enumerate1/togo

Cadidate: Danh Nguyen Hoang - nguyendanhtravel@gmail.com

I. My improvement

1. Split services layer to use case and transport layer

2. Change to use chi-go router. Why chi-go? Because it lightweight, idiomatic, and composable router for building Go HTTP services. Especially, chi's router is based on Radix trie, so it'll handle the request as fast as possible if we have a lot of handlers in the future.

3. We shouldn't use GET method for login because it have some problem it will save the user's information url, another user can find id and password in the browser's history,..So I have changed to POST method for /login

4.1 Add config (with file - just easy for testing) - after load config file, it will overwrite the variable environment, so this project still abide by 12factor https://12factor.net/ .P/s: Again the config file just save the infomation for quick run, when in production, use variable environment.

4.2 Variable Environment in this project:

Key	Example value	Description
APP_ENV	dev	represent the current app environment
SERVICE	todo	name of the current service
JWT_KEY	wqGyEBBfPK9w3Lxw	JWTKey
LOG_LEVEL	info	represent level out the log
ADDRESS	:5050	the address or port when the app will deploy
LDB_PATH	./data.db	the path of sqlite
PDB_USERNAME	postgres	the username in postgres
PDB_PASSWORD	secret	the password with username in postgres
PDB_HOST	127.0.0.1	the host of postgres
PDB_PORT	5432	the port of postgres
PDB_DBNAME	todo	the dbname of postgres

5. Added logging for this project with json format, for easily tracing log (error), using zap here (uber).

6. Remove unnecessary pointer variable (replaced by variable) to avoid memory allocate in the runtime to much.

7. Complete main requirement, limit N task per day each user.

8. Add postgres DB to project, add prepared statement for sqlite, use pgx as driver to work with postgres database (included prepared statement). In pq's github, they still encourage use pgx.

9. Store password in database as hashed password (bcrypt algorithm), to protect the user:the developer shouldn't know the user's plain password, protect against rainbow table attacks and so on and so forth.

10. New schema for postgres, postgre have uuid type (16 bytes, because it save as binary) to save memory instead use text or varchar (36 bytes) save the uuid. Attention: litesql doesn't have uuid type, so still use text.

-- users definition

CREATE TABLE users (
	id varchar(50) NOT NULL,
	password varchar(60) NOT NULL,
	max_todo INTEGER DEFAULT 5 NOT NULL,
	CONSTRAINT users_PK PRIMARY KEY (id)
);

INSERT INTO users (id, password, max_todo) VALUES('firstUser', '$2a$10$hBqrcwfOt/HBKLXKxa48tu1SMDn62pSU8iZYWIXTxTCXQ8PoXvvi2', 5);

-- tasks definition

CREATE TABLE tasks (
	id uuid NOT NULL,
	content TEXT NOT NULL,
	user_id varchar(50) NOT NULL,
    created_date TEXT NOT NULL,
	CONSTRAINT tasks_PK PRIMARY KEY (id),
	CONSTRAINT tasks_FK FOREIGN KEY (user_id) REFERENCES users(id)
);

11. Added dockerfile, docker-compose with postgres for the app. The .env included environment variable for togo app, .env_postgres included environment variable for postgres.

12. Add dockertest to working integration test with postgres. With dockertest, it'll create a new container to work with the test, after the end of the test, automatically purge this container. After run the test, I decide to make validator value for all field (will be implement later). (integrationtest/togo_test.go)

13. Add unit test for service (internal/transport/togo_handler_test.go) now is transport and usecase (but not cover usecase).

14. Unfortunately, with pgx, we can't use mocksql to test unittest, but we can use dockertest integration with the postgres container to test each function. (internal/storages/postgres/postgres_test.go)

15. Add validator for datetime and content in task have to not null.

II. How to run

1. Run test:

	go test ./...

2.1 Run project with quick test with file config:

	go build -ldflags="-w -s" && ./togo

2.2 Run project with variable environment:

	go build -ldflags="-w -s" && APP_ENV=debug ...(add all the Variable Environment in the table above) && ./togo

3. Docker:

	docker-compose build && docker-compose up

---

Overview

This is a simple backend for a good old todo service, right now this service can handle login/list/create simple tasks.
To make it run:

• go run main.go
• Import Postman collection from docs to check example

Candidates are invited to implement below requirements but the point is not to resolve everything in a perfect way but selective what you can do best in a limited time.
Thus, there is no correct-or-perfect answer, your solutions are way for us to continue the discussion and collaboration.

Requirements

Right now a user can add many task as they want, we want ability to limit N task per day.

Example: users are limited to create only 5 task only per day, if the daily limit is reached, return 4xx code to client and ignore the create request.

Backend requirements

• A nice README on how to run, what is missing, what else you want to improve but don't have enough time
• Fork this repo and show us your development progess by a PR.
• Write integration tests for this project
• Make this code DRY
• Write unit test for services layer
• Change from using SQLite to Postgres with docker-compose
• This project include many issues from code to DB strucutre, feel free to optimize them.

Frontend requirements

• A nice README on how to run, what is missing, what else you want to improve but don't have enough time
• https://github.com/manabie-com/mana-do
• Fork the above repo and show us your development progess by a PR.

Optional requirements

• Write unit test for storages layer
• Split services layer to use case and transport layer

DB Schema

-- users definition

CREATE TABLE users (
	id TEXT NOT NULL,
	password TEXT NOT NULL,
	max_todo INTEGER DEFAULT 5 NOT NULL,
	CONSTRAINT users_PK PRIMARY KEY (id)
);

INSERT INTO users (id, password, max_todo) VALUES('firstUser', '$2a$10$hBqrcwfOt/HBKLXKxa48tu1SMDn62pSU8iZYWIXTxTCXQ8PoXvvi2', 5);

-- tasks definition

CREATE TABLE tasks (
	id TEXT NOT NULL,
	content TEXT NOT NULL,
	user_id TEXT NOT NULL,
    created_date TEXT NOT NULL,
	CONSTRAINT tasks_PK PRIMARY KEY (id),
	CONSTRAINT tasks_FK FOREIGN KEY (user_id) REFERENCES users(id)
);

Sequence diagram