backend/app/core/metrics.py

"""Prometheus metrics configuration."""

from prometheus_client import Counter, Histogram, Gauge, generate_latest
from starlette.responses import Response

from app.core.config import settings

# Request metrics
http_requests_total = Counter(
    "http_requests_total",
    "Total HTTP requests",
    ["method", "endpoint", "status"],
)

http_request_duration = Histogram(
    "http_request_duration_seconds",
    "HTTP request duration",
    ["method", "endpoint"],
    buckets=(0.1, 0.5, 1.0, 2.5, 5.0, 10.0, 30.0, 60.0),
)

# Generation metrics
generation_requests_total = Counter(
    "generation_requests_total",
    "Total generation requests",
    ["type", "status"],
)

generation_duration = Histogram(
    "generation_duration_seconds",
    "Generation duration",
    ["type"],
    buckets=(5.0, 10.0, 30.0, 60.0, 120.0, 300.0),
)

active_generations = Gauge(
    "active_generations",
    "Currently active generations",
    ["type"],
)

# System metrics
audio_storage_bytes = Gauge(
    "audio_storage_bytes",
    "Total audio storage size in bytes",
)


def setup_metrics() -> None:
    """Setup metrics collection."""
    if not settings.ENABLE_METRICS:
        return


def metrics_endpoint() -> Response:
    """Prometheus metrics endpoint."""
    return Response(
        content=generate_latest(),
        media_type="text/plain",
    )