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# frozen_string_literal: true
# Copyright 2023 Google LLC
#
# 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
#
# https://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 "google/cloud/env/lazy_value"
module Google
module Cloud
class Env
##
# Access to the SMBIOS information needed to determine if this Ruby
# process is running on a Google compute platform.
#
# This information lives at a file system path on Linux, but in the
# Registry on Windows.
#
# You can provide an override to "mock out" the behavior of this object.
#
class ComputeSMBIOS
##
# Create an SMBIOS access object
#
def initialize
@product_name_cache = LazyValue.new { load_product_name }
@override_product_name = nil
end
##
# Read the product name. On a Google compute platform, this should
# include the word "Google".
#
# This method may read the file system (on Linux) or registry (on
# Windows) the first time it is called, but it will cache the result
# for subsequent calls.
#
# @return [String] Product name, or the empty string if not found.
#
def product_name
@override_product_name || @product_name_cache.get.first
end
##
# The source of the product name data. Will be one of the following:
#
# * `:linux` - The data comes from the Linux SMBIOS under /sys
# * `:windows` - The data comes from the Windows Registry
# * `:error` - The data could not be obtained
# * `:override` - The data comes from an override
#
# This method may read the file system (on Linux) or registry (on
# Windows) the first time it is called, but it will cache the result
# for subsequent calls.
#
# @return [Symbol] The source
#
def product_name_source
@override_product_name ? :override : @product_name_cache.get.last
end
##
# Determine whether the SMBIOS state suggests that we are running on a
# Google compute platform.
#
# This method may read the file system (on Linux) or registry (on
# Windows) the first time it is called, but it will cache the result
# for subsequent calls.
#
# @return [true,false]
#
def google_compute?
product_name.include? "Google"
end
##
# The current override value for the product name, either a string
# value, or nil to disable mocking.
#
# @return [nil,String]
#
attr_accessor :override_product_name
##
# Run the given block with the product name mock modified. This is
# generally used for debugging/testing/mocking.
#
# @param override_name [nil,String]
#
def with_override_product_name override_name
old_override = @override_product_name
begin
@override_product_name = override_name
yield
ensure
@override_product_name = old_override
end
end
private
# @private The Windows registry key path
WINDOWS_KEYPATH = "SYSTEM\\HardwareConfig\\Current"
# @private The Windows registry key name
WINDOWS_KEYNAME = "SystemProductName"
# @private The Linux file path
LINUX_FILEPATH = "/sys/class/dmi/id/product_name"
private_constant :WINDOWS_KEYPATH, :WINDOWS_KEYNAME, :LINUX_FILEPATH
def load_product_name
require "win32/registry"
Win32::Registry::HKEY_LOCAL_MACHINE.open WINDOWS_KEYPATH do |reg|
return [reg[WINDOWS_KEYNAME].to_s, :windows]
end
rescue LoadError
begin
File.open LINUX_FILEPATH do |file|
return [file.readline(chomp: true), :linux]
end
rescue IOError, SystemCallError
["", :error]
end
end
end
end
end
end
|
