To try this out:
docker-compose up -d
Look in the logs-out directory for the aggregate all.log and then the
host-container specific logs organized by directory per host.
In my case I saw the following files:
> find logs-out
logs-out
logs-out/all.log
logs-out/moby
logs-out/moby/trydockerlogginggelf_noise-date_1-2017.06.13.log
logs-out/moby/trydockerlogginggelf_noise-ping_1-2017.06.13.log