The Serverless Application Model (SAM) is a framework developed by Amazon Web Services (AWS) for building serverless applications. It is an open-source framework that allows developers to define their serverless applications in a simple and concise way. SAM is designed to help streamline the process of developing, deploying, and managing serverless applications.
Serverless computing, a key concept in cloud computing, is a model where the cloud provider is responsible for executing a piece of code by dynamically allocating the resources. And only for the time when the code is running, the user is charged. This is a significant shift from the traditional model, where the user is responsible for managing the server's resources, irrespective of whether their code is running or not.
Definition of Serverless Application Model (SAM)
The Serverless Application Model (SAM) is a model for serverless applications. It is a specification that provides a standard way of expressing serverless resources in AWS CloudFormation templates. SAM extends AWS CloudFormation to provide a simplified way of defining the Amazon API Gateway APIs, AWS Lambda functions, and Amazon DynamoDB tables needed by your serverless application.
SAM templates are an extension of AWS CloudFormation templates, with some additional components that make it easier to manage and deploy serverless applications. With SAM, you can define your serverless application���s resources using code. This allows you to use version control systems to store your serverless application���s configuration, and enables you to easily replicate your serverless application across different AWS regions and accounts.
Components of SAM
The Serverless Application Model consists of several key components, including SAM templates and the SAM CLI. SAM templates are JSON or YAML formatted files that specify the configuration of your serverless application. They include information about the functions, APIs, permissions, and other resources your application needs to run.
The SAM CLI is a command-line interface that provides a set of commands for developing, testing, and deploying your serverless applications. It includes commands for packaging and deploying your application, invoking your functions locally, and debugging your application.
Benefits of SAM
One of the main benefits of SAM is that it simplifies the process of building and deploying serverless applications. By providing a standard way of defining serverless resources, SAM makes it easier to manage your serverless application���s infrastructure. This can help reduce the complexity and overhead associated with managing serverless applications.
Another benefit of SAM is that it allows you to define your serverless application���s resources using code. This makes it easier to version control your application���s configuration, and enables you to easily replicate your application across different AWS regions and accounts.
History of SAM
The Serverless Application Model (SAM) was introduced by Amazon Web Services (AWS) in 2016 as a way to simplify the process of building and deploying serverless applications. AWS recognized the need for a simpler way to manage serverless applications, and developed SAM to meet this need.
Since its introduction, SAM has been widely adopted by developers building serverless applications on AWS. It has also been updated and expanded to include new features and capabilities, such as support for step functions, additional event sources, and the ability to use SAM templates to define AWS CloudFormation stacks.
Evolution of SAM
Over the years, SAM has evolved to include more features and capabilities. One of the major updates to SAM was the introduction of the SAM CLI in 2017. The SAM CLI provides a set of commands for developing, testing, and deploying serverless applications, and has become a key component of the SAM framework.
Another significant update to SAM was the addition of support for AWS step functions in 2018. This update made it possible to define step functions in SAM templates, making it easier to build and manage serverless workflows.
Use Cases of SAM
The Serverless Application Model (SAM) can be used in a variety of scenarios, ranging from simple applications to complex, multi-tier architectures. Some of the most common use cases for SAM include building web applications, processing data in real time, and creating microservices.
Web applications are a common use case for SAM. By using SAM, developers can easily define the resources they need for their web application, such as Lambda functions and API Gateway APIs, in a single SAM template. This makes it easier to manage and deploy the application.
Data Processing
Data processing is another common use case for SAM. With SAM, developers can easily define the resources they need to process data in real time, such as Lambda functions and DynamoDB tables. This makes it easier to build and manage real-time data processing applications.
For example, a developer might use SAM to build a real-time analytics application. The developer could define a Lambda function to process incoming data, a DynamoDB table to store the processed data, and an API Gateway API to provide access to the data.
Microservices
Microservices are a common use case for SAM. With SAM, developers can easily define the resources they need for each microservice, such as Lambda functions and API Gateway APIs, in a separate SAM template. This makes it easier to manage and deploy each microservice independently.
For example, a developer might use SAM to build a microservice-based e-commerce application. The developer could define a separate SAM template for each microservice, such as the product catalog service, the shopping cart service, and the order processing service.
Examples of SAM
There are many examples of how the Serverless Application Model (SAM) can be used to build and deploy serverless applications. Here are a few specific examples.
One example is a serverless web application. In this case, a developer could use SAM to define a Lambda function to handle HTTP requests, an API Gateway API to route requests to the Lambda function, and a DynamoDB table to store data. The developer could then use the SAM CLI to package and deploy the application to AWS.
Real-Time Data Processing
Another example is a real-time data processing application. In this case, a developer could use SAM to define a Lambda function to process incoming data, a Kinesis stream to ingest the data, and a DynamoDB table to store the processed data. The developer could then use the SAM CLI to package and deploy the application to AWS.
This type of application could be used to analyze social media data in real time, for example. The Lambda function could analyze incoming tweets, the Kinesis stream could ingest the tweets, and the DynamoDB table could store the results of the analysis.
Microservice-Based Application
A third example is a microservice-based application. In this case, a developer could use SAM to define the resources for each microservice in a separate SAM template. Each microservice could include a Lambda function to handle requests, an API Gateway API to route requests to the Lambda function, and a DynamoDB table to store data.
This type of application could be used to build a scalable e-commerce platform, for example. Each microservice could handle a different aspect of the platform, such as product catalog, shopping cart, and order processing.