使用Azure Pipelines部署Flask应用至Azure Web App仅显示默认页面

问题详情 #

• Pipeline执行成功，但访问Azure Web App时仅显示平台默认页面
• 操作依据微软官方文档，使用官方提供的Flask教程仓库
• 为解决初始构建失败问题，修改后的YAML配置如下：

trigger:
- main

pool:
  vmImage: ubuntu-latest

stages:
  - stage: Deploy
    displayName: 'Deploy Stage'
    jobs:
      - job: DeploymentJob
        displayName: 'Deploy to Azure Web App'
        steps:
        - task: UsePythonVersion@0
          inputs:
              versionSpec: '3.9'
          displayName: 'Use Python 3.9'

        - script: |
              python -m venv antenv
              source antenv/bin/activate
              python -m pip install --upgrade pip
              pip install setup
              pip install --target="./.python_packages/lib/site-packages" -r ./requirements.txt
          workingDirectory: $(Build.SourcesDirectory)
          displayName: "Install requirements"

        - task: ArchiveFiles@2
          inputs:
            rootFolderOrFile: '$(Build.SourcesDirectory)'
            includeRootFolder: false
            archiveType: 'zip'
            archiveFile: '$(Build.SourcesDirectory)/$(Build.BuildId).zip'
            replaceExistingArchive: true
        - task: PublishPipelineArtifact@1
          inputs:
            targetPath: '$(Build.ArtifactStagingDirectory)'
            artifactName: 'drop'
            publishLocation: 'pipeline'
          
        - task: DownloadBuildArtifacts@1
          inputs:
            buildType: 'current'
            downloadType: 'single'
            artifactName: 'drop'
            downloadPath: '$(System.ArtifactsDirectory)'
        
        - task: AzureWebApp@1
          inputs:
            appType : 'webApp'
            azureSubscription: 'azure-cloud-exampele'
            appName: 'xyz'
            package: '$(Build.SourcesDirectory)/$(Build.BuildId).zip'
            startUpCommand: 'gunicorn --bind=0.0.0.0 --workers=4 startup:app'

问题原因及解决方案 #

1. 冗余的发布/下载步骤 #

你配置的PublishPipelineArtifact和DownloadBuildArtifacts完全多余：

• 生成的zip文件存放在$(Build.SourcesDirectory)，但发布任务的目标路径是$(Build.ArtifactStagingDirectory)，这个目录里没有任何内容，相当于发布了空的工件
• 后续的下载步骤也没有实际作用，最后部署用的还是原目录的zip，这部分步骤可以直接删除，避免混淆。

2. 不必要的pip install setup #

setup不是标准Python包，这个命令大概率会报错（虽Pipeline显示成功，但可能被忽略），直接删除这一行。

3. Gunicorn依赖缺失风险 #

如果你的requirements.txt里没有包含gunicorn，启动命令会执行失败。要么在requirements中添加，要么在安装脚本里显式安装。

4. 归档路径优化 #

建议将生成的zip文件放在$(Build.ArtifactStagingDirectory)，这是Pipeline中存放构建产物的标准目录，更符合规范。

修正后的YAML配置 #

trigger:
- main

pool:
  vmImage: ubuntu-latest

stages:
  - stage: Deploy
    displayName: 'Deploy Stage'
    jobs:
      - job: DeploymentJob
        displayName: 'Deploy to Azure Web App'
        steps:
        - task: UsePythonVersion@0
          inputs:
              versionSpec: '3.9'
          displayName: 'Use Python 3.9'

        - script: |
              python -m venv antenv
              source antenv/bin/activate
              python -m pip install --upgrade pip
              pip install --target="./.python_packages/lib/site-packages" -r ./requirements.txt
              # 确保gunicorn被安装，如果requirements.txt未包含则添加此行
              pip install --target="./.python_packages/lib/site-packages" gunicorn
          workingDirectory: $(Build.SourcesDirectory)
          displayName: "Install requirements"

        - task: ArchiveFiles@2
          inputs:
            rootFolderOrFile: '$(Build.SourcesDirectory)'
            includeRootFolder: false
            archiveType: 'zip'
            archiveFile: '$(Build.ArtifactStagingDirectory)/$(Build.BuildId).zip'
            replaceExistingArchive: true
          displayName: 'Archive application files'
        
        - task: AzureWebApp@1
          inputs:
            appType : 'webApp'
            azureSubscription: 'azure-cloud-exampele'
            appName: 'xyz'
            package: '$(Build.ArtifactStagingDirectory)/$(Build.BuildId).zip'
            startUpCommand: 'gunicorn --bind=0.0.0.0 --workers=4 startup:app'
          displayName: 'Deploy to Azure Web App'

后续排查步骤 #

1. 检查requirements.txt，确认包含flask和gunicorn
2. 登录Web App的Kudu工具，查看site/wwwroot目录：
   • 确认存在startup.py、templates、static等应用文件
   • 确认.python_packages/lib/site-packages下有Flask和Gunicorn依赖
3. 查看Web App的日志流，检查启动命令是否有报错（比如模块找不到、端口占用等）

内容的提问来源于stack exchange，提问作者Asi