ruby - 如何为 Ruby Capybara 刮刀编写 Dockerfile？

Question

我正在尝试编写一个 Dockerfile 来在 docker 容器上运行 Ruby Capybara 刮板。我在我的主机操作系统上测试了以下代码。但它在 docker 容器上出错。

Dockerfile

FROM ruby:2.6.6

RUN apt-get update -y && \
apt-get install -y xvfb

RUN wget https://ftp.mozilla.org/pub/firefox/releases/80.0.1/linux-x86_64/en-US/firefox-80.0.1.tar.bz2
RUN tar -xjf firefox-80.0.1.tar.bz2
RUN mv firefox /opt/firefox80
RUN ln -s /opt/firefox80/firefox /usr/bin/firefox
RUN ls /opt/firefox80

RUN wget -N https://github.com/mozilla/geckodriver/releases/download/v0.27.0/geckodriver-v0.27.0-linux64.tar.gz
RUN tar -xvzf geckodriver-v0.27.0-linux64.tar.gz
RUN chmod +x geckodriver
RUN mv -f geckodriver /usr/local/share/geckodriver
RUN ln -s /usr/local/share/geckodriver /usr/local/bin/geckodriver
RUN ln -s /usr/local/share/geckodriver /usr/bin/geckodriver
RUN mkdir capybara
WORKDIR /capybara/
COPY . /capybara

RUN bundle install

主文件

require 'capybara'
require 'capybara/dsl'
require 'selenium-webdriver'

include Capybara::DSL

Capybara.register_driver :selenium_headless_firefox do |app|
  browser_options = ::Selenium::WebDriver::Firefox::Options.new()
  browser_options.args << '--headless'

  Capybara::Selenium::Driver.new(
    app,
    browser: :firefox,
    options: browser_options
  )
end

target = "https://maps.google.com/?cid=13666314335012854449"

session = Capybara::Session.new(:selenium_headless_firefox)
session.visit(target)

宝石文件

source 'https://rubygems.org'

gem 'selenium-webdriver'
gem 'capybara', '~>3.30'
gem 'geckodriver-helper'

Docker 上的错误消息

/usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/response.rb:72:in `assert_ok': invalid argument: can't kill an exited process (Selenium::WebDriver::Error::UnknownError)
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/response.rb:34:in `initialize'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/http/common.rb:88:in `new'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/http/common.rb:88:in `create_response'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/http/default.rb:114:in `request'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/http/common.rb:64:in `call'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/bridge.rb:167:in `execute'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/remote/bridge.rb:102:in `create_session'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/firefox/marionette/driver.rb:44:in `initialize'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/firefox/driver.rb:33:in `new'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/firefox/driver.rb:33:in `new'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver/common/driver.rb:54:in `for'
        from /usr/local/bundle/gems/selenium-webdriver-3.142.7/lib/selenium/webdriver.rb:88:in `for'
        from /usr/local/bundle/gems/capybara-3.33.0/lib/capybara/selenium/driver.rb:52:in `browser'
        from /usr/local/bundle/gems/capybara-3.33.0/lib/capybara/selenium/driver.rb:71:in `visit'
        from /usr/local/bundle/gems/capybara-3.33.0/lib/capybara/session.rb:278:in `visit'

这是我在 docker 容器上运行 main.rb 文件时得到的。我期待着开发者社区的任何帮助。

我运行了 main.rb 文件docker run [docker_image] ruby main.rb

标签： rubydockerseleniumcapybara

Answer 1

问题不在于 Capybara，而在于 Firefox -tar.bz2您下载的文件不包含其依赖项，这会导致它崩溃。最简单的解决方案是通过 apt 安装它。假设您的所有文件都在同一个目录中，您Dockerfile应该如下所示：

FROM ruby:2.6.6

WORKDIR /app

COPY . .

RUN apt-get update -y && \
    apt-get install -y xvfb firefox-esr && \
    wget -N https://github.com/mozilla/geckodriver/releases/download/v0.27.0/geckodriver-v0.27.0-linux64.tar.gz && \
    tar -xvzf geckodriver-v0.27.0-linux64.tar.gz && \
    chmod +x geckodriver && \
    mv -f geckodriver /usr/local/share/geckodriver && \
    ln -s /usr/local/share/geckodriver /usr/local/bin/geckodriver && \
    ln -s /usr/local/share/geckodriver /usr/bin/geckodriver && \
    bundle install && \
    apt-get clean && \
    rm geckodriver-v0.27.0-linux64.tar.gz && \
    rm -rf /var/lib/apt/lists/*

CMD [ "ruby", "/app/main.rb" ]

然后你可以运行：

docker build -t capybara:latest . # Build image
docker run -it --rm --env DISPLAY=$DISPLAY --volume="$HOME/.Xauthority:/root/.Xauthority:rw" --net=host capybara:latest firefox # Verify Firefox works
docker run -it --rm capybara:latest # Run your script

注意：第二个命令只能在 Linux 上运行，在 Windows 上运行 dockerized Linux GUI 应用程序有点困难，需要一些额外的设置。

编辑：

没有“在 Docker 上”安装东西这样的事情。Docker 不是操作系统。它是一个应用程序容器化框架。它可以在容器内运行各种操作系统（或根本不运行操作系统 - 请参阅基本映像）。这意味着在 Docker 映像（或容器 - 不推荐）中安装某些内容的方法取决于已安装的内容。

在这种情况下，您的基础映像ruby:2.6.6基于 Debian Buster 映像（请参阅Dockerfile），因此您需要安装浏览器，就像在系统的常规桌面或服务器安装上一样。

Debian Buster 没有随 Chrome 一起提供，因为它不是开源的。要安装它的开源等效项 - Chromium - 修改Dockerfile如下：

FROM ruby:2.6.6

WORKDIR /app

COPY . .

RUN apt-get update -y && \
    apt-get install -y xvfb chromium && \
    wget -N https://github.com/mozilla/geckodriver/releases/download/v0.27.0/geckodriver-v0.27.0-linux64.tar.gz && \
    tar -xvzf geckodriver-v0.27.0-linux64.tar.gz && \
    chmod +x geckodriver && \
    mv -f geckodriver /usr/local/share/geckodriver && \
    ln -s /usr/local/share/geckodriver /usr/local/bin/geckodriver && \
    ln -s /usr/local/share/geckodriver /usr/bin/geckodriver && \
    bundle install && \
    apt-get clean && \
    rm geckodriver-v0.27.0-linux64.tar.gz && \
    rm -rf /var/lib/apt/lists/*

CMD [ "ruby", "/app/main.rb" ] 

如果您确实需要 Chrome，请遵循官方文档（请记住，您需要在安装后删除存档文件）。话虽如此Dockerfile，Chrome 将是：

FROM ruby:2.6.6

WORKDIR /app

COPY . .

RUN apt-get update -y && \
    apt-get install -y xvfb && \
    wget https://dl.google.com/linux/direct/google-chrome-stable_current_amd64.deb && \
    apt install -y ./google-chrome-stable_current_amd64.deb && \
    wget -N https://github.com/mozilla/geckodriver/releases/download/v0.27.0/geckodriver-v0.27.0-linux64.tar.gz && \
    tar -xvzf geckodriver-v0.27.0-linux64.tar.gz && \
    chmod +x geckodriver && \
    mv -f geckodriver /usr/local/share/geckodriver && \
    ln -s /usr/local/share/geckodriver /usr/local/bin/geckodriver && \
    ln -s /usr/local/share/geckodriver /usr/bin/geckodriver && \
    bundle install && \
    apt-get clean && \
    rm google-chrome-stable_current_amd64.deb && \
    rm geckodriver-v0.27.0-linux64.tar.gz && \
    rm -rf /var/lib/apt/lists/*

CMD [ "ruby", "/app/main.rb" ]