eto-app

Simple application to train some programming and DevOps skills. It contains:

• Backend API (Python, FastAPI, SQLAlchemy, Pydantic)
• Frontend (NodeJS, React)
• Database (default - local SQLite file)

Backend

Base API CRUD Python application, working with fastapi, sqlalchemy, pydantic.

By default works with SQLite file-based database stored in the container — all data will be deleted after restart.

You can set your own database connection in backend/.env file or with a DB_CONN variable (See docker-compose.yml).

You can find swagger at /api/docs. Main API enpoint is /api/servers

How to run backend

Local

Fill in the .env file:

mv .env.example .env
nano .env

cd backend
python3 -m pip install -r requirements.py
uvicorn app.main:app

Load example data

To load some predifined data from dataset.csv use:

python3 load.py

Backend Version

To set backend version which will appear at the very bottom of the frontend page, you should set BACKEND_VERSION environment variable, e.g. BACKEND_VERSION=1.1.2. This value will be in the response on /api/version API endpoint.

Docker

Fill in the .env file in backend directory:

cd backend
mv .env.example .env
nano .env

Works as non-root user worker. You can build your own image:

cd backend
docker build -t eto-backend:latest .
docker run --env-file .env -p 8000:8000 eto-backend:latest

Or run my image from DockerHub:

docker run --env-file .env -p 8000:8000 etoosamoe/eto-backend:latest

Example of usage

curl --request POST \
  --url http://127.0.0.1:8000/api/servers \
  --header 'Content-Type: application/json' \
  --header 'accept: application/json' \
  --data '{
  "hostname": "ci00",
  "type": "hw",
  "cores": 32,
  "ram": 64,
  "disk": 1100
}'

Frontend

Frontend works with NodeJS and uses React. It makes requests to backend API to get some data about servers.

How to run frontend

Local

By default REACT_APP_BACKEND_URL is empty, which means frontend will use relative URLs.

If you want to run frontend without container (which includes Nginx and will redirect /api requests to backend), you must set REACT_APP_BACKEND_URL env variable, e.g.:

cd frontend
npm install
REACT_APP_BACKEND_URL=http://127.0.0.1:8000 npm start

Then go to http://127.0.0.1:3000.

To build static files:

cd frontend
npm ci
npm run build

Files will be in the build directory.

Frontend Version

To set frontend version which will appear at the very bottom of the page, you should set REACT_APP_FRONT_VERSION environment variable, e.g. REACT_APP_FRONT_VERSION=1.1.1.

Docker

This is a multi-stage build, and final image contains only Nginx web-server, static files from build image, and Nginx configuration file (frontend/nginx.conf). Nginx also proxy-passes all requests to /api/servers, /api/version, /api/docs locations to backend instance. (See frontend/Dockerfile)

Fill in the .env file in frontend directory:

cd frontend
mv .env.example .env
nano .env

Then run build container image:

cd frontend
docker build -t eto-frontend:latest .
docker run --env-file .env -p 3000:3000 eto-frontend:latest

Or run my image from DockerHub:

docker run --env-file .env -p 3000:3000 etoosamoe/eto-frontend:latest

How to run entire app

Docker Compose

Fill in the .env file in frontend and backend directories:

mv .env.example .env
nano .env

Tip

If you use ARM arch (e.g. mac m1 cpu), you should uncomment arch directive in docker-compose.yml file.

The run these commands from the root directory:

docker compose pull
docker compose up -d
or
docker compose up -d --no-build

Kubernetes

Manifests in k8s directory includes:

• db.yml as Postgres deployment, with configmap
• backend.yml and frontend.yml to deploy application
• namespace creation

If you already have a database just fill in db and host to configmap (1 step), and fill in the user and password to secrets.yml. Then go straight to 4 step.

1. Fill in the configmap parameters in k8s/db.yml with database name and database host.
2. Add base64-encoded values of postgres-user and postgres-password to secrets.yml.
3. Deploy the database:

cd k8s
kubectl apply -f namespace.yml
kubectl apply -f db.yml

4. Deploy the application:

# If you need a database uncomment the line below
# kubectl apply -f db.yml
kubectl apply -f namespace.yml
kubectl apply -f backend.yml
kubectl apply -f frontend.yml

Helm

WIP

Monitoring

Healthcheck

Backend has /healthcheck endpoint which returns status-code 200.

Sentry

You can add Sentry DSN as SENTRY_DSN env. variable, e.g. SENTRY_DSN="https://<dsn>.ingest.sentry.io/<id>".

Metrics

Prometheus-like metrics endpoint: WIP

Endpoints

/flaky — this API enpoint will raise an 500 error sometimes. Default probability is 0.1 which means 10% of all requests. It can be modified by FLAKY_ERROR_PROBABILITY env. variable. e.g. if probability=1 every request to /flaky endpoint will raise an error.