Merge pull request #6990 from chef/swap

Add swap_file resource from the swap cookbook

3 files changed, 250 insertions, 0 deletions

diff --git a/lib/chef/resource/swap_file.rb b/lib/chef/resource/swap_file.rb
new file mode 100644
index 0000000000..6beb20c976
--- /dev/null
+++ b/lib/chef/resource/swap_file.rb
@@ -0,0 +1,209 @@
+#
+# Copyright 2012-2018, Seth Vargo
+# Copyright 2017-2018, Chef Software, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require "chef/resource"
+
+class Chef
+  class Resource
+    class SwapFile < Chef::Resource
+      resource_name :swap_file
+      provides :swap_file
+
+      description "Use the swap_file resource to create or delete swap files on Linux systems."
+      introduced "14.0"
+
+      property :path, String,
+               description: "The path to put the swap file on the system.",
+               name_property: true
+
+      property :size, Integer,
+               description: "The size (in MBs) for the swap file."
+
+      property :persist, [TrueClass, FalseClass],
+               description: "Persist the swapon.",
+               default: false
+
+      property :timeout, Integer,
+               description: "Timeout for dd/fallocate.",
+               default: 600
+
+      property :swappiness, Integer,
+               description: "The swappiness value to set on the system."
+
+      action :create do
+        description "Create a swapfile."
+
+        if swap_enabled?
+          Chef::Log.debug("#{new_resource} already created - nothing to do")
+        else
+          begin
+            Chef::Log.info "starting first create: #{node['virtualization']['system']}"
+            do_create(swap_creation_command)
+          rescue Mixlib::ShellOut::ShellCommandFailed => e
+            Chef::Log.warn("#{new_resource} Rescuing failed swapfile creation for #{new_resource.path}")
+            Chef::Log.debug("#{new_resource} Exception when creating swapfile #{new_resource.path}: #{e}")
+            do_create(dd_command)
+          end
+        end
+        if new_resource.swappiness
+          declare_resource(:sysctl, "vm.swappiness") do
+            value new_resource.swappiness
+          end
+        end
+      end
+
+      action :remove do
+        description "Remove a swapfile and disable swap."
+
+        swapoff if swap_enabled?
+        remove_swapfile if ::File.exist?(new_resource.path)
+      end
+
+      action_class do
+        def do_create(command)
+          create_swapfile(command)
+          set_permissions
+          mkswap
+          swapon
+          persist if persist?
+        end
+
+        def create_swapfile(command)
+          converge_by "create empty swapfile at #{new_resource.path}" do # ~FC054
+            shell_out!(command, timeout: new_resource.timeout)
+          end
+        end
+
+        def set_permissions
+          permissions = "600"
+          converge_by "set permissions on #{new_resource.path} to #{permissions}" do
+            shell_out!("chmod #{permissions} #{new_resource.path}")
+          end
+        end
+
+        def mkswap
+          converge_by "make #{new_resource.path} swappable" do
+            shell_out!("mkswap -f #{new_resource.path}")
+          end
+        end
+
+        def swapon
+          converge_by "enable swap for #{new_resource.path}" do
+            shell_out!("swapon #{new_resource.path}")
+          end
+        end
+
+        def swapoff
+          converge_by "turn off swap for #{new_resource.path}" do
+            shell_out!("swapoff #{new_resource.path}")
+          end
+        end
+
+        def remove_swapfile
+          converge_by "remove swap file #{new_resource.path}" do
+            ::FileUtils.rm(new_resource.path)
+          end
+        end
+
+        def swap_enabled?
+          enabled_swapfiles = shell_out("swapon --summary").stdout
+          # Regex for our resource path and only our resource path
+          # It will terminate on whitespace after the path it match
+          # /testswapfile would match
+          # /testswapfiledir/someotherfile will not
+          swapfile_regex = Regexp.new("^#{new_resource.path}[\\s\\t\\n\\f]+")
+          !swapfile_regex.match(enabled_swapfiles).nil?
+        end
+
+        def swap_creation_command
+          command = if compatible_filesystem? && compatible_kernel && !docker?
+                      fallocate_command
+                    else
+                      dd_command
+                    end
+          Chef::Log.debug("#{new_resource} swap creation command is '#{command}'")
+          command
+        end
+
+        def fallback_swap_creation_command
+          command = dd_command
+          Chef::Log.debug("#{new_resource} fallback swap creation command is '#{command}'")
+          command
+        end
+
+        # The block size (1MB)
+        def block_size
+          1_048_576
+        end
+
+        def fallocate_size
+          size = block_size * new_resource.size
+          Chef::Log.debug("#{new_resource} fallocate size is #{size}")
+          size
+        end
+
+        def fallocate_command
+          size = fallocate_size
+          command = "fallocate -l #{size} #{new_resource.path}"
+          Chef::Log.debug("#{new_resource} fallocate command is '#{command}'")
+          command
+        end
+
+        def dd_command
+          command = "dd if=/dev/zero of=#{new_resource.path} bs=#{block_size} count=#{new_resource.size}"
+          Chef::Log.debug("#{new_resource} dd command is '#{command}'")
+          command
+        end
+
+        def compatible_kernel
+          fallocate_location = shell_out("which fallocate").stdout
+          Chef::Log.debug("#{new_resource} fallocate location is '#{fallocate_location}'")
+          ::File.exist?(fallocate_location.chomp)
+        end
+
+        def compatible_filesystem?
+          compatible_filesystems = %w{xfs ext4}
+          parent_directory = ::File.dirname(new_resource.path)
+          # Get FS info, get second line as first is column headings
+          command = "df -PT #{parent_directory} | awk 'NR==2 {print $2}'"
+          result = shell_out(command).stdout
+          Chef::Log.debug("#{new_resource} filesystem listing is '#{result}'")
+          compatible_filesystems.any? { |fs| result.include? fs }
+        end
+
+        def persist?
+          !!new_resource.persist
+        end
+
+        def persist
+          fstab = "/etc/fstab"
+          contents = ::File.readlines(fstab)
+          addition = "#{new_resource.path} swap swap defaults 0 0"
+
+          if contents.any? { |line| line.strip == addition }
+            Chef::Log.debug("#{new_resource} already added to /etc/fstab - skipping")
+          else
+            Chef::Log.info("#{new_resource} adding entry to #{fstab} for #{new_resource.path}")
+
+            contents << "#{addition}\n"
+            ::File.open(fstab, "w") { |f| f.write(contents.join("")) }
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/chef/resources.rb b/lib/chef/resources.rb
index e123cc5915..c232ce04e1 100644
--- a/lib/chef/resources.rb
+++ b/lib/chef/resources.rb
@@ -90,6 +90,7 @@ require "chef/resource/script"
 require "chef/resource/service"
 require "chef/resource/sudo"
 require "chef/resource/sysctl"
+require "chef/resource/swap_file"
 require "chef/resource/systemd_unit"
 require "chef/resource/windows_service"
 require "chef/resource/subversion"
diff --git a/spec/unit/resource/swap_file_spec.rb b/spec/unit/resource/swap_file_spec.rb
new file mode 100644
index 0000000000..905e12646a
--- /dev/null
+++ b/spec/unit/resource/swap_file_spec.rb
@@ -0,0 +1,40 @@
+#
+# Copyright:: Copyright 2018, Chef Software, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require "spec_helper"
+
+describe Chef::Resource::SwapFile do
+  let(:resource) { Chef::Resource::SwapFile.new("swapfile") }
+
+  it "sets resource name as :swap_file" do
+    expect(resource.resource_name).to eql(:swap_file)
+  end
+
+  it "sets the path as its name" do
+    expect(resource.path).to eql("swapfile")
+  end
+
+  it "sets the default action as :create" do
+    expect(resource.action).to eql([:create])
+  end
+
+  it "supports :create and :remove actions" do
+    expect { resource.action :create }.not_to raise_error
+    expect { resource.action :remove }.not_to raise_error
+    expect { resource.action :delete }.to raise_error(ArgumentError)
+  end
+end