Tool to help backup the contents of Docker volumes to a tar file on the Docker host

container-export.sh

#!/bin/bash

# based on https://docs.docker.com/storage/volumes/#back-up-restore-or-migrate-data-volumes

container_name="$1"
volume_path="$2"
backup_path="$3"

function usage() {
	echo "container-export.sh container_name container_path backup_path"
	exit 1
}

if [ -z "$backup_path" ]; then
	usage
fi

backup_name="`basename "$backup_path"`"
backup_dir="`dirname "$backup_path"`"

mkdir -p "$backup_dir"

docker run --rm --volumes-from "$container_name" -v "$backup_dir:/backup" ubuntu tar cvf "/backup/$backup_name" "$volume_path"