[Selenium Grid]：无法在远程机器上启动机器人测试

Question

我已经在本地机器上设置了 selenium 网格，并且在远程机器上设置了一个节点。

节点正在运行

java -jar selenium-server-standalone-3.8.1.jar -role node  -hub http://<hub_machine>:4444/grid/register

现在我已经编写了机器人测试来在远程机器上运行脚本，如下所示：

Open Browser   google.com   chrome  None  http://<hub_machine>:4444/wd/hub  desired_capabilities=browserName:chrome,platform:WINDOWS

我也尝试使用远程Webdriver如下：

${executor}=    Evaluate    str('http://<hub_machine>:4444/wd/hub')
    ${desired capabilities}=    Evaluate    { "browserName": "chrome", "version": "", "platform": "VISTA", "javascriptEnabled": True}
    Create Webdriver    Remote    desired_capabilities=${desired capabilities}    command_executor=${executor} 

但是代码抛出如下错误：

2018-02-20 13:33:41.655:WARN:osjs.HttpChannel:qtp662736689-13: /wd/hub/session java.io.IOException: org.openqa.grid.common.exception.GridException: Cannot extract a capabilities from the request: {"capabilities": {"alwaysMatch": {"version": "", "platform": "VISTA", "browserName": "chrome", "javascriptEnabled": true}, "firstMatch": []}, "desiredCapabilities": {"version": "", "platform": "VISTA", "browserName": "chrome", "javascriptEnabled": true}}

请建议如何解决此问题。

Answer 1

错误说明了一切：

/wd/hub/session java.io.IOException: org.openqa.grid.common.exception.GridException: Cannot extract a capabilities from the request: {"capabilities": {"alwaysMatch": {"version": "", "platform": "VISTA", "browserName": "chrome", "javascriptEnabled": true}, "firstMatch": []}, "desiredCapabilities": {"version": "", "platform": "VISTA", "browserName": "chrome", "javascriptEnabled": true}}

要启动 Selenium 网格节点，您应该提供 WebDriver 变体作为参数，如下所示：

• Mozilla Firefox：

  java -Dwebdriver.gecko.driver=geckodriver.exe -jar selenium-server-standalone-3.8.1.jar -role node -hub http://<hub_machine>:4444/grid/register
  

• Chrome：

  java -Dwebdriver.chrome.driver=chromedriver.exe -jar selenium-server-standalone-3.8.1.jar -role node -hub http://<hub_machine>:4444/grid/register
  

• Internet Explorer：

  java -Dwebdriver.ie.driver=IEDriverServer.exe -jar selenium-server-standalone-3.8.1.jar -role node -hub http://<hub_machine>:4444/grid/register
  

---

更新

由于您仍然看到相同的错误，您需要：

• 提供完整的url，包括https://www.google.com 的协议（而不仅仅是google.com）
• 从您的 IDE 中清理 Project
• 使用CCleaner 工具清除所有操作系统琐事。
• 执行您的测试

Answer 2

请注意，如果您需要在多个系统上运行机器人测试，那么 Grid 就是最佳选择。但是如果你只需要一台远程机器，你可以在独立模式下使用 selenium 服务器。

我刚刚解决了这个问题。这是我为 Grid 做的：

启动集线器和节点 Selenium 服务器

注意我在 python 的虚拟环境中运行来控制版本。所以下面的 virPath 是我放置 selenium 服务器 jar 文件的 bin 目录的完整路径

#! /bin/bash
virPath="$(echo $PATH | cut -f 1 -d':')"

java -jar ${virPath}/selenium-server.jar \
     -role hub \
     >/tmp/selenium_server_hub.log 2>&1 &

sleep 3

java -jar ${virPath}/selenium-server.jar \
     -role node \
     -hub http://localhost:4444/grid/register \
     -maxSession 10 \
     -browser browserName=chrome,maxInstances=10 \ 
     >/tmp/selenium_server_node.log 2>&1 &

运行机器人测试

当我想使用远程服务器运行机器人测试时，我将标志传递给 pybot：

--variable Use Selenium Server:True
--variable Selenium Server URL:http://localhost:4444/wd/hub

我有许多关键字可以根据我的环境打开浏览器，但最终归结为这些：

Open Chrome Browser to Page
| | [Documentation]
| | ... | Opens Google Chrome to a given web page using Create Webdriver so
| | ... | arguments can be passed to webdriver in the form of capabilities.
| | ... | For more information on what capabilities that Google Chrome
| | ... | supports, see [http://chromedriver.chromium.org/capabilities] and
| | ... | [https://peter.sh/experiments/chromium-command-line-switches/]
| | ... |
| | ... | Webdriver can be run remotely using the selenium remote server.
| | ... | This can be done in 'Grid' mode with both a Hub server and
| | ... | Node servers where the tests are route to by the Hub to be run.
| | ... | See run_tests.sh for options to use this feature.
| | [Arguments] | ${url} |
| | ${ws}= | Set Variable | window-size=1080,1080 |
| | ${chrome_options}= | Evaluate | sys.modules['selenium.webdriver'].ChromeOptions() | sys |
| | Call Method | ${chrome_options} | add_argument | disable-infobars          |
| | Call Method | ${chrome_options} | add_argument | test-type                 |
| | Call Method | ${chrome_options} | add_argument | disable-extensions        |
| | Call Method | ${chrome_options} | add_argument | ignore-certificate-errors |
| | Call Method | ${chrome_options} | add_argument | allow-insecure-localhost  |
| | Call Method | ${chrome_options} | add_argument | disable-browser-side-navigation |
| | Call Method | ${chrome_options} | add_argument | ${ws} |
| | Run Keyword If | ${Use Chrome Headless} |
| | ... | Call Method | ${chrome_options} | add_argument | headless |
| | Run Keyword If | ${Use Selenium Server} |
| | ...        | Create Remote Chrome Webdriver | ${chrome_options} |
| | ... | ELSE | Create Local Chrome Webdriver  | ${chrome_options} |
| | Go To | ${url} |

Create Remote Chrome Webdriver
| | [Arguments] | ${chrome options} |
| | Comment | Convert webdriver options to capabilities for Selenium server |
| | ${options}= |  Call Method |  ${chrome_options} | to_capabilities |
| | ${status} | ${resp}= | Run Keyword And Ignore Error |
| | ... | Create Webdriver | Remote | command_executor=${Selenium Server URL} | desired_capabilities=${options}
| | Run Keyword If | '${status}'=='FAIL' | Fail | Could not connect to Selenium Server.  Is it up?\nError: ${resp} |

Create Local Chrome Webdriver
| | [Arguments] | ${chrome options} |
| | ${status} | ${resp}= | Run Keyword And Ignore Error |
| | ... | Create Webdriver | Chrome | chrome_options=${chrome_options} |
| | Run Keyword If | '${status}'=='FAIL' | Fail | Could not start browser.  Are tests being run locally?\nError: ${resp} |

工具版本

Robot env 需要很多不同的包，所以我有一个 bash 脚本来列出我使用的所有内容：

        Tool |      Version       | Path
-------------+--------------------+-------------------------------------
  Linux Dist | Ubuntu 16.04.4 LTS | NA
Linux Kernel | 4.4.0-116-generic  | NA
  Git commit | 9d7739b            | NA
  Virtualenv | 15.0.1             | /usr/bin/virtualenv
      Python | 2.7.12             | /home/bm/devel/work/rf/bin/python
          RF | 3.0.2              | /home/bm/devel/work/rf/bin/pybot
 RF Selenium | 3.1.0              | /home/bm/devel/work/rf/lib/python2.7/site-packages
    Selenium | 3.9.0              | /home/bm/devel/work/rf/lib/python2.7/site-packages
    Requests | 2.18.4             | /home/bm/devel/work/rf/lib/python2.7/site-packages
    Easysnmp | 0.2.5              | /home/bm/devel/work/rf/lib/python2.7/site-packages
      Poster | 0.8.1              | /home/bm/devel/work/rf/lib/python2.7/site-packages
      Chrome | 65.0.3325.181      | /usr/bin/google-chrome
chromedriver | 2.35.528139        | /home/bm/devel/work/rf/bin/chromedriver
     Firefox | 59.0.2             | /usr/bin/firefox
 Geckodriver | 0.19.1             | /home/bm/devel/work/rf/bin/geckodriver
------------------------------------------------------------------------