Tracking FastApi URL hit count over a period of time using Grafana and Prometheus

Setting up Grafana and Prometheus

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Install dependencies using pip

pip install prometheus_client==0.20.0
pip install prometheus-fastapi-instrumentator==7.0.0

Now lets create a sample FastAPI server. Here is the main.py file

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def root():
    return {"message": "Hello World"}

Now lets add Prometheus client to it

from prometheus_fastapi_instrumentator import Instrumentator
from prometheus_client import Counter

Add Instrumentor to FastAPI app

instrumentator = Instrumentator().instrument(app)

@app.on_event("startup")
async def _startup():
    instrumentator.expose(app)

Now lets see the whole file

from fastapi import FastAPI
from prometheus_fastapi_instrumentator import Instrumentator
from prometheus_client import Counter
import time

app = FastAPI()

instrumentator = Instrumentator().instrument(app)

@app.on_event("startup")
async def _startup():
    instrumentator.expose(app)

REQUEST_COUNT = Counter(
    'app_request_count',
    'Application Request Count',
    ['method', 'endpoint', 'http_status']
)

@app.get("/")
async def root():
    start_time = time.time()
    REQUEST_COUNT.labels('GET', '/', 200).inc()
    return {"message": "Hello World"}

This server will be running at port http://localhost:7070/

Now lets add this entry to prometheus.yml file

global:
  scrape_interval: 5s

scrape_configs:
  - job_name: 'app'
    metrics_path: '/metrics'
    static_configs:
      - targets: ['localhost:7070']

  - job_name: 'node'
    static_configs:
      - targets: ['localhost:9100']

remote_write:
- url: http://localhost:3000
  basic_auth:
    username: admin
    password: admin

restart Prometheus server

Now open browser and hit http://localhost:7070/ muliple times. and goto Grafana dashboard