sm email service

A simple email service

Documentation

Prerequisites

docker and docker compose (lastest version) Docker & Docker-Compose
Mailgun and Sendgrid accounts

commands to get you started

git clone https://github.com/asjadsaboor/sm-email-service.git and go to project folder.
create .env file in config directory
npm install (install packages locally, since we don't mount node_modules in container)
npm run build:docker
npm run start:docker

A collection of useful commands which might be helpful

Logs

npm run logs

Linting / Code prettify

npm run lint
npm run lint:fix
npm run format:check
npm run format:fix:all

Run tests

npm run test

Create apidocs

npm run apidocs

Debug

uncomment following line from docker-compose.yml

#- --inspect-brk=0.0.0.0

create launch.json in .vscode folder, and copy following code

{
  "version": "0.2.0",
  "configurations": [{
    "type": "node",
    "request": "attach",
    "name": "Docker: Attach to Node",
    "port": 9229,
    "address": "localhost",
    "localRoot": "${workspaceFolder}/src",
    "remoteRoot": "/api/src",
    "protocol": "inspector"
  }]
}

Sample .env

NODE_ENV=local
PORT=4001
API_KEY_SENDGRID=XXX
API_KEY_MAILGUN=XXX
MAILGUN_DOMAIN=xxx

API Details

API Docs

http://sm-email-service-2058030217.us-east-1.elb.amazonaws.com/api/docs/

URL

http://sm-email-service-2058030217.us-east-1.elb.amazonaws.com/api/v1/

Methods

POST email/send

Example Request to send email

Body

{
	"to":["asjadsaboor@gmail.com"],
	"cc":["asjadsaboor1@yopmail.com"],
	"bcc":["asjadsaboor2@yopmail.com"],
	"subject": "my subject",
	"body":"my email body"
}

CURL

curl -X POST \
  http://sm-email-service-2058030217.us-east-1.elb.amazonaws.com/api/v1/email/send \
  -H 'Content-Type: application/json' \
  -H 'cache-control: no-cache' \
  -d '{
	"to":["asjadsaboor@gmail.com"],
	"cc":["asjadsaboor1@yopmail.com"],
	"bcc":["asjadsaboor2@yopmail.com"],
	"subject": "from em service1 aws",
	"body":"from em service1 aws"
}'

Deployment

API is deployed on AWS Elastic Container service and attached to elastic load balancer.

Codepipeline is used for automated deployment.

Problem Statement and Solution

Implement a email service using 2 service providers, such that if one goes down that service can quickly switch to the other

When a user call REST API to send emails, first the request is send using the primary server.If the request of primary server fails, a key is set in in-memmory cache to deactivate primary server for few minutes and secondary email service will be used till the primaryserver key expires.

What will happen if both providers are down? A rare possibility, but in this case all request can be send to a SQS and a lambda can be attached to SQS to retry these requests.

Note: SQS is not yet implemented.

TODO List

Implement logger and push logs to cloudwatch or similar service.
Make tslint a little more strict and run lint/test in CI/CD.
Implement API rate limiting
Add integration tests
Implement Queue based solution for eg( SQS and lambda ), so that we can push requests to queue in case all email providers are down.
attach SSL to aws elastic load balancer and redirect http to https.
Enable auto scaling in ECS to handle heavy traffic.
Whitelabel / authenticate sender domain.

asjadsaboor-10p / sm-email-service