Design:

An addEmailServer is running, serving many async clients sending users' email id. This server adds these email ids to RabbitMQ. Another server (sendEmailServer) is running, which is serving clients asynchronously. It uses the sender email id and email body from the client requests; it consumes the receiver email id from RabbitMQ and sends an email using send grid API. The project uses gRPC in golang.

How to Run:

Step 1:

Setup rabbitMQ locally (instructions for mac)

brew install rabbitmq 
export PATH=$PATH:/usr/local/sbin 
rabbitmq-server start 

Step 2:

Setup project

Run go mod download from project root
From project root run cd emailService

Step 3:

Start local server to add email ids to RabbitMQ

Run go run addEmailServer/server.go

Step 4:

Send async request from add email client to add email ids (100 emails)

Run go run addEmailClient/client.go

Step 5:

Generate Send Grid Api Key and store it locally

Create an account with sendgrid and generate your API key reger
Create an environment variable with your API Key and registered email id

echo "export SENDGRID_API_KEY='YOUR-API-KEY'" > sendgrid.env
echo "export SENDER_EMAIL_ID='YOUR-REGISTRED-EMAIL-ID" > sendgrid.env
echo "sendgrid.env" >> .gitignore
source ./sendgrid.env

Step 6:

Start send grid server to consume email IDs from RabbitMQ and send emails using sengrid API

Run source ./sendgrid.env && go run sendgridServer/sendgridServer.go

Step 7:

Send async request from send email client to send emails to email ids consumed from RabbitMQ

Run source ./sendgrid.env && go run sendEmailClient/sendgridClient.go

Project Structure

├── LICENSE
├── Readme.md
├── emailService
│   ├── addEmailClient
│   │   └── client.go
│   ├── addEmailServer
│   │   └── server.go
│   ├── proto
│   │   ├── email.pb.go
│   │   ├── email.proto
│   │   └── email_grpc.pb.go
│   ├── sendEmailClient
│   │   └── sendgridClient.go
│   ├── sendEmailServer
│   │   └── sendgridServer.go
│   └── sendgrid.env
├── go.mod
└── go.sum