LongLonghaoran

初级架构师都干些什么？

LongLonghaoran — Mon, 19 Jul 2021 23:08:02 +0800

听我女朋友说她们公司之前招聘了 2 个应届实习生，现在转正了，岗位定的是初级架构师，惊了，架构师还带初级这种说法的吗？而且还是应届生，上网搜索了一下，还真有很多初级架构师的招聘，真让我备受冲击啊。。

require、load 加载机制

LongLonghaoran — Tue, 01 Jun 2021 15:53:53 +0800

require 会按照$LOAD_PATH 中的路径来加载，但是 gems 路径并不在$LOAD_PATH 中，为什么也可以加载的到呢？

load 方法：

load 方法用于根据相对路径、绝对路径、LOAD_PATH 来加载 ruby 文件，ruby 文件中的方法、类、常量都会导入，但是局部变量不会导入
特点：多次 load 同一个文件，会加载多次，也就是会多次执行被 load 的文件内的代码

$LOAD_PATH:

$LOAD_PATH 中存储了一组目录的绝对路径，对于 load 和 require 方法来说，如果方法参数只是一个不带路径的文件名的话，这时候就会去$LOAD_PATH 中定义的路径中去查找

默认的 require:

与 load 最大的不同是不会加载同一个文件两次，多次 require 同一个文件只会加载一次，所有被加载过的文件，都会记录在一个全局变量$LOADED_FEATURES 中，不论是 load 还是 require，都无法在不加路径（相对路径，绝对路径）的情况下直接加载文件，因为当前路径不在$LOAD_PATH 中

rubygems 中的 require，gems 是如何加载的呢？

rubygems是安装ruby是会默认一同安装的库，并且在启动ruby时会默认加载，比如启动irb之后，通过查看$LOADED_FEATURES就会发现，已经有很多.rb文件被加载进来了,ruby默认的Kernel#require这个方法已经被rubygems重写了

打开该文件会发现，该文件正是重写了默认的Kernel#require方法:

这个重写的版本最大的特点，就是可以用来加载已经安装好的 gem，加载的流程大致是这样的：
- 当 require(‘xx’) 的时候，先从$LOAD_PATH 中查找，是否能从$LOAD_PATH 中定义的路径中直接找到同名文件，如果找到的话，那么就按照默认情况直接加载
- 如果没有找到，那么将会安装 gems 的目录查找，找到之后，activating(激活),将该 gem 所在目录 (比如 rails-6.0.3.6) 添加到$LOAD_PATH，这个 gem 中的 gemspec 还会声明该 gem 需要 require 的其他路径，按照惯例，一般都只会添加 lib 这个目录
- 在$LOAD_PATH 被添加好之后，再次执行来查找 xx 这个文件，这次由于 gem 所在目录的 lib 也被添加到$LOAD_PATH，所以这次能够加载到了
一般来说 xx.rb，这个与 gem 包同名的 rb 文件中还会继续 require 该 gem 所需依赖的其他文件，随便查看一个 gem 看下，比如 tzinfo 这个 gem:

这些 require 的文件全部都在该 gem 的 lib 目录下，所以都能够正常加载，以这个 tzinfo 为例，再 require(‘tzinfo’) 之后，$LOADED_FEATURES 自然就多了一大堆已加载的文件列表：

Kernel#gem方法:

如果同时安装了一个 gem 的多个版本，比如 rails-6.0.3.7 和 rails-6.0.3.6，那么通过gem方法，可以将指定的gem的路径存入$LOAD_PATH，这样子之后在require该gem的时候，也就能按照指定的版本来加载了，上面的Kernel#require方法实际也是使用了gem方法，来将gem的路径放入$LOAD_PATH

rails 中加载 gems:

在 rails 的初始化加载/启动加载文件中 (比如 config/boot.rb)，会加载 bundler，我这里看到的是加载了 bundler/setup 这个文件，bundler/setup 的目的就是用来加载 Gemfile 中列出的 gem，执行流程大致是：
- 1.读取 Gemfile.lock 文件，根据 Gemfile.lock 文件中 spec 下的描述，获取该项目所需加载的 gem 的名称以及版本号
- 2.调用 gem 方法，来激活该 gem，也就是将 gem 的相关路径加入到$LOAD_PATH
- 3.最后在 application.rb 中，调用 Bundler.require，这个时候由于$LOAD_PATH 中已经存入了定义好的目录，所以 require 可以顺利的加载

有人了解 theforeman 这个项目吗？

LongLonghaoran — Tue, 18 May 2021 15:06:38 +0800

不卖关子，我是来寻求帮助的

官方链接

theforeman

以我这段时间的理解，非常简要的介绍一下

这是一个用于管理软件生命周期、主机、SSL 证书、HTTP 代理等很多与进行主机配置有关的操作的工具，涉及到技术插件比较多
这是它官方的架构图
如图所示，该项目是以 foreman(一个用 rails 框架开发的 web 项目) 为中心的系统管理平台，利用它进一步管理其余多台主机
除了这个 web 项目以外，其余的的涉及到外部主机管理的功能主要通过插件 plugin 的来提供，大致会用到的技术有：
libvirt 远程虚拟机管理
smart-proxy 智能代理，借助智能代理，统一管理外部主机配置（具体怎么用我现在也不是很清楚）
katello，内容管理，这个内容指的是软件包，比如用 katello 来管理使用 yum、apt 时下载软件包时，需要使用到的源，或者利用 katello 也可以自己搭建一个源
candlepin，这个好像是和 katello 集成在一起的，用于处理发布订阅，主机订阅之后，可以定期将我们搭建好的源中的内容推送给主机，使用 java+tomcat
pulp，这个好像也是和 katello 集成的，用于构建软件源仓库的，使用 python 编写
puppet，用于自动化安装、配置主机，内部使用 jruby 编写
....etc
接下来是 foreman 这个 web 项目本身，其用到的 gem、技术也和我之前写的 ruby on rails 截然不同
gettext 对应 i18n
rabl 对应 jbuilder
angular+react+webpacker-rails 对应 asset-pipeline(前端这块我挺傻眼的，代码规模有点大)
dynflow 对应 workflow
sidekiq 对应 foreman-task(其实仍然是用的 sidekiq，但是它封装了一层)
...etc

其实我被这个项目弄的很头疼

这个项目其实用到的技术挺多的，如果只是考虑搭建起来自己使用的话，还是比较方便的，官方提供了 foreman-installer 以及很多安装文档，尤其是 foreman-installer，在 rhel 环境是可以一键安装并运行的
但是对于如何开发这个项目我就很头疼了 (公司已经在使用这个项目进行运维管理，会有少数开发需求，主要集中在 foreman 和 katello)，不知道有没有人进行这方面开发工作，这该如何上手，看着 foreman 明明是一个 rails 项目，现在却只能在生产模式下改代码然后给它重启，着实难受

请教一个线程安全的问题

LongLonghaoran — Tue, 29 Dec 2020 16:20:22 +0800

本意是想模拟一下线程不安全的情况

本意是想模拟一下线程不安全的情况，于是写了一下代码，创建 2 个线程共用 1 个变量，每个线程里面将共用变量 number 减 1

arr = []
number = 10
2.times do |i|
    arr << Thread.new do
        puts "t#{i} 剩余#{number}颗豆子\n"
        while(number != 0 ) do
            sleep(1)
            puts "t#{i} 剩余#{number}颗豆子\n"
            number -= 1
            # puts "t#{i} 减去1颗后，剩余#{number}颗豆子\n"
        end
    end
end

但是一旦将 puts 语句放在 number -= 1 下方，就又不会出现这种问题了，这到底是为何

arr = []
number = 10
2.times do |i|
    arr << Thread.new do
        puts "t#{i} 剩余#{number}颗豆子\n"
        while(number != 0 ) do
            sleep(1)
            #puts "t#{i} 剩余#{number}颗豆子\n"
            number -= 1
            puts "t#{i} 减去1颗后，剩余#{number}颗豆子\n"
        end
    end
end

RSpec + FactoryBot 出现奇怪的问题

LongLonghaoran — Wed, 22 May 2019 22:57:10 +0800

application.rb:

config.generators do |g|
  g.test_framework :rspec,
                   fixtures: false,
                   view_specs: false,
                   helper_specs: false,
                   routing_specs: false,
                   controller_specs: false,
                   request_specs: false
  g.factory_bot dir: 'spec/factories'
end

Gemfile:

group :test, :development do
  gem "rspec-rails"
  gem 'factory_bot_rails'
end

这是 spec 下文件的样式:

spec/factories/users.rb

FactoryBot.define do
  100.times do |i|
    factory :user, class: "User" do
      login "test001"
      uid i
    end
  end
end

spec_helper.rb

# This file was generated by the `rails generate rspec:install` command. Conventionally, all
# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
# The generated `.rspec` file contains `--require spec_helper` which will cause
# this file to always be loaded, without a need to explicitly require it in any
# files.
#
# Given that it is always loaded, you are encouraged to keep this file as
# light-weight as possible. Requiring heavyweight dependencies from this file
# will add to the boot time of your test suite on EVERY test run, even for an
# individual file that may not need all of that loaded. Instead, consider making
# a separate helper file that requires the additional dependencies and performs
# the additional setup, and require it from the spec files that actually need
# it.
#
# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
RSpec.configure do |config|
  # rspec-expectations config goes here. You can use an alternate
  # assertion/expectation library such as wrong or the stdlib/minitest
  # assertions if you prefer.
  config.expect_with :rspec do |expectations|
    # This option will default to `true` in RSpec 4. It makes the `description`
    # and `failure_message` of custom matchers include text for helper methods
    # defined using `chain`, e.g.:
    #     be_bigger_than(2).and_smaller_than(4).description
    #     # => "be bigger than 2 and smaller than 4"
    # ...rather than:
    #     # => "be bigger than 2"
    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
  end

  # rspec-mocks config goes here. You can use an alternate test double
  # library (such as bogus or mocha) by changing the `mock_with` option here.
  config.mock_with :rspec do |mocks|
    # Prevents you from mocking or stubbing a method that does not exist on
    # a real object. This is generally recommended, and will default to
    # `true` in RSpec 4.
    mocks.verify_partial_doubles = true
  end

  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
  # have no way to turn it off -- the option exists only for backwards
  # compatibility in RSpec 3). It causes shared context metadata to be
  # inherited by the metadata hash of host groups and examples, rather than
  # triggering implicit auto-inclusion in groups with matching metadata.
  config.shared_context_metadata_behavior = :apply_to_host_groups

# The settings below are suggested to provide a good initial experience
# with RSpec, but feel free to customize to your heart's content.
=begin
  # This allows you to limit a spec run to individual examples or groups
  # you care about by tagging them with `:focus` metadata. When nothing
  # is tagged with `:focus`, all examples get run. RSpec also provides
  # aliases for `it`, `describe`, and `context` that include `:focus`
  # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
  config.filter_run_when_matching :focus

  # Allows RSpec to persist some state between runs in order to support
  # the `--only-failures` and `--next-failure` CLI options. We recommend
  # you configure your source control system to ignore this file.
  config.example_status_persistence_file_path = "spec/examples.txt"

  # Limits the available syntax to the non-monkey patched syntax that is
  # recommended. For more details, see:
  #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
  #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
  #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
  config.disable_monkey_patching!

  # Many RSpec users commonly either run the entire suite or an individual
  # file, and it's useful to allow more verbose output when running an
  # individual spec file.
  if config.files_to_run.one?
    # Use the documentation formatter for detailed output,
    # unless a formatter has already been configured
    # (e.g. via a command-line flag).
    config.default_formatter = "doc"
  end

  # Print the 10 slowest examples and example groups at the
  # end of the spec run, to help surface which specs are running
  # particularly slow.
  config.profile_examples = 10

  # Run specs in random order to surface order dependencies. If you find an
  # order dependency and want to debug it, you can fix the order by providing
  # the seed, which is printed after each run.
  #     --seed 1234
  config.order = :random

  # Seed global randomization in this process using the `--seed` CLI option.
  # Setting this allows you to use `--seed` to deterministically reproduce
  # test failures related to randomization by passing the same `--seed` value
  # as the one that triggered the failure.
  Kernel.srand config.seed
=end
end

rails_helper:

# This file is copied to spec/ when you run 'rails generate rspec:install'
require 'spec_helper'
require 'support/factory'
ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)
# Prevent database truncation if the environment is production
abort("The Rails environment is running in production mode!") if Rails.env.production?
require 'rspec/rails'
# Add additional requires below this line. Rails is not loaded until this point!

# Requires supporting ruby files with custom matchers and macros, etc, in
# spec/support/ and its subdirectories. Files matching `spec/**/*_spec.rb` are
# run as spec files by default. This means that files in spec/support that end
# in _spec.rb will both be required and run as specs, causing the specs to be
# run twice. It is recommended that you do not name files matching this glob to
# end with _spec.rb. You can configure this pattern with the --pattern
# option on the command line or in ~/.rspec, .rspec or `.rspec-local`.
#
# The following line is provided for convenience purposes. It has the downside
# of increasing the boot-up time by auto-requiring all files in the support
# directory. Alternatively, in the individual `*_spec.rb` files, manually
# require only the support files necessary.
#
# Dir[Rails.root.join('spec', 'support', '**', '*.rb')].each { |f| require f }

# Checks for pending migrations and applies them before tests are run.
# If you are not using ActiveRecord, you can remove these lines.
begin
  ActiveRecord::Migration.maintain_test_schema!
rescue ActiveRecord::PendingMigrationError => e
  puts e.to_s.strip
  exit 1
end
RSpec.configure do |config|
  # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
  config.fixture_path = "#{::Rails.root}/spec/fixtures"

  # If you're not using ActiveRecord, or you'd prefer not to run each of your
  # examples within a transaction, remove the following line or assign false
  # instead of true.
  config.use_transactional_fixtures = true

  # RSpec Rails can automatically mix in different behaviours to your tests
  # based on their file location, for example enabling you to call `get` and
  # `post` in specs under `spec/controllers`.
  #
  # You can disable this behaviour by removing the line below, and instead
  # explicitly tag your specs with their type, e.g.:
  #
  #     RSpec.describe UsersController, :type => :controller do
  #       # ...
  #     end
  #
  # The different available types are documented in the features, such as in
  # https://relishapp.com/rspec/rspec-rails/docs
  config.infer_spec_type_from_file_location!

  # Filter lines from Rails gems in backtraces.
  config.filter_rails_from_backtrace!
  # arbitrary gems may also be filtered via:
  # config.filter_gems_from_backtrace("gem name")
end

一切看起来没什么问题啊，但是就是会一个奇怪的错误，在运行 rspec 命令之后：

An error occurred while loading ./spec/models/apply_spec.rb.
Failure/Error: login 'test001'

NoMethodError:
  undefined method 'login' in 'user' factory
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/factory_bot-5.0.2/lib/factory_bot/definition_proxy.rb:97:in `method_missing'
# ./spec/factories/users.rb:3:in `block (2 levels) in <top (required)>'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/factory_bot-5.0.2/lib/factory_bot/syntax/default.rb:18:in `instance_eval'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/factory_bot-5.0.2/lib/factory_bot/syntax/default.rb:18:in `factory'
# ./spec/factories/users.rb:2:in `block in <top (required)>'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/factory_bot-5.0.2/lib/factory_bot/syntax/default.rb:49:in `instance_eval'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/factory_bot-5.0.2/lib/factory_bot/syntax/default.rb:49:in `run'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/factory_bot-5.0.2/lib/factory_bot/syntax/default.rb:7:in `define'
# ./spec/factories/users.rb:1:in `<top (required)>'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/activesupport-5.1.7/lib/active_support/dependencies.rb:286:in `load'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/activesupport-5.1.7/lib/active_support/dependencies.rb:286:in `block in load'
# /Users/a123/.rvm/gems/ruby-2.4.1@oa_saas/gems/activesupport-5.1.7/lib/active_support/dependencies.rb:258:in `load_dependen

尝试很多办法去修改配置了还是不行，实在没办法了

如何从两个二维数组建立 range 对象并且进行遍历操作

LongLonghaoran — Fri, 14 Sep 2018 14:49:20 +0800

问题是这样的，根据开始时间和结束时间，去遍历从开始到结束时间的年份和月份。

year1 = start_time1.year
month1 = start_time1.month
year2 = end_time.year
month2 = end_time.month

然后希望能够已这样的方式去遍历

([year1, month1]..[year2, month2]).each do |y, m|
### y和m分别从开始到结束时间的年和月
end

求帮助~，谢谢🙏

RubyMine、RubyMine 的终端、系统自带的终端中运行 gem install 以及 bundle install 的时候 gem 分别会安装到哪个位置去？

LongLonghaoran — Mon, 16 Apr 2018 22:19:55 +0800

如题请问这三种情况下安装 gem 的位置有什么不同？最近看了一个很老的项目，clone 下来准备本地跑一下的，结果 bundle 出错，关键有个时候不同环境下报错还不一致，尝试了好一会还是没什么办法，想请教下各位 !

RubyMine 的 bundle install:

RubyMine 的终端的 bundle install

系统自带的终端: