Simple Bank

This repository contains the codes of the Backend Master Class course by TECH SCHOOL.

You can also find it on Udemy at this link.

And don't hesitate to join Tech School's Discord group to chat directly with me and other students.

In this course, you will learn step-by-step how to design, develop and deploy a backend web service from scratch. I believe the best way to learn programming is to build a real application. Therefore, throughout the course, you will learn how to build a backend web service for a simple bank. It will provide APIs for the frontend to do the following things:

Create and manage bank accounts.
Record all balance changes to each of the accounts.
Perform a money transfer between 2 accounts.

The programming language we will use to develop the service is Golang, but the course is not just about coding in Go. You will learn a lot of different topics regarding backend web development. They are presented in 6 sections:

In the 1st section, you will learn deeply about how to design the database, generate codes to talk to the DB in a consistent and reliable way using transactions, understand the DB isolation levels, and how to use it correctly in production. Besides the database, you will also learn how to use docker for local development, how to use Git to manage your codes, and how to use GitHub Action to run unit tests automatically.
In the 2nd section, you will learn how to build a set of RESTful HTTP APIs using Gin - one of the most popular Golang frameworks for building web services. This includes everything from loading app configs, mocking DB for more robust unit tests, handling errors, authenticating users, and securing the APIs with JWT and PASETO access tokens.
In the 3rd section, you will learn how to build your app with Docker and deploy it to a production Kubernetes cluster on AWS. The lectures are very detailed with a step-by-step guide, from how to build a minimal docker image, set up a free-tier AWS account, create a production database, store and retrieve production secrets, create a Kubernetes cluster with EKS, use GitHub Action to automatically build and deploy the image to the EKS cluster, buy a domain name and route the traffics to the service, secure the connection with HTTPS and auto-renew TLS certificate from Let's Encrypt.
In the 4th section, we will discuss several advanced backend topics such as managing user sessions, building gRPC APIs, using gRPC gateway to serve both gRPC and HTTP requests at the same time, embedding Swagger documentation as part of the backend service, partially updating a record using optional parameters, and writing structured logger HTTP middlewares and gRPC interceptors.
Then the 5th section will introduce you to asynchronous processing in Golang using background workers and Redis as its message queue. We'll also learn how to create and send emails to users via Gmail SMTP server. Along the way, we'll learn more about writing unit tests for our gRPC services that might involve mocking multiple dependencies at once.
The final section 6th concludes the course with lectures about how to improve the stability and security of the server. We'll keep updating dependency packages to the latest version, use Cookies to make the refresh token more secure, and learn how to gracefully shut down the server to protect the processing resources. As this part is still a work in progress, we will keep making and uploading new videos about new topics in the future. So please come back here to check them out from time to time.

This course is designed with a lot of details, so that everyone, even with very little programming experience can understand and do it by themselves. I strongly believe that after the course, you would be able to work much more confidently and effectively on your projects.

Course videos

Lecture #0: Setup development environment on Windows: WSL2 + Go + VSCode + Docker + Make + Sqlc

Simple bank service

The service that we’re going to build is a simple bank. It will provide APIs for the frontend to do following things:

Create and manage bank accounts, which are composed of owner’s name, balance, and currency.
Record all balance changes to each of the account. So every time some money is added to or subtracted from the account, an account entry record will be created.
Perform a money transfer between 2 accounts. This should happen within a transaction, so that either both accounts’ balance are updated successfully or none of them are.

Setup local development

Install tools

Docker desktop
TablePlus
Golang
Homebrew
Migrate
```
brew install golang-migrate
```
DB Docs
```
npm install -g dbdocs
dbdocs login
```

DBML CLI

npm install -g @dbml/cli
dbml2sql --version

Sqlc
```
brew install sqlc
```

Gomock

go install github.com/golang/mock/mockgen@v1.6.0

Setup infrastructure

Create the bank-network
```
make network
```
Start postgres container:
```
make postgres
```
Create simple_bank database:
```
make createdb
```
Run db migration up all versions:
```
make migrateup
```
Run db migration up 1 version:
```
make migrateup1
```
Run db migration down all versions:
```
make migratedown
```
Run db migration down 1 version:
```
make migratedown1
```

Documentation

Generate DB documentation:
```
make db_docs
```
Access the DB documentation at this address. Password: secret

How to generate code

Generate schema SQL file with DBML:
```
make db_schema
```
Generate SQL CRUD with sqlc:
```
make sqlc
```
Generate DB mock with gomock:
```
make mock
```

Create a new db migration:

make new_migration name=<migration_name>

How to run

Run server:
```
make server
```
Run test:
```
make test
```

Deploy to kubernetes cluster

Install nginx ingress controller:

kubectl apply -f https://raw.githubusercontent.com/kubernetes/ingress-nginx/controller-v0.48.1/deploy/static/provider/aws/deploy.yaml

Install cert-manager:

kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v1.4.0/cert-manager.yaml

techschool / simplebank

Simple Bank

Course videos

Section 1: Working with database [Postgres]

Section 2: Building RESTful HTTP JSON API [Gin]

Section 3: Deploying the application to production [Kubernetes + AWS]

Section 4: Advanced Backend Topics [Sessions + gRPC]

Section 5: Asynchronous processing with background workers [Asynq + Redis]

Section 6: Improve the stability and security of the server