About

Serverless functions, such as Lambda functions, provide an alternative to traditional applications or services. The functions run on servers that you do not have to manage yourself, and you pay for only for the compute time you use. However, you might want to invoke your serverless functions from other services or apps, such as the Kubernetes workloads that run in your Gloo Gateway environment. By abstracting a Lambda as a type of destination in your Gloo Gateway environment, your workloads can send requests to the Lambda destination in the same way that you set up routing through Gloo Gateway to other types of destinations. Gloo Gateway does the work of assuming an AWS IAM role to invoke the actual Lambda function in your AWS account.

For more information, see the AWS Lambda documentation on configuring Lambda functions as targets.

Before you begin

  1. Follow the Get started guide to install Gloo Gateway, set up a gateway resource, and deploy the httpbin sample app.

  2. Get the external address of the gateway and save it in an environment variable.

Create an AWS credentials secret

Create a Kubernetes secret that contains your AWS access key and secret key. Gloo Gateway uses this secret to connect to AWS Lambda for authentication and function invocation.

  1. Get the access key, secret key, and session token for your AWS account. If your AWS account setup does not require a session token, you can remove the session token parameter from the Kubernetes secret. Note that your AWS credentials must have the appropriate permissions to interact with AWS Lambda.

  2. Create a Kubernetes secret that contains the AWS access key and secret key.

      glooctl create secret aws \
        --name 'aws-creds' \
        --namespace gloo-system \
        --access-key ${AWS_ACCESS_KEY_ID} \
        --secret-key ${AWS_SECRET_ACCESS_KEY} \
        --session-token ${AWS_SESSION_TOKEN}
      

Create a Lambda function

Create an AWS Lambda function to test Gloo Gateway routing.

  1. Log in to the AWS console and navigate to the Lambda page.

  2. Click the Create Function button.

  3. Name the function echo and click Create function.

  4. Replace the default contents of index.mjs with the following Node.js function, which returns a response body that contains exactly what was sent to the function in the request body.

      export const handler = async(event) => {
        const response = {
            statusCode: 200,
            body: `Response from AWS Lambda. Here's the request you just sent me: ${JSON.stringify(event)}`
        };
        return response;
    };
      
  5. Click Deploy.

Create an Upstream and HTTPRoute

Create Gloo Gateway Upstream and HTTPRoute resources to route requests to the Lambda function.

  1. In your terminal, create an Upstream resource that references the Lambda secret. Update the region with your AWS account region, such as us-east-1.

      kubectl apply -f - <<EOF
    apiVersion: gloo.solo.io/v1
    kind: Upstream
    metadata:
      name: lambda
      namespace: gloo-system
    spec:
      aws:
        region: <region>
        secretRef:
          name: aws-creds
          namespace: gloo-system
        lambdaFunctions:
        - lambdaFunctionName: echo
          logicalName: echo
          qualifier: $LATEST
    EOF
      
  2. Create an HTTPRoute resource that references the lambda Upstream.

      kubectl apply -f - <<EOF
    apiVersion: gateway.networking.k8s.io/v1beta1
    kind: HTTPRoute
    metadata:
      name: lambda
      namespace: gloo-system
    spec:
      parentRefs:
        - name: http
          namespace: gloo-system
      rules:
      - matches:
        - path:
            type: PathPrefix
            value: /echo
        backendRefs:
        - name: lambda
          namespace: gloo-system
          group: gloo.solo.io
          kind: Upstream
          filters:
            - type: ExtensionRef
              extensionRef:
                group: "gloo.solo.io"
                kind: Parameter
                name: echo
    EOF
      
  3. Confirm that Gloo Gateway correctly routes requests to Lambda by sending a curl request to the echo function.

    Example response:

      {"statusCode":200,"body":"Response from AWS Lambda. Here's the request you just sent me: {\"key1\":\"value1\",\"key2\":\"value2\"}"}% 
      

At this point, Gloo Gateway is routing directly to the echo Lambda function!

Cleanup

You can optionally remove the resources that you set up as part of this guide.

  1. Delete the lambda HTTPRoute and lambda Upstream.

      kubectl delete HTTPRoute lambda -n gloo-system
    kubectl delete Upstream lambda -n gloo-system
      
  2. Delete the aws-creds secret.

      kubectl delete secret aws-creds -n gloo-system
      
  3. Use the AWS Lambda console to delete the echo test function.

Known limitations

  • Currently, the only parameter that is supported for the backendRefs.filters.extensionRef field in the HTTPRoute resource is the name of the Lambda function. Additional parameters, such as wrapAsApiGateway, unwrapAsApiGateway, or invocationStyle, are not supported.
  • Authenticating with your AWS account by using IAM Roles for Service Accounts (IRSA) is currently unsupported.