服务器端使用pipenv执行Django迁移失败问题排查

一、Capistrano迁移任务代码 #

task :migrate do 
  on roles(:app) do
    execute "cd #{release_path} && /home/ubuntu/.pyenv/shims/pipenv install"
    execute "cd #{release_path} && /home/ubuntu/.pyenv/shims/pipenv run python #{release_path}/manage.py makemigrations" 
    execute "cd #{release_path} && /home/ubuntu/.pyenv/shims/pipenv run python #{release_path}/manage.py migrate"
 end

二、Pipfile配置 #

[[source]]
url = "https://pypi.org/simple"
verify_ssl = true
name = "pypi"

[packages]
django = "*"
pandas = "*"
djangorestframework = "*"
markdown = "*"
django-filter = "*"
django-webpack-loader = "*"
django-crispy-forms = "*"
pymysql = "*"
beautifulsoup4 = "*"

[dev-packages]

[requires]
python_version = "3.9"

三、报错信息 #

DEBUG [42151ee5]    Installing dependencies from Pipfile.lock (4abb36)...
 DEBUG [42151ee5]   To activate this project's virtualenv, run pipenv shell.
Alternatively, run a command inside the virtualenv with pipenv run.
  INFO [42151ee5] Finished in 19.917 seconds with exit status 0 (successful).
  INFO [35fb8a90] Running cd /var/www/html/myappp/releases/20220923122448 && /home/ubuntu/.pyenv/shims/pipenv run python /var/www/html/myapp/releases/20220923122448/manage.py makemigrations as ubuntu@panda.example.jp
 DEBUG [35fb8a90] Command: cd /var/www/html/muapp/releases/20220923122448 && /home/ubuntu/.pyenv/shims/pipenv run python /var/www/html/myapp/releases/20220923122448/manage.py makemigrations
 DEBUG [35fb8a90]   Traceback (most recent call last):
  File "/home/ubuntu/.local/share/virtualenvs/20220923122448-VTt_Iizv/lib/python3.8/site-packages/django/utils/timezone.py", line 10, in <module>
    import zoneinfo
ModuleNotFoundError: No module named 'zoneinfo'

    raise ImportError(
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?

问题根源 #

1. Python版本不匹配：Pipfile指定使用Python3.9，但实际虚拟环境用的是Python3.8（从报错路径/lib/python3.8/site-packages/...可看出）。zoneinfo是Python3.9及以上版本自带的模块，3.8没有该模块，而Django 4.x+依赖这个模块，所以触发导入错误，最终导致提示“找不到Django”。
2. Capistrano任务路径拼写错误：命令中出现myappp、muapp等错误路径，与实际的myapp路径不符，可能导致执行命令时找不到正确的项目文件。

解决步骤 #

1. 确保服务器使用Python3.9创建虚拟环境
   在服务器的项目目录下执行：

   # 设置当前目录使用Python3.9（需先通过pyenv安装对应版本）
   pyenv local 3.9.x
   # 删除现有错误的虚拟环境
   pipenv --rm
   # 重新安装依赖，确保使用指定的Python版本
   pipenv install --deploy
   

2. 修正Capistrano任务中的路径问题
   改用within方法自动切换到发布目录，避免手动拼接路径出错，同时简化命令：

   task :migrate do
     on roles(:app) do
       within release_path do
         execute "/home/ubuntu/.pyenv/shims/pipenv install --deploy"
         execute "/home/ubuntu/.pyenv/shims/pipenv run python manage.py makemigrations"
         execute "/home/ubuntu/.pyenv/shims/pipenv run python manage.py migrate"
       end
     end
   end
   

3. 可选：锁定Django版本
   Pipfile中django = "*"会安装最新版Django，若服务器Python版本无法兼容，建议指定兼容3.9的具体版本，比如：

   django = "~=4.2"
   

内容的提问来源于stack exchange，提问作者whitebear