Ruby FOG and custom openstack provider: NotImplementedError - ruby-on-rails

Question

I'm using a Paperclip and Fog to work with cloud storage. Cloud storage provides Openstack API, and here is my setup:
paperclip_defaults.rb:
Paperclip::Attachment.default_options.update({
:path => "images/:class/:id/:attachment/:style/img_:fingerprint",
:storage => :fog,
:fog_credentials => {
:provider => 'OpenStack',
:openstack_auth_url => 'myurl',
:openstack_username => 'login',
:openstack_api_key => 'pass'
},
:fog_directory => 'dir',
:fog_public => true,
})
Everything works fine for upload, but I can't download a picture!
Here is stacktrace:
fog (1.23.0) lib/fog/openstack/models/storage/directory.rb:35:in `public_url'
fog (1.23.0) lib/fog/openstack/models/storage/files.rb:67:in `get_url'
fog (1.23.0) lib/fog/openstack/models/storage/file.rb:81:in `public_url'
paperclip (4.2.0) lib/paperclip/storage/fog.rb:136:in `public_url'
paperclip (4.2.0) lib/paperclip/storage/fog.rb:51:in `block (2 levels) in extended'
paperclip (4.2.0) lib/paperclip/interpolations.rb:34:in `block (2 levels) in interpolate'
paperclip (4.2.0) lib/paperclip/interpolations.rb:33:in `gsub'
paperclip (4.2.0) lib/paperclip/interpolations.rb:33:in `block in interpolate'
paperclip (4.2.0) lib/paperclip/interpolations.rb:32:in `each'
paperclip (4.2.0) lib/paperclip/interpolations.rb:32:in `inject'
paperclip (4.2.0) lib/paperclip/interpolations.rb:32:in `interpolate'
paperclip (4.2.0) lib/paperclip/url_generator.rb:13:in `for'
paperclip (4.2.0) lib/paperclip/attachment.rb:142:in `url'
NotImplementedError
public_url always returns this error for openstack storage. What's wrong?

Answer 1

You need to set "fog_host" to your object storage service endpoint.
Here is an example.
https://gist.github.com/withhawaii/4527bfdbe4fd1d52f67a
You can find your endpoint in Openstack Horizon.
Login to Horizon and click "Access & Security" => "API Access".
You will find the URL for Object Storage service endpoint.
It's basically an URL, where your users can access files.
Your system administrator may set up a proxy or something.
If that's the case, set the URL your system administrator gave to you.
Hope this will help.
GT