You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: step_docker.go
    path of file: ./repos/act/pkg/runner
    
    the code of the file until where you have to start completion: package runner

import (
	"context"
	"fmt"
	"strings"

	"github.com/kballard/go-shellquote"
	"github.com/nektos/act/pkg/common"
	"github.com/nektos/act/pkg/container"
	"github.com/nektos/act/pkg/model"
)

type stepDocker struct {
	Step       *model.Step
	RunContext *RunContext
	env        map[string]string
}

func (sd *stepDocker) pre() common.Executor {
	return func(ctx context.Context) error {
		return nil
	}
}

func (sd *stepDocker) main() common.Executor {
	sd.env = map[string]string{}

	return runStepExecutor(sd, stepStageMain, sd.runUsesContainer())
}

func (sd *stepDocker) post() common.Executor {
	return func(ctx context.Context) error {
		return nil
	}
}

func (sd *stepDocker) getRunContext() *RunContext {
	return sd.RunContext
}

func (sd *stepDocker) getGithubContext(ctx context.Context) *model.GithubContext {
	return sd.getRunContext().getGithubContext(ctx)
}

func (sd *stepDocker) getStepModel() *model.Step {
	return sd.Step
}

func (sd *stepDocker) getEnv() *map[string]string {
	return &sd.env
}

func (sd *stepDocker) getIfExpression(_ context.Context, _ stepStage) string {
	return sd.Step.If.Value
}

func (sd *stepDocker) runUsesContainer() common.Executor {
	rc := sd.RunContext
	step := sd.Step

	return func(ctx context.Context) error {
		image := strings.TrimPrefix(step.Uses, "docker://")
		eval := rc.NewExpressionEvaluator(ctx)
		cmd, err := shellquote.Split(eval.Interpolate(ctx, step.With["arg
    
func (sd *stepDocker) newStepContainer(ctx context.Context, image string, cmd []string, entrypoint []string) container.Container {
	rc := sd.RunContext
	step := sd.Step

	rawLogger := common.Logger(ctx).WithField("raw_output", true)
	logWriter := common.NewLineWriter(rc.commandHandler(ctx), func(s string) bool {
		if rc.Config.LogOutput {
			rawLogger.Infof("%s", s)
		} else {
			rawLogger.Debugf("%s", s)
		}
		return true
	})
	envList := make([]string, 0)
	for k, v := range sd.env {
		envList = append(envList, fmt.Sprintf("%s=%s", k, v))
	}

	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_TOOL_CACHE", "/opt/hostedtoolcache"))
	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_OS", "Linux"))
	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_ARCH", container.RunnerArch(ctx)))
	envList = append(envList, fmt.Sprintf("%s=%s", "RUNNER_TEMP", "/tmp"))

	binds, mounts := rc.GetBindsAndMounts()
	stepContainer := ContainerNewContainer(&container.NewContainerInput{
		Cmd:         cmd,
		Entrypoint:  entrypoint,
		WorkingDir:  rc.JobContainer.ToContainerPath(rc.Config.Workdir),
		Image:       image,
		Username:    rc.Config.Secrets["DOCKER_USERNAME"],
		Password:    rc.Config.Secrets["DOCKER_PASSWORD"],
		Name:        createContainerName(rc.jobContainerName(), step.ID),
		Env:         envList,
		Mounts:      mounts,
		NetworkMode: fmt.Sprintf("container:%s", rc.jobContainerName()),
		Binds:       binds,
		Stdout:      logWriter,
		Stderr:      logWriter,
		Privileged:  rc.Config.Privileged,
		UsernsMode:  rc.Config.UsernsMode,
		Platform:    rc.Config.ContainerArchitecture,
	})
	return stepContainer
}