如何在 Mac 上的 Dockerized Rails 环境中使用 Selenium 和 Chrome 运行 Capybara 测试

Question

我觉得我很接近，但已经碰壁了，所以希望得到一些建议。

我的目标是能够使用 Chrome 运行我的系统测试和（截屏）。

使用 :rack_test 的非 JS 测试通过。

当由:remote_browser（我的 Chrome 设置）驱动时，我可以访问路径，截屏显示 无法访问此站点 127.0.0.1 拒绝连接。

另外值得一提的是，如果我尝试将 vnc 与 open vnc://localhost:5900 一起使用，我会收到错误 Connection failed to “localhost” 无法与 “localhost” 通信。确保远程计算机可用并且防火墙未阻止屏幕共享。

我知道我错过了一些东西，但不知道是什么。

这是我的docker-compose.yml 文件。我正在使用独立的 Chrome 映像。

version: '3'

services:

  app: &app
    build: .
    tmpfs:
      - /tmp

  backend: &backend
    <<: *app
    stdin_open: true
    tty: true
    volumes:
      - .:/usr/src/app:cached
      - rails_cache:/usr/src/app/tmp/cache
      - bundle:/usr/local/bundle
      - node_modules:/app/node_modules
      - packs:/app/public/packs
    env_file:
      - .env/development/database
      - .env/development/web
    environment:
      - WEBPACKER_DEV_SERVER_HOST=webpack-dev-server

  web:
    <<: *backend
    entrypoint: ./bin/docker-entrypoint.sh
    command: bundle exec rails server -b 0.0.0.0
    ports:
      - "3000:3000"

  chrome:
    image: selenium/standalone-chrome:3.141.59
    ports:
      - "4444:4444"
      - "5900:5900"

  webpack-dev-server:
    <<: *app
    command: ./bin/webpack-dev-server
    volumes:
      - .:/usr/src/app:cached
      - bundle:/usr/local/bundle
      - node_modules:/app/node_modules
      - packs:/app/public/packs
    ports:
      - "3035:3035"
    environment:
      - WEBPACKER_DEV_SERVER_HOST=0.0.0.0

  database:
    image: postgres
    env_file:
      - .env/development/database
    volumes:
      - db_data:/var/lib/postgresql/data

volumes:
  db_data:
  rails_cache:
  bundle:
  node_modules:
  packs:

我的Gemfile 包括capybara 和selenium-webdriver

group :test do
  gem 'capybara', '~> 3.32', '>= 3.32.1'
  gem 'selenium-webdriver', '~> 3.142', '>= 3.142.7'
end

然后我的rails_helper.rb 文件包含这个

require 'capybara/rspec'
require 'selenium-webdriver'

Capybara.server_host = '0.0.0.0'
Capybara.server_port = 3000
Capybara.app_host = "http://localhost:3000"

Capybara.register_driver :remote_browser do |app|
  capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(
    chromeOptions: { args: %w(disable-gpu no-sandbox) }
  )

  Capybara::Selenium::Driver.new(app,
    :browser => :remote,
    url: "http://chrome:4444/wd/hub",
    desired_capabilities: capabilities
  )
end

Capybara.javascript_driver = :remote_browser

当我运行测试时，我会启动 Docker

docker-compose up chrome database

在我的日志中，我看到有关 Chrome 服务启动的信息。

chrome_1              | 2020-04-24 16:17:05,059 INFO spawned: 'xvfb' with pid 10
chrome_1              | 2020-04-24 16:17:05,060 INFO spawned: 'selenium-standalone' with pid 11
chrome_1              | 16:17:05.229 INFO [GridLauncherV3.parse] - Selenium server version: 3.141.59, revision: e82be7d358
chrome_1              | 2020-04-24 16:17:05,230 INFO success: xvfb entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
chrome_1              | 2020-04-24 16:17:05,230 INFO success: selenium-standalone entered RUNNING state, process has stayed up for > than 0 seconds (startsecs)
chrome_1              | 16:17:05.289 INFO [GridLauncherV3.lambda$buildLaunchers$3] - Launching a standalone Selenium Server on port 4444
chrome_1              | 2020-04-24 16:17:05.328:INFO::main: Logging initialized @260ms to org.seleniumhq.jetty9.util.log.StdErrLog
chrome_1              | 16:17:05.486 INFO [WebDriverServlet.<init>] - Initialising WebDriverServlet
chrome_1              | 16:17:05.548 INFO [SeleniumServer.boot] - Selenium Server is up and running on port 4444

然后我用这个运行系统测试

docker-compose run --rm web bundle exec rspec spec/system/example_spec.rb

我的示例测试很简单

require 'rails_helper'

RSpec.describe "Example", type: :system do
  before do
    driven_by(:remote_browser)
  end

  it "should take a screenshot of root path" do
    visit root_path
    take_screenshot
  end
end

它运行并通过

[Screenshot]: /usr/src/app/tmp/screenshots/r_spec_example_598.png
.

Finished in 0.77216 seconds (files took 1.73 seconds to load)
1 example, 0 failures

这是日志

chrome_1              | 16:29:55.662 INFO [ActiveSessionFactory.apply] - Capabilities are: {
chrome_1              |   "browserName": "chrome",
chrome_1              |   "chromeOptions": {
chrome_1              |     "args": [
chrome_1              |       "disable-gpu",
chrome_1              |       "no-sandbox"
chrome_1              |     ]
chrome_1              |   },
chrome_1              |   "cssSelectorsEnabled": true,
chrome_1              |   "javascriptEnabled": true,
chrome_1              |   "nativeEvents": false,
chrome_1              |   "rotatable": false,
chrome_1              |   "takesScreenshot": false,
chrome_1              |   "version": ""
chrome_1              | }
chrome_1              | 16:29:55.662 INFO [ActiveSessionFactory.lambda$apply$11] - Matched factory org.openqa.selenium.grid.session.remote.ServicedSession$Factory (provider: org.openqa.selenium.chrome.ChromeDriverService)
chrome_1              | Starting ChromeDriver 81.0.4044.69 (6813546031a4bc83f717a2ef7cd4ac6ec1199132-refs/branch-heads/4044@{#776}) on port 13909
chrome_1              | Only local connections are allowed.
chrome_1              | Please protect ports used by ChromeDriver and related test frameworks to prevent access by malicious code.
chrome_1              | [1587745795.669][SEVERE]: bind() failed: Cannot assign requested address (99)
chrome_1              | 16:29:55.943 INFO [ProtocolHandshake.createSession] - Detected dialect: W3C
chrome_1              | 16:29:55.943 INFO [RemoteSession$Factory.lambda$performHandshake$0] - Started new session d8f42b8387f0160b95f333eac5c1b576 (org.openqa.selenium.chrome.ChromeDriverService)
chrome_1              | 16:29:56.287 INFO [ActiveSessions$1.onStop] - Removing session d8f42b8387f0160b95f333eac5c1b576 (org.openqa.selenium.chrome.ChromeDriverService)

而且截图是这样的……

另外，这是我尝试打开vnc://localhost:5900时的错误消息

已经到了我接近承认失败并且不测试这些用例的地步，所以非常感谢一些建议。谢谢！

Answer 1

感谢 Thomas Walpole 为我指明了正确的方向。

我现在可以正常工作，我想我会发布解决方案，以防其他人难以让设置正常工作。

第一点——vnc 不工作

这很容易解决——我使用的 Chrome 版本不包括这个，必须使用 debug selenium 版本。

docker-compose.yml 中的selenium_chrome 服务变成这个

  selenium_chrome:
    image: selenium/standalone-chrome-debug:3.141.59
    ports:
      - "5900:5900"

主要网络问题

这与 Thomas Walpole 解释的 Capybara.app_host 有关。

解决方案采取了许多步骤。首先，测试服务器现在在不同的端口 4000 上广播。

docker-compose.yml 中的web 服务添加了端口。

  web:
    <<: *backend
    entrypoint: ./bin/docker-entrypoint.sh
    command: bundle exec rails server -b 0.0.0.0
    ports:
      - "3000:3000"
      - "4000:4000"

rails_helper.rb 使用此端口，web 是web 服务的 Docker 内部网络地址。

    Capybara.server_host = '0.0.0.0'
    Capybara.server_port = 4000
    Capybara.app_host = "http://web:4000"

我的代码的最后一个问题是该代码的位置。它还需要在Rspec.config 块内。

完成rails_helper.rb代码

因此，rails_helper.rb 中完整的工作最终相关代码是这样的。

require 'capybara/rspec'
require 'selenium-webdriver'

Capybara.register_driver :headless_selenium_chrome_in_container do |app|
  capabilities = Selenium::WebDriver::Remote::Capabilities.chrome(
    chromeOptions: { args: %w(headless disable-gpu window-size=1440x768) }
  )

  Capybara::Selenium::Driver.new(app,
    :browser => :remote,
    url: "http://selenium_chrome:4444/wd/hub",
    desired_capabilities: capabilities
  )
end

Capybara.register_driver :selenium_chrome_in_container do |app|
  Capybara::Selenium::Driver.new(app,
    :browser => :remote,
    url: "http://selenium_chrome:4444/wd/hub",
    desired_capabilities: :chrome
  )
end

RSpec.configure do |config|
  ...

  config.before(:each, type: :system) do
    Capybara.server_host = '0.0.0.0'
    Capybara.server_port = 4000
    Capybara.app_host = "http://web:4000"
    driven_by(:headless_selenium_chrome_in_container)
  end
end

注意：这提供了以无头方式运行 Chrome 或使用可通过vnc://localhost:5900 访问的浏览器的选项。