ASGI Prometheus Exporter

A middleware for ASGI applications that exports Prometheus metrics. This middleware is compatible with any ASGI framework (Django, FastAPI, Starlette, etc.) and ASGI Servers.

• Django (with Django ASGI)
• FastAPI
• Starlette
• Quart
• Sanic
• Any other ASGI-compatible framework

Tested with FastAPI

Features

• Request duration metrics
• Request count metrics
• Response status code metrics
• Custom metrics support (TODO)
• Compatible with any ASGI framework (UNDER EVALUATION)
• Easy to integrate

Installation

pip install asgi-prometheus-exporter

Usage

Basic Usage with FastAPI

from fastapi import FastAPI
from asgi_prometheus_exporter import PrometheusMiddleware

app = FastAPI()
app.add_middleware(PrometheusMiddleware)

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

Usage with Django

In your Django project's asgi.py:

import os
from django.core.asgi import get_asgi_application
from asgi_prometheus_exporter import PrometheusMiddleware

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'myproject.settings')

# Get the Django ASGI application
django_asgi_app = get_asgi_application()

# Wrap it with the Prometheus middleware
application = PrometheusMiddleware(
    django_asgi_app,
    metrics_path="/metrics",  # Optional: customize metrics endpoint
    custom_labels={
        "app": "django_app",
        "environment": "production"
    }
)

Then in your settings.py:

ASGI_APPLICATION = 'myproject.asgi.application'

Usage with Starlette

from starlette.applications import Starlette
from starlette.responses import JSONResponse
from asgi_prometheus_exporter import PrometheusMiddleware

app = Starlette()
app.add_middleware(PrometheusMiddleware)

@app.route("/")
async def homepage(request):
    return JSONResponse({"message": "Hello World"})

Custom Metrics Endpoint

By default, metrics are exposed at /metrics. You can customize this by passing the metrics_path parameter:

app.add_middleware(
    PrometheusMiddleware,
    metrics_path="/custom/metrics/path"
)

Custom Labels

You can add custom labels to your metrics:

app.add_middleware(
    PrometheusMiddleware,
    custom_labels={
        "app": "myapp",
        "environment": "production"
    }
)

Available Metrics

The middleware exposes the following metrics:

• asgi_http_requests_total: Total number of HTTP requests
• asgi_http_request_duration_seconds: HTTP request duration in seconds
• asgi_http_requests_in_progress: Number of HTTP requests in progress
• asgi_http_responses_total: Total number of HTTP responses by status code

Running with Different ASGI Servers

Uvicorn

uvicorn myproject.asgi:application

Daphne (Django)

daphne myproject.asgi:application

Hypercorn

hypercorn myproject.asgi:application

License

MIT License