Sample metadata.rb which reads its dependencies from Berksfile.lock. This is meant for use in "top-level cookbooks" only (~= "environment cookbook" pattern but using metadata rather than environments for locking deps)

Berksfile

source "https://api.berkshelf.com"

metadata

metadata.rb

name             'test'
maintainer       ''
maintainer_email ''
license          ''
description      'Installs/Configures test'
long_description 'Installs/Configures test'
version          '0.1.0'

if not File.exist? 'Berksfile.lock'
  # state direct dependencies. need to remove Berksfile.lock when updating these.
  depends "apache2", "1.10.4"
else
  # read resolved dependencies from Berksfile.lock, i.e. lock the complete dependency graph
  IO.read('Berksfile.lock').lines.keep_if { |line| line.match(/^\s{2}\w+\s\(.*\)/)}.each do |entry|
    dep_name, dep_version = entry.strip.match(/^(\w+)\s\((.*)\)/).captures
    depends(dep_name, dep_version) unless dep_name.eql? name
  end
end

this needs to be cleaned up a bit, e.g.:

• forward to "GRAPH" part in Berksfile.lock
• add self-reference to Berksfile
• check if this works with chef-client too
• fix the berks update anomaly

Full example here:
https://github.com/tknerr/sample-toplevel-cookbook

FYI - in the current state it breaks berks update -- you would have to remove the Berksfile.lock first in order to have berks update succeed

berks list -F json might be an easier to consume output, right? But interesting stuff :-)