fix: use scale for restarting

The other approach wasn't working. Duplicating containers on restart.
You'd end up with 2 containers per restart...

pkg/upstream/service/scale.go

@@ -0,0 +1,44 @@
+package upstream
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/client"
+	"github.com/sirupsen/logrus"
+)
+
+// RunServiceScale scales a service (useful for restart action)
+func RunServiceScale(ctx context.Context, cl *client.Client, serviceID string, scale uint64) error {
+	service, _, err := cl.ServiceInspectWithRaw(ctx, serviceID, types.ServiceInspectOptions{})
+	if err != nil {
+		return err
+	}
+
+	serviceMode := &service.Spec.Mode
+	if serviceMode.Replicated != nil {
+		serviceMode.Replicated.Replicas = &scale
+	} else if serviceMode.ReplicatedJob != nil {
+		serviceMode.ReplicatedJob.TotalCompletions = &scale
+	} else {
+		return fmt.Errorf("scale can only be used with replicated or replicated-job mode")
+	}
+
+	response, err := cl.ServiceUpdate(
+		ctx,
+		service.ID,
+		service.Version,
+		service.Spec,
+		types.ServiceUpdateOptions{},
+	)
+	if err != nil {
+		return err
+	}
+
+	for _, warning := range response.Warnings {
+		logrus.Warn(warning)
+	}
+
+	return nil
+}