[在 Jenkins 上运行 cypress]：缺少 X 服务器或 $DISPLAY，平台初始化失败

Question

所以，让我首先在这里给出整个背景：

-> 我们有 cypress UI end2end 测试套件，我们希望每晚运行它，作为 Jenkins 每晚构建的一部分。我们正在无头模式下运行 cypress 测试，但已经通过了

--record

标签，以便我们将视频录制保存到仪表板中。

-> 作为 jenkins 管道步骤的一部分，我们正在 docker 镜像中运行 cypress 测试。

这是

cypress_run.sh

文件，用作在 jenkins 中运行测试的起点：

# Update package list
apt-get update

apt-get install apache2

# Install NVM (Node Version Manager)
curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.1/install.sh | bash

# Load NVM
export NVM_DIR="$HOME/.nvm"
. "$NVM_DIR/nvm.sh"

# Use NVM to install the specified version of Node.js
nvm install 20

# Use npm to install the specified version of npm
npm install -g npm@9

# Display versions for verification
echo "NVM version: \$(nvm --version), Node version: \$(node --version), npm version: \$(npm --version)"

apt-get update

apt-get install libgtk2.0-0 libgtk-3-0 libgbm-dev libnotify-dev libnss3 libxss1 libasound2 libxtst6 xauth xvfb

echo "Running Cypress Command"
npm install --legacy-peer-deps
# Install Xvfb
apt-get install -y xvfb

# Start Xvfb
Xvfb :99 -screen 0 1024x768x24 > /dev/null 2>&1 &

# Set the display environment variable
export DISPLAY=:99
echo "Installed NPM Packages!"
export CYPRESS_BASE_URL="$UNIFIED_URL"
export CYPRESS_USERNAME="admin"
export CYPRESS_PASSWORD="password"
echo "Cypress base Url: ${CYPRESS_BASE_URL}"
npx cypress run --record --key <KEY> --browser chrome --headless --config-file cypress.config.js --config baseUrl="$CYPRESS_BASE_URL" username="$CYPRESS_USERNAME" password="$CYPRESS_PASSWORD"

现在，这段代码的整个设置在大多数情况下都运行良好，但偶尔它会开始在 jenkins 上抛出以下错误，然后我无法解决这个问题：

[2024-04-01T18:58:54.001Z] Cypress base Url: https://mondaytestingcypress.jfrogdev.org

[2024-04-01T18:58:54.001Z] [STARTED] Task without title.

[2024-04-01T18:58:54.559Z] [FAILED] Cypress failed to start.

[2024-04-01T18:58:54.559Z] [FAILED] 

[2024-04-01T18:58:54.559Z] [FAILED] This may be due to a missing library or dependency. https://on.cypress.io/required-dependencies

[2024-04-01T18:58:54.559Z] [FAILED] 

[2024-04-01T18:58:54.559Z] [FAILED] Please refer to the error below for more details.

[2024-04-01T18:58:54.559Z] [FAILED] 

[2024-04-01T18:58:54.559Z] [FAILED] ----------

[2024-04-01T18:58:54.559Z] [FAILED] 

[2024-04-01T18:58:54.559Z] [FAILED] [1606:0401/185854.356170:ERROR:ozone_platform_x11.cc(240)] Missing X server or $DISPLAY

[2024-04-01T18:58:54.560Z] [FAILED] [1606:0401/185854.356223:ERROR:env.cc(255)] The platform failed to initialize.  Exiting.

[2024-04-01T18:58:54.560Z] [FAILED] 

[2024-04-01T18:58:54.560Z] [FAILED] ----------

[2024-04-01T18:58:54.560Z] [FAILED] 

[2024-04-01T18:58:54.560Z] [FAILED] Platform: linux-x64 (Debian - 11.8)

[2024-04-01T18:58:54.560Z] [FAILED] Cypress Version: 12.17.4

[2024-04-01T18:58:54.560Z] Cypress failed to start.

[2024-04-01T18:58:54.560Z] 

[2024-04-01T18:58:54.560Z] This may be due to a missing library or dependency. https://on.cypress.io/required-dependencies

[2024-04-01T18:58:54.560Z] 

[2024-04-01T18:58:54.560Z] Please refer to the error below for more details.

[2024-04-01T18:58:54.560Z] 

[2024-04-01T18:58:54.560Z] ----------

[2024-04-01T18:58:54.560Z] 

[2024-04-01T18:58:54.560Z] [1606:0401/185854.356170:ERROR:ozone_platform_x11.cc(240)] Missing X server or $DISPLAY

[2024-04-01T18:58:54.560Z] [1606:0401/185854.356223:ERROR:env.cc(255)] The platform failed to initialize.  Exiting.

[2024-04-01T18:58:54.560Z] 

[2024-04-01T18:58:54.560Z] ----------

[2024-04-01T18:58:54.560Z] 

[2024-04-01T18:58:54.560Z] Platform: linux-x64 (Debian - 11.8)

[2024-04-01T18:58:54.560Z] Cypress Version: 12.17.4

[2024-04-01T18:58:54.560Z] ./cypress_run.sh: line 44:  1582 Aborted                 (core dumped) Xvfb :"$RANDOM_DISPLAY_PORT_NUMBER" -screen 0 1024x768x24 > /dev/null 2>&1

我尝试了多种方法，暂时解决了问题，但是当它再次出现时，后续所有的jenkins构建都失败了。

-> 我手动硬编码了一个不同的显示端口号，比如说 100，这在有限的时间内解决了问题，但又开始使构建失败。

Xvfb :100 -screen 0 1024x768x24 > /dev/null 2>&1 &

# Set the display environment variable
export DISPLAY=:100

因此，我认为端口号可能是问题所在。因此，在每次构建时，我都会生成给定范围内的随机数，并将端口分配给该数字。

RANDOM_DISPLAY_PORT_NUMBER=$(shuf -i 10-98 -n 1)

# Start Xvfb
Xvfb :"$RANDOM_DISPLAY_PORT_NUMBER" -screen 0 1024x768x24 > /dev/null 2>&1 &

# Set the display environment variable
export DISPLAY=":$RANDOM_DISPLAY_PORT_NUMBER"
echo "DISPLAY PORT NUMBER SELECTED IS: $RANDOM_DISPLAY_PORT_NUMBER"

这解决了很长一段时间的问题，然后我一周都没有遇到这个问题，但构建再次开始失败。现在，无论我手动触发构建多少次，我每次都会收到相同的错误消息。

Answer 1

Cypress 将忽略您的

DISPLAY

变量（以及任何其他环境变量），除非您在其前面添加

CYPRESS_

- 请参阅 cypress 环境变量文档，其中相关部分指出：

在命令行或 CI 提供程序中设置的任何以

CYPRESS_

或

cypress_

开头的导出环境变量都将被 Cypress 自动解析。

此语句也可以通过逆向推理来理解：任何不带有CYPRESS_

前缀的变量将不会被Cypress解析。

您还可以使用任何其他

方法通过 Cypress 设置变量。