Namespace the container resolver into Linux

FreeBSD has containers (jails) but already handled through the 'virutal'
resolver, so for now we just consider Linux being able to handle
containers as the code aleady depend on Linux-specific resolvers.

lib/facter/facts/linux/hypervisors/docker.rb

@@ -12,7 +12,7 @@ def call_the_resolver
         end
 
         def check_docker
-          info = Facter::Resolvers::Containers.resolve(:hypervisor)
+          info = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
           info[:docker] if info
         end
       end

lib/facter/facts/linux/hypervisors/lxc.rb

@@ -12,7 +12,7 @@ def call_the_resolver
         end
 
         def check_lxc
-          info = Facter::Resolvers::Containers.resolve(:hypervisor)
+          info = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
           info[:lxc] if info
         end
       end

lib/facter/facts/linux/hypervisors/systemd_nspawn.rb

@@ -12,7 +12,7 @@ def call_the_resolver
         end
 
         def check_nspawn
-          info = Facter::Resolvers::Containers.resolve(:hypervisor)
+          info = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
           info[:systemd_nspawn] if info
         end
       end

lib/facter/facts/linux/system_uptime/days.rb

@@ -8,7 +8,7 @@ class Days
         ALIASES = 'uptime_days'
 
         def call_the_resolver
-          hypervisors = Facter::Resolvers::Containers.resolve(:hypervisor)
+          hypervisors = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
 
           fact_value = if hypervisors && hypervisors[:docker]
                          Facter::Resolvers::Linux::DockerUptime.resolve(:days)

lib/facter/facts/linux/system_uptime/hours.rb

@@ -8,7 +8,7 @@ class Hours
         ALIASES = 'uptime_hours'
 
         def call_the_resolver
-          hypervisors = Facter::Resolvers::Containers.resolve(:hypervisor)
+          hypervisors = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
 
           fact_value = if hypervisors && hypervisors[:docker]
                          Facter::Resolvers::Linux::DockerUptime.resolve(:hours)

lib/facter/facts/linux/system_uptime/seconds.rb

@@ -8,7 +8,7 @@ class Seconds
         ALIASES = 'uptime_seconds'
 
         def call_the_resolver
-          hypervisors = Facter::Resolvers::Containers.resolve(:hypervisor)
+          hypervisors = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
 
           fact_value = if hypervisors && hypervisors[:docker]
                          Facter::Resolvers::Linux::DockerUptime.resolve(:seconds)

lib/facter/facts/linux/system_uptime/uptime.rb

@@ -8,7 +8,7 @@ class Uptime
         ALIASES = 'uptime'
 
         def call_the_resolver
-          hypervisors = Facter::Resolvers::Containers.resolve(:hypervisor)
+          hypervisors = Facter::Resolvers::Linux::Containers.resolve(:hypervisor)
 
           fact_value = if hypervisors && hypervisors[:docker]
                          Facter::Resolvers::Linux::DockerUptime.resolve(:uptime)

lib/facter/framework/core/file_loader.rb

@@ -52,7 +52,6 @@
 require_relative '../../resolvers/augeas'
 require_relative '../../resolvers/az'
 require_relative '../../resolvers/base_resolver'
-require_relative '../../resolvers/containers'
 require_relative '../../resolvers/debian_version'
 require_relative '../../resolvers/dmi_decode'
 require_relative '../../resolvers/ec2'
@@ -503,6 +502,7 @@
     require_relative '../../facts/linux/virtual'
     require_relative '../../facts/linux/xen'
 
+    require_relative '../../resolvers/linux/containers'
     require_relative '../../resolvers/linux/disks'
     require_relative '../../resolvers/linux/dmi'
     require_relative '../../resolvers/linux/docker_uptime'

lib/facter/resolvers/linux/containers.rb

@@ -0,0 +1,81 @@
+# frozen_string_literal: true
+
+module Facter
+  module Resolvers
+    module Linux
+      class Containers < BaseResolver
+        # :virtual
+        # :hypervisor
+
+        init_resolver
+
+        INFO = { 'docker' => 'id', 'lxc' => 'name' }.freeze
+
+        class << self
+          private
+
+          def post_resolve(fact_name, _options)
+            @fact_list.fetch(fact_name) do
+              read_environ(fact_name) || read_cgroup(fact_name)
+            end
+          end
+
+          def read_cgroup(fact_name)
+            output_cgroup = Facter::Util::FileHelper.safe_read('/proc/1/cgroup', nil)
+            return unless output_cgroup
+
+            output_docker = %r{docker/(.+)}.match(output_cgroup)
+            output_lxc = %r{^/lxc/([^/]+)}.match(output_cgroup)
+
+            info, vm = extract_vm_and_info(output_docker, output_lxc)
+            @fact_list[:vm] = vm
+            @fact_list[:hypervisor] = { vm.to_sym => info } if vm
+            @fact_list[fact_name]
+          end
+
+          def read_environ(fact_name)
+            begin
+              container = Facter::Util::Linux::Proc.getenv_for_pid(1, 'container')
+            rescue StandardError => e
+              log.warn("Unable to getenv for pid 1, '#{e}'")
+              return nil
+            end
+            return if container.nil? || container.empty?
+
+            info = {}
+            case container
+            when 'lxc'
+              vm = 'lxc'
+            when 'podman'
+              vm = 'podman'
+            when 'crio'
+              vm = 'crio'
+            when 'systemd-nspawn'
+              vm = 'systemd_nspawn'
+              info = { 'id' => Facter::Util::FileHelper.safe_read('/etc/machine-id', nil).strip }
+            else
+              vm = 'container_other'
+              log.warn("Container runtime, '#{container}', is unsupported, setting to '#{vm}'")
+            end
+            @fact_list[:vm] = vm
+            @fact_list[:hypervisor] = { vm.to_sym => info } if vm
+            @fact_list[fact_name]
+          end
+
+          def extract_vm_and_info(output_docker, output_lxc)
+            vm = nil
+            if output_docker
+              vm = 'docker'
+              info = output_docker[1]
+            elsif output_lxc
+              vm = 'lxc'
+              info = output_lxc[1]
+            end
+
+            [info ? { INFO[vm] => info } : {}, vm]
+          end
+        end
+      end
+    end
+  end
+end

lib/facter/util/facts/posix/virtual_detector.rb

@@ -16,7 +16,7 @@ def platform
             private
 
             def check_docker_lxc
-              Facter::Resolvers::Containers.resolve(:vm)
+              Facter::Resolvers::Linux::Containers.resolve(:vm)
             end
 
             def check_gce

spec/facter/facts/linux/hypervisors/docker_spec.rb

@@ -5,7 +5,7 @@
     subject(:fact) { Facts::Linux::Hypervisors::Docker.new }
 
     before do
-      allow(Facter::Resolvers::Containers).to \
+      allow(Facter::Resolvers::Linux::Containers).to \
         receive(:resolve).with(:hypervisor).and_return(hv)
     end
 

spec/facter/facts/linux/hypervisors/lxc_spec.rb

@@ -5,7 +5,7 @@
     subject(:fact) { Facts::Linux::Hypervisors::Lxc.new }
 
     before do
-      allow(Facter::Resolvers::Containers).to \
+      allow(Facter::Resolvers::Linux::Containers).to \
         receive(:resolve).with(:hypervisor).and_return(hv)
     end
 

spec/facter/facts/linux/hypervisors/systemd_nspawn_spec.rb

@@ -5,7 +5,7 @@
     subject(:fact) { Facts::Linux::Hypervisors::SystemdNspawn.new }
 
     before do
-      allow(Facter::Resolvers::Containers).to \
+      allow(Facter::Resolvers::Linux::Containers).to \
         receive(:resolve).with(:hypervisor).and_return(hv)
     end
 

spec/facter/facts/linux/system_uptime/days_spec.rb

@@ -8,7 +8,7 @@
 
     context 'when on linux' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
         allow(Facter::Resolvers::Uptime).to receive(:resolve).with(:days).and_return(value)
       end
 
@@ -21,7 +21,7 @@
 
     context 'when in docker container' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
         allow(Facter::Resolvers::Linux::DockerUptime).to receive(:resolve).with(:days).and_return(value)
       end
 

spec/facter/facts/linux/system_uptime/hours_spec.rb

@@ -8,7 +8,7 @@
 
     context 'when on linux' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
         allow(Facter::Resolvers::Uptime).to receive(:resolve).with(:hours).and_return(value)
       end
 
@@ -21,7 +21,7 @@
 
     context 'when in docker container' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
         allow(Facter::Resolvers::Linux::DockerUptime).to receive(:resolve).with(:hours).and_return(value)
       end
 

spec/facter/facts/linux/system_uptime/seconds_spec.rb

@@ -8,7 +8,7 @@
 
     context 'when on linux' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
         allow(Facter::Resolvers::Uptime).to receive(:resolve).with(:seconds).and_return(value)
       end
 
@@ -21,7 +21,7 @@
 
     context 'when in docker container' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
         allow(Facter::Resolvers::Linux::DockerUptime).to receive(:resolve).with(:seconds).and_return(value)
       end
 

spec/facter/facts/linux/system_uptime/uptime_spec.rb

@@ -8,7 +8,7 @@
 
     context 'when on linux' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return(nil)
         allow(Facter::Resolvers::Uptime).to receive(:resolve).with(:uptime).and_return(value)
       end
 
@@ -21,7 +21,7 @@
 
     context 'when in docker container' do
       before do
-        allow(Facter::Resolvers::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
+        allow(Facter::Resolvers::Linux::Containers).to receive(:resolve).with(:hypervisor).and_return({ docker: '123' })
         allow(Facter::Resolvers::Linux::DockerUptime).to receive(:resolve).with(:uptime).and_return(value)
       end
 

spec/facter/resolvers/containers_spec.rb → spec/facter/resolvers/linux/containers_spec.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
-describe Facter::Resolvers::Containers do
-  subject(:containers_resolver) { Facter::Resolvers::Containers }
+describe Facter::Resolvers::Linux::Containers do
+  subject(:containers_resolver) { Facter::Resolvers::Linux::Containers }
 
   before do
     allow(Facter::Util::FileHelper).to receive(:safe_read)