Add swap_percent_used metric

Change-Id: I1ac8dc82ecfd9c52ceaa58fbe06edfcea9576a05

deployment_scripts/puppet/modules/lma_collector/files/plugins/decoders/collectd.lua

@@ -34,6 +34,7 @@ local processes_map = {
 -- this is needed for the libvirt metrics because in that case, collectd sends
 -- the instance's ID instead of the hostname in the 'host' attribute
 local hostname = read_config('hostname') or error('hostname must be specified')
+local swap_size = (read_config('swap_size') or 0) + 0
 
 function replace_dot_by_sep (str)
     return string.gsub(str, '%.', sep)
@@ -375,6 +376,14 @@ function process_message ()
             if not skip_it then
                 utils.inject_tags(msg)
                 utils.safe_inject_message(msg)
+                if metric_source == 'swap' and metric_name == 'swap_used' and swap_size > 0 then
+                    -- collectd 5.4.0 doesn't report the used swap in
+                    -- percentage, this is why the metric is computed and
+                    -- injected by this plugin.
+                    msg['Fields']['name'] = 'swap_percent_used'
+                    msg['Fields']['value'] = value / swap_size
+                    utils.safe_inject_message(msg)
+                end
             end
         end
     end

deployment_scripts/puppet/modules/lma_collector/manifests/collectd/base.pp

@@ -133,7 +133,8 @@ class lma_collector::collectd::base (
     config_dir       => $lma_collector::params::metric_config_dir,
     filename         => "${lma_collector::params::plugins_dir}/decoders/collectd.lua" ,
     config           => {
-      hostname => $real_hostname
+      hostname  => $real_hostname,
+      swap_size => $::swapsize_mb * 1024 * 1024,
     },
     module_directory => $lua_modules_dir,
     notify           => Class['lma_collector::service::metric'],

deployment_scripts/puppet/modules/lma_collector/spec/classes/lma_collector_collectd_base_spec.rb

@@ -16,7 +16,8 @@ require 'spec_helper'
 describe 'lma_collector::collectd::base' do
     let(:facts) do
         {:kernel => 'Linux', :operatingsystem => 'Ubuntu',
-         :osfamily => 'Debian', :concat_basedir => '/foo'}
+         :osfamily => 'Debian', :concat_basedir => '/foo',
+         :swapsize_mb => 1024}
     end
 
     describe 'with defaults' do
@@ -27,7 +28,7 @@ describe 'lma_collector::collectd::base' do
         let(:facts) do
             {:kernel => 'Linux', :operatingsystem => 'Ubuntu',
              :osfamily => 'Debian', :concat_basedir => '/foo',
-             :interfaces => 'br-mgmt,en0,bond0,lo'}
+             :interfaces => 'br-mgmt,en0,bond0,lo', :swapsize_mb => 1024}
         end
 
         it { is_expected.to contain_class('collectd').with_purge(false) }

doc/user/source/metrics/system.rst

@@ -133,6 +133,8 @@ Swap
 * ``swap_io_in``, the number of swap bytes written per second.
 * ``swap_io_out``, the number of swap bytes read per second.
 * ``swap_used``, the amount of used memory (in bytes) that is in the swap.
+* ``swap_percent_used``, the amount of used memory (in percentages) that is in
+  the swap.
 
 Users
 ^^^^^