Docker --format with json. Specific placeholder syntax for multiple placeholders

Question

I am trying to produce an output that looks like this using docker ps and the json format command

{"Names":"name"}

docker ps --format '{{json .Names}}'

outputs {"name"} without the label.

docker ps --format '{{json .}}' gives all the container info with labels, but I don't want everything.

Preferably based on all the placeholder names below, I would like to have an output like the below with the fields that I chose in the order I chose:

{"ID":"Container ID", "Image":"Image ID", "Names":"name"}

Placeholder Description
.ID Container ID
.Image  Image ID
.Command    Quoted command
.CreatedAt  Time when the container was created.
.RunningFor Elapsed time since the container was started.
.Ports  Exposed ports.
.Status Container status.
.Size   Container disk size.
.Names  Container names.
.Labels All labels assigned to the container.
.Label  Value of a specific label for this container. For example '{{.Label "com.docker.swarm.cpu"}}'
.Mounts Names of the volumes mounted in this container.
.Networks   Names of the networks attached to this container.

score 11 · Accepted Answer · answered Apr 30 '20 at 16:56

11

You can do it with this format:

docker ps --format '{"ID":"{{ .ID }}", "Image": "{{ .Image }}", "Names":"{{ .Names }}"}'

It outputs:

{"ID":"ed3c992b7472", "Image": "alpine:3.9", "Names":"wizardly_buck"}

answered Apr 30 '20 at 16:56

Mickael B.

4,755
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6

You can also use `docker ps --all --no-trunc --format='{{json .}}'` and then format it using `| jq .`. The final command looks like this `docker ps --all --no-trunc --format='{{json .}}' | jq .`. – mcuenez Dec 16 '21 at 11:48

score 1 · Answer 2 · answered Feb 22 '23 at 23:04

as @mcuenez told as a comment. His proposal is in my opinion better that that from @Mickael B. since it is more generic and you don't have to write a very long command go get all the data.

docker ps --all --no-trunc --format='{{json .}}'

and to formant the output you could use jq.

docker ps --all --no-trunc --format="{{json . }}" | jq --tab .

The output would be something like this

{
        "Command": "zsh",
        "CreatedAt": "2023-02-22 23:40:37 +0100 CET",
        "ID": "b2163d5d7229",
        "Image": "local-image-with-zsh",
        "Labels": "org.opencontainers.image.ref.name=ubuntu,org.opencontainers.image.version=22.04",
        "LocalVolumes": "0",
        "Mounts": "",
        "Names": "nervous_einstein",
        "Networks": "bridge",
        "Ports": "",
        "RunningFor": "14 minutes ago",
        "Size": "215kB (virtual 1.22GB)",
        "State": "running",
        "Status": "Up 14 minutes"
}
{
        "Command": "bash",
        "CreatedAt": "2023-02-22 23:39:22 +0100 CET",
        "ID": "1281e43c27a4",
        "Image": "ghcr.io/example-user/remote-image-with-bash",
        "Labels": "org.opencontainers.image.ref.name=ubuntu,org.opencontainers.image.version=22.04",
        "LocalVolumes": "0",
        "Mounts": "",
        "Names": "hardcore_cerf",
        "Networks": "bridge",
        "Ports": "",
        "RunningFor": "15 minutes ago",
        "Size": "216kB (virtual 1.22GB)",
        "State": "running",
        "Status": "Up 15 minutes"
}

With jq you can even create a valid json out of the single entries with a -s flag.

[
        {
                "Command": "zsh",
                "CreatedAt": "2023-02-22 23:40:37 +0100 CET",
                "ID": "b2163d5d7229",
                "Image": "local-image-with-zsh",
                "Labels": "org.opencontainers.image.ref.name=ubuntu,org.opencontainers.image.version=22.04",
                "LocalVolumes": "0",
                "Mounts": "",
                "Names": "nervous_einstein",
                "Networks": "bridge",
                "Ports": "",
                "RunningFor": "20 minutes ago",
                "Size": "215kB (virtual 1.22GB)",
                "State": "running",
                "Status": "Up 20 minutes"
        },
        {
                "Command": "bash",
                "CreatedAt": "2023-02-22 23:39:22 +0100 CET",
                "ID": "1281e43c27a4",
                "Image": "ghcr.io/example-user/remote-image-with-bash",
                "Labels": "org.opencontainers.image.ref.name=ubuntu,org.opencontainers.image.version=22.04",
                "LocalVolumes": "0",
                "Mounts": "",
                "Names": "hardcore_cerf",
                "Networks": "bridge",
                "Ports": "",
                "RunningFor": "21 minutes ago",
                "Size": "216kB (virtual 1.22GB)",
                "State": "running",
                "Status": "Up 21 minutes"
        }
]

`--format='{{json .}}'` is much slower for my 46 containers than simply formatting the JSON string as suggested in the [accepted answer](https://stackoverflow.com/a/61528784/3408342). — tukusejssirs, Apr 28 '23 at 09:02
yes this is the downsite of the generic solution. This is because docker has to generate a json with all the informations and not only with the asked and hardcoded ones. — FBattle206, Apr 28 '23 at 12:36

Docker --format with json. Specific placeholder syntax for multiple placeholders

2 Answers2