TODO list (coding challenge)

Write a simple REST API for a Todo list application.

• Develop and test it without opening the browser or using curl, postman, etc.
• Use as few external dependencies as possible

Requirements

• go >= 1.19
• Docker - to run it as container

General considerations

I chose a flat structure since the application is small and there are not too many pieces. If it keeps growing I would consider using different packages for service, repositories, domain, etc.

I use go-chi because it is elegant and it saves me time to parse path parameters and test on http methods.

The application uses 2 types of persistence: SQL database (MariaDB/Mysql) or in-memory (if connecting to the database fails).

At startup the application tries to connect to the database. It includes a retry mechanism with exponential backoff. The retry parameters are hardcoded for now, should be passed in as arguments.

If an empty string is passed as dsn argument then the application will not even try to connect to a database and use the In Memory persistence directly.

There are integration tests provided in /tests.

There are some unit tests provided, but the coverage is not great due to time limitations:

go test -v -cover -coverprofile=cover.out ./pkg/todos/...
go tool cover -html=cover.out

Endpoints provided

The list of provided endpoints is dynamically generated (no update needed if a new pattern + handler is added) and printed when the program starts.

[GET]           /health


[GET]           /todos/
[POST]          /todos/

[GET]           /todos/search/tags


[GET]           /todos/{id:[0-9a-z-]+}/
[PUT]           /todos/{id:[0-9a-z-]+}/
[DELETE]        /todos/{id:[0-9a-z-]+}/

[POST]          /todos/{id:[0-9a-z-]+}/complete

Build and run

go build -o todos ./main.go
./todos --help

Run the application in a shell:

./todos --http 127.0.0.1:7070 --dsn ''

and the integration tests in a separate shell:

go test ./tests/... -args -api-url='http://127.0.0.1:7070'

Run with Docker

Build and run the container and keep attached to see the logs

docker compose up --build

Run the tests against the running container

go test ./tests/... -args -api-url='http://127.0.0.1:7070'