API Gateway proxy integration with Node.js

This project creates a function and supporting resources:

• function - A Node.js function.
• template.yml - An AWS CloudFormation template that creates an application.
• 1-create-bucket.sh, 2-deploy.sh, etc. - Shell scripts that use the AWS CLI to deploy and manage the application.

The sample application is a Lambda function that processes events from an API Gateway REST API. The API provides a public endpoint that you can access with a web browser or other HTTP client. When you send a request to the endpoint, the API serializes the request and sends it to the function. The function calls the Lambda API to get utilization data and returns it to the API in the required format.

⚠️ The application creates a public API endpoint that is accessible over the internet. When you are done testing, run the cleanup script to delete it.

Use the following instructions to deploy the sample application.

Requirements

• Node.js 10 with npm
• The Bash shell. For Linux and macOS, this is included by default. In Windows 10, you can install the Windows Subsystem for Linux to get a Windows-integrated version of Ubuntu and Bash.
• The AWS CLI.

Setup

Download or clone this repository.

$ git clone git@github.com:awsdocs/aws-lambda-developer-guide.git
$ cd aws-lambda-developer-guide/sample-apps/nodejs-apig

Run 1-create-bucket.sh to create a new bucket for deployment artifacts. Or, if you already have a bucket, create a file named bucket-name.txt that contains the name of your bucket.

nodejs-apig$ ./1-create-bucket.sh
make_bucket: lambda-artifacts-a5e491dbb5b22e0d

Deploy

Run 2-deploy.sh to deploy the application.

nodejs-apig$ ./2-deploy.sh
added 16 packages from 18 contributors and audited 18 packages in 0.926s
added 17 packages from 19 contributors and audited 19 packages in 0.916s
Uploading to e678bc216e6a0d510d661ca9ae2fd941  2737254 / 2737254.0  (100.00%)
Successfully packaged artifacts and wrote output template to file out.yml.
Waiting for changeset to be created..
Waiting for stack create/update to complete
Successfully created/updated stack - nodejs-apig

This script uses AWS CloudFormation to deploy the Lambda functions and an IAM role. If the AWS CloudFormation stack that contains the resources already exists, the script updates it with any changes to the template or function code.

Test

Run 3-invoke.sh to invoke the function directly with a test event (event.json).

nodejs-apig$ ./3-invoke.sh
{
    "StatusCode": 200,
    "ExecutedVersion": "$LATEST"
}

To invoke the function with the REST API, run the 4-get.sh script. This script uses cURL to send a GET request to the API endpoint.

nodejs-apig$ ./4-get.sh
> GET /api/ HTTP/1.1
> Host: mf2fxmplbj.execute-api.us-east-2.amazonaws.com
> Accept: */*
>
< HTTP/1.1 200 OK
< Content-Type: application/json
< Content-Length: 55
< Connection: keep-alive
< x-amzn-RequestId: cb863771-xmpl-47cb-869e-3433209223a8
< X-Custom-Header: My value
< X-Custom-Header: My other value
< X-Amzn-Trace-Id: Root=1-5e67ea83-4826xmpl9be7bf422bf70049
...
{
  "TotalCodeSize": 184440616,
  "FunctionCount": 39
}

The functions in this application are instrumented with AWS X-Ray. Open the X-Ray console to view the service map. The following service map shows the function invoked in two ways.

Choose a node in the main function graph. Then choose View traces to see a list of traces. Choose any trace to view a timeline that breaks down the work done by the function.

Finally, view the application in the Lambda console.

To view the output

1. Open the applications page in the Lambda console.
2. Choose nodejs-apig.

Cleanup

To delete the application, run 5-cleanup.sh.

nodejs-apig$ ./5-cleanup.sh