Chef: Jenkins cookbook recipe for enabling security - security

Question

I am currently using the Chef supermarket Jenkins cookbook to deploy an instance of Jenkins. I am attempting to enable security in my configuration of the jenkins instance in the _master_war_.rb recipe file. Code to enable security and create a user using an RSA key is below:
require 'openssl'
require 'net/ssh'
unless node.run_state[:jenkins_private_key]
# defaults to /etc/chef-jenkins-api.key
key_path = node['jenkins_chefci']['jenkins_private_key_path']
begin
Chef::Log.info 'Trying to read private key from ' + key_path + ' for the chef user in jenkins'
key = OpenSSL::PKey::RSA.new File.read(key_path)
Chef::Log.info 'Successfully read existing private key'
rescue
key = OpenSSL::PKey::RSA.new 2048
Chef::Log.info 'Generating new key pair for the chef user in jenkins in ' + key_path
file key_path do
content key.to_pem
mode 0500
sensitive true
end
end
public_key = [key.ssh_type, [key.to_blob].pack('m0'), 'auto-generated key'].join(' ')
# Create the Jenkins user with the public key
jenkins_user 'chef' do
id 'chef#' + Chef::Config[:node_name]
full_name 'Chef Client'
public_keys [public_key]
end
# Set the private key on the Jenkins executor
node.run_state[:jenkins_private_key] = key.to_pem
end
When I attempt to apply this recipe in a run list on a managed node, I receive the following error:
NoMethodError
-------------
undefined method `[]' for nil:NilClass
The stacktrace indicates that the error is related to this particular line of code from my recipe file:
>> key_path = node['jenkins_chefci']['jenkins_private_key_path']
I have seen this error (undefined method `[]' for nil:NilClass), quite a bit online, however have not been able to narrow down the root cause in my recipe. Could I be missing something in my recipe file? I'm wondering if the root cause of the error could be related to these couple lines:
require 'openssl'
require 'net/ssh'