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://supermarket.chef.io"

# manage direct dependencies here in Berksfile
cookbook "apache2", "1.10.4"

# dependency on self
cookbook "my-app", path: "."

Berksfile.lock

DEPENDENCIES
  apache2 (= 1.10.4)
  my-app
    path: .

GRAPH
  apache2 (1.10.4)
    iptables (>= 0.0.0)
    logrotate (>= 0.0.0)
    pacman (>= 0.0.0)
  iptables (0.14.1)
  logrotate (1.7.0)
  pacman (1.1.1)
  my-app (0.1.0)
    apache2 (= 1.10.4)
    iptables (= 0.14.1)
    logrotate (= 1.7.0)
    pacman (= 1.1.1)

metadata.rb

name             'my-app'
maintainer       ''
maintainer_email ''
license          ''
description      'Installs/Configures my-app'
long_description 'Installs/Configures my-app'
version          '0.1.0'

# read resolved dependencies from Berksfile.lock, i.e. lock the complete dependency graph
locked_deps = IO.read('Berksfile.lock').lines.drop_while { |l| l != "GRAPH\n" }
locked_deps.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

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 :-)