It would be nice to have a clear error message if HA runs into file access problems.
Came across this while setting up SSL encryption and found that others ran into the sam (eg. http://disq.us/p/19llaru).
Symptom
16-11-01 10:40:55 homeassistant.bootstrap: The following platforms contain invalid configuration: http (please check your configuration)not a file for dictionary value @ data['http']['ssl_key']. Got '/etc/ssl/private/hostname.local.key'. Please check the docs at https://home-assistant.io/components/http/
Reason
I run HA on Raspbian and placed the key according to debian standard. The HA user has no read right on this directory. Only after reading http://disq.us/p/19llaru I understood that not the file itself is the problem but HA cannot access it.
Feature request
Give a clear hint a la “Cannot access file.”