Production-ready Simple Order Service Demo

4 Requirements and 4 Bonuses

1. View list of products
2. Add/Remove product from cart
3. Create new order with payment
4. Users can login, sign up

---

1. Cleanly structured and CI integration
2. Well-documented
3. Well-tested
4. Containerized

Authorization Rules

// From the server's routes, add authentication middleware, using Paseto Token with local symmetric encryption
tokenMaker, _ := token.NewPasetoMaker(config.TokenSymmetricKey)
authRoutes := router.Group("/").Use(authMiddleware(tokenMaker))
// These 6 endpoints need authorization, implements in their handlers repsectively
authRoutes.GET("/users", server.listUsers)
authRoutes.POST("/products", server.createProduct)
authRoutes.POST("/products/cart/add", server.addToCart)
authRoutes.POST("/products/cart/remove", server.removeFromCart)
authRoutes.GET("/orders", server.listOrders)
authRoutes.POST("/orders", server.createOrder)

0. An admin user {"username":"admin",password:"secret"} have all the powers, is created upon migrate up, log in as admin to test all of the endpoints
1. A logged-in user can only view their own user's details
2. A logged-in user can create a product
3. A logged-in user can add a product to cart
4. A logged-in user can remove a product from card
5. A logged-in user can create an order
6. A logged-in user can only view a the orders that they've made

API Endpoints

See details

See Booting Up running and testing instructions in the section below first, and then continue:

Rqm4.1: Create user via endpoint

curl "http://localhost:8080/users" -H "Content-Type: application/json" -d '{"username":"tien1","full_name":"Tien La","email":"tien@email.com","password":"secret"}' | jq

# Should return
{
  "username": "tien1",
  "full_name": "Tien La",
  "email": "tien@email.com",
  "password_change_at": "0001-01-01T00:00:00Z",
  "created_at": "2021-12-26T18:24:12.73219Z"
}

Rqm4.2: User login with wrong password

curl "http://localhost:8080/users/login" -H "Content-Type: application/json" -d '{"username":"tien1","password":"abc123"}' | jq

# Should return (401)
{
  "error": "crypto/bcrypt: hashedPassword is not the hash of the given password"
}

Rqm4.3: User log in

After logged-in, copy the access_token to the TOKEN variable to be use in appropriated endpoints' -H 'Authorization: Bearer ...'. Or use Postman/Insomnia/vscode-rest, ...

If having the error token has expired, log in again

curl "http://localhost:8080/users/login" -H "Content-Type: application/json" -d '{"username":"tien1","password":"secret"}' | jq

# Should return
{
  "access_token": "v2.local.iMAQ5gAOXIWxvl446dWq_Z7D7tV_J9MzRQov7HXEi0cbXFU0ZBhsR2GsHlhAeyMbpKMXH8ie-XTW6aKnIFgEfxZNnWXpsUl_QVTsuum1X2H_97UA0iqyP4NEG4JvWdqtrQ30HFN-BdvvXle98eUnKbCFn-28ot60kMGotwRySXJvI-LKCl04crKV31C6yjmKsj-2kPQ14d7eWM7bW8TyDm2DkPy5ZyrmrUTptk3LPLKZSCHPFDa9nfVwO_u4DcG-XZh_Nt6QB3NRTvSwVw.bnVsbA",
  "user": {
    "username": "tien1",
    "full_name": "Tien La",
    "email": "tien@email.com",
    "password_change_at": "0001-01-01T00:00:00Z",
    "created_at": "2021-12-26T18:24:12.73219Z"
  }
}

# Set TOKEN variable
TOKEN='v2.local.iMAQ5gAOXIWxvl446dWq_Z7D7tV_J9MzRQov7HXEi0cbXFU0ZBhsR2GsHlhAeyMbpKMXH8ie-XTW6aKnIFgEfxZNnWXpsUl_QVTsuum1X2H_97UA0iqyP4NEG4JvWdqtrQ30HFN-BdvvXle98eUnKbCFn-28ot60kMGotwRySXJvI-LKCl04crKV31C6yjmKsj-2kPQ14d7eWM7bW8TyDm2DkPy5ZyrmrUTptk3LPLKZSCHPFDa9nfVwO_u4DcG-XZh_Nt6QB3NRTvSwVw.bnVsbA'

Rqm4.4: List users

curl "http://localhost:8080/users?page_id=1&page_size=5" -H "Authorization: Bearer $TOKEN" | jq

# Should return
[
  {
    "username": "tien1",
    "full_name": "Tien La",
    "email": "tien@email.com",
    "password_change_at": "0001-01-01T00:00:00Z",
    "created_at": "2021-12-26T18:24:12.73219Z"
  }
]

Rqm1: View list of products

curl "http://localhost:8080/products?page_id=1&page_size=3" | jq

# Should return
[
  {
    "id": 1,
    "name": "ndomrf",
    "cost": 789,
    "quantity": 4,
    "created_at": "2021-12-26T18:20:27.991534Z"
  },
  {
    "id": 2,
    "name": "qsuwja",
    "cost": 913,
    "quantity": 5,
    "created_at": "2021-12-26T18:20:28.05339Z"
  },
  {
    "id": 3,
    "name": "jesmsw",
    "cost": 754,
    "quantity": 9,
    "created_at": "2021-12-26T18:20:28.11771Z"
  }
]

Rqm2.1: Add product to cart

curl "http://localhost:8080/products/cart/add" -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' -d '{"product_id":1,"quantity":2}' | jq

# Should return
{
  "product": {
    "id": 1,
    "name": "ndomrf",
    "cost": 789,
    "quantity": 2,
    "created_at": "2021-12-26T18:20:27.991534Z"
  }
}

Rqm2.2: Remove product from cart

curl "http://localhost:8080/products/cart/remove" -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' -d '{"product_id":1,"quantity":2}' | jq

# Should return
{
  "product": {
    "id": 1,
    "name": "ndomrf",
    "cost": 789,
    "quantity": 6,
    "created_at": "2021-12-26T18:20:27.991534Z"
  }
}

Rqm3.1: Create new order with payment

curl "http://localhost:8080/orders" -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' -d '{"user_id":1,"product_id":1,"quantity":2}' | jq

# Should return
{
  "user": {
    "username": "tien1",
    "full_name": "Tien La",
    "email": "tien@email.com",
    "password_change_at": "0001-01-01T00:00:00Z",
    "created_at": "2021-12-26T18:24:12.73219Z"
  },
  "product": {
    "id": 1,
    "name": "ndomrf",
    "cost": 789,
    "quantity": 2,
    "created_at": "2021-12-26T18:20:27.991534Z"
  },
  "order": {
    "id": 24,
    "owner": "tien1",
    "product_id": 1,
    "quantity": 2,
    "price": 1578,
    "created_at": "2021-12-26T18:26:26.003027Z"
  }
}

Rqm3.2: Check the result

curl "http://localhost:8080/orders?page_id=1&page_size=5" -H "Authorization: Bearer $TOKEN" | jq

# Should return
[
  {
    "id": 24,
    "owner": "tien1",
    "product_id": 1,
    "quantity": 2,
    "price": 1578,
    "created_at": "2021-12-26T18:26:26.003027Z"
  }
]

Database UML

Technology Stack

• Go 1.17: Leverage the standard libraries as much as possible
• SQLc: Generates efficient native SQL CRUD code
• PostgreSQL: RDBMS of choice because of faster read due to its indexing model and safer transaction with better isolation levels handling
• Gin: Fast and have respect for native net/http API
• Paseto Token: Better choice than JWT because of enforcing better cryptographic standards and debloated of useless information
• JWT Token: Also implemented to demonstrate the decoupility
• Golang-Migrate: Efficient schema generating, up/down migrating
• GoMock: Generates mocks of about anything
• Docker + Docker-Compose: Containerization, what else to say ...
• Github Actions CI: Make sure we don't push trash code into the codebase
• Viper: Add robustness to configurations

Philosophy and Architecture

• Adaptive Minimalism: I always keep it as simple as possible, but with a highly decoupled structure we ensure high adaptivity and extensibility, on top of that minimal solid head start. Things are implement only when they're absolutely needed

Booting Up

Non-docker way

• Spin up a PostgreSQL instance, run createdb and migrateup:

make network

make postgres

make createdb

make migrateup

• Run test and populate products:

# go get github.com/golang/mock/mockgen/model

# make mock

make test

• Run server:

make server

# make migratedown

Docker way

make network

make postgres

make createdb

make migrateup

make test

make build

make order-demo

# Rebuild server image
# make build

# make clean

Docker Compose way

docker compose up -d

# docker compose down

# make clean

Development Infrastructure Setup

Helpful Commands

# Update Go toolings
go get -u
go mod tidy

# Spin up a container for local development, for example postgres
# The default database will be root, the same name as POSTGRES_USER
docker run --name postgres -p 5432:5432 -e POSTGRES_USER=root -e POSTGRES_PASSWORD=secret -d postgres:alpine

# To access postgres psql
docker exec -it postgres psql -U root

# To access container console and run postgres commands
docker exec -it postgres /bin/sh

# To quit the console
\q

# To view its logs
docker logs postgres

# To stop it
docker stop postgres

# To just run it again
docker start postgres

# To remove it completely
docker rm postgres

Tooling Installation Guide

Expand

• Golang:

# Go to go.dev/dl and download a binary, in this example it's version 1.17.5

sudo rm -rf /usr/local/go && sudo tar -C /usr/local -xzf go1.17.5.linux-amd64.tar.gz

# Add these below to your .bashrc or .zshrc
export GOPATH=/home/<username>/go
export GOBIN=/home/<username>/go/bin
export PATH=$PATH:/usr/local/go/bin
export PATH=$PATH:$GOBIN

• Docker:

sudo apt remove docker docker-engine docker.io containerd runc

sudo apt update

sudo apt install apt-transport-https ca-certificates curl gnupg lsb-release software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

echo \
  "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

sudo apt update

apt-cache policy docker-ce

sudo apt install docker-ce docker-ce-cli containerd.io

sudo usermod -aG docker $USER

newgrp docker

# Restart the machine then test the installation

docker run hello-world

# On older system you also need to activate the services

sudo systemctl enable docker.service

sudo systemctl enable containerd.service

• Docker-Compose:

# Check their github repo for latest version number
sudo curl -L "https://github.com/docker/compose/releases/download/v2.2.2/docker-compose-linux-x86_64" -o /usr/local/bin/docker-compose && sudo chmod +x /usr/local/bin/docker-compose

# To self-update docker-compose
docker-compose migrate-to-labels

• Golang-Migrate:

go install -tags 'postgres' github.com/golang-migrate/migrate/v4/cmd/migrate@latest

• SQLc:

go install github.com/kyleconroy/sqlc/cmd/sqlc@latest

• GoMock:

go install github.com/golang/mock/mockgen@latest

• Viper:

go install https://github.com/spf13/viper@latest

• Gin:

go install github.com/gin-gonic/gin@latest

go get -u github.com/gin-gonic/gin

• Paseto:

go get -u github.com/o1egl/paseto

• JWT:

go get -u https://github.com/golang-jwt/jwt

• CURL + JQ + Chocolatery + Make:

sudo apt install curl jq

# These tools are needed only for Windows users

# Run this in an Admin cmd to install Chocolatery first
@"%SystemRoot%\System32\WindowsPowerShell\v1.0\powershell.exe" -NoProfile -InputFormat None -ExecutionPolicy Bypass -Command "[System.Net.ServicePointManager]::SecurityProtocol = 3072; iex ((New-Object System.Net.WebClient).DownloadString('https://community.chocolatey.org/install.ps1'))" && SET "PATH=%PATH%;%ALLUSERSPROFILE%\chocolatey\bin"

# Then install GNU-Make, cURL, and jq via Chocolatery in Admin pwsh
choco install make curl jq

Infrastructure

• Create order-demo-network

make network

• Start postgres container:

make postgres

• Create order_demo database

make createdb

• Run DB migrate up for all versions:

make migrateup

• Run DB migrate down for all versions:

make migratedown

Code Generation

• Generate SQL CRUD via SQLc:

make sqlc

• Generate DB mock via GoMock:

make mock

• Start postgres container:

migrate create -ext sql -dir db/migration -seq <migration_name>