Github Runner部署Lambda时未安装requirements.txt依赖（FastAPI缺失）

Github Actions的CI阶段执行完成，但将应用部署到AWS Lambda后，运行时出现报错提示无法找到FastAPI模块，而FastAPI已明确包含在requirements.txt文件中。怀疑问题出在CD部署环节，尝试多种教程后仍未解决。

原Github Actions工作流配置 #

name: API CI/CD

on:
  # Trigger the workflow on push
  push:
    branches:
      # Push events on main branch
      - main

# The Job defines a series of steps that execute on the same runner.

jobs:
  CI:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2

      - name: Set up Python
        uses: actions/setup-python@v2
        with:
          python-version: 3.9

      - name: Install dependencies
        run: pip3 install -r ./app/requirements.txt

      - name: Create application ZIP archive
        run: cd ./app && zip -r app.zip .

      - name: Upload app.zip artifact
        uses: actions/upload-artifact@v2
        with:
          name: app
          path: ./app/app.zip

      - name: Upload swagger.json artifact
        uses: actions/upload-artifact@v2
        with:
          name: swagger
          path: ./app/swagger.json

  CD:
    runs-on: ubuntu-latest
    needs: [ CI ]
    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
    steps:
      - name: Install AWS CLI
        uses: unfor19/install-aws-cli-action@v1
        with:
          version: 1
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: ${{ secrets.AWS_DEFAULT_REGION }}

      - name: Download Lambda app.zip
        uses: actions/download-artifact@v2
        with:
          name: app

      - name: Download swagger.json artifact
        uses: actions/download-artifact@v2
        with:
          name: swagger

      - name: Upload app.zip to S3
        run: aws s3 cp app.zip s3://telidexapigithubdeploy/app.zip
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: ${{ secrets.AWS_DEFAULT_REGION }}

      - name: Upload swagger.json to S3
        run: aws s3 cp swagger.json s3://telidexapiswaggerjson/swagger.json
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: ${{ secrets.AWS_DEFAULT_REGION }}

      - name: Deploy new Lambda
        run: aws lambda update-function-code --function-name telidexapi --s3-bucket telidexapigithubdeploy --s3-key app.zip
        env:
          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_ID }}
          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          AWS_DEFAULT_REGION: ${{ secrets.AWS_DEFAULT_REGION }}

AWS Lambda报错信息 #

----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|   timestamp   |                                                                               
  message                                                                                
  |
|---------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | 1692052249122 | INIT_START Runtime Version: python:3.9.v26 Runtime Version ARN: arn:aws:lambda:us-east-1::runtime:130681a0855afedf31b2b3fbcc2fbf1ca62875e0500edb56fd16cad65045b05b   |
 | 1692052249226 | START RequestId: 9a247ffa-5364-4eb5-9596-e1015c45bd84 Version: $LATEST                                                                                               
 |
 | 1692052249226 | [ERROR] Runtime.ImportModuleError: Unable to import module 'main': No module named 'fastapi' Traceback (most recent call last):                                      
 |
 | 1692052249228 | END RequestId: 9a247ffa-5364-4eb5-9596-e1015c45bd84                                                                                                                  
 |
 | 1692052249228 | REPORT RequestId: 9a247ffa-5364-4eb5-9596-e1015c45bd84 Duration: 2.36 ms Billed Duration: 3 ms Memory Size: 128 MB Max Memory Used: 36 MB Init Duration: 103.49 ms   |
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

问题根源 #

CI阶段只是把依赖安装到了Github Runner的系统环境里，并没有将依赖包打包到app.zip中。AWS Lambda的运行环境没有预先安装FastAPI，所以执行时找不到对应的模块。

修复方案 #

修改CI阶段的依赖安装步骤，将依赖包直接安装到app目录下，这样打包时就能把代码和依赖一起包含进去：

1. 修改CI中的Install dependencies步骤，添加-t ./app参数指定安装路径：

pip3 install -r ./app/requirements.txt -t ./app

-t参数会把所有依赖包安装到指定的./app目录，和你的代码文件放在一起。

2. 保持后续的打包步骤不变，此时生成的app.zip会包含你的代码以及所有依赖包。

额外检查项 #

• 确认requirements.txt中确实包含FastAPI，例如fastapi>=0.100.0
• 确保AWS Lambda的运行时设置为Python 3.9，与CI阶段使用的Python版本一致

修改后的CI阶段示例 #

CI:
  runs-on: ubuntu-latest
  steps:
    - uses: actions/checkout@v2
    - name: Set up Python
      uses: actions/setup-python@v2
      with:
        python-version: 3.9
    - name: Install dependencies to app directory
      run: pip3 install -r ./app/requirements.txt -t ./app
    - name: Create application ZIP archive
      run: cd ./app && zip -r app.zip .
    - name: Upload app.zip artifact
      uses: actions/upload-artifact@v2
      with:
        name: app
        path: ./app/app.zip
    - name: Upload swagger.json artifact
      uses: actions/upload-artifact@v2
      with:
        name: swagger
        path: ./app/swagger.json

内容的提问来源于stack exchange，提问作者Kyle Sponable