inspect: add type flag to inspect command

[89luca89]

Right now nerdctl inspect does not have a --type flag similar to
docker and podman.

This PR aims to add this, allowing for the basic values:

• container
• image

It will default to container to match docker's behaviour

Example of the command:

./nerdctl inspect --format '{{json .}}' --type image registry.fedoraproject.org/fedora-toolbox:35
./nerdctl inspect --format '{{json .}}' --type container fedora-toolbox-35

Signed-off-by: Luca Di Maio luca.dimaio1@gmail.com

[AkihiroSuda]

Thanks, but please use real name for Signed-off-by line

[AkihiroSuda]

Please squash commits

[89luca89]

Ok I now get what's happening
before with the "all" it would just do image or container, so if unspecified, it would find either of them
now it's either container or you must specify image, so that would make test fail

Docker works by default in the "all" style, so probably will need to find another way to put the logic in inspectAction

[AkihiroSuda]

Docker works by default in the "all" style

Slightly different from the "all" style.

When both the container and the image exists, Docker only shows the container

$ docker run -d --name nginx nginx
58f268d9a42c0bd861f95d75c396e271be218191e0d94eb3575d58fac26b27f2

$ docker inspect nginx
[
    {
        "Id": "58f268d9a42c0bd861f95d75c396e271be218191e0d94eb3575d58fac26b27f2",
        "Created": "2022-04-06T09:39:48.330069568Z",
        "Path": "/docker-entrypoint.sh",
        "Args": [
            "nginx",
            "-g",
            "daemon off;"
        ],
        "State": {
            "Status": "running",
...
            "MacAddress": "02:42:ac:11:00:02",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "bd938a276106bfa3b7b791976dbc16b6f88520ae7c712ed39b1e3c176a59450f",
                    "EndpointID": "18d9f5f42293017de4db6105b8609703ed9a235ec2fba11486ce9540e9794010",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

[89luca89]

Docker works by default in the "all" style

Slightly different from the "all" style.

When both the container and the image exists, Docker only shows the container

$ docker run -d --name nginx nginx
58f268d9a42c0bd861f95d75c396e271be218191e0d94eb3575d58fac26b27f2

$ docker inspect nginx
[
    {
        "Id": "58f268d9a42c0bd861f95d75c396e271be218191e0d94eb3575d58fac26b27f2",
        "Created": "2022-04-06T09:39:48.330069568Z",
        "Path": "/docker-entrypoint.sh",
        "Args": [
            "nginx",
            "-g",
            "daemon off;"
        ],
        "State": {
            "Status": "running",
...
            "MacAddress": "02:42:ac:11:00:02",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "bd938a276106bfa3b7b791976dbc16b6f88520ae7c712ed39b1e3c176a59450f",
                    "EndpointID": "18d9f5f42293017de4db6105b8609703ed9a235ec2fba11486ce9540e9794010",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

I see, I can revert to the "all" flag (maybe call it "any"?) and make it behave this way by default

[AkihiroSuda]

I see, I can revert to the "all" flag (maybe call it "any"?) and make it behave this way by default

Should be just "" (empty)

[89luca89]

Ok implemented with empty string and inverted the logic in the last check, so that we prioritize containers over images

[AkihiroSuda]

$ nerdctl -v
nerdctl version 0.18.0-17-g2d3de8c
$ nerdctl run -d --name nginx nginx
55185a099977d453b24e5197bae31cfb828a5e3ea5712ea0afef60b7df4a3bc1
$ nerdctl inspect nginx
FATA[0000] multiple IDs found with provided prefix: nginx 

OTOH, Docker shows the information of the container.

[89luca89]

$ nerdctl -v
nerdctl version 0.18.0-17-g2d3de8c
$ nerdctl run -d --name nginx nginx
55185a099977d453b24e5197bae31cfb828a5e3ea5712ea0afef60b7df4a3bc1
$ nerdctl inspect nginx
FATA[0000] multiple IDs found with provided prefix: nginx 

OTOH, Docker shows the information of the container.

mmh I see, this seems to stem from lines 114-116:

if ni != 0 && nc != 0 || nc > 1 {
    return fmt.Errorf("multiple IDs found with provided prefix: %s", req)
}

I've tested simply dropping them, as now we have a default (containers first, like in docker) and a way to disambiguate if needed (the type flag)

Also I've arranged the ifs in a way that we can simply have a hierarchy of defaults if in future we'll add more things to inspect (eg: container, image, network etc...)

[AkihiroSuda]

Thanks