app.py

"""
Module define fastapi server configuration
"""

from fastapi import FastAPI
from hypercorn.asyncio import serve
from hypercorn.config import Config as HyperCornConfig
from prometheus_client import Counter, generate_latest, CONTENT_TYPE_LATEST
from starlette.responses import Response

app = FastAPI()

REQUESTS = Counter('server_requests_total', 'Total number of requests to this webserver')
HEALTHCHECK_REQUESTS = Counter('healthcheck_requests_total', 'Total number of requests to healthcheck')
MAIN_ENDPOINT_REQUESTS = Counter('main_requests_total', 'Total number of requests to main endpoint')
BYE_ENDPOINT_REQUESTS = Counter('bye_request_total', 'Total number of requests to bye endpoint')

class SimpleServer:
    """
    SimpleServer class define FastAPI configuration and implemented endpoints
    """

    _hypercorn_config = None

    def __init__(self):
        self._hypercorn_config = HyperCornConfig()

    async def run_server(self):
        """Starts the server with the config parameters"""
        self._hypercorn_config.bind = ['0.0.0.0:8081']
        self._hypercorn_config.keep_alive_timeout = 90
        await serve(app, self._hypercorn_config)

    @app.get("/health")
    async def health_check():
        """Implement health check endpoint"""
        # Increment counter used for register the total number of calls in the webserver
        REQUESTS.inc()
        # Increment counter used for register the requests to healtcheck endpoint
        HEALTHCHECK_REQUESTS.inc()
        return {"health": "ok"}

    @app.get("/")
    async def read_main():
        """Implement main endpoint"""
        # Increment counter used for register the total number of calls in the webserver
        REQUESTS.inc()
        # Increment counter used for register the total number of calls in the main endpoint
        MAIN_ENDPOINT_REQUESTS.inc()
        return {"msg": "Hello World"}
    
    @app.get("/bye")
    async def read_bye():
        """Implement bye endpoint"""
        # Increment counter used for register the total number of calls in the webserver
        REQUESTS.inc()
        # Increment counter used for register the total number of calls in the main endpoint
        BYE_ENDPOINT_REQUESTS.inc()
        return {"msg": "So long, and thanks for all the fish"}
    
    @app.get("/metrics")
    async def metrics():
        """Expose Prometheus metrics"""
        return Response(generate_latest(), media_type=CONTENT_TYPE_LATEST)