I recently worked on a Django web application which was deployed on a Linux Server with SSH access. Deployments were done manually and the CI/CD pipeline was still in planning.
We had to perform these tasks every time to deploy the latest changes.
- SSH into the server
- Goto directory where the code is present
- Activate Virtual Environment
- Pull the latest changes on the current branch using Git
- Install any newly added libraries from requirements.txt
- Run migrations for the database
- Run command to generate static files
- Restart Nginx and Supervisor
I found the process repetitive and researched on whether it was possible to automate the commands I need to run after SSHing into the server.
ssh -i "webapp.pem" email@example.com
Turns out, we can write a shell script to automate the task.
Create a new shell script file
deploy.sh with the following content. Modify it to point to your PEM file, username, and IP address.
#!/bin/bash ssh -i "webapp.pem" firstname.lastname@example.org << EOF echo "Hello World" EOF
The above code prints ‘Hello World’ on the remote server.
You can write any shell commands between the two
EOF and it will be run on the remote server.
Add the sequence of commands you currently run manually on the server to this script.
For the Django project, I wrote the following commands that pulls the latest code and restarts the services.
#!/bin/bash ssh -i "webapp.pem" email@example.com << EOF cd /var/www/webapp/ echo "Switching to www-data user" sudo -Hu www-data bash echo "Pulling Latest Changes" git pull echo "Activating Virtual Environment" source venv/bin/activate echo "Installing any new libraries" pip install -r requirements.txt echo "Migrating Database" python manage.py migrate echo "Returning back to Ubuntu user" exit echo "Restarting Supervisor and Nginx" sudo service supervisor restart sudo service nginx restart echo "Deployment Finished" EOF
Run the below command to change permissions of the script and make it executable.
chmod a+x deploy.sh
Run the script and it will perform all the deployment.
This simple script has saved me a lot of time until the CI/CD process is in place.