Deploying Django

Introduction

Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design. This section describes how to use Nginx and uWSGI to deploy a Django project in HCE 2.0.

Preparations

Prepare an ECS and assign a public IP address or EIP to the ECS.

Ensure that inbound security group rules allow traffic to flow to the ECS over ports 80, 8001, and 8002.

Prerequisites

A yum repository has been configured. For details about how to configure a yum repository accessed over the Internet, see Configuring Repositories and Installing Software for HCE.

Procedure

Install Nginx.
1. Run the following command to install Nginx:
```
dnf install nginx
```
2. Run the following command to start Nginx:
```
systemctl start nginx
```
3. Run the following command to check the Nginx status:
```
systemctl status nginx
```
  If active (running) is displayed, Nginx is started.
Install uWSGI.
1. Run the following command to install uWSGI dependencies:
```
dnf install python3-devel gcc
```
2. Run the following command to install uWSGI:
```
pip install uwsgi
```
3. Run the following command to check the uWSGI version:
```
uwsgi --version
```
4. Edit the hello.py file and enter the following information:
```
def application(env, reply):
    reply('200 ok',[('Content-Type','text/html')])
    return [b"Hello!"]
```
5. Run the following command to start uWSGI:
```
uwsgi --http :8001 --wsgi-file hello.py
```
6. Enter http://<Public IP address>:8001 in the address box of the browser to access uWSGI.
  Figure 1 Accessing the uWSGI service
Install the Django environment.
1. Run the following command to install Django:
```
pip install Django
```
2. Run the following command to initialize the project:
```
python -m django startproject django_project
```
3. Go to the project directory django_project, edit the django_project/settings.py configuration file, and change the value of ALLOWED_HOSTS as follows:
```
ALLOWED_HOSTS = ["*"]
```
4. Run the following command to start Django:
```
python manage.py runserver 0.0.0.0:8002
```
5. Enter http://<Public IP address>:8002 in the address box of the browser to access Django.
  Figure 2 Accessing the Django service
Configure the environment.
1. Edit the django_project/settings.py file.
  1. Add the following statement at the beginning of the file to import the OS library:
```
import os
```
  2. Add the following parameter to the end of the file:
```
STATIC_ROOT = os.path.join(BASE_DIR, "static/")
```
  3. Run the following command to collect all static files:
```
sudo python manage.py collectstatic
```
    For example, the command output is as follows:
```
[root@hce2 django_project]# sudo python manage.py collectstatic

125 static files copied to '/root/django_project/static'.
```
    A static directory is added to the project directory django_project. The project structure is as follows:
```
[root@hce2 django_project]# ls
db.sqlite3  django_project  manage.py  static
```
2. Edit the /etc/nginx/nginx.conf file to configure Nginx.
  1. Locate http and add the following content:
```
upstream django {
    server 127.0.0.1:8001;
}
```
  2. Locate server under http and configure it as follows (the result is shown in Figure 3):
```
server {
    listen       80;
    server_name  django_project;
 
    charset      utf-8;
    location  /static {
        autoindex on;
        alias /root/django_project/static;
    }   
    location / {
        uwsgi_pass 127.0.0.1:8001;
        include uwsgi_params;
        include /etc/nginx/uwsgi_params;
        uwsgi_param UWSGI_SCRIPT iCourse.wsgi;
        uwsgi_param UWSGI_CHDIR /iCourse;
        index index.html index.htm;
        client_max_body_size 35m;
        index index.html index.htm;
}
```
    Figure 3 Example
3. Create the uwsgi_config.ini file in the project directory django_project and enter the following content:
```
[uwsgi]
socket = 127.0.0.1:8001
chdir = /root/django_project/
wsgi-file = django_project/wsgi.py
processes = 4
threads = 2
vacuum = true
buffer-size = 65536
```
  - socket: address and port to be listened on. The port 8001 in the example must be the same as the uwsgi_pass port defined in the Nginx configuration file.
  - chdir: project directory. In this example, the project directory is /root/django_project/. Change it based on the project requirements.
  - wsgi-file: Django's wsgi file. Change it based on project requirements.
  - processes: maximum number of worker processes
  - threads: number of threads started after each worker process is started
  - vacuum: automatically clears the environment when exiting
  - buffer-size: size of the internal buffer for parsing uWSGI packages (value: 64 KB; default: 4 KB)
Verify Django.
1. Run the following command to restart Nginx:
```
systemctl restart nginx
```
2. Run the following command in the project directory django_project to start uWSGI:
```
uwsgi --ini uwsgi_config.ini
```
3. Enter http://<Public IP address> in the address box of the browser to access Django.
  Figure 4 Django page