docker-container: restart-policy opt

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

docs/reference/buildx_create.md

@@ -153,6 +153,7 @@ No driver options.
 - `image=IMAGE` - Sets the container image to be used for running buildkit.
 - `network=NETMODE` - Sets the network mode for running the buildkit container.
 - `cgroup-parent=CGROUP` - Sets the cgroup parent of the buildkit container if docker is using the "cgroupfs" driver. Defaults to `/docker/buildx`.
+- `restart-policy=POLICY` - Sets the [restart policy](https://docs.docker.com/engine/reference/run/#restart-policies---restart) of the buildkit container.
 
 #### `kubernetes` driver
 

driver/docker-container/driver.go

@@ -39,6 +39,7 @@ type Driver struct {
 	netMode       string
 	image         string
 	cgroupParent  string
+	restartPolicy container.RestartPolicy
 	env           []string
 }
 
@@ -111,6 +112,7 @@ func (d *Driver) create(ctx context.Context, l progress.SubLogger) error {
 	if err := l.Wrap("creating container "+d.Name, func() error {
 		hc := &container.HostConfig{
 			Privileged:    true,
+			RestartPolicy: d.restartPolicy,
 			Mounts: []mount.Mount{
 				{
 					Type:   mount.TypeVolume,

driver/docker-container/factory.go

@@ -6,12 +6,14 @@ import (
 	"strings"
 
 	"github.com/docker/buildx/driver"
+	dockeropts "github.com/docker/cli/opts"
 	dockerclient "github.com/docker/docker/client"
 	"github.com/pkg/errors"
 )
 
 const prioritySupported = 30
 const priorityUnsupported = 70
+const defaultRestartPolicy = "unless-stopped"
 
 func init() {
 	driver.Register(&factory{})
@@ -39,7 +41,15 @@ func (f *factory) New(ctx context.Context, cfg driver.InitConfig) (driver.Driver
 	if cfg.DockerAPI == nil {
 		return nil, errors.Errorf("%s driver requires docker API access", f.Name())
 	}
-	d := &Driver{factory: f, InitConfig: cfg}
+	rp, err := dockeropts.ParseRestartPolicy(defaultRestartPolicy)
+	if err != nil {
+		return nil, err
+	}
+	d := &Driver{
+		factory:       f,
+		InitConfig:    cfg,
+		restartPolicy: rp,
+	}
 	for k, v := range cfg.DriverOpts {
 		switch {
 		case k == "network":
@@ -51,6 +61,11 @@ func (f *factory) New(ctx context.Context, cfg driver.InitConfig) (driver.Driver
 			d.image = v
 		case k == "cgroup-parent":
 			d.cgroupParent = v
+		case k == "restart-policy":
+			d.restartPolicy, err = dockeropts.ParseRestartPolicy(v)
+			if err != nil {
+				return nil, err
+			}
 		case strings.HasPrefix(k, "env."):
 			envName := strings.TrimPrefix(k, "env.")
 			if envName == "" {