EVOX

REST API written in the FastAPI framework for message persistence with authentication built-in.

Requirements:

• Docker
• docker-compose

Framework used

This app is built using FastAPI framework https://fastapi.tiangolo.com.

It consists of the Starlette ASGI framework and Pydantic library.

Running the app

Because this app requires a PostgreSQL database instance running alongside, the easiest way to run it is to use docker-compose.

docker-compose up

This docker-compose config uses volumes for PostgreSQL container, so it should retain data between restarts.

Running unit and integration tests

The following script will run tests in an isolated docker environment, so you don't have to set up a database yourself.

./scripts/test-docker.sh

API

Endpoints list

HTTP method	Authentication required	Path	Description	Possible HTTP codes
GET	NO	/api/v1/messages/{id}	Get message by id	200, 400, 401, 404
POST	YES	/api/v1/messages	Create new message	200, 400, 401
PUT	YES	/api/v1/messages/{id}	Update existing message	200, 400, 401, 404
DELETE	YES	/api/v1/messages/{id}	Delete message	200, 400, 401, 404

REST API Documentation using swagger:

https://evox.rasztabiga.me/docs

It also allows users to test the API using a simple interface.

REST API Documentation using redoc:

https://evox.rasztabiga.me/redoc

Both documentations include examples of request and response bodies.

Implementation details

Data format

This REST API uses JSON data type for request and response bodies.

Example of request body:

{
    "content": "New message"
}

Example of response body:

{
    "content": "New content",
    "views_count": 5,
    "id": 3
}

Persistence

Persistence is provided by SQLAlchemy ORM library and PostgreSQL database.

For SQL migrations I'm using Alembic. They are located under alembic directory.

Authentication

API Key required to call protected endpoints:

HTTP Header:
Authorization: ca9c1d4509ec6c9b9550fecfab3817a9b87e5e06bcbfe94298b12ce14ca8e428

This key works for evox.rasztabiga.me server. It's being set by environmental variable passed to docker container running the app.

Unit and integration tests

This API is covered with both unit and integration tests.

Unit tests are testing message service and cover mostly business logic. They are executed by the pytest library.

Integration tests are executed with FastAPI test HTTP client and call API endpoints, verifying their correctness.

Deployment

This app is deployed on my private Kubernetes cluster. Configuration used for the deployment is located in the k8s directory.

Currently, it's running 3 replicas of backend pods, so it's easily scalable.

App is listening on the following URL: https://evox.rasztabiga.me/api/v1/messages

SSL certificate and DDoS protection is provided by Cloudflare.

CI / CD

I'm using GitHub Actions job to execute linter and tests on each push to GitHub. It also builds and pushes Docker image of the app to DockerHub.

You can locate it here: https://hub.docker.com/r/navareth/evox

Environment variables

This app uses the following environment variables:

• API_KEY - API key used to authenticate requests
• POSTGRES_SERVER - hostname of PostgreSQL database
• POSTGRES_USER - username for PostgreSQL database
• POSTGRES_PASSWORD - password for PostgreSQL database
• POSTGRES_DB - database name for PostgreSQL database
• BACKEND_CORS_ORIGINS - allowed origins for CORS mechanism

API usage

Following examples use the demo server https://evox.rasztabiga.me

API_KEY=ca9c1d4509ec6c9b9550fecfab3817a9b87e5e06bcbfe94298b12ce14ca8e428

You will have to replace MESSAGE_ID placeholder if you want to run these examples by yourself.

Create message

curl --location --request POST 'https://evox.rasztabiga.me/api/v1/messages' \
--header 'Authorization: ca9c1d4509ec6c9b9550fecfab3817a9b87e5e06bcbfe94298b12ce14ca8e428' \
--header 'Content-Type: application/json' \
--data-raw '{
    "content": "New message"
}'

View message

curl --location --request GET 'https://evox.rasztabiga.me/api/v1/messages/{MESSAGE_ID}'

Update message

curl --location --request PUT 'https://evox.rasztabiga.me/api/v1/messages/{MESSAGE_ID}' \
--header 'Authorization: ca9c1d4509ec6c9b9550fecfab3817a9b87e5e06bcbfe94298b12ce14ca8e428' \
--header 'Content-Type: application/json' \
--data-raw '{
    "content": "New content"
}'

Delete message

curl --location --request DELETE 'https://evox.rasztabiga.me/api/v1/messages/{MESSAGE_ID}' \
--header 'Authorization: ca9c1d4509ec6c9b9550fecfab3817a9b87e5e06bcbfe94298b12ce14ca8e428'