Add support for *BSD load averages

.rubocop_todo.yml

@@ -6,7 +6,7 @@
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 80
+# Offense count: 81
 # Configuration parameters: CustomTransform, IgnoreMethods.
 RSpec/FilePath:
   Exclude:
@@ -37,6 +37,7 @@ RSpec/FilePath:
     - 'spec/facter/resolvers/aix/architecture_resolver_spec.rb'
     - 'spec/facter/resolvers/aix/ffi_helper_spec.rb'
     - 'spec/facter/resolvers/aix/hardware_resolver_spec.rb'
+    - 'spec/facter/resolvers/bsd/ffi_helper_spec.rb'
     - 'spec/facter/resolvers/disk_resolver_spec.rb'
     - 'spec/facter/resolvers/dmi_resolver_spec.rb'
     - 'spec/facter/resolvers/filesystems_resolver_spec.rb'
@@ -191,7 +192,7 @@ RSpec/SubjectStub:
     - 'spec/custom_facts/util/fact_spec.rb'
     - 'spec/custom_facts/util/resolution_spec.rb'
 
-# Offense count: 169
+# Offense count: 180
 # Configuration parameters: IgnoreNameless, IgnoreSymbolicNames.
 RSpec/VerifiedDoubles:
   Exclude:
@@ -227,6 +228,7 @@ RSpec/VerifiedDoubles:
     - 'spec/facter/resolvers/aix/architecture_resolver_spec.rb'
     - 'spec/facter/resolvers/aix/ffi_helper_spec.rb'
     - 'spec/facter/resolvers/aix/hardware_resolver_spec.rb'
+    - 'spec/facter/resolvers/bsd/ffi_helper_spec.rb'
     - 'spec/facter/resolvers/macosx/mountpoints_resolver_spec.rb'
     - 'spec/facter/resolvers/mountpoints_resolver_spec.rb'
     - 'spec/facter/resolvers/solaris/current_zone_resolver_spec.rb'

lib/facts/bsd/load_averages.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Facts
+  module Bsd
+    class LoadAverages
+      FACT_NAME = 'load_averages'
+
+      def call_the_resolver
+        fact_value = Facter::Resolvers::Bsd::LoadAverages.resolve(:load_averages)
+        Facter::ResolvedFact.new(FACT_NAME, fact_value)
+      end
+    end
+  end
+end

lib/resolvers/bsd/ffi/ffi_helper.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'ffi'
+
+module Facter
+  module Bsd
+    module FfiHelper
+      module Libc
+        extend FFI::Library
+
+        ffi_lib 'c'
+        attach_function :getloadavg, %i[pointer int], :int
+      end
+
+      def self.read_load_averages
+        raw_loadavg = FFI::MemoryPointer.new(:double, 3)
+
+        res = Libc.getloadavg(raw_loadavg, 3)
+        return unless res == 3
+
+        raw_loadavg.read_array_of_double(res)
+      end
+    end
+  end
+end

lib/resolvers/bsd/load_averages_resolver.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+module Facter
+  module Resolvers
+    module Bsd
+      class LoadAverages < BaseResolver
+        @semaphore = Mutex.new
+        @fact_list ||= {}
+        class << self
+          private
+
+          def post_resolve(fact_name)
+            @fact_list.fetch(fact_name) { read_load_averages(fact_name) }
+          end
+
+          def read_load_averages(fact_name)
+            require_relative 'ffi/ffi_helper'
+            @fact_list[:load_averages] = %w[1m 5m 15m].zip(Facter::Bsd::FfiHelper.read_load_averages).to_h
+
+            @fact_list[fact_name]
+          end
+        end
+      end
+    end
+  end
+end

spec/facter/facts/bsd/load_averages_spec.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+describe Facts::Bsd::LoadAverages do
+  describe '#call_the_resolver' do
+    subject(:fact) { Facts::Bsd::LoadAverages.new }
+
+    let(:value) { { '1m' => 0.01, '5m' => 0.02, '15m' => 0.03 } }
+
+    before do
+      allow(Facter::Resolvers::Bsd::LoadAverages).to receive(:resolve).with(:load_averages).and_return(value)
+    end
+
+    it 'calls Facter::Resolvers::Bsd::LoadAverages' do
+      fact.call_the_resolver
+      expect(Facter::Resolvers::Bsd::LoadAverages).to have_received(:resolve).with(:load_averages)
+    end
+
+    it 'returns load_averages fact' do
+      expect(fact.call_the_resolver).to be_an_instance_of(Facter::ResolvedFact).and \
+        have_attributes(name: 'load_averages', value: value)
+    end
+  end
+end

spec/facter/resolvers/bsd/ffi_helper_spec.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+describe Facter::Bsd::FfiHelper do
+  let(:averages) { double('FFI::MemoryPointer') }
+
+  before do
+    allow(FFI::MemoryPointer).to receive(:new).with(:double, 3).and_return(averages)
+    allow(averages).to receive(:size).and_return(24)
+  end
+
+  after do
+    Facter::Resolvers::Bsd::LoadAverages.invalidate_cache
+  end
+
+  it 'returns load average' do
+    allow(Facter::Bsd::FfiHelper::Libc).to receive(:getloadavg).and_return(3)
+    allow(averages).to receive(:read_array_of_double).with(3).and_return([0.19482421875, 0.2744140625, 0.29296875])
+
+    expect(Facter::Bsd::FfiHelper.read_load_averages).to eq([0.19482421875, 0.2744140625, 0.29296875])
+  end
+
+  it 'does not return load average' do
+    allow(Facter::Bsd::FfiHelper::Libc).to receive(:getloadavg).and_return(-1)
+    expect(Facter::Bsd::FfiHelper.read_load_averages).to be_nil
+  end
+end

spec/facter/resolvers/bsd/load_averages_resolver_spec.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+describe Facter::Resolvers::Bsd::LoadAverages do
+  let(:load_averages) { [0.01, 0.02, 0.03] }
+
+  before do
+    allow(Facter::Bsd::FfiHelper).to receive(:read_load_averages)
+      .and_return(load_averages)
+  end
+
+  it 'returns load average' do
+    result = Facter::Resolvers::Bsd::LoadAverages.resolve(:load_averages)
+
+    expect(result).to eq('15m' => 0.03, '1m' => 0.01, '5m' => 0.02)
+  end
+end