在golang sdk中为docker api的ContainerCreate函数设置PortBindings配置

Question

Basically i need to something like this

docker run -p something:something --name xxxx imagename

in golang sdk (this one https://docs.docker.com/engine/api/sdks/) for docker api, my current code looks like this

exposedPorts, portBindings, _ := nat.ParsePortSpecs([]string{
    "127.0.0.1:8080:2368",
})
// Running the ghost container
createdBody, err := dockerClient.ContainerCreate(context.Background(),
    &container.Config{
        Image:        "ghost:latest",
        ExposedPorts: exposedPorts,// it supposed to be nat.PortSet
    },
    &container.HostConfig{
        PortBindings: portBindings,// it supposed to be nat.PortMap
    },
    &network.NetworkingConfig{},
    containerName)

I'm using this https://github.com/docker/go-connections/blob/master/nat/nat.go#L126 ParsePortSpecs function which return (map[Port]struct{}, map[Port][]PortBinding, error) but fail since the container.Config.ExposedPorts is nat.PortSet (it's actually map[Port]struct{} tho) and containter.HostConfig.PortBindins is nat.PortMap

I'm not sure if i want to use this client https://github.com/fsouza/go-dockerclient since my current version of docker API is 1.25 and it doesn't support API version above 1.23

Answer 1

The Docker Client Go SDK might have changed a bit since Jan, but I just got this working so I'll document what I did here.

If you need a port exposed, which would look like 4140/tcp under PORTS on docker ps then you can do the following:

config := &container.Config{
    Image: "nginx",
    ExposedPorts: nat.PortSet{
        "4140/tcp": struct{}{},
    },
}

hostConfig := &container.HostConfig{}

ctx := context.Background()
containerResp, err := Docker.ContainerCreate(ctx, config, hostConfig, nil, "")
if err != nil {
    panic(err)
}

if err := Docker.ContainerStart(ctx, containerResp.ID, types.ContainerStartOptions{}); err != nil {
    panic(err)
}

If you'd like to bind that port to the host on 0.0.0.0, which would look like 0.0.0.0:4140->4140/tcp under PORTS on docker ps you need to add in the port bindings to the hostConfig:

config := &container.Config{
    Image: "nginx",
    ExposedPorts: nat.PortSet{
        "4140/tcp": struct{}{},
    },
}

hostConfig := &container.HostConfig{
    PortBindings: nat.PortMap{
        "4140/tcp": []nat.PortBinding{
            {
                HostIP: "0.0.0.0",
                HostPort: "4140",
            },
        },
    },
}

ctx := context.Background()
containerResp, err := Docker.ContainerCreate(ctx, config, hostConfig, nil, "")
if err != nil {
    panic(err)
}

if err := Docker.ContainerStart(ctx, containerResp.ID, types.ContainerStartOptions{}); err != nil {
    panic(err)
}

Hopefully this'll save somebody some time :)