姜戈 Nginx 502

正在寻找如何使用 Elastic Beanstalk 与 Django 修复 nginx 502 Bad Gateway 的解决方案。 Django 应用程序是正确的，本地一切都可以无缝运行。当我尝试将该应用程序部署到 AWS EC2 时出现问题。

我使用 AWS PostgreSQL 数据库。

所有环境变量都正确保存在 AWS 环境中。已遍历所有解决方案，但没有任何帮助。

某些库是否可能会产生冲突，导致 502 Bad Gateway？

使用 Python 3.11.9

**requitements.txt**
asgiref==3.8.1
boto3==1.34.141
botocore==1.34.141
certifi==2024.7.4
charset-normalizer==3.3.2
colorama==0.4.6
crispy-bootstrap5==2024.2
Django==5.0.6
django-autoslug==1.9.9
django-crispy-forms==2.2
django-environ==0.11.2
django-mathfilters==1.0.0
django-storages==1.14.4
django-utils-six==2.0
djangorestframework==3.15.2
gunicorn==20.1.0
idna==3.7
jmespath==1.0.1
packaging==24.1
phonenumbers==8.13.40
pillow==10.3.0
psycopg2-binary==2.9.9
requests==2.32.3
s3transfer==0.10.2
six==1.16.0
sqlparse==0.5.0
tzdata==2024.1
urllib3==2.2.2

然后

**.ebextensions/django.config**
option_settings:
  aws:elasticbeanstalk:container:python:
    WSGIPath: ecommerce.wsgi:application

然后|| |然后

**Procfile**
web: gunicorn ecommerce.wsgi:application --bind 0.0.0.0:8000

然后

**ecommerce/ecommerce/wsgi.py**
import os

from django.core.wsgi import get_wsgi_application

os.environ.setdefault("DJANGO_SETTINGS_MODULE", "ecommerce.settings")

application = get_wsgi_application()

CMD 输出：

**.ebignore**
requirements.dev.txt

.pytest_cache/
tests/
.pytest_cache/
*.test.py
test_*.py

*.local
.env
.env.example

.git/
README.md
.prettierignore
.vscode/
.idea/

*.pyc
__pycache__/
.mypy_cache/
.nox/
.coverage
.tox/
.venv/

CMD Output:

>eb logs
Retrieving logs...
===========================
----------------------------------------
/var/log/web.stdout.log
web[2267]:  File "/var/app/venv/staging-LQM1lest/lib64/python3.11/site-packages/gunicorn/util.py", line 359, in import_app

The 502 Bad Gateway error you're getting on your Django application deployed on AWS Elastic Beanstalk indicates that your Nginx server (acting as a reverse proxy) cannot communicate properly with your Django application served by Gunicorn. Here's a breakdown of common causes and how to troubleshoot them:

1. Application Log Analysis

• Start with your application logs: The most crucial information resides in your Django application logs. Access these logs on Elastic Beanstalk. Look for:

  • Startup errors: Issues during the application's initialization, such as incorrect database credentials, missing environment variables, or import problems.
  • Runtime errors: Exceptions thrown during request processing, indicating potential code flaws.

• Example log location: /var/log/python/error.log (may vary based on your setup).

2. Gunicorn Configuration and Bindings

• Binding to the Correct Address: Your Gunicorn process in the Procfile is correctly bound to 0.0.0.0:8000 . This makes it accessible to Nginx.

• Verify Gunicorn is Running:

  • SSH into your EC2 instance.
  • List running processes: ps aux | grep gunicorn
  • Ensure Gunicorn is running and listening on the expected port (8000).

3. Nginx Configuration

• Inspect Nginx Configuration: The Nginx configuration is crucial. You'll need to ensure it's properly configured to proxy requests to your Gunicorn socket.

  • Example location: /etc/nginx/conf.d/myproject.conf (path can vary)

• Key Points in Nginx Configuration:

  • server block: Should listen on port 80 (default HTTP) and potentially 443 (HTTPS).
  • location / block:
    • proxy_pass : Should point to your Gunicorn socket (e.g., http://127.0.0.1:8000 ).
    • Other headers: You'll likely need to set headers like proxy_set_header Host $host; for proper request forwarding.

4. Environment Variables and Settings

• Double-Check Environment Variables:
  • Ensure your Django settings file ( ecommerce/settings.py ) correctly reads environment variables.
  • Use the Elastic Beanstalk environment configuration to securely store and manage these variables.
  • Common variables: DATABASE_URL , SECRET_KEY , DEBUG , etc.

5. Resource Constraints and Timeouts

• Insufficient Resources: A common reason for 502 errors is the EC2 instance running out of resources (RAM, CPU).

  • Monitoring: Monitor your instance's resource utilization through the AWS console.
  • Scaling: Consider increasing instance size or using Elastic Beanstalk's auto-scaling features if needed.

• Timeouts: Long-running requests can also cause 502s.

  • Nginx: Increase timeout settings in your Nginx configuration if you anticipate handling lengthy requests.
  • Gunicorn: Adjust Gunicorn's worker timeout settings ( --timeout option) as necessary.

Debugging Steps

1. SSH into Your EC2 Instance: This is essential for direct troubleshooting.

2. Check Application Logs: Carefully examine the Django application logs for any error messages.

3. Test Gunicorn Directly: Temporarily bypass Nginx:

4. Access your EC2 instance's public IP address or domain name with port 8000 in your browser (e.g., http://your-instance-ip:8000/ ).

5. If this works, the issue likely lies in your Nginx configuration.

6. Examine Nginx Logs: Nginx logs provide details about web server errors.

   • Typical location: /var/log/nginx/error.log

7. Restart Services: Sometimes, simply restarting Nginx and Gunicorn can resolve transient issues:

   • sudo service nginx restart
   • sudo supervisorctl restart gunicorn (or equivalent depending on your Gunicorn management)

Additional Tips:

• Simplify: Temporarily simplify your Django application (e.g., a "Hello, World!" view) to rule out code-specific problems.
• Library Conflicts: While less likely, if you suspect a library conflict, try:
  • Creating a new virtual environment and reinstalling your dependencies.
  • Checking for incompatible library versions.

If you've gone through these steps and are still encountering the 502 error, please provide the following information so we can assist you further:

• Relevant parts of your Django application logs.
• Your Nginx configuration file ( /etc/nginx/conf.d/myproject.conf or similar).
• The output of eb logs from your Elastic Beanstalk environment.