swift-aws-lambda-runtime/Examples/HummingbirdLambda

Hummingbird Lambda

This is a simple example of an AWS Lambda function using the Hummingbird web framework, invoked through an Amazon API Gateway.

Code

The Lambda function uses Hummingbird's router to handle HTTP requests. It defines a simple GET endpoint at /hello that returns "Hello".

The code creates a Router with AppRequestContext (which is a type alias for BasicLambdaRequestContext<APIGatewayV2Request>). The router defines HTTP routes using Hummingbird's familiar syntax.

The APIGatewayV2LambdaFunction wraps the Hummingbird router to make it compatible with AWS Lambda and API Gateway V2 events.

APIGatewayV2Request is defined in the Swift AWS Lambda Events library, and the Hummingbird Lambda integration is provided by the Hummingbird Lambda package.

Build & Package

To build the package, type the following commands.

swift build
swift package archive --allow-network-connections docker

If there is no error, there is a ZIP file ready to deploy. The ZIP file is located at .build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager/HBLambda/HBLambda.zip

Deploy

The deployment must include the Lambda function and the API Gateway. We use the Serverless Application Model (SAM) to deploy the infrastructure.

Prerequisites : Install the SAM CLI

The example directory contains a file named template.yaml that describes the deployment.

To actually deploy your Lambda function and create the infrastructure, type the following sam command.

sam deploy \
--resolve-s3 \
--template-file template.yaml \
--stack-name HummingbirdLambda \
--capabilities CAPABILITY_IAM 

At the end of the deployment, the script lists the API Gateway endpoint. The output is similar to this one.

-----------------------------------------------------------------------------------------------------------------------------
Outputs                                                                                                                     
-----------------------------------------------------------------------------------------------------------------------------
Key                 APIGatewayEndpoint                                                                                      
Description         API Gateway endpoint URL"                                                                                
Value               https://a5q74es3k2.execute-api.us-east-1.amazonaws.com                                                  
-----------------------------------------------------------------------------------------------------------------------------

Invoke your Lambda function

To invoke the Lambda function, use this curl command line to call the /hello endpoint.

curl https://a5q74es3k2.execute-api.us-east-1.amazonaws.com/hello

Be sure to replace the URL with the API Gateway endpoint returned in the previous step.

This should print:

Hello

Undeploy

When done testing, you can delete the infrastructure with this command.

sam delete 

⚠️ Security and Reliability Notice

These are example applications for demonstration purposes. When deploying such infrastructure in production environments, we strongly encourage you to follow these best practices for improved security and resiliency:

• Enable access logging on API Gateway (documentation)
• Ensure that AWS Lambda function is configured for function-level concurrent execution limit (concurrency documentation, configuration guide)
• Check encryption settings for Lambda environment variables (documentation)
• Ensure that AWS Lambda function is configured for a Dead Letter Queue (DLQ) (documentation)
• Ensure that AWS Lambda function is configured inside a VPC when it needs to access private resources (documentation, code example)