There's a bit of duplication between `get_internal_config` and `get_external_config`. How about defining:

```
get_internal_config() ->
    get_config(s3_internal_url()).

get_config(S3Url) ->
    {ok, S3AccessKeyId } =  application:get_env(chef_objects, s3_access_key_id),
    {ok, S3SecretKeyId } =  application:get_env(chef_objects, s3_secret_key_id),
    mini_s3:new(S3AccessKeyId, S3SecretKeyId, S3Url, path).
```