📨 Notification Service

A notification service is a software system that manages the sending of notifications across different channels and devices.

The Launch of

To run an application in a container, you need to configure the command:

make build

Description of the service

This service is a microservice that is responsible for sending notifications to various channels.

The service is implemented using a queue - RabbitMQ to implement a Worker Pool with a guarantee of sending messages. Each channel has its own topic, and within the topic there is a priority of messages.

Messages are sent using a proprietary SMTP server running with Postfix. An external client is used to send SMS messages

Environment Variables and Configuration

For the application to work correctly, you must specify environment variables in the .env file in the root directory. Below are the variables themselves and a brief description:

POSTGRES_USER, POSTGRES_DB, POSTGRES_PASSWORD, RABBITMQ_DEFAULT_USER, RABBITMQ_DEFAULT_PASS - parameters for initializing the Postgresql database and RabbitMQ messaging in docker-compose.

SMTP_DOMAIN, SMTP_USERNAME, SMTP_PASSWORD - required parameters for using the SMTP service

TWILIO_ACCOUNT_SID, TWILIO_AUTH_TOKEN, TWILIO_MESSAGING_SERVICE_SID - parameters for the client sending SMS messages

GF_SECURITY_ADMIN_USER, GF_SECURITY_ADMIN_PASSWORD - parameters for the Grafana

PG_URL - link to connect to Postgresql.

RMQ_URL - link to the rabbitmq queue.

There is also a configs file in which the remaining data is specified.

The technology stack used

Golang gRPC PostgreSQL RabbitMQ

Features

• ✅ Using Event Driven Architecture on top of RabbitMQ Message Broker
• ✅ Using Data-Centric Architecture based on CRUD
• ✅ Using Event Sourcing in Audit Based services
• ✅ Using CQRS Pattern on top
• ✅ Using gRPC for internal service communication
• ✅ Using Postgres to write databases with fully supported transactions(ACID)
• ✅ Using OpenTelemetry for collection Distributed Tracing with using Grafana
• ✅ Using Prometheus for collection Metrics with using Grafana
• ✅ Using Unit Test for testing small units with mocking dependent classes
• ✅ Using End2End Test and Integration Test for testing features with all of their real dependencies using docker containers (cleanup tests) and testcontainers-go library
• ✅ Using docker and docker-compose for deployment
• ✅ Using Domain Driven Design in some of the services
• ✅ Using Helm and Kubernetes for deployment
• ✅ Using Outbox Pattern to guarantee sending