Building Serverless Applications with Ease: A Practical Guide to IaC Tools and Frameworks for AWS ⚡️
Tags: serverless, aws, infrastructureascode, lambda
Published: 2023-05-10 18:56:06

## Introduction

Serverless computing has emerged as a popular paradigm for building modern cloud-native applications. With serverless, developers can focus on writing code and let the cloud providers take care of the underlying infrastructure. However, deploying & managing serverless applications can be challenging. **Infrastructure-as-Code** (**IaC**) tools and frameworks help developers easily deploy and manage serverless applications.

In this guide, we will explore some of the popular IaC tools and frameworks for serverless computing on AWS. We will discuss the benefits of each tool, and provide a few basic examples to help you understand better.

## **The Benefits of Infrastructure-as-Code**

Before we dive into the specific IaC tools and frameworks for serverless on AWS, let's briefly discuss the benefits of using IaC tools.

Infrastructure-as-code is the practice of defining and managing infrastructure using code, rather than manual processes. This allows developers to treat infrastructure as just another part of the code. Here are some of the key benefits of infrastructure-as-code:

* **Consistency and repeatability:** IaC tools allow you to define infrastructure as code, which can be versioned, tested, and deployed in a consistent and repeatable manner. This eliminates the risk of configuration drift and ensures that your infrastructure is always in the desired state.
    
* **Agility and flexibility:** IaC tools make creating and modifying infrastructure on demand easy, especially in a cloud-native environment. Developers can quickly spin up new resources, test changes, and tear down resources when they are no longer needed.
    
* **Collaboration:** IaC tools enable collaboration among team members by allowing them to work together on infrastructure code. This makes it easy to review changes, track issues, and deploy changes in a controlled and coordinated manner.
    

Overall, using IaC tools and frameworks can help you deploy and manage serverless applications with ease. In the next section, we will discuss some of the popular IaC tools and frameworks for serverless computing on AWS.

## **Serverless Framework**

The Serverless Framework is the most popular and powerful open-source tool for building serverless applications. It's often considered the industry standard for building serverless applications on AWS due to its ease of use, flexibility, and rich plugin ecosystem. With the Serverless Framework, developers can define their serverless application infrastructure as code using YAML, JSON, or even TypeScript.

### **Benefits of Serverless Framework**

The Serverless Framework offers many benefits to developers, including:

* **Easy to Use:** The Serverless Framework is very easy to set up and use, making it a great choice for developers who are new to serverless computing.
    
* **Flexible:** The Serverless Framework is very flexible and can be used with a wide range of programming languages and AWS services.
    
* **Plugin Ecosystem:** The Serverless Framework has a vast ecosystem of plugins that allow developers to extend the framework's functionality and add new AWS services or third-party services to their serverless applications.
    
* **Debugging and Deployment:** The Serverless Framework provides powerful tools for local debugging and deploying serverless applications, making it easy to identify and fix issues in your code.
    

### **Example: Writing a Lambda Function**

Here's an example of how you can use the Serverless Framework to write a simple Lambda function that responds to HTTP requests:

1. Install the Serverless Framework using your node package manager:
    

```plaintext
npm install -g serverless
```

1. Create a new Serverless service:
    

```plaintext
serverless create --template aws-nodejs --path my-service
```

1. Define your Lambda function in the `serverless.yml` file:
    

```yaml
service: my-service

provider:
  name: aws
  runtime: nodejs14.x

functions:
  hello:
    handler: handler.hello
    events:
      - http:
          path: /hello
          method: get
```

This file defines a simple Lambda function called `hello` that responds to HTTP GET requests on the `/hello` path. The function is implemented in the `handler.js` file using Node.js.

1. Deploy your service to AWS:
    

```plaintext
serverless deploy
```

This will create and deploy your Lambda function to AWS, along with any necessary resources such as an API Gateway.

That's it! With just a few simple steps, you've created a fully functional serverless application using the Serverless Framework.

## **AWS Cloud Development Kit (CDK)**

The AWS Cloud Development Kit (CDK) is an open-source software development framework to define cloud infrastructure in code and provision it through AWS CloudFormation. With the CDK, you can define your infrastructure using familiar programming languages, such as TypeScript, JavaScript, Python, Java, and C#.

### **Benefits of Using the CDK**

* **Familiarity:** Developers can use their preferred programming language to define infrastructure, making it easier to onboard new developers to your infrastructure codebase.
    
* **Reusability:** You can create reusable code snippets, called constructs, that encapsulate best practices for a specific AWS resource or application pattern.
    
* **Automation:** Using the CDK allows you to automate infrastructure provisioning, including creating, updating, and deleting resources with AWS CloudFormation.
    
* **Flexibility:** The CDK supports a wide range of AWS services and resource types, making it suitable for any type of application, from simple serverless applications to complex distributed systems.
    

### **Example**

Here’s a simple example of how to define an AWS Lambda function using the CDK in TypeScript:

```typescript
import * as cdk from 'aws-cdk-lib';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import * as apigateway from 'aws-cdk-lib/aws-apigateway';

export class MyServerlessAppStack extends cdk.Stack {
  constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Define an AWS Lambda function
    const helloLambda = new lambda.Function(this, 'HelloLambda', {
      runtime: lambda.Runtime.NODEJS_14_X,
      handler: 'hello.handler',
      code: lambda.Code.fromAsset('lambda'),
    });

    // Define an AWS API Gateway REST API
    new apigateway.LambdaRestApi(this, 'HelloEndpoint', {
      handler: helloLambda,
    });
  }
}
```

In this example, we're defining an AWS Lambda function that responds to an HTTP request using the AWS API Gateway REST API. The **lambda.Function** and **apigateway.LambdaRestApi** constructs encapsulate best practices for defining Lambda functions and API Gateway REST APIs, making it easier to write reliable and scalable serverless applications using the CDK.

## **AWS Serverless Application Model (SAM)**

The SAM is AWS's answer to Serverless Framework, it is an open-source framework used to build serverless applications on AWS. SAM is designed to simplify the development and deployment of serverless applications by providing a simplified syntax for defining the Amazon API Gateway APIs, AWS Lambda functions, and Amazon DynamoDB tables needed by your serverless application. SAM also includes a local testing feature that allows developers to test their serverless applications locally before deployment. (I love their local testing feature, even though I am a fan of Serverless Framework 😁)

### **Benefits of using SAM**

* **Simplified syntax for defining AWS resources:** SAM uses CloudFormation syntax to define and deploy your serverless applications, making it easy to manage your infrastructure as code.
    
* **Built-in local testing:** SAM CLI provides a Lambda-like execution environment locally, allowing you to test your serverless application locally before deployment.
    
* **Easy deployment:** SAM provides a simple deployment process by packaging your serverless application in a SAM package and deploying it to AWS CloudFormation.
    

### **Example**

Here is an example of using SAM to create a simple AWS Lambda function:

```yaml
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Resources:
  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: hello_world/
      Handler: app.lambda_handler
      Runtime: python3.8
      Events:
        HelloWorld:
          Type: Api
          Properties:
            Path: /hello
            Method: get
```

In this example, we are defining a Lambda function that will handle HTTP GET requests at `/hello` using the Python 3.8 runtime. The function code is located in the `hello_world/` directory, and the `app.lambda_handler` function is the entry point to the application.

SAM provides an easy way to define the API Gateway event trigger that will invoke this Lambda function. In this case, we define an API Gateway event named `HelloWorld` that maps to the `/hello` resource and the HTTP GET method.

Overall, SAM simplifies how developers define and deploy serverless applications on AWS. With easy-to-use syntax and built-in testing capabilities, developers can manage their serverless infrastructure as code and quickly improve their applications.

## **AWS CloudFormation**

AWS CloudFormation is the OG of IaC tools for AWS, it is a managed service by AWS that enables you to define your infrastructure as code using JSON or YAML templates. You can use CloudFormation to model and provision almost all the AWS resources, such as Amazon EC2 instances, Amazon RDS databases, Amazon S3 buckets, etc.

CloudFormation provides a way to describe the entire stack of AWS resources that you need for your application. The templates can be version controlled and treated like any other code. This enables you to easily manage your infrastructure as code in a scalable and consistent way.

### **Benefits of AWS CloudFormation**

* **Ease of use:** CloudFormation provides a simple way to describe your infrastructure as code. You can use either JSON or YAML templates to define your resources.
    
* **Automation:** With CloudFormation, you can automate the provisioning and management of your AWS resources. This makes it easier to deploy and manage your infrastructure at scale.
    
* **Flexibility:** CloudFormation provides flexibility in terms of resource types and attributes. You can use any AWS resource that is available in your region, and you can specify different configurations for each resource.
    

### **Example: Writing a Lambda Function with AWS CloudFormation**

To give you a brief idea of how CloudFormation works, let's take a simple example of deploying a Lambda function using CloudFormation.

Here's an example CloudFormation template that provisions a Lambda function with an S3 trigger:

```yaml
Resources:
  MyFunction:
    Type: AWS::Lambda::Function
    Properties:
      Code:
        S3Bucket: my-bucket
        S3Key: my-function.zip
      Handler: index.handler
      Role: arn:aws:iam::123456789012:role/MyLambdaRole
      Runtime: nodejs14.x
  MyBucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName: my-bucket
  MyBucketNotification:
    Type: AWS::S3::BucketNotification
    Properties:
      Bucket: !Ref MyBucket
      NotificationConfiguration:
        LambdaConfigurations:
        - Event: s3:ObjectCreated:*
          Function: !GetAtt MyFunction.Arn
```

In the above template, we define two resources - a Lambda function and an S3 bucket. We then specify an S3 trigger for the Lambda function that gets triggered whenever a new object is created in the S3 bucket.

When you deploy this template using CloudFormation, it provisions the Lambda function and the S3 bucket with the specified configurations.

AWS CloudFormation provides ways to describe your infrastructure as code using templates. With CloudFormation, you can automate the provisioning and management of your AWS resources.

It's important to follow best practices when using CloudFormation to ensure your infrastructure is scalable, maintainable, and secure.

I prefer to use CDK over CF for its simplicity & ease of use.

## Comparison

Each of the infrastructure-as-code tools has its strengths and weaknesses. To help you make an informed decision about which tool is best for your project, I have created a comparison table of the tools covered in this blog.

| Tool | Cloud Provider | Language Support | Ease of Use | Learning Curve | Community Support | Cost |
| --- | --- | --- | --- | --- | --- | --- |
| Serverless Framework | AWS, Azure, GCP, and more | JavaScript, Python, Java, TypeScript, and more | Easy | Low | Large and active | Free |
| AWS CDK | AWS | TypeScript, JavaScript, Python, Java, C#, and more | Moderate | Moderate | Large and growing | Free |
| AWS SAM | AWS | YAML, JSON, and more | Easy | Low | Large and growing | Free |
| AWS CloudFormation | AWS | YAML, JSON, and more | Moderate | Moderate | Large and growing | Free |

**Note:** These tools are free but you’ll be charged for the resources you provision with these tools, The cost depends on the Services & the cloud providers

*💡 In addition to the above comparison, it's worth considering other factors such as the availability of plugins and integrations, the level of support for advanced features, and the overall fit for your specific project requirements.*

## Best Practices for Infrastructure as Code with Serverless Applications

In the previous sections, we covered many Infrastructure-as-Code tools and frameworks that can be used to build serverless applications on AWS. While these tools and frameworks offer great benefits, it is important to follow some best practices when writing infrastructure as code for serverless applications.

1. **Use version control for infrastructure code**
    

Version control is essential for managing infrastructure as code. It helps you keep track of changes and roll back to previous versions if something goes wrong. Use a version control system like Git to manage your infrastructure code.

1. **Modularize your code**
    

Serverless applications can become complex quickly. To keep your infrastructure code organized and easy to manage, modularize your code. Split your infrastructure code into separate modules that are responsible for specific functions or resources.

1. **Use parameterization**
    

Parameterization allows you to create reusable templates that can be used across multiple environments. Instead of hard-coding values into your infrastructure code, use parameters to make it more flexible.

1. **Use environment variables**
    

Serverless applications often rely on environment variables to store configuration values. Use environment variables to store sensitive information such as database credentials, API keys, and other secrets.

1. **Test your infrastructure code**
    

Just like application code, infrastructure code should be tested to ensure that it works as expected. Use testing frameworks to write automated tests for your infrastructure code.

1. **Follow the principle of least privilege**
    

The principle of least privilege states that a user or application should only have the minimum level of access necessary to perform its function. Apply this principle to your serverless applications by using IAM roles and policies to restrict resource access.

1. **Monitor your infrastructure**
    

Monitoring is crucial for identifying issues and optimizing performance. Use a monitoring tool like CloudWatch or Datadog to keep an eye on your serverless application's performance and identify any issues before they become major problems.

*By following these best practices, you can ensure that your infrastructure as code is well-organized, efficient, and secure.*

## Conclusion

> Choosing the right IaC tool for your serverless application depends on various factors such as your team's expertise, application complexity, and project requirements. It's essential to choose a tool that aligns with your project goals and allows for efficient development and maintenance of your serverless application.

*In conclusion, I hope that this guide has helped you understand the different IaC tools and frameworks available for building serverless applications on AWS. By selecting the right tool and following the best practices, you can ensure that your serverless application is scalable, cost-effective, and easy to maintain.*