Support 'I' (TASK_IDLE) process state introduced by Linux kernel 4.14

 - default behavior counts I in the same bucket as D (uninterruptible)

Add --idle-state, -I option to split out TASK_IDLE processes into
a .idle metric

CHANGELOG.md

@@ -5,6 +5,12 @@ This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins
 
 
 ## [Unreleased]
+### Fixed
+- metrics-processes-threads-count.rb:  Backward compatible support for TASK_IDLE process state in Linux 4.14+ (@awangptc)
+
+### Added
+- metrics-processes-threads-count.rb:  Add option to separate out TASK_IDLE process into it's own metric (@awangptc)
+
 
 ## [3.1.0] - 2018-05-02
 ### Added

bin/metrics-processes-threads-count.rb

@@ -58,6 +58,13 @@ class ProcessesThreadsCount < Sensu::Plugin::Metric::CLI::Graphite
          boolean: true,
          default: false
 
+  option :idle_state,
+         description: 'If specified, count TASK_IDLE (I) state in separate .idle metric.  Note: TASK_IDLE is only available on Linux Kernels 4.14 and higher',
+         short: '-I',
+         long: '--idle-state',
+         boolean: true,
+         default: false
+
   # Takes a value to be tested as an integer. If a new Integer instance cannot be created from it, return 1.
   # See the comments on get_process_threads() for why 1 is returned.
   def test_int(i)
@@ -95,9 +102,14 @@ def count_processes_by_status(ps_table)
     %w[S R D T t X Z].each do |v|
       list_proc[v] = 0
     end
+    list_proc['I'] = 0 if config[:idle_state]
     if ps_table.first.respond_to?(:state)
       ps_table.each do |pr|
-        list_proc[pr[:state]] += 1
+        state = pr[:state]
+        if state == 'I'
+          state = 'D' unless config[:idle_state]
+        end
+        list_proc[state] += 1
       end
     end
     list_proc
@@ -131,6 +143,8 @@ def run
           output "#{[config[:scheme], 'dead'].join('.')} #{proc_count} #{timestamp}"
         when 'Z'
           output "#{[config[:scheme], 'zombie'].join('.')} #{proc_count} #{timestamp}"
+        when 'I'
+          output "#{[config[:scheme], 'idle'].join('.')} #{proc_count} #{timestamp}"
         end
       end
     end

test/metrics-processes-threads-count_spec.rb

@@ -45,6 +45,30 @@
     ptcount = ProcessesThreadsCount.new
     expect(ptcount.count_threads(table)).to eq(10)
   end
+
+  it 'should be able to count processes in each state - count I toward D for 4.14+ kernels' do
+    states = %w[S R D T t X Z I]
+    ps_entry = Struct.new(:state)
+    table = states.map { |state| ps_entry.new(state) }
+    ptcount = ProcessesThreadsCount.new
+    counts = ptcount.count_processes_by_status(table)
+    states.each do |state|
+      expect(counts[state]).to eq(2) if state == 'D'
+      expect(counts[state]).to be_nil if state == 'I'
+    end
+  end
+
+  it 'should be able to count processes in each state with :idle_state enabled - count I separate' do
+    states = %w[S R D T t X Z I]
+    ps_entry = Struct.new(:state)
+    table = states.map { |state| ps_entry.new(state) }
+    ptcount = ProcessesThreadsCount.new
+    ptcount.config[:idle_state] = true
+    counts = ptcount.count_processes_by_status(table)
+    states.each do |state|
+      expect(counts[state]).to eq(1)
+    end
+  end
 end
 
 describe ThreadsCount, 'run' do