APIv2: container list limit handling seems to differ from docker-API

[rsommer]

Is this a BUG REPORT or FEATURE REQUEST? (leave only one on its own line)

/kind bug

Description

While trying out podman API with traefik, I came across differences in API behaviour:

Steps to reproduce the issue:

1. podman --log-level debug system service -t 0
2. podman run nginx
3. curl -s --unix-socket /var/run/user/1000/podman/podman.sock "http://v1.24/containers/json?limit=0" (which is what is requested using the docker client used by traefik)
   This yields an empty array '[]', using 'limit=1', you'll get the expected container

On the other hand:

1. Start docker daemon
2. docker run nginx
3. curl -s --unix-socket /var/run/docker.sock "http://v1.24/containers/json?limit=0"
   [{"Id":"fa3efdb9c1e2e5484c33ebcb03ae309c677ee3907b5e6094f87efcf333c63175","Names":["/pedantic_sanderson"],"Image":"nginx","ImageID":"sha256:7e4d58f0e5f3b60077e9a5d96b4be1b974b5a484f54f9393000a99f3b6816e3d","Command":"/docker-entrypoint.sh nginx -g 'daemon off;'","Created":1600779318,"Ports":[{"PrivatePort":80,"Type":"tcp"}],"Labels":{"maintainer":"NGINX Docker Maintainers <docker-maint@nginx.com>"},"State":"running","Status":"Up 15 seconds","HostConfig":{"NetworkMode":"default"},"NetworkSettings":{"Networks":{"bridge":{"IPAMConfig":null,"Links":null,"Aliases":null,"NetworkID":"7fbf25166e9904904e9fc4937058f644cf73da9aea191ff556772d8a8a89541f","EndpointID":"e066dd7864e74d0ec7bf4348eabd79ab459287bb69333d4c5ad73ea2fda57de0","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}}},"Mounts":[]}]

Describe the results you received:
podman API yields an empty array using the same API call, while docker returns a list of containers.

Describe the results you expected:
I would expect the same behaviour due to API-compatibility.

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

Output of podman version:

Version:      2.0.6
API Version:  1
Go Version:   go1.14.2
Built:        Thu Jan  1 01:00:00 1970
OS/Arch:      linux/amd64

Output of podman info --debug:

host:
  arch: amd64
  buildahVersion: 1.15.1
  cgroupVersion: v1
  conmon:
    package: 'conmon: /usr/libexec/podman/conmon'
    path: /usr/libexec/podman/conmon
    version: 'conmon version 2.0.20, commit: '
  cpus: 4
  distribution:
    distribution: ubuntu
    version: "20.04"
  eventLogger: file
  hostname: aragorn
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
  kernel: 5.4.0-47-generic
  linkmode: dynamic
  memFree: 216760320
  memTotal: 8223502336
  ociRuntime:
    name: runc
    package: 'cri-o-runc: /usr/lib/cri-o-runc/sbin/runc'
    path: /usr/lib/cri-o-runc/sbin/runc
    version: 'runc version spec: 1.0.2-dev'
  os: linux
  remoteSocket:
    path: /run/user/1000/podman/podman.sock
  rootless: true
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: 'slirp4netns: /usr/bin/slirp4netns'
    version: |-
      slirp4netns version 1.1.4
      commit: unknown
      libslirp: 4.3.1-git
      SLIRP_CONFIG_VERSION_MAX: 3
  swapFree: 1144066048
  swapTotal: 2147479552
  uptime: 31h 43m 36.79s (Approximately 1.29 days)
registries:
  search:
  - docker.io
  - quay.io
store:
  configFile: /home/codex/.config/containers/storage.conf
  containerStore:
    number: 34
    paused: 0
    running: 0
    stopped: 34
  graphDriverName: vfs
  graphOptions: {}
  graphRoot: /home/codex/.local/share/containers/storage
  graphStatus: {}
  imageStore:
    number: 48
  runRoot: /run/user/1000/containers
  volumePath: /home/codex/.local/share/containers/storage/volumes
version:
  APIVersion: 1
  Built: 0
  BuiltTime: Thu Jan  1 01:00:00 1970
  GitCommit: ""
  GoVersion: go1.14.2
  OsArch: linux/amd64
  Version: 2.0.6

Package info (e.g. output of rpm -q podman or apt list podman):

podman/unknown,now 2.0.6~2 amd64 [installed]

Have you tested with the latest version of Podman and have you checked the Podman Troubleshooting Guide?

Yes

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

$ docker version
Client:
 Version:           19.03.8
 API version:       1.40
 Go version:        go1.13.8
 Git commit:        afacb8b7f0
 Built:             Tue Jun 23 22:26:12 2020
 OS/Arch:           linux/amd64
 Experimental:      false

Server:
 Engine:
  Version:          19.03.8
  API version:      1.40 (minimum version 1.12)
  Go version:       go1.13.8
  Git commit:       afacb8b7f0
  Built:            Thu Jun 18 08:26:54 2020
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          1.3.3-0ubuntu2
  GitCommit:        
 runc:
  Version:          spec: 1.0.1-dev
  GitCommit:        
 docker-init:
  Version:          0.18.0
  GitCommit:        

[mheon]

@ParkerVR Mind taking this one?