Flash Coupon Delivery Mechanism Design and Implementation

Requirement Description

1. Coupons are issued daily at 23:00, requiring users to reserve 1-5 minutes in advance. The number of coupons is 20% of the number of reserved users.
2. During the coupon grab, each user can only grab once, and there is only 1 minute for the grab. How to ensure that the user's probability of grabbing the coupon is as close to 20% as possible?

Architecture Design

Overall Process

1. Reservation Stage: Users make reservations between 22:55 and 23:00.
2. Distribution Stage: At 23:00, calculate the number of coupons based on the number of reserved users (20% of reserved users) and generate corresponding coupons.
3. Grab Stage: From 23:00 to 23:01, users can grab the coupons, and each user can only grab once.

Technology Stack

• Programming Language: Go
• Framework: Gin
• Database: PostgreSQL
• SQL Generation Tool: sqlc

Installation and Configuration

Install Dependencies

Ensure you have installed the following software:

• Go
• PostgreSQL (in Docker Environment)
• sqlc
• K6 (for load testing)

Then install the Go dependencies:

go mod download

Set up the database

make postgres
make createdb
make migrationup

Run the server

make server

Load Testing with K6

k6 run script