using berkshelf programmatically

i am managing my cookbooks with berkshelf. i would like to play a little bit with the cookbook dependency graph. for instance:

• given a cookbook, get its dependencies (the same as the resolver does it)
• given a cookbook, get depended cookbooks (same as berks contingent)

i tried

require 'berkshelf'
Berkshelf::Lockfile.new(file_path: './Berksfile.lock')

but it did not work.

how can berkshelf be invoked programmatically under ruby and achieve the above?

If you have Berksfile, It might be helpful for you.

require 'berkshelf'

# initializing berksfile
s = Berkshelf::Berksfile.from_file('./find_versions/Berksfile')

#install dependencies to create Berksfile.lock 
s.install()

# parse lockfile
s.lockfile().parse()

# find dependencies
puts s.find('cookbook_name').locked_version