onShutDown not being called when docker container stopped

When one uses groovy hooks with tinkerpop server hosted within the official docker the onStartUp hook will be called at server startup but the onShutDown will not be called.

I am using tinkergraph server for local testing and i would like to persist the data upon the server exit. i've added a graph.close to the onShutDown hook but i havent been able to get it called.

It will be called of course if you use the server start / server stop shell script but not if you kill / stop the docker container.

If there is some other way to persist the date i.e. call the graph.close from code and note via the console it would also be great as using it from node javascript i havent been able to find a way to call the graph.close directly.