node_merge.rb

#!/usr/bin/env ruby
# Copyright 2012 Opscode <legal@opscode.com>
#
# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements.  See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
# 
#   http://www.apache.org/licenses/LICENSE-2.0
# 
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.
#
# Merges a node json on disk in a repository with the current node object
# on the chef server. DeepMerge can't tell at what level you want it to
# overwrite instead of merge, so everything is merged. (Think run lists).
#
# 2012-09-27 Initial writeup - Bryan McLellan <btm@opscode.com>

require 'rubygems'
require 'json'
require 'chef/mash'
require 'chef/mixin/deep_merge'

if ARGV.length != 1
  puts STDERR, "Missing node name argument"
  puts STDERR, "merge_node.rb NODE_NAME"
  exit 1
end

unless File.directory?('nodes')
  puts STDERR, "Cannot find nodes directory, run from chef-repo"
  exit 1
end

def fetch_node(node_name)
  result = system("knife node show #{node_name} -Fj -l > nodes/.tmp.#{node_name}.json")

  unless result
    puts STDERR, "Unable to get node #{node_name} from server"
    exit 1
  end
end

def upload_node(node_name)
  result = system("knife node from file nodes/.tmp.#{node_name}.json")

  unless result
    puts STDERR, "Unable to save node #{node_name} to server"
    exit 1
  end
end

node_name = ARGV[0]

fetch_node(node_name)

current_node = JSON.parse(IO.read("nodes/.tmp.#{node_name}.json"))
repo_node = JSON.parse(IO.read("nodes/#{node_name}.json"))

new_node = Chef::Mixin::DeepMerge.merge(current_node, repo_node)

node_file = File.open("nodes/.tmp.#{node_name}.json", "w")
node_file.write(JSON.pretty_generate(new_node))
node_file.close

upload_node(node_name)

#File.delete("nodes/.tmp.#{node_name}.json")

puts "Merged node #{node_name} from repository"