(MODULES-1715) Add FQDN-based random string generator

README.markdown

@@ -244,6 +244,23 @@ This function flattens any deeply nested arrays and returns a single flat array
 Returns the largest integer less than or equal to the argument.
 Takes a single numeric value as an argument. *Type*: rvalue
 
+#### `fqdn_rand_string`
+
+Generates a random alphanumeric string using an optionally-specified character set (default is alphanumeric), combining the `$fqdn` fact and an optional seed for repeatable randomness.
+
+*Usage:*
+```
+fqdn_rand_string(LENGTH, [CHARSET], [SEED])
+```
+*Examples:*
+```
+fqdn_rand_string(10)
+fqdn_rand_string(10, 'ABCDEF!@#$%^')
+fqdn_rand_string(10, '', 'custom seed')
+```
+
+*Type*: rvalue
+
 #### `fqdn_rotate`
 
 Rotates an array a random number of times based on a node's fqdn. *Type*: rvalue

lib/puppet/parser/functions/fqdn_rand_string.rb

@@ -0,0 +1,34 @@
+Puppet::Parser::Functions::newfunction(
+  :fqdn_rand_string,
+  :arity => -2,
+  :type => :rvalue,
+  :doc => "Usage: `fqdn_rand_string(LENGTH, [CHARSET], [SEED])`. LENGTH is
+  required and must be a positive integer. CHARSET is optional and may be
+  `undef` or a string. SEED is optional and may be any number or string.
+
+  Generates a random string LENGTH characters long using the character set
+  provided by CHARSET, combining the `$fqdn` fact and the value of SEED for
+  repeatable randomness. (That is, each node will get a different random
+  string from this function, but a given node's result will be the same every
+  time unless its hostname changes.) Adding a SEED can be useful if you need
+  more than one unrelated string. CHARSET will default to alphanumeric if
+  `undef` or an empty string.") do |args|
+    raise(ArgumentError, "fqdn_rand_string(): wrong number of arguments (0 for 1)") if args.size == 0
+    Puppet::Parser::Functions.function('is_integer')
+    raise(ArgumentError, "fqdn_rand_base64(): first argument must be a positive integer") unless function_is_integer([args[0]]) and args[0].to_i > 0
+    raise(ArgumentError, "fqdn_rand_base64(): second argument must be undef or a string") unless args[1].nil? or args[1].is_a? String
+
+    Puppet::Parser::Functions.function('fqdn_rand')
+
+    length = args.shift.to_i
+    charset = args.shift.to_s.chars.to_a
+
+    charset = (0..9).map { |i| i.to_s } + ('A'..'Z').to_a + ('a'..'z').to_a if charset.empty?
+
+    rand_string = ''
+    for current in 1..length
+      rand_string << charset[function_fqdn_rand([charset.size, (args + [current.to_s]).join(':')]).to_i]
+    end
+
+    rand_string
+end

spec/acceptance/fqdn_rand_base64_spec.rb

@@ -0,0 +1,60 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper_acceptance'
+
+describe 'fqdn_rand_base64 function', :unless => unsupported_platforms.include?(fact('operatingsystem')) do
+  describe 'success' do
+    let(:facts_d) do
+      if fact('is_pe', '--puppet') == "true"
+        if fact('osfamily') =~ /windows/i
+          if fact('kernelmajversion').to_f < 6.0
+            'c:/documents and settings/all users/application data/puppetlabs/facter/facts.d'
+          else
+            'c:/programdata/puppetlabs/facter/facts.d'
+          end
+        else
+          '/etc/puppetlabs/facter/facts.d'
+        end
+      else
+        '/etc/facter/facts.d'
+      end
+    end
+    after :each do
+      shell("if [ -f '#{facts_d}/fqdn.txt' ] ; then rm '#{facts_d}/fqdn.txt' ; fi")
+    end
+    before :each do
+      #no need to create on windows, pe creates by default
+      if fact('osfamily') !~ /windows/i
+        shell("mkdir -p '#{facts_d}'")
+      end
+    end
+    it 'generates random base64 strings' do
+      shell("echo fqdn=fakehost.localdomain > '#{facts_d}/fqdn.txt'")
+      pp = <<-eos
+      $l = 10
+      $o = fqdn_rand_base64($l)
+      notice(inline_template('fqdn_rand_base64 is <%= @o.inspect %>'))
+      eos
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/fqdn_rand_base64 is "8ySYp0dq0B"/)
+      end
+    end
+    it 'generates random base64 strings with custom seeds' do
+      shell("echo fqdn=fakehost.localdomain > '#{facts_d}/fqdn.txt'")
+      pp = <<-eos
+      $l = 10
+      $s = 'seed'
+      $o = fqdn_rand_base64($l, $s)
+      notice(inline_template('fqdn_rand_base64 is <%= @o.inspect %>'))
+      eos
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/fqdn_rand_base64 is "6J2c4oMRUJ"/)
+      end
+    end
+  end
+  describe 'failure' do
+    it 'handles improper argument counts'
+    it 'handles non-numbers for length argument'
+  end
+end

spec/acceptance/fqdn_rand_string_spec.rb

@@ -0,0 +1,60 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper_acceptance'
+
+describe 'fqdn_rand_string function', :unless => unsupported_platforms.include?(fact('operatingsystem')) do
+  describe 'success' do
+    let(:facts_d) do
+      if fact('is_pe', '--puppet') == "true"
+        if fact('osfamily') =~ /windows/i
+          if fact('kernelmajversion').to_f < 6.0
+            'c:/documents and settings/all users/application data/puppetlabs/facter/facts.d'
+          else
+            'c:/programdata/puppetlabs/facter/facts.d'
+          end
+        else
+          '/etc/puppetlabs/facter/facts.d'
+        end
+      else
+        '/etc/facter/facts.d'
+      end
+    end
+    after :each do
+      shell("if [ -f '#{facts_d}/fqdn.txt' ] ; then rm '#{facts_d}/fqdn.txt' ; fi")
+    end
+    before :each do
+      #no need to create on windows, pe creates by default
+      if fact('osfamily') !~ /windows/i
+        shell("mkdir -p '#{facts_d}'")
+      end
+    end
+    it 'generates random alphanumeric strings' do
+      shell("echo fqdn=fakehost.localdomain > '#{facts_d}/fqdn.txt'")
+      pp = <<-eos
+      $l = 10
+      $o = fqdn_rand_string($l)
+      notice(inline_template('fqdn_rand_string is <%= @o.inspect %>'))
+      eos
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/fqdn_rand_string is "7oDp0KOr1b"/)
+      end
+    end
+    it 'generates random alphanumeric strings with custom seeds' do
+      shell("echo fqdn=fakehost.localdomain > '#{facts_d}/fqdn.txt'")
+      pp = <<-eos
+      $l = 10
+      $s = 'seed'
+      $o = fqdn_rand_string($l, $s)
+      notice(inline_template('fqdn_rand_string is <%= @o.inspect %>'))
+      eos
+
+      apply_manifest(pp, :catch_failures => true) do |r|
+        expect(r.stdout).to match(/fqdn_rand_string is "3HS4mbuI3E"/)
+      end
+    end
+  end
+  describe 'failure' do
+    it 'handles improper argument counts'
+    it 'handles non-numbers for length argument'
+  end
+end

spec/functions/fqdn_rand_string_spec.rb

@@ -0,0 +1,91 @@
+#! /usr/bin/env ruby -S rspec
+require 'spec_helper'
+
+describe "the fqdn_rand_string function" do
+  let(:scope) { PuppetlabsSpec::PuppetInternals.scope }
+
+  it "should exist" do
+    expect(Puppet::Parser::Functions.function("fqdn_rand_string")).to eq("function_fqdn_rand_string")
+  end
+
+  it "should raise an ArgumentError if there is less than 1 argument" do
+    expect { fqdn_rand_string() }.to( raise_error(ArgumentError, /wrong number of arguments/))
+  end
+
+  it "should raise an ArgumentError if argument 1 isn't a positive integer" do
+    expect { fqdn_rand_string(0) }.to( raise_error(ArgumentError, /first argument must be a positive integer/))
+    expect { fqdn_rand_string(-1) }.to( raise_error(ArgumentError, /first argument must be a positive integer/))
+    expect { fqdn_rand_string(0.5) }.to( raise_error(ArgumentError, /first argument must be a positive integer/))
+  end
+
+  it "provides a valid alphanumeric string when no character set is provided" do
+    length = 100
+    string = %r{\A[a-zA-Z0-9]{#{length}}\z}
+    expect(fqdn_rand_string(length).match(string)).not_to eq(nil)
+  end
+
+  it "provides a valid alphanumeric string when an undef character set is provided" do
+    length = 100
+    string = %r{\A[a-zA-Z0-9]{#{length}}\z}
+    expect(fqdn_rand_string(length, :charset => nil).match(string)).not_to eq(nil)
+  end
+
+  it "provides a valid alphanumeric string when an empty character set is provided" do
+    length = 100
+    string = %r{\A[a-zA-Z0-9]{#{length}}\z}
+    expect(fqdn_rand_string(length, :charset => '').match(string)).not_to eq(nil)
+  end
+
+  it "uses a provided character set" do
+    length = 100
+    charset = '!@#$%^&*()-_=+'
+    string = %r{\A[#{charset}]{#{length}}\z}
+    expect(fqdn_rand_string(length, :charset => charset).match(string)).not_to eq(nil)
+  end
+
+  it "provides a random string exactly as long as the given length" do
+    expect(fqdn_rand_string(10).size).to eql(10)
+  end
+
+  it "provides the same 'random' value on subsequent calls for the same host" do
+    expect(fqdn_rand_string(10)).to eql(fqdn_rand_string(10))
+  end
+
+  it "considers the same host and same extra arguments to have the same random sequence" do
+    first_random = fqdn_rand_string(10, :extra_identifier => [1, "same", "host"])
+    second_random = fqdn_rand_string(10, :extra_identifier => [1, "same", "host"])
+
+    expect(first_random).to eql(second_random)
+  end
+
+  it "allows extra arguments to control the random value on a single host" do
+    first_random = fqdn_rand_string(10, :extra_identifier => [1, "different", "host"])
+    second_different_random = fqdn_rand_string(10, :extra_identifier => [2, "different", "host"])
+
+    expect(first_random).not_to eql(second_different_random)
+  end
+
+  it "should return different strings for different hosts" do
+    val1 = fqdn_rand_string(10, :host => "first.host.com")
+    val2 = fqdn_rand_string(10, :host => "second.host.com")
+
+    expect(val1).not_to eql(val2)
+  end
+
+  def fqdn_rand_string(max, args = {})
+    host = args[:host] || '127.0.0.1'
+    charset = args[:charset]
+    extra = args[:extra_identifier] || []
+
+    scope = PuppetlabsSpec::PuppetInternals.scope
+    scope.stubs(:[]).with("::fqdn").returns(host)
+    scope.stubs(:lookupvar).with("::fqdn").returns(host)
+
+    function_args = [max]
+    if args.has_key?(:charset) or !extra.empty?
+      function_args << charset
+    end
+    function_args += extra
+    scope.function_fqdn_rand_string(function_args)
+  end
+end