Configuration for replacing path prefixes

[kellrott]

Use case: workflow engine expects files to be mounted on local file system, but worker nodes will be receiving files from object storage.

Possible solution:

1. Mount object store on head node using fuse mount, such as s3fs-fuse, to path like /var/run/s3-bucket
2. Configure funnel to replace path prefix /var/run/s3-bucket with object storage downloads

Configuration could look something like:

path-remap:
    "/var/run/s3-bucket":
         driver: GenericS3
         base: s3://my-bucket/data