New feature: resizing existing swapfiles

lib/puppet/parser/functions/difference_within_margin.rb

@@ -0,0 +1,62 @@
+# When given an array of two numbers and a margin, returns true
+# if the difference is less than the margin. Basically statistical
+# range with a margin.
+#
+# @example Difference between 150 and 100 is 50, margin is 60. So true
+#   $within_margin = difference_within_margin([100,150],60)
+#
+# @example Difference between 150 and 100 is 50, margin is 40. So false
+#   $within_margin = difference_within_margin([100,150],40)
+#
+# @return [Boolean] whether the difference between two numbers is within in a margin
+#
+# @param num_a [Array] array of two numbers to compare
+# @param num_b [Float] the margin to compare the two numbers
+module Puppet::Parser::Functions
+  newfunction(:difference_within_margin, :type => :rvalue, :doc => <<-EOS
+Get's the difference between two numbers, with a third argument as a margin
+
+*Example:*
+
+    compare_with_margin(100,150,60)
+
+Would result in:
+
+    true
+
+    compare_with_margin(100,150,40)
+
+Would result in:
+
+    false
+
+    EOS
+  ) do |arguments|
+
+    # Check that more than 2 arguments have been given ...
+    raise(Puppet::ParseError, "compare_with_margin(): Wrong number of arguments " +
+      "given (#{arguments.size} for 2)") unless arguments.size == 2
+
+    # Check that the first parameter is an array
+    unless arguments[0].is_a?(Array)
+      raise(Puppet::ParseError, 'difference_within_margin(): Requires array to work with')
+    end
+
+    # Check that the first parameter is an array
+    if arguments[0].empty?
+      raise(Puppet::ParseError, 'difference_within_margin(): arg[0] array cannot be empty')
+    end
+
+    arguments[0].collect! { |i| i.to_f }
+
+    difference = arguments[0].minmax[1].to_f - arguments[0].minmax[0].to_f
+
+    if difference < arguments[1].to_f
+      return true
+    else
+      return false
+    end
+  end
+end
+
+# vim: set ts=2 sw=2 et :

manifests/files.pp

@@ -40,6 +40,9 @@
   $options       = 'defaults',
   $timeout       = 300,
   $cmd           = 'dd',
+  $resize_existing = false,
+  $resize_margin   = '50MB',
+  $resize_verbose  = false,
 )
 {
   # Parameter validation
@@ -49,6 +52,27 @@
   validate_bool($add_mount)
 
   if $ensure == 'present' {
+
+    if ($resize_existing and $::swapfile_sizes) {
+
+      if (is_hash($::swapfile_sizes)) {
+
+        if (has_key($::swapfile_sizes,$swapfile)) {
+          ::swap_file::resize { $swapfile:
+            swapfile_path          => $swapfile,
+            margin                 => $resize_margin,
+            expected_swapfile_size => $swapfilesize,
+            actual_swapfile_size   => $::swapfile_sizes[$swapfile],
+            verbose                => $resize_verbose,
+            before                 => Exec["Create swap file ${swapfile}"],
+          }
+        }
+
+      } else {
+        fail('$resize_existing was set to true and stringify_facts was not false. This currently does not work, but will in the future. See https://github.com/petems/petems-swap_file/issues/57')
+      }
+    }
+
     exec { "Create swap file ${swapfile}":
       creates => $swapfile,
       timeout => $timeout,

manifests/resize.pp

@@ -0,0 +1,51 @@
+# A defined type to resize an existing swapfile
+#
+# @example
+#   ::swap_file::resize { '/mnt/swap.1:
+#     swapfile_path          => '/mnt/swap.1',
+#     margin                 => '500 MB',
+#     expected_swapfile_size => '1 GB,
+#   }
+#
+# @param [String] swapfile_path Path to the swapfile
+# @param [String] expected_swapfile_size Expected size of the swapfile
+# @param [String] actual_swapfile_size Actual size of the swapfile
+# @param [String] margin Margin that is checked before resizing the swapfile
+# @param [Boolean] verbose Adds a notify to explain why the change was made
+#
+# @author - Peter Souter
+#
+define swap_file::resize (
+  $swapfile_path,
+  $expected_swapfile_size,
+  $actual_swapfile_size,
+  $margin                 = '50MB',
+  $verbose                = false,
+)
+{
+  $margin_bytes                  = to_bytes($margin)
+  $existing_swapfile_bytes       = to_bytes("${actual_swapfile_size}kb")
+  $expected_swapfile_size_bytes  = to_bytes($expected_swapfile_size)
+
+  if !($expected_swapfile_size_bytes == $existing_swapfile_bytes) {
+    if !(difference_within_margin([$existing_swapfile_bytes, $expected_swapfile_size_bytes],$margin_bytes)) {
+      if ($verbose) {
+        $alert_message = "Existing : ${existing_swapfile_bytes}B\nExpected: ${expected_swapfile_size_bytes}B\nMargin: ${margin_bytes}B"
+        notify{"Resizing Swapfile Alert ${swapfile_path}":
+          name => $alert_message,
+        }
+      }
+      exec { "Detach swap file ${swapfile_path} for resize":
+        command => "/sbin/swapoff ${swapfile_path}",
+        onlyif  => "/sbin/swapon -s | grep ${swapfile_path}",
+      }
+      ->
+      exec { "Purge ${swapfile_path} for resize":
+        command => "/bin/rm -f ${swapfile_path}",
+        onlyif  => "test -f ${swapfile_path}",
+        path    => [ '/bin/', '/sbin/' , '/usr/bin/', '/usr/sbin/' ],
+      }
+    }
+  }
+
+}

spec/acceptance/swap_file_resizing_spec.rb

@@ -0,0 +1,50 @@
+require 'spec_helper_acceptance'
+
+describe 'swap_file class', :unless => UNSUPPORTED_PLATFORMS.include?(fact('osfamily')) do
+
+  context 'disable stringify_facts' do
+    shell('puppet config set stringify_facts false --section=agent', { :acceptable_exit_codes => [0,1] })
+    shell('puppet config set stringify_facts false', { :acceptable_exit_codes => [0,1] })
+  end
+
+  context 'swap_file' do
+    context 'swapfilesize => 100' do
+      it 'should work with no errors' do
+        pp = <<-EOS
+        swap_file::files { 'default':
+          ensure       => present,
+          swapfilesize => '100MB',
+          resize_existing => true,
+        }
+        EOS
+
+        # Run it twice and test for idempotency
+        apply_manifest(pp, :catch_failures => true)
+        apply_manifest(pp, :catch_changes  => true)
+      end
+      it 'should contain the given swapfile with the correct size (102396/100MB)' do
+        shell('/sbin/swapon -s | grep /mnt/swap.1', :acceptable_exit_codes => [0])
+        shell('/bin/cat /proc/swaps | grep 102396', :acceptable_exit_codes => [0])
+      end
+    end
+    context 'resize swap file' do
+      it 'should work with no errors' do
+        pp = <<-EOS
+        swap_file::files { 'default':
+          ensure          => present,
+          swapfilesize    => '200MB',
+          resize_existing => true,
+        }
+        EOS
+
+        # Run it twice and test for idempotency
+        apply_manifest(pp, :catch_failures => true)
+        apply_manifest(pp, :catch_changes => true)
+      end
+      it 'should contain the given swapfile with the resized size (204796kb/200MB)' do
+        shell('/sbin/swapon -s | grep /mnt/swap.1', :acceptable_exit_codes => [0])
+        shell('/bin/cat /proc/swaps | grep 204796', :acceptable_exit_codes => [0])
+      end
+    end
+  end
+end

spec/acceptance/swap_file_resizing_stringify_true_spec.rb

@@ -0,0 +1,48 @@
+require 'spec_helper_acceptance'
+
+describe 'swap_file class', :unless => UNSUPPORTED_PLATFORMS.include?(fact('osfamily')) do
+
+  context 'disable stringify_facts' do
+    shell('puppet config set stringify_facts true --section=agent', { :acceptable_exit_codes => [0,1] })
+    shell('puppet config set stringify_facts true', { :acceptable_exit_codes => [0,1] })
+  end
+
+  context 'swap_file' do
+    context 'swapfilesize => 100' do
+      it 'should work with no errors' do
+        pp = <<-EOS
+        swap_file::files { 'default':
+          ensure          => present,
+          swapfilesize    => '100MB',
+          resize_existing => true,
+        }
+        EOS
+
+        # Run it twice and test for idempotency
+        apply_manifest(pp, :catch_failures => true)
+        apply_manifest(pp, :catch_changes  => true)
+      end
+      it 'should contain the given swapfile with the correct size (102396/100MB)' do
+        shell('/sbin/swapon -s | grep /mnt/swap.1', :acceptable_exit_codes => [0])
+        shell('/bin/cat /proc/swaps | grep 102396', :acceptable_exit_codes => [0])
+      end
+    end
+    context 'resize swap file' do
+      it 'errors out if stringify_facts is true and resize_existing is true' do
+        pp = <<-EOS
+        swap_file::files { 'default':
+          ensure       => present,
+          swapfilesize => '100MB',
+          resize_existing => true,
+        }
+        EOS
+
+        # Run it twice and test for idempotency
+        apply_manifest(pp, :expect_failures => true) do |r|
+          expect(r.stderr).to match(/stringify_facts was true/)
+        end
+      end
+    end
+  end
+
+end