如何将现有Django应用迁移至virtualenv虚拟环境？

Hey there! Great call moving your Django app into a virtual environment—it’s the perfect way to shield it from system-wide software changes, especially since you plan to upgrade your LTS down the line. Let’s walk through this step-by-step for your specific setup (Ubuntu 16.04.3, Apache2, Python 3.5, Django 2.0):

1. Prepare the Virtual Environment Tool #

Python 3.5 comes with the venv module built-in, but Ubuntu might have split it into a separate package. First, make sure it’s installed:

sudo apt-get update && sudo apt-get install python3-venv

2. Create Your Virtual Environment #

Pick a directory to store your virtual environments (I like keeping them separate from projects for clarity, but you can put it in your project root too):

# Create a folder for envs (if it doesn't exist)
mkdir ~/django_virtual_envs && cd ~/django_virtual_envs

# Create the virtual environment (name it something meaningful, like myapp_env)
python3 -m venv myapp_env

3. Activate the Virtual Environment #

Activate it to start using the isolated Python environment:

source myapp_env/bin/activate

You’ll see (myapp_env) at the start of your command line—this means you’re working inside the virtual environment.

4. Migrate Your App’s Dependencies #

First, we need to replicate your current dependency setup in the virtual environment:

• If you don’t already have a requirements.txt file, export your current system dependencies first (run this outside the virtual environment, or use the full path to system Python):

  pip3 freeze > /path/to/your/django/project/requirements.txt
  

• Then, back in your activated virtual environment, install those dependencies:

  pip install -r /path/to/your/django/project/requirements.txt
  

  This will install Django 2.0 and all other packages your app uses, exactly as they are now, into the isolated environment.

5. Configure Apache to Use the Virtual Environment #

Since you’re using Apache with mod_wsgi, you need to update your app’s Apache config to point to the virtual environment’s Python interpreter.

Open your app’s Apache config file (usually in /etc/apache2/sites-available/your_app.conf) and modify it with one of these setups:

Option 1: Basic Setup #

Add these lines to your config (adjust paths to match your setup):

# Point to the virtual environment's Python home
WSGIPythonHome /home/your_username/django_virtual_envs/myapp_env
# Point to your Django project's root directory
WSGIPythonPath /path/to/your/django/project

Option 2: Daemon Mode (Recommended) #

For better performance and isolation, use daemon mode:

# Define a daemon process tied to your virtual environment
WSGIDaemonProcess myapp python-home=/home/your_username/django_virtual_envs/myapp_env python-path=/path/to/your/django/project
# Tell Apache to use this process for your app
WSGIProcessGroup myapp

After updating the config, restart Apache to apply changes:

sudo systemctl restart apache2

6. Verify the Setup Worked #

To make sure your app is using the virtual environment, add a quick test view to your Django project:

# In one of your app's views.py
from django.http import HttpResponse
import sys
import django

def check_env(request):
    env_details = f"Python Executable: {sys.executable}<br>"
    env_details += f"Django Version: {django.get_version()}"
    return HttpResponse(env_details)

Add a URL pattern for this view, then visit it in your browser. You should see the Python path pointing to myapp_env/bin/python and Django version 2.0—confirming the virtual environment is active.

Key Notes for Future LTS Upgrades #

• When you upgrade your Ubuntu LTS, your virtual environment will remain untouched—all your dependencies are stored locally, so system updates won’t break your app.
• If you need to update dependencies later, just activate the virtual environment and use pip as usual—no impact on the system’s global Python setup.
• Make sure the Apache user (www-data) has read access to your virtual environment and project directories. If you run into permission issues, adjust permissions with:

  sudo chmod -R 755 ~/django_virtual_envs/myapp_env
  sudo chown -R your_username:www-data /path/to/your/django/project
  

That’s it! Your Django app is now safely isolated from system changes. If you hit any hiccups (like mod_wsgi compatibility or permission issues), feel free to troubleshoot those specific bits—this core process should get you 90% of the way there.

内容的提问来源于stack exchange，提问作者4dummies