Puppet parser function that takes unsorted hash and outputs sorted JSON object.

sorted_json.rb

#
# LICENSE: https://gist.github.com/aj-jester/e0078c38db9eb7c1ef45
#
require 'json'

module JSON
  class << self
    @@loop = 0

    def sorted_generate(obj)
      case obj
        when Fixnum, Float, TrueClass, FalseClass, NilClass
          return obj.to_json
        when String
          # Convert quoted integers (string) to int
          return (obj.match(/\A[-]?[0-9]+\z/) ? obj.to_i : obj).to_json
        when Array
          arrayRet = []
          obj.each do |a|
            arrayRet.push(sorted_generate(a))
          end
          return "[" << arrayRet.join(',') << "]";
        when Hash
          ret = []
          obj.keys.sort.each do |k|
            ret.push(k.to_json << ":" << sorted_generate(obj[k]))
          end
          return "{" << ret.join(",") << "}";
        else
          raise Exception("Unable to handle object of type <%s>" % obj.class.to_s)
      end
    end

    def sorted_pretty_generate(obj, indent_len=4)

      # Indent length
      indent = " " * indent_len

      case obj

        when Fixnum, Float, TrueClass, FalseClass, NilClass
          return obj.to_json

        when String
          # Convert quoted integers (string) to int
          return (obj.match(/\A[-]?[0-9]+\z/) ? obj.to_i : obj).to_json

        when Array
          arrayRet = []

          # We need to increase the loop count before #each so the objects inside are indented twice.
          # When we come out of #each we decrease the loop count so the closing brace lines up properly.
          #
          # If you start with @@loop = 1, the count will be as follows
          #
          # "start_join": [     <-- @@loop == 1
          #   "192.168.50.20",  <-- @@loop == 2
          #   "192.168.50.21",  <-- @@loop == 2
          #   "192.168.50.22"   <-- @@loop == 2
          # ] <-- closing brace <-- @@loop == 1
          #
          @@loop += 1
          obj.each do |a|
            arrayRet.push(sorted_pretty_generate(a, indent_len))
          end
          @@loop -= 1

          return "[\n#{indent * (@@loop + 1)}" << arrayRet.join(",\n#{indent * (@@loop + 1)}") << "\n#{indent * @@loop}]";

        when Hash
          ret = []

          # This loop works in a similar way to the above
          @@loop += 1
          obj.keys.sort.each do |k|
            ret.push("#{indent * @@loop}" << k.to_json << ": " << sorted_pretty_generate(obj[k], indent_len))
          end
          @@loop -= 1

          return "{\n" << ret.join(",\n") << "\n#{indent * @@loop}}";
        else
          raise Exception("Unable to handle object of type <%s>" % obj.class.to_s)
      end

    end # end def

  end # end class

end # end module


module Puppet::Parser::Functions
  newfunction(:sorted_json, :type => :rvalue, :doc => <<-EOS
This function takes unsorted hash and outputs JSON object making sure the keys are sorted.
Optionally you can pass 2 additional parameters, pretty generate and indent length.

*Examples:*

    -------------------
    -- UNSORTED HASH --
    -------------------
    unsorted_hash = {
      'client_addr' => '127.0.0.1',
      'bind_addr'   => '192.168.34.56',
      'start_join'  => [
        '192.168.34.60',
        '192.168.34.61',
        '192.168.34.62',
      ],
      'ports'       => {
        'rpc'   => 8567,
        'https' => 8500,
        'http'  => -1,
      },
    }

    -----------------
    -- SORTED JSON --
    -----------------

    sorted_json(unsorted_hash)

    {"bind_addr":"192.168.34.56","client_addr":"127.0.0.1",
    "ports":{"http":-1,"https":8500,"rpc":8567},
    "start_join":["192.168.34.60","192.168.34.61","192.168.34.62"]}

    ------------------------
    -- PRETTY SORTED JSON --
    ------------------------
    Params: data <hash>, pretty <true|false>, indent <int>.

    sorted_json(unsorted_hash, true, 4)

    {
        "bind_addr": "192.168.34.56",
        "client_addr": "127.0.0.1",
        "ports": {
            "http": -1,
            "https": 8500,
            "rpc": 8567
        },
        "start_join": [
            "192.168.34.60",
            "192.168.34.61",
            "192.168.34.62"
        ]
    }

    EOS
  ) do |args|

    unsorted_hash = args[0]      || {}
    pretty        = args[1]      || false
    indent_len    = args[2].to_i || 4

    unsorted_hash.reject! {|key, value| value == :undef }

    if pretty
      return JSON.sorted_pretty_generate(unsorted_hash, indent_len) << "\n"
    else
      return JSON.sorted_generate(unsorted_hash)
    end
  end
end

sorted_json_spec.rb

#
# LICENSE: https://gist.github.com/aj-jester/e0078c38db9eb7c1ef45
#
require 'spec_helper'

describe 'sorted_json', :type => :puppet_function do

  let(:test_hash){ { 'z' => 3, 'a' => '1', 'p' => '2', 's' => '-7' } }
  before do
    @json = subject.call([test_hash, true])
  end
  it "sorts keys" do
    expect( @json.index('a') ).to be < @json.index('p')
    expect( @json.index('p') ).to be < @json.index('s')
    expect( @json.index('s') ).to be < @json.index('z')
  end

  it "prints pretty json" do
    expect(@json.split("\n").size).to eql(test_hash.size + 2) # +2 for { and }
  end

  it "prints ugly json" do
    json = subject.call([test_hash]) # pretty=false by default
    expect(json.split("\n").size).to eql(1)
  end

  it "validate ugly json" do
    json = subject.call([test_hash]) # pretty=false by default
    expect(json).to match("{\"a\":1,\"p\":2,\"s\":-7,\"z\":3}")
  end

  context 'nesting' do

    let(:nested_test_hash){ { 'z' => [{'l' => 3, 'k' => '2', 'j'=> '1'}],
                              'a' => {'z' => '3', 'x' => '1', 'y' => '2'},
                              'p' => [ '9','8','7'] } }
    before do
      @json = subject.call([nested_test_hash, true])
    end

    it "sorts nested hashes" do
      expect( @json.index('x') ).to be < @json.index('y')
      expect( @json.index('y') ).to be < @json.index('z')
    end

  end
end

z-LICENSE

The MIT License (MIT)

Copyright (c) 2015 aj-jester

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

sorted_json

Sorting a hash in Ruby is rather confusing. Add puppet type casting on top and each time the result could be different. Here is a good explanation. This causes puppet to notify services on config changes when the order of the hash keys changes on every puppet run.

• Sorts deep nested hashes and converts them to JSON
• Multiple data types supported
• Integers are placed without quotes (negative ints supported)
• Generates human readable JSON config

Example

Pass an unsorted hash to the function and returns a sorted json blob.

$sorted_json_config = sorted_json($unsorted_hash)

or use it directly with file's content attribute:

file { '/etc/service.json':
  content => sorted_json($unsorted_hash),
}

Prettier example

It optionally takes boolean as a second parameter to enable human readable config; defaults to false. You can also toggle indentation length using a third parameter; defaults to 4.

$unsorted_hash = {
  'client_addr' => '127.0.0.1',
  'bind_addr'   => '192.168.34.56',
  'start_join'  => [
    '192.168.34.60',
    '192.168.34.61',
    '192.168.34.62',
  ],
  'ports'       => {
    'rpc'   => 8567,
    'https' => 8500,
    'http'  => -1,
  },
}

sorted_json($unsorted_hash, true, 4)

{
    "bind_addr": "192.168.34.56",
    "client_addr": "127.0.0.1",
    "ports": {
        "http": -1,
        "https": 8500,
        "rpc": 8567
    },
    "start_join": [
        "192.168.34.60",
        "192.168.34.61",
        "192.168.34.62"
    ]
}

Authors

https://github.com/aj-jester
https://github.com/halkeye (https://gist.github.com/halkeye/2287885)
https://github.com/falzm (https://gist.github.com/falzm/8575549)
https://github.com/teaforthecat (tests)

newfunction() is Puppet 3 Syntax. Please move to create_function()