docker/swarmkit

package flagparser

import (
    "strconv"
    "strings"

    "github.com/moby/swarmkit/v2/api"
    "github.com/pkg/errors"
    "github.com/spf13/pflag"
)

func parsePorts(flags *pflag.FlagSet, spec *api.ServiceSpec) error {
    if !flags.Changed("ports") {
        return nil
    }
    portConfigs, err := flags.GetStringSlice("ports")
    if err != nil {
        return err
    }

    ports := []*api.PortConfig{}
    for _, portConfig := range portConfigs {
        name, protocol, port, swarmPort, err := parsePortConfig(portConfig)
        if err != nil {
            return err
        }

        ports = append(ports, &api.PortConfig{
            Name:          name,
            Protocol:      protocol,
            TargetPort:    port,
            PublishedPort: swarmPort,
            // In swarmctl all ports are by default
            // PublishModeHost
            PublishMode: api.PublishModeHost,
        })
    }

    spec.Endpoint = &api.EndpointSpec{
        Ports: ports,
    }

    return nil
}

func parsePortConfig(portConfig string) (string, api.PortConfig_Protocol, uint32, uint32, error) {
    protocol := api.ProtocolTCP
    parts := strings.Split(portConfig, ":")
    if len(parts) < 2 {
        return "", protocol, 0, 0, errors.New("insufficient parameters in port configuration")
    }

    name := parts[0]

    portSpec := parts[1]
    protocol, port, err := parsePortSpec(portSpec)
    if err != nil {
        return "", protocol, 0, 0, errors.Wrap(err, "failed to parse port")
    }

    if len(parts) > 2 {
        var err error

        portSpec := parts[2]
        nodeProtocol, swarmPort, err := parsePortSpec(portSpec)
        if err != nil {
            return "", protocol, 0, 0, errors.Wrap(err, "failed to parse node port")
        }

        if nodeProtocol != protocol {
            return "", protocol, 0, 0, errors.New("protocol mismatch")
        }

        return name, protocol, port, swarmPort, nil
    }

    return name, protocol, port, 0, nil
}

func parsePortSpec(portSpec string) (api.PortConfig_Protocol, uint32, error) {
    parts := strings.Split(portSpec, "/")
    p := parts[0]
    port, err := strconv.ParseUint(p, 10, 32)
    if err != nil {
        return 0, 0, err
    }

    if len(parts) > 1 {
        proto := parts[1]
        protocol, ok := api.PortConfig_Protocol_value[strings.ToUpper(proto)]
        if !ok {
            return 0, 0, errors.Errorf("invalid protocol string: %s", proto)
        }

        return api.PortConfig_Protocol(protocol), uint32(port), nil
    }

    return api.ProtocolTCP, uint32(port), nil
}