default_metrics_asgi 0.1.0

A helper package for collecting default Prometheus metrics in ASGI applications.

default_metrics_fastapi

A helper package for collecting default Prometheus metrics in ASGI applications (such as FastAPI, Starlette, etc.).

Features

• Automatic request/response metrics: Tracks request counts, response codes, exceptions, durations, and in-progress requests.
• Prometheus-compatible: Exposes metrics in Prometheus text format.
• Configurable exception logging: Optionally logs unhandled exceptions at the middleware level.
• ASGI compatible: Works with FastAPI, Starlette, and other ASGI frameworks.

Usage

from fastapi import FastAPI
from default_metrics_asgi import PrometheusMiddleware, metrics

app = FastAPI()
app.add_middleware(PrometheusMiddleware)  # log_exceptions=True by default
app.add_route("/metrics", metrics)

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

Optional: Disable Middleware Exception Logging

app.add_middleware(PrometheusMiddleware, log_exceptions=False)

Metrics Collected

• api_app_info: Application info (gauge)
• api_requests_total: Total number of requests received by method and path (counter)
• api_responses_total: Total number of responses sent by method, path, and status code (counter)
• api_requests_duration_seconds: Histogram of request processing time by method and path (histogram)
• api_exceptions_total: Total number of exceptions raised by method, path, and exception type (counter)
• api_requests_in_progress: Number of requests currently being processed by method and path (gauge)

Exporting Metrics

Visit /metrics endpoint to see the Prometheus metrics.

License

MIT License