No certificates generated fro traefik 2.2.1

[leifnel]

In my dockerfile I have `
certs:

 image: snowmb/traefik-certificate-extractor

 volumes:

  - /etc/traefik/acme/acme.json:/app/data/acme.json:ro

  - /etc/certs:/app/certs:rw

  - /var/run/docker.sock:/var/run/docker.sock

 command: -r 

 restart: always

`
Log just shows

`DEBUG: watching path: data/acme.json

DEBUG: output path: certs`

The input file is readable, the output dir is writeable from within the container.