Apigee X Lambda JavaScript Sample

This sample lets you create an API that can create a signed request (AWS4-HMAC-SHA256) to securely access an AWS Lambda function.

It uses:

• A KVM to store the AWS Lambda function key and secret, and other configuration information (e.g. region, host),
• an Assign Message policy to prepare the request,
• a JavaScript policy to create the canonical values for the signature,
• and an Assign Message policy to create the HMAC keys and signature using HMAC calculation functions.

Disclaimer

This example is not an official Google product, nor is it part of an official Google product.

License

This material is copyright 2019, Google LLC. and is licensed under the Apache 2.0 license. See the LICENSE file included.

This code is open source.

Prerequisites

1. Existing AWS Lambda function
2. Apigee X
3. Apigeecli

Setup Instructions

1. Clone the respository

   git clone https://github.com/kurtkanaskie/apigeex-lambda-javascript.git
   

2. Install apigeecli

   curl -L https://raw.githubusercontent.com/apigee/apigeecli/main/downloadLatest.sh | sh -
   

3. Get the details from you Lambda function (keys, function URL and region
4. Edit the env.sh and configure the ENV vars and source env.sh

   source env.sh
   

Sample Lambda function

hello-app/index.mjs

export const handler = async (event) => {
  // TODO implement
  const body = {
    message:'Hello Kurt from Lambda hello-app',
    eventPath:event.rawPath
    // ,eventTotal:event
  };
  
  if( event.rawQueryString ) {
    body.queryString = decodeURI(event.rawQueryString);
  }
  if( event.body ) {
    body.content = JSON.parse(event.body);
  }
  
  const response = {
    statusCode: 200,
    body: JSON.stringify(body),
  };
  return response;
};

Deploy Apigee components

Next, let's deploy our lambda-javascript-v1 proxy.

deploy-lambda-javascript-v1.sh

Test the proxy

curl -s https://$APIGEE_HOST/lambda-javascript | jq
{
  "message": "Hello Kurt from Lambda hello-app",
  "eventPath": "/",
  "eventQueryString": ""
}

curl -s https://$APIGEE_HOST/lambda-javascript/ | jq
{
  "message": "Hello Kurt from Lambda hello-app",
  "eventPath": "/",
  "eventQueryString": ""
}

curl -s https://$APIGEE_HOST/lambda-javascript/somepathsuffix | jq
{
  "message": "Hello Kurt from Lambda hello-app",
  "eventPath": "/somepathsuffix",
  "eventQueryString": ""
}

curl -s https://$APIGEE_HOST/'lambda-javascript/somepathsuffix?hello=sunshine&goodbye=rain' | jq
{
  "message": "Hello Kurt from Lambda hello-app",
  "eventPath": "/somepathsuffix",
  "eventQueryString": "hello=sunshine&goodbye=rain"
}

curl -s https://$APIGEE_HOST/'lambda-javascript/prompt?question=What%20is%20the%20meaning%20of%20life%3F' | jq
{
  "message": "Hello Kurt from Lambda hello-app",
  "eventPath": "/prompt",
  "eventQueryString": "question=What%20is%20the%20meaning%20of%20life%3F"
}

curl --location --request POST https://$APIGEE_HOST/'lambda-javascript/prompts?prompt=What%20is%20the%20meaning%20of%20life' \
--header 'Content-Type: application/json' \
--data-raw '{
    "prompt":"What is the meaning of life?",
    "options": {
        "detailLevel":"HIGH",
        "errorTolerance":"LOW",
        "mode":"SYNCHRONOUS"
    }
}'
{
  "message": "Hello Kurt from Lambda hello-app",
  "eventPath": "/prompts",
  "eventQueryStringDecoded": "prompt=What is the meaning of life",
  "eventBody": {
    "prompt": "What is the meaning of life?",
    "options": {
      "detailLevel": "HIGH",
      "errorTolerance": "LOW",
      "mode": "SYNCHRONOUS"
    }
  }
}

Conclusion & Cleanup

Congratulations! You've successfully created Apigee API to securely access ans AWS Lambda function.

To clean up the artifacts created source your env.sh script and run the following to delete your sample CORS proxy:

./clean-lambda-javascript-v1.sh

References

AWS Lambda

• Getting Started with Lambda
• Creating Signed Request
• AWS SDK JS v4.js

Apigee X

• Apigee HMAC Calculation Functions with AWS example
• Apigee Javascript Crypto Object - SHA-256
• apigeecli

TODO

• Include body in canonical string