Docker-compose file to terraform ecs fargate task definition

I have a docker-compose file which I want to run in Fargate in AWS ECS, all controlled with Terraform.
I already have the VPC, load balancer, certificates, target group, ECS service, IAM role, and cluster created in terraform, but I'm having trouble with the syntax of the task definition. Specifically creating volumes and then mounting them inside the containers.

I'd love someone who has done this before to jump on and just help me out to get past this hurdle.

Please note, Terraform makes the task definition look a bit different to just the JSON that the AWS management console can pump out for us, and I also have used that cute little open source Python app which purports to be able to convert docker-compose files to task definitions. So Terraform and AWS ECS domain knowledge is required for this.