[APIv2] events?filters return 500

[skywalker512]

/kind bug

Description

treafik v2.2.1 will call on /v1.24/events?filters=%7B%22type%22%3A%7B%22container%22%3Atrue%7D%7D but return 500

Steps to reproduce the issue:

1. podman system service -t 0 tcp:0.0.0.0:9999

2. start treafik with endpoint = "tcp://127.0.0.1:9999" config

Describe the results you received:

{
    "cause": "runtime error: index out of range [0] with length 0",
    "message": "runtime error: index out of range [0] with length 0",
    "response": 500
}

Describe the results you expected:

{"Type":"container","Action":"stop","Actor":{"ID":"7f6e4f3b81349a57bd253cebb20f7b4fa98597d331f23fe767f862dcc21ece34","Attributes":{"containerExitCode":"0","image":"docker.io/library/traefik:latest","name":"traefik-main"}},"scope":"local","time":1594180142,"timeNano":1594180142023436891}

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

Output of podman version:

Version:      2.0.2
API Version:  1
Go Version:   go1.14
Git Commit:   201c9505b88f451ca877d29a73ed0f1836bb96c7-dirty
Built:        Thu Jan  1 08:00:01 1970
OS/Arch:      linux/amd64

Output of podman info --debug:

host:
  arch: amd64
  buildahVersion: 1.15.0
  cgroupVersion: v1
  conmon:
    package: Unknown
    path: /usr/libexec/podman/conmon
    version: 'conmon version 2.0.19-dev, commit: ce64ca841e1b12954cb3c972e0c06ec69a7b31ce'
  cpus: 2
  distribution:
    distribution: ubuntu
    version: "20.04"
  eventLogger: file
  hostname: iZ2ze8mxxl9wg4rrytkeuqZ
  idMappings:
    gidmap: null
    uidmap: null
  kernel: 5.4.0-31-generic
  linkmode: static
  memFree: 1043369984
  memTotal: 4127342592
  ociRuntime:
    name: runc
    package: Unknown
    path: /usr/bin/runc
    version: |-
      runc version 1.0.0-rc91
      spec: 1.0.2-dev
  os: linux
  remoteSocket:
    path: /run/podman/podman.sock
  rootless: false
  slirp4netns:
    executable: ""
    package: ""
    version: ""
  swapFree: 0
  swapTotal: 0
  uptime: 23h 47m 10.39s (Approximately 0.96 days)
registries:
  docker.io:
    Blocked: false
    Insecure: false
    Location: docker.io
    MirrorByDigestOnly: false
    Mirrors:
    - Insecure: false
      Location: 1nj0zren.mirror.aliyuncs.com
    Prefix: docker.io
  search:
  - docker.io
store:
  configFile: /etc/containers/storage.conf
  containerStore:
    number: 2
    paused: 0
    running: 1
    stopped: 1
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /var/lib/containers/storage
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Using metacopy: "false"
  imageStore:
    number: 4
  runRoot: /var/run/containers/storage
  volumePath: /var/lib/containers/storage/volumes
version:
  APIVersion: 1
  Built: 1
  BuiltTime: Thu Jan  1 08:00:01 1970
  GitCommit: 201c9505b88f451ca877d29a73ed0f1836bb96c7-dirty
  GoVersion: go1.14
  OsArch: linux/amd64
  Version: 2.0.2

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

(paste your output here)

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

[vrothberg]

Thanks for opening the issue!

There's definitely a bug causing the panic but /v1.24/events?filters=%7B%22type%22%3A%7B%22container%22%3Atrue%7D%7D seems to not be marshalled correctly

Failed to Unmarshal {"type":{"container":true}}: json ...

Does the call work with Docker?

[vrothberg]

Opened #6902 which will fix the panic.

[skywalker512]

Does the call work with Docker?

Yes, it work fine, and traefik code is here

https://github.com/containous/traefik/blob/master/pkg/provider/docker/docker.go#L271-L299

[vrothberg]

Thanks, I can reproduce locally when running the docker client against the podman.sock

~ $ sudo docker -H unix:///run/podman/podman.sock events --filter type=container
Error response from daemon: empty value for filter "type"

[vrothberg]

Fun... the Docker API states that filters are a map[string][]string while they are actually:

// Args stores a mapping of keys to a set of multiple values.
type Args struct {
	fields map[string]map[string]bool
}

@baude, I guess we need to change the wiring on our side to be compatible. WDYT?

[vrothberg]

This explains the unmarshal error on our side:

Failed to Unmarshal {"type":{"container":true}}: json: cannot unmarshal object into Go value of type []string

[mheon]

@vrothberg Are you sure the filter typing didn't change between v1.24 and v1.40?

[vrothberg]

I can have a look at older implementations but the docs of v1.24 and v1.40 didn't change

[baude]

but arent you saying the docs are actually wrong?

[vrothberg]

but arent you saying the docs are actually wrong?

The docs in v1.40 are wrong. I will look at v1.24 code to check if it has always behaved like that or if the implementation has changed over time.

[mheon]

Can we verify this with another filter? the Type filter looks unusual enough that it might be handled specially

[vrothberg]

It's independent of the filter as the types are different (see #6899 (comment)).

We follow the documentation with using a map[string][]string but docker uses map[string]map[string]bool.

[vrothberg]

but arent you saying the docs are actually wrong?

The docs in v1.40 are wrong. I will look at v1.24 code to check if it has always behaved like that or if the implementation has changed over time.

I just checked. v1.24 (Docker 1.12.) was also using a map[string]map[string]bool so I guess it has always been a bug in the Docker docs.

[vrothberg]

@baude @mheon ... do you agree to change our docs and implementation to use a map[string]map[string]bool for compat and libpod?

[mheon]

Sure. Ensuring compatibility with the actual implementation is more important than compatibility with their docs.