New deltacloud-client feature

[Michal Fojtik <mf...@redhat.com>]

Hi,

Today I want to introduce you a new 'cool' feature of the new
deltacloud-client code I've put together.

Last week I discovered that you can use MockSession[1] with
combination with the Rack::Test::Session[2] from rack-test
to completely mock the Deltacloud::API server. How does it work?

require 'deltacloud_rack'

# ... initialize DC server ...
#
@app = Rack::Test::Session.new(
  Rack::MockSession.new(Deltacloud::API)
)

@app.get '/instances' # => XML with list of instances

The last '@app#get' method *does not* do any 'real' HTTP request
but it is querying the internal Sinatra::Base methods to get the
response.

This in fact allow us to hook up the whole Deltacloud::API server into
the Faraday middleware[3] and instead of doing a 'real' request do DC
API, fire all requests to the mock DC server mounted there.

I know it sounds complicated :-) so I will demonstrate what you can do
with this stuff:

**Without** starting a new Deltacloud API server, run the 'rake console'
task inside deltacloud-client repository:

[1] pry(main)> c = Deltacloud::Connect :mock, 'mockuser', 'mockpassword'

[2] pry(main)> c.realms

=> [#<Deltacloud::Client::Realm> {:state=>"AVAILABLE", :limit=>nil,
  :name=>"United States", :description=>nil, :_id=>"us"},
#<Deltacloud::Client::Realm> {:state=>"AVAILABLE", :limit=>nil,
  :name=>"Europe", :description=>nil, :_id=>"eu"}]

It is not just realms. **All** unit tests for client pass with this
mocked Deltacloud::API. That means you can create instances, list images,
create blobs as usual, without DC running and without using the internal
DC driver API.

However there are 2 problems (there are always 2 problems ;-)

1. If you run the Deltacloud::Connect method, it took approx. 6 seconds
   on my laptop to require all drivers/collections/etc. (but that is only
   first time, next time you call that method is fast)

2. You need to have 'deltacloud-core' and 'rack-test' installed *as gems*.

If you want to play with this stuff, just clone my github[4] repo and run:

$ bundle
$ gem install deltacloud-core rack-test
$ rake console

Then you can run the code above :-)


Cheers,
  -- Michal

[1] http://rubydoc.info/gems/rack-test/0.5.6/Rack/MockSession
[2] http://rdoc.info/github/brynary/rack-test/master/Rack/Test/Session
[3] https://github.com/mifo/deltacloud-client/blob/master/lib/deltacloud/server.rb
[4] https://github.com/mifo/deltacloud-client

-- 
Michal Fojtik <mf...@redhat.com>
Deltacloud API, CloudForms