Serverless Facebook Messenger Bot in Node.js and AWS

Introduction

This example app will run on top of AWS serverless services such as:

• AWS DynamoDb
• AWS Lambda
• AWS REST API Gateway

The IaS (Infrastructure as Code) .yml file has been provided to help you deploying any necessary resources to run the application.

What you can do with this app

• Say hi to initiate the chat bot app and talk to Bot
• Get any messages on REST API
  • /messages
  • /messages/:msg_id
  • /summary
• Deploying serverless based app

Chat bot example

rest api example

How to deploy

Prerequisite

• AWS Cloudwatch only showing the AWS lambda logs when you intentionally write logs to console

• You need to create Business Page on Facebook to do integration with fb-messenger

• You must subscribe to messages & messaging_postbacks webhook events on FB-messenger setup page

• Also read this external resources for preparing your own integration and deployment :

  • FB-Messenger for developer
  • AWS SAM
  • AWS Cloudformation

• Make sure your choice of AWS Regions support any of this services:

  • AWS DynamoDb
  • AWS Lambda
  • AWS REST API Gateway
  • AWS Elastic IP

Requirement

• NodeJs version >= 12.x.x
• Facebook webhook version 13.0
• Facebook developer account
• AWS Account
• AWS CLI
• AWS SAM installed

Apps and serverless resources deployment

Choose one from the two options below.

CI/CD deployment with AWS Code pipeline and automated testing

1. RUN sam pipeline bootstrap will bootstraping all the required AWS resources to connecting CI/CD system
2. RUN sam deploy -t codepipeline.yaml --capabilities=CAPABILITY_IAM --stack-name <STACK-NAME> --region <AWS-REGIONS> --parameter-overrides ProdStackName=<STACK-NAME>
3. After creating the stack, the CodeStar Connection is in PENDING status by default. You must complete the OAuth handshake with the third-party provider using the installation associated with your connection via AWS console
4. RUN aws cloudformation describe-stacks --stack-name <STACK-NAME> --region <AWS-REGIONS> to get endpoint URL on stack Outputs

Manual deployment with AWS SAM

1. Change WEBHOOK_VERIFY_TOKEN env placeholder of your choice on serverless.yml
2. Change PAGE_ACCESS_TOKEN env placeholder on serverless.yml. Get generated access tokens from FB for Developer App Page on messenger settings
3. RUN sam build on projects root folder
4. RUN sam deploy --guided on projects root folder
   • enter stack name of your choice (ex: bot-test-app)
   • enter ap-southeast-1 for AWS regions
   • choose N for Confirm changes before deploy ?
   • choose Y for Allow SAM CLI IAM role creation
   • choose N for Disable rollback
   • choose Y for Save arguments to configuration file
   • choose default name for SAM configuration file [samconfig.toml]
   • choose default name for SAM configuration environment [default]
5. Notes the Cloudformation output value of endpointApi when successfully finished SAM deployment as your REST API base URL
6. Add URL from point 5 as callback URL on FB-Messenger for developer setup page
   • Add /webhook path to base URL (ex: https://BASE_URL/webhook)
   • Add Verify token with the same token of your choice as point no.1
7. Go to the FB-Page you created before and say hi on chat

How to clean-up

1. RUN sam delete -t serverless.yml on projects root folder
2. Choose Y for the remaining options
3. Go to AWS console to manually release elastic IP on VPC menu --> Elastic IP submenu

Notes: AWS Cloudformation will not automatically release unused Elastic IP so you have to do it manually to avoid any unnecessary billing.

Cheers!