Application Metrics

Introduction

Metrics provide quantitative data about your application's performance and health.

Key Metrics

Request Rate: Requests per second.

Latency: Response time (p50, p95, p99).

Error Rate: Percentage of failed requests.

Saturation: Resource utilization (CPU, memory).

django-prometheus Setup

python
# pip install django-prometheus

INSTALLED_APPS = ['django_prometheus']

MIDDLEWARE = [
    'django_prometheus.middleware.PrometheusBeforeMiddleware',
    ...,
    'django_prometheus.middleware.PrometheusAfterMiddleware',
]

# urls.py
path('metrics/', include('django_prometheus.urls')),

Custom Metrics

python
from prometheus_client import Counter, Histogram

ORDERS = Counter('orders_total', 'Total orders', ['status'])
LATENCY = Histogram('api_latency_seconds', 'API latency')

@LATENCY.time()
def api_view(request):
    ORDERS.labels(status='success').inc()

Best Practices

1. Track RED metrics: Rate, Errors, Duration.
2. Use labels wisely: Avoid high cardinality.
3. Set up dashboards: Grafana for visualization.

Summary

Metrics help you understand application performance. Track request rate, latency, and errors. Use Prometheus and Grafana for collection and visualization.