/message-sending-system

Primary LanguageGoGNU General Public License v3.0GPL-3.0

message-sending-system

This project is an automated message sending service. The system is designed to periodically retrieve a specified number of unsent messages from the database and send them to the designated recipients. The retrieval and sending process takes place at regular intervals to ensure that messages are delivered on time. The interval duration and the number of messages retrieved can be configured based on the specific requirements of the application.

Getting Started

Prerequisites

  • Go 1.21 or higher
  • Docker

How to run

  1. Clone the project
git clone git@github.com:anilsenay/message-sending-system.git
cd message-sending-system
  1. Build and Deploy project via Docker Compose
docker-compose up --build
  1. Visit http://localhost:8080/swagger/

Configuration

Application's default configs placed in /internal/config/config.go

I like my own config package instead of using config packages such as dotenv.

Project Layout

.
├── cmd                       # Main applications
│   └── server                  # Server app's main.go placed here
│
├── internal                  # Private application packages
│   ├── apps                    # Dependency injections and application setups
│   ├── client                  # Clients used in application such as redis and message client
│   ├── config                  # The configs to be used in the application
│   ├── handlers                # The "endpoints" that the application serves
│   ├── models                  # The data models used in the application
│   ├── repositories            # Database operations within the application
│   ├── services                # It provides communication between "handlers" and "repositories" within the application and logical operations are performed here.
│   └── worker                  # Automatic message sender worker
│
└── pkg                       # The codes, written with the intention that they can be used in other projects, are available here as a package.

Swagger

I used my own package swagno for Swagger documentation. SwaggerUI can be accessible from http://localhost:8080/swagger/

resim

Architectural Decisions

  • Message Service could be 2 seperate applications, one of which is just an API and the other is just a cron job. But I decided to make them as same application for simplicity of start/stop functionality.
  • I used PostgreSQL to benefit from its atomicity and locking mechanisms. But, since there was no relationship, a non-relational database could be used.
  • To prevent different instances from processing the same records when scaling the application, I used PostgreSQL's locking mechanism while retrieving messages from DB. While retrieving messages to process, it locks records and update their status as processing, so other instances could not retrieve same messages.
  • Because it depends on business needs, I did not implement any retry mechanism for failures(may result in sending duplicate messages etc.). I just decided to change the status of the message to failed in DB.

Diagrams

resim

resim