Support `podman version --format '{{ json . }}'` for docker compatibility #2671

wjt · 2019-03-15T16:09:19Z

/kind feature

Description

I tried to use Karton (which uses the docker CLI) with docker as a symlink to podman. I failed at the first hurdle because it tries to run docker version --format '{{ json . }}', which fails:

$ podman version --format '{{ json . }}'
Error: template parsing error: template: image:1: function "json" not defined

podman version --format json works, but produces output like this:

$ podman version --format json
{
    "RemoteAPIVersion": 1,
    "Version": "1.0.1-dev",
    "GoVersion": "go1.11.5",
    "GitCommit": "",
    "Built": 0,
    "OsArch": "linux/amd64"
}

Whereas according to the Docker documentation, Docker produces differently-formatted output:

$ docker version --format '{{json .}}'

{"Client":{"Version":"1.8.0","ApiVersion":"1.20","GitCommit":"f5bae0a","GoVersion":"go1.4.2","Os":"linux","Arch":"amd64","BuildTime":"Tue Jun 23 17:56:00 UTC 2015"},"ServerOK":true,"Server":{"Version":"1.8.0","ApiVersion":"1.20","GitCommit":"f5bae0a","GoVersion":"go1.4.2","Os":"linux","Arch":"amd64","KernelVersion":"3.13.2-gentoo","BuildTime":"Tue Jun 23 17:56:00 UTC 2015"}}

I'm calling this a feature request, but depending on the policy on docker CLI compatibility, maybe it's a bug. (Arguably I should just teach Karton about podman.)

Steps to reproduce the issue:

Run podman version --format '{{json .}}'

Describe the results you received:

Error: template parsing error: template: image:1: function "json" not defined

Describe the results you expected:

Output of the same shape as docker version --format '{{json .}}'.

Additional information you deem important (e.g. issue happens only occasionally):

Output of podman version:

Version:            1.0.1-dev
RemoteAPI Version:  1
Go Version:         go1.11.5
OS/Arch:            linux/amd64

Output of podman info --debug:

debug:
  compiler: gc
  git commit: ""
  go version: go1.11.5
  podman version: 1.0.1-dev
host:
  BuildahVersion: 1.7-dev
  Conmon:
    package: 'cri-o-1.12: /usr/lib/crio/bin/conmon'
    path: /usr/lib/crio/bin/conmon
    version: 'conmon version 1.12.4-dev, commit: '
  Distribution:
    distribution: '"endless"'
    version: 3.6.0
  MemFree: 4667650048
  MemTotal: 8262066176
  OCIRuntime:
    package: 'cri-o-runc: /usr/sbin/runc'
    path: /usr/sbin/runc
    version: 'runc version spec: 1.0.1-dev'
  SwapFree: 12393095168
  SwapTotal: 12393095168
  arch: amd64
  cpus: 4
  hostname: tensionsheet-redux
  kernel: 4.20.0-2-generic
  os: linux
  rootless: true
  uptime: 14m 31.45s
insecure registries:
  registries: []
registries:
  registries:
  - docker.io
  - registry.fedoraproject.org
  - quay.io
  - registry.access.redhat.com
  - registry.centos.org
store:
  ConfigFile: /sysroot/home/wjt/.config/containers/storage.conf
  ContainerStore:
    number: 0
  GraphDriverName: vfs
  GraphOptions: null
  GraphRoot: /sysroot/home/wjt/.local/share/containers/storage
  GraphStatus: {}
  ImageStore:
    number: 0
  RunRoot: /run/user/1001
debug:
  compiler: gc
  git commit: ""
  go version: go1.11.5
  podman version: 1.0.1-dev
host:
  BuildahVersion: 1.7-dev
  Conmon:
    package: 'cri-o-1.12: /usr/lib/crio/bin/conmon'
    path: /usr/lib/crio/bin/conmon
    version: 'conmon version 1.12.4-dev, commit: '
  Distribution:
    distribution: '"endless"'
    version: 3.6.0
  MemFree: 4667650048
  MemTotal: 8262066176
  OCIRuntime:
    package: 'cri-o-runc: /usr/sbin/runc'
    path: /usr/sbin/runc
    version: 'runc version spec: 1.0.1-dev'
  SwapFree: 12393095168
  SwapTotal: 12393095168
  arch: amd64
  cpus: 4
  hostname: tensionsheet-redux
  kernel: 4.20.0-2-generic
  os: linux
  rootless: true
  uptime: 14m 31.45s
insecure registries:
  registries: []
registries:
  registries:
  - docker.io
  - registry.fedoraproject.org
  - quay.io
  - registry.access.redhat.com
  - registry.centos.org
store:
  ConfigFile: /sysroot/home/wjt/.config/containers/storage.conf
  ContainerStore:
    number: 0
  GraphDriverName: vfs
  GraphOptions: null
  GraphRoot: /sysroot/home/wjt/.local/share/containers/storage
  GraphStatus: {}
  ImageStore:
    number: 0
  RunRoot: /run/user/1001

Additional environment details (AWS, VirtualBox, physical, etc.):

I'm using the development branch of Endless OS, which as of 24 hours ago include podman.

The text was updated successfully, but these errors were encountered:

`podman` is an almost-CLI-compatible replacement for `docker`, which allows unprivileged users to run containers, with no daemon. On some systems, `docker` is a symbolic link to `podman`. I say "almost" because one command that is not compatible is `docker version --format '{{ json . }}'`, used by Karton to detect whether docker is present and usable. containers/podman#2671 To work around this, if _try_docker() fails, but running `podman version` succeeds, use `podman` instead. Otherwise, behave as before.

baude · 2019-03-15T18:59:59Z

on most of our comments where format is offered, you can pass --format json ... not the absence of go templating.

mheon · 2019-03-15T19:38:42Z

I don't know how much sense mimicing docker version format here makes - we don't have a server, so the client and server split doesn't make any sense. Adding some of the missing information might be a good idea, though I think we print most of that in podman info

rhatdan · 2019-03-16T11:53:13Z

Can't we support
podman version --format '{{ json . }}'

rhatdan · 2019-03-16T12:08:58Z

If you remove the json it works.
podman version --format '{{ . }}

baude · 2019-03-17T14:49:45Z

yeah this can be done I think ... @rhatdan if you want me to kick this out, assign this to me and I'll assume that means you want it done.

mheon · 2019-03-17T16:43:09Z

@baude IMO if we do this, we add the .json Go template, but we don't try and match the Docker JSON output, we just output the JSON we normally would for version.

…

On Sun, Mar 17, 2019, 08:49 Brent Baude ***@***.***> wrote: yeah this can be done I think ... @rhatdan <https://github.com/rhatdan> if you want me to kick this out, assign this to me and I'll assume that means you want it done. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#2671 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AHYHCIZR5hnqoJ2_gwKFfaN5gmSwgJIFks5vXlYLgaJpZM4b2zz3> .

wjt · 2019-03-17T17:04:05Z

@baude IMO if we do this, we add the .json Go template, but we don't try and match the Docker JSON output, we just output the JSON we normally would for version.

FWIW Karton, the tool I was trying to use with podman, explicitly checks for the "Client" and "Server" keys so would have still failed in this case.

https://github.com/karton/karton/blob/5a9c46a5590923a7a9a77a05b9f90a234431bcc3/karton/dockerctl.py#L77-L82

baude · 2019-03-17T17:26:44Z

@mheon agree but again, if it is no help due to the keys, then ...

rhatdan · 2019-03-18T11:53:09Z

@baude I think we should support it. But we really can not support the Client/Server keys since they make no sense for Podman.
@wjt WDYT?

wjt · 2019-03-18T11:58:45Z

I understand that the keys don't make sense for Podman; I guess there comes a point where it cannot be an absolutely 100% CLI-compatible drop-in replacement for Docker.

I wrote a small patch to make karton check for podman if docker version --format '{{ json . }} fails, and use it if found; I could equally well make it check whether the returned JSON indicates that docker is actually podman (if "Client" and/or "Server" are not present). I have no idea how many other tools might be parsing this JSON; perhaps the answer is 0 😄

rhatdan · 2019-03-18T13:37:54Z

Well we can only go so far before it starts lying. Podman is not a client/server application, so adding these fields makes no sense.

for podman version, we now support a GO template for json output. fixes containers#2671 Signed-off-by: baude <bbaude@redhat.com>

`podman` is an almost-CLI-compatible replacement for `docker`, which allows unprivileged users to run containers, with no daemon. On some systems, `docker` is a symbolic link to `podman`. I say "almost" because one command that is not compatible is `docker version --format '{{ json . }}'`, used by Karton to detect whether docker is present and usable. containers/podman#2671 To work around this, if _try_docker() fails, but running `podman version` succeeds, use `podman` instead. Otherwise, behave as before.

christian-korneck · 2021-03-19T13:03:08Z

Podman is not a client/server application, so adding these fields makes no sense.

as podman is now a client/server app, does this still stand? (Noticed this docker/podman cli difference when trying to use podman-remote for vscode devcontainers [1] [2])

rhatdan · 2021-03-22T20:46:37Z

When run in remote mode, it does show that data, but not in local mode.

podman --remote version --format json
{"Client":{"APIVersion":"3.0.0","Version":"3.0.1","GoVersion":"go1.16","GitCommit":"","BuiltTime":"Mon Feb 22 09:08:57 2021","Built":1614002937,"OsArch":"linux/amd64"},"Server":{"APIVersion":"3.0.0","Version":"3.0.1","GoVersion":"go1.16","GitCommit":"","BuiltTime":"Mon Feb 22 09:08:57 2021","Built":1614002937,"OsArch":"linux/amd64"}}

openshift-ci-robot added the kind/feature Categorizes issue or PR as related to a new feature. label Mar 15, 2019

wjt mentioned this issue Mar 15, 2019

dockerctl: use 'podman' if present and 'docker version' fails karton/karton#11

Merged

rhatdan assigned baude Mar 18, 2019

baude mentioned this issue Mar 18, 2019

support GO template {{ json . }} #2688

Merged

baude added a commit to baude/podman that referenced this issue Mar 18, 2019

support GO template {{ json . }}

6aa8d14

for podman version, we now support a GO template for json output. fixes containers#2671 Signed-off-by: baude <bbaude@redhat.com>

openshift-merge-robot closed this as completed in #2688 Mar 18, 2019

rgolangh mentioned this issue Jun 30, 2019

does not work anymore rgolangh/gnome-shell-extension-containers#2

Closed

slimjim2234 mentioned this issue Oct 31, 2019

Support GO Template #4391

Closed

christian-korneck mentioned this issue Mar 19, 2021

remote containers - podman over ssh not working microsoft/vscode-remote-release#4643

Closed

baude mentioned this issue Jul 6, 2021

vscode remote containers - podman over ssh not working #9688

Closed

github-actions bot added the locked - please file new issue/PR Assist humans wanting to comment on an old issue or PR with locked comments. label Sep 22, 2023

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Support `podman version --format '{{ json . }}'` for docker compatibility #2671

Support `podman version --format '{{ json . }}'` for docker compatibility #2671

wjt commented Mar 15, 2019

baude commented Mar 15, 2019

mheon commented Mar 15, 2019

rhatdan commented Mar 16, 2019

rhatdan commented Mar 16, 2019

baude commented Mar 17, 2019

mheon commented Mar 17, 2019 via email

wjt commented Mar 17, 2019

baude commented Mar 17, 2019

rhatdan commented Mar 18, 2019

wjt commented Mar 18, 2019

rhatdan commented Mar 18, 2019

christian-korneck commented Mar 19, 2021

rhatdan commented Mar 22, 2021

Support podman version --format '{{ json . }}' for docker compatibility #2671

Support podman version --format '{{ json . }}' for docker compatibility #2671

Comments

wjt commented Mar 15, 2019

baude commented Mar 15, 2019

mheon commented Mar 15, 2019

rhatdan commented Mar 16, 2019

rhatdan commented Mar 16, 2019

baude commented Mar 17, 2019

mheon commented Mar 17, 2019 via email

wjt commented Mar 17, 2019

baude commented Mar 17, 2019

rhatdan commented Mar 18, 2019

wjt commented Mar 18, 2019

rhatdan commented Mar 18, 2019

christian-korneck commented Mar 19, 2021

rhatdan commented Mar 22, 2021

Support `podman version --format '{{ json . }}'` for docker compatibility #2671

Support `podman version --format '{{ json . }}'` for docker compatibility #2671