How do I use map[string]struct{}

So I am busy using http://godoc.org/github.com/samalba/dockerclient

Using CreateContainer (http://godoc.org/github.com/samalba/dockerclient#DockerClient.CreateContainer)

To setup a new container

containerConfig := &dockerclient.ContainerConfig{
	Image:        imageName,
	AttachStdin:  true,
	AttachStdout: true,
	AttachStderr: true}

containerID, err = docker.CreateContainer(containerConfig, containerName)

works correctly and I get a container, however, there is no exposed ports. Looking at the docker API(https://docs.docker.com/reference/api/docker_remote_api_v1.15/), I need to set

"ExposedPorts - An object mapping ports to an empty object in the form of: "ExposedPorts": { "<port>/<tcp|udp>: {}" }"

Looking at the godoc for the Go dockclient lib I am using, I see you can pass it as

ExposedPorts    map[string]struct{}

But I have no idea on what to do here, from the docker api example passing :

 "ExposedPorts":{
             "22/tcp": {}
     }

is enough, so how do I do the struct bit in the my containerConfig?

Put this in your containerConfig

ExposedPorts: map[string]struct{}{
	"22/tcp": {},
}

Eg

containerConfig := &dockerclient.ContainerConfig{
    Image:        imageName,
    AttachStdin:  true,
    AttachStdout: true,
    AttachStderr: true,
	ExposedPorts: map[string]struct{}{
		"22/tcp": {},
	},
}

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