Getting Started with Serverless Application Model: SAM Essentials
If you’re here, chances are you’re just moving to the cloud or already going serverless. If so, this article is your go-to guide on one of the most popular solutions — AWS SAM. Learn more about this framework by relying on our 10-year experience in cloud development.
But why choose serverless over traditional application development in the first place? Better scalability, savvy cost allocation, and increased efficiency are just several compelling reasons. When you opt for SAM specifically, you access an extensive AWS toolkit.
This post will cover the Serverless Application Model in the tiniest details. We’ll explore SAM’s features, components, and deployment workflow. Also, we’ll show real-life use cases and best practices for leveraging this framework.
The Serverless Application Model (SAM) is a dev toolkit that streamlines serverless app development, deployment, and management. It’s a part of the AWS ecosystem that extends the AWS CloudFormation’s capabilities. Here’s what this framework covers:
- Deploying serverless apps on AWS automatically.
- Describing functions and resources using templates.
- Combining familiar CloudFormation syntax with SAM’s serverless features.
As part of the AWS environment, the SAM framework easily integrates with other AWS services. It tailors Lambda functions, API Gateway, and DynamoDB for serverless development.
You can also read about Serverless Framework vs. AWS SAM.
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Key Components of SAM
The AWS Serverless Application Model comprises two primary components:
- AWS SAM template specification is an open-source, CloudFormation-based framework. Devs can use it to describe and manage the infrastructure code of their serverless apps. SAM adds an abstract, short-hand syntax to CloudFormation, enabling easier and faster serverless development.
- AWS SAM command line interface (AWS SAM CLI) is a command line tool for AWS SAM and CloudFormation templates. It also works with supported third-party products like Terraform. With AWS SAM CLI, developers build serverless apps, handle testing and debugging, deploy applications, and synchronize local changes with the cloud.
Apart from these major components, there are several additional ones. Here are some examples:
- SAM build command prepares your app for further testing or deployment.
- SAM template Globals section defines settings that apply globally to all resources within the SAM template.
- SAM templates metadata is specific metadata within templates defining serverless resource structure and behavior.
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Features of Serverless Application Model
The AWS Serverless Application Model brings numerous features distinguishing it from other serverless frameworks. Let’s review the most significant SAM functionalities:
- Nested applications: Developers can define nested stacks – a feature essential to modularize and organize the serverless app’s architecture. This capability enables breaking down complex applications into more manageable resources.
- Amazon EventBridge: Devs use EventBridge as an event source for their serverless apps. This feature triggers specific Lambda functions following Amazon services or third-party integration events.
- Lambda functions: SAM focuses on Lambda functions. These services let developers run their code without managing servers.
- Lambda layers: Apart from Lambda functions, SAM offers Lambda layers. These zip file archives share code, libraries, and resources across multiple functions.
- Application auto-scaling: This feature sets the auto-scaling rules for Lambda functions. The metrics they follow include concurrency, CPU usage, and more.
- Step Functions workflows: SAM supports AWS Step Functions. Devs use this feature to execute complex processes and build structured multi-step workflows.
Getting Started with SAM
Now that you know the key components and features of the SAM model, it’s time to learn how to use it. Your first step involves installing and setting up the SAM command line interface. Here’s how to do it:
- If you’re new to AWS, create an AWS account.
- Sign up for an IAM user account.
- Generate an access key ID and secret access key to use CLI.
- Go to the official SAM CLI installation page.
- Choose the installation method for your operating system.
- Follow the installation instructions.
- Configure your AWS credentials, including access key ID, secret access key, AWS region, and output format.
- At this point, you’re ready to use SAM CLI.
Now, let’s see how to create a simple serverless application using SAM. Here are the steps for building a Hello World app:
- To start a SAM project, open your command line tool, choose the directory, and run a sam init command.
- Go to AWS Quick Start Templates. Then, select and download the Hello World Example template.
- Choose the Python runtime and zip as a package type.
- Create a name for your app.
- Go to the Hello World project directory.
- Run a sam build command to build your app.
- Execute a sam deploy --guided command to deploy your application to the cloud.
Once you complete the above steps, you can run your simple app and test if it works correctly.
SAM Development Workflow
Let’s explore the development workflow of a SAM application in greater depth. With this framework, it’s possible to handle the following processes:
Local Development with SAM
Use serverless SAM for local development. For that, run the sam local command. Alternatively, store the output of the sam deploy --guided command in a samconfig.toml configuration file.
Testing Serverless Applications
The AWS SAM framework also provides the following subcommands for local app testing:
- sam local generate-event: Use it to generate AWS events for local testing.
- sam local invoke: Leverage this command to invoke your Lambda functions locally.
- sam local start-api: Use it to execute Lambda functions on a local HTTP server.
- sam local start-lambda: Run this command to execute your Lambda functions on a local HTTP server compatible with the AWS CLI or SDKs.
Deploying Applications on AWS Using SAM
You can deploy your apps to serverless databases using the following methods:
- CI/CD pipelines
- AWS SAM CLI and the sam deploy command
- AWS CodeDeploy for gradual deployment
Integration with AWS Services
As mentioned, the Serverless Application Model is an integral part of an AWS ecosystem. Therefore, SAM integrates seamlessly with other AWS services.
SAM and AWS Lambda
AWS SAM integrates with Lambda and offers smooth serverless function deployment. In particular, it enables the following:
- Function definition: Outline your Lambda functions in the SAM template.
- Event sources: Use SAM and EventBridge to configure event sources to trigger the necessary actions from Lambda functions.
- Local testing: Adopt SAM CLI and test Lambda functions locally.
SAM and API Gateway
Integrate SAM with API Gateway to create and manage REST APIs easily. In particular, you can handle the following:
- API definition: Describe your API in the SAM template and integrate it with Lambda functions.
- Supporting resources: Automatically get various resources after defining your API. These include API Gateway request models, routes, deployment, stage, and permissions to the resource.
SAM and DynamoDB
SAM supports DynamoDB and allows you to improve data management in your serverless apps. It includes the following:
- DynamoDB table definition: Include DynamoDB tables in your SAM template and define their property and specifications.
- Integration with Lambda: Connect Lambda functions to DynamoDB tables.
Best Practices for SAM
When working with the Amazon Serverless Application Model, it’s worth following specific recommendations. Here are the tips from our experience:
- Design and architecture considerations: Leverage modular design through nested stacks and break down complex apps into smaller components. Consider your scaling requirements and implement an efficient auto-scaling policy following your needs.
- Security best practices: Use SAM’s Resource Policies to control access permissions. Set up role permissions through IAM and protect sensitive data by introducing environment-specific configurations.
- Optimization tips: Leverage Lambda layers for code reusability. Set up reasonable Lambda function timeout and memory settings and constantly monitor your serverless app’s performance.
Real-World Use Cases and Examples
Discover the applications of the AWS Serverless Application Model (SAM) in real-world settings. Here are several examples:
- Microservices architecture: Implement microservices architecture through Lambda functions. Develop, test, and deploy each microservice using SAM.
- Event-driven apps: You can use SAM for event-driven applications since this framework integrates with EventBridge.
- Real-time data processing: Adopt AWS SAM in real-time data processing scenarios using Lambda functions and operating on an event-driven architecture.
- Serverless web apps: To develop and deploy serverless web applications, leverage SAM’s integrations with API Gateway and Lambda functions.
- CI/CD systems: Use the sam pipeline command to create and adjust pipelines for your CI/CD systems.
Our Team as Your Serverless Partner
Count on our team to transform your traditional infrastructure into a serverless one. We did just that in over 200 successful projects. Our experts acknowledge the pros and cons of serverless SAM and handle its peculiarities skillfully. Here are the essential aspects of our well-established and consistent approach:
- Ensure future-proof solutions.
- Leverage reusable, modular code.
- Provide feedback swiftly.
- Guarantee transparent communication.
Our projects demonstrate our relentless efforts best. One example is migrating from a monolith architecture to a serverless solution using various AWS tools. Our client, the MasterStream telecom service provider, needed a scalable and up-to-date architecture. We introduced the following improvements:
- DynamoDB for data storage
- Lambda for function execution
- API Gateway for RESTful API creation and management
Want to learn more about our work? Check out our extensive portfolio.
The Serverless Application Model is a robust framework for serverless projects. It offers unparalleled scalability, straightforward development and deployment, and effortless app management.
If you’re interested in using AWS SAM to your benefit, our team at Serverless is here for you. We’re ready to facilitate your success with our profound understanding of this solution and solid serverless deployment experience. Reach out to our experts today!
Can SAM be used with other cloud providers?
No, SAM only works within the AWS ecosystem. However, it supports third-party API integrations.
How does SAM handle local development and testing?
The SAM server uses a command line interface for local development and testing. Developers can leverage sam local, sam local invoke, and other commands to run these processes.
Are there any limitations or challenges when using SAM?
SAM’s exclusive compatibility with AWS can be a significant drawback for some businesses. The framework may also lack plugins and extensions. But its developer community is gradually growing.
Can I use SAM with existing serverless applications, or is it only for new projects?
You can use AWS SAM for your existing serverless projects. However, you may need to migrate your app to a new ecosystem.
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