Building Serverless Django Applications with AWS Lambda and Zappa

Are you tired of the hassle of managing your own servers for your Django applications? Want to take advantage of the scalability and cost-savings of serverless computing? Look no further! In this article, we'll show you how to build and deploy serverless Django applications using AWS Lambda and Zappa.

What is AWS Lambda?

AWS Lambda is a serverless compute service that runs your code in response to events and automatically manages the underlying compute resources for you. This means you don't have to worry about provisioning, scaling, or maintaining any servers - you can just focus on writing your code. AWS Lambda is event-driven, which means it can be triggered by a wide variety of events such as an HTTP request, a change in a database, or the arrival of a file in S3.

What is Zappa?

Zappa is a Python library that makes it easy to build and deploy serverless Python applications, including Django apps, on AWS Lambda. It takes care of all the heavy lifting for you, including packaging and deploying your code, setting up API Gateway, and configuring all necessary resources on AWS. Zappa is easy to use and allows you to get your serverless application up and running quickly.

Prerequisites

Before we get started, you'll need to make sure you have the following:

• An AWS account
• Python and pip installed on your system
• A Django application set up and ready to go

Step 1: Install Zappa and Dependencies

First, we'll need to install Zappa and any dependencies that are required for your Django application. Open up a terminal and run the following command to install Zappa:

pip install zappa        

Next, install any other dependencies that your Django application requires. You can use the pip freeze command to generate a list of your current project dependencies and save it to a requirements.txt file:

pip freeze > requirements.txt        

Then, install the dependencies from the requirements.txt file:

pip install -r requirements.txt        

Step 2: Set Up Your Django Application

Next, navigate to the root directory of your Django application in your terminal. Then, run the following command to set up your Django app for deployment with Zappa:

zappa init        

This will walk you through a series of prompts to set up your application for deployment. You will be asked to provide the name of your Django settings module and the AWS region where you want to deploy your application. You can also specify the runtime (e.g. python3.8) and the name of an IAM profile with the necessary permissions to create and manage resources on AWS.

When you're done, you'll have a zappa_settings.json file in your root directory that looks something like this:

{
    "dev": {
        "app_function": "app.app",
        "aws_region": "us-east-1",
        "profile_name": "default",
        "project_name": "my-django-app",
        "runtime": "python3.7",
        "s3_bucket": "zappa-12345678"
    }
}        

The zappa_settings.json file contains the configuration for your Zappa deployment. In this example, the dev environment is defined with the following properties:

• app_function: The name of the WSGI application function in your Django project.
• aws_region: The AWS region where you want to deploy your application.
• profile_name: The name of the IAM profile with the necessary permissions to create and manage resources on AWS.
• project_name: A unique name for your project that will be used to name the resources created on AWS.
• runtime: The Python runtime for your Lambda function.
• s3_bucket: The name of the S3 bucket where Zappa will store your deployment package.

You can add additional environments to the zappa_settings.json file, such as prod for production, and specify different configurations for each environment.

Step 3: Deploy Your Application

Now it's time to deploy your application! Run the following command to deploy it to AWS Lambda:

zappa deploy dev        

This will create all the necessary resources on AWS, including a Lambda function, an API Gateway API, and a DynamoDB table for storing Zappa events, and deploy your application to them. This process may take a few minutes. When it's done, you'll see a message with the URL of your deployed application.

You can also use the zappa update command to update your application with the latest code and configurations.

Step 4: Test Your Deployment

Now that your application is deployed, let's make sure it's working. Open up the URL of your application in a web browser and see if it loads correctly. If everything looks good, you're all set! Your Django application is now running on AWS Lambda and can scale automatically to meet demand.

Step 5: Configure Domain and HTTPS

By default, the URL of your application will be the endpoint of the API Gateway API that was created by Zappa. This URL will be in the following format: https://{api_id}.execute-api.{region}.amazonaws.com/{stage}/.

If you want to use your own domain and enable HTTPS, you can follow the AWS documentation to set up a custom domain for your API and obtain an SSL certificate for HTTPS.

Step 6: Set Up Event Triggers

AWS Lambda functions can be triggered by a wide variety of events, such as an HTTP request, a change in a database, or the arrival of a file in S3. You can set up event triggers for your Lambda function by updating the zappa_settings.json file and adding an event_source key for the desired event.

For example, to trigger your Lambda function when a new object is created in an S3 bucket, you can add the following to the zappa_settings.json file:

"event_source": {
    "arn": "arn:aws:s3:::my-bucket",
    "events": [
        "s3:ObjectCreated:*"
    ]
}        

Then, run the zappa update command to update your deployment with the new event source. Your Lambda function will now be triggered whenever a new object is created in the specified S3 bucket.

For more information on setting up event triggers, see the Zappa documentation and the AWS documentation.

Step 7: Monitor and Debug Your Application

Zappa integrates with AWS CloudWatch for monitoring and debugging your serverless application. CloudWatch logs all the requests to your application and any errors that occur. You can use the CloudWatch console or the AWS CLI to view the logs and troubleshoot any issues.

To view the logs for your application, navigate to the CloudWatch console and select the Logs menu. Then, select the log group for your Zappa deployment

(e.g. /aws/lambda/{project_name}-dev) and choose a log stream to view the logs.

You can also use the zappa tail command to view the logs in real-time:

zappa tail dev         

This command will stream the logs from CloudWatch to your terminal. Use CTRL+C to stop the stream.

Wrapping Up

Congratulations, you now know how to build and deploy serverless Django applications with AWS Lambda and Zappa! Serverless computing can be a great option for Django applications because it allows you to scale easily and only pay for the compute resources you use. Give it a try and see how it can benefit your projects.

I hope you found this article helpful and fun to read! If you have any questions, please add it in comments Happy coding!

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