Trying AWS Lambda

Documented Steps

Posted by Tomy Jaya on May 14, 2017
Tags: aws, lambda, serverless

Pre-amble

Serverless, or more specifically in the AWS world, Lambda, seems to be the buzzword recently. So, I decided to give it a try. Getting an appropriate use-case is the difficult one. A simple Hello World tutorial wouldn’t give you enough exposure. Hence, after much thoughts, I decided to try to “Lambda”-dize (convert existing backendful service to a Lambda function) a function to send email notification upon contact form’s submission from my static website. Not to complex but not to simple either.

Pre-requisites

  1. Familiarity with the AWS Console
  2. Basic knowledge of node, npm, and JavaScript as we’ll be using the Node API
  3. Basic knowledge of IAM (e.g. Role/ Policy), S3, and SES

Setting Up Your Lambda Function

Follow the steps here: https://github.com/eleven41/aws-lambda-send-ses-email

Some helpful pointers/ resources:

  1. Creating a New Policy Using Policy Editor
  2. When creating the deployment package, go to the SendSesEmail folder of the downloaded zip and type npm install in the Terminal
  3. When zipping the deployment package, make sure you zip the content files instead of the SendSesEmail directory.
  4. Follow the instructions here to create a lambda function. But instead of writing the code in the web editor, opt to upload your zip file.

Setting up

The Lambda function needs to be exposed as a RESTful service. Here’s where API Gateway comes into the picture. Steps can be found below:

Build an API to Expose a Lambda Function

Caveats (README!!!)

  1. SES is only available in selected regions. At first, I tried with ap-southeast-1 region Singapore and encountered region not available issue. At the end, I decided to host everything in us-east-1.

  2. Make sure to run npm install to download all the dependencies before zipping your deployment package. You will encounter ‘markup-js’ not found error if you don’t.

  3. Make sure you zip the content files instead of the directory when creating the deployment package.

  4. Somehow sending to a Yahoo mail server doesn’t work with SES sandbox that well. My GMail account has no problem though.