jq .
{

  "APIVersion": "4.6.1",
  "Version": "4.6.1",
  "GoVersion": "go1.20.6",
  "GitCommit": "",
  "BuiltTime": "Mon Oct  9 16:15:55 2023",
  "Built": 1696868155,
  "OsArch": "linux/amd64",
  "Os": "linux"
}

Describe the results you received

See above.

Describe the results you expected

$ podman version --format '{{.Client | json}}' | jq .
{
  "Platform": {
    "Name": "Podman"
  },
  "APIVersion": "4.6.1",
  "Version": "4.6.1",
  "GoVersion": "go1.20.6",
  "GitCommit": "",
  "BuiltTime": "Mon Oct  9 16:15:55 2023",
  "Built": 1696868155,
  "OsArch": "linux/amd64",
  "Os": "linux"
}

podman info output

N/A

Podman in a container

No

Privileged Or Rootless

None

Upstream Latest Release

Yes

Additional environment details

N/A

Additional information

N/A

[felipecrs]

One caveat however is that very old versions of docker, like 17.04, won't have this key set either.

[Luap99]

Generally speaking version checks are not that great especially considering the RHEL world where also features are backported sometimes. It is much better to actually check for the features you need if possible.

It is not clear to me how much .Client.Platform.Name would help you with that either. Assuming you have a script you either call podman or docker so you should already know what you are using. Or are you worried about users symlinking docker -> podman?

[felipecrs]

Generally speaking version checks are not that great especially considering the RHEL world where also features are backported sometimes. It is much better to actually check for the features you need if possible.

That ain't a bad idea. I guess I can do:

if docker run --help | grep -w -- --quiet; then
  supports_quiet=true
else
  supports_quiet=false
fi

It is not clear to me how much .Client.Platform.Name would help you with that either.

I would be able to perform different version range comparisons depending on the client.

Assuming you have a script you either call podman or docker so you should already know what you are using.

I see your point, but my intention was to make the transition as transparent as possible. I didn't want to refactor my whole scripts. Also, my scripts are not meant to have first class support for podman.

Or are you worried about users symlinking docker -> podman?

Exactly. My scripts require docker, but I don't want to reject users if they decide to symlink or shim docker to podman.

This is a little worse considering that on RHEL 8 yum install docker actually installs podman and creates the docker shim.

[felipecrs]

All that said, I quite like your idea of checking the features. That's smart. If you don't believe this issue is worth implementing then, please close it.

[Luap99]

Given you seem to have a solution and nobody else has brought up this difference in the meantime I am going to close it and assume it is not really needed in practice