sepehr
4a992e2c90
CONTENT_TYPE_LSP doesn't exist in prometheus_client, causing ImportError. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
86 lines
2.5 KiB
Python
86 lines
2.5 KiB
Python
"""
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Prometheus metrics middleware for FastAPI.
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Exposes /metrics endpoint in Prometheus text format.
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Tracks HTTP requests, translations, and file uploads.
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"""
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import time
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import logging
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from starlette.middleware.base import BaseHTTPMiddleware
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from starlette.requests import Request
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from starlette.responses import Response
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from prometheus_client import Counter, Histogram, generate_latest, CONTENT_TYPE_LATEST
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logger = logging.getLogger(__name__)
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# ---- Metrics definitions ----
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http_requests_total = Counter(
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"http_requests_total",
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"Total HTTP requests",
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["method", "path", "status"],
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)
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translation_total = Counter(
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"translation_total",
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"Total translations processed",
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["provider", "file_type", "status"],
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)
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translation_duration_seconds = Histogram(
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"translation_duration_seconds",
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"Translation processing duration in seconds",
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["provider", "file_type"],
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buckets=(0.5, 1, 2, 5, 10, 30, 60, 120, 300),
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)
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file_size_bytes = Histogram(
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"file_size_bytes",
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"Uploaded file size in bytes",
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["file_type"],
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buckets=(100_000, 500_000, 1_000_000, 5_000_000, 10_000_000, 25_000_000, 50_000_000),
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)
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# Paths to skip from metrics (noisy health checks)
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_SKIP_PATHS = {"/health", "/ready", "/metrics", "/favicon.ico"}
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def record_translation(provider: str, file_type: str, duration: float, status: str = "success"):
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translation_total.labels(provider=provider, file_type=file_type, status=status).inc()
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translation_duration_seconds.labels(provider=provider, file_type=file_type).observe(duration)
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def record_file_size(file_type: str, size_bytes: int):
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file_size_bytes.labels(file_type=file_type).observe(size_bytes)
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class PrometheusMiddleware(BaseHTTPMiddleware):
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async def dispatch(self, request: Request, call_next):
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if request.url.path in _SKIP_PATHS:
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return await call_next(request)
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start = time.time()
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response: Response = await call_next(request)
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duration = time.time() - start
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path = request.url.path
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# Group dynamic paths to avoid label explosion
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if path.startswith("/api/v1/translations/"):
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path = "/api/v1/translations/{id}"
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elif path.startswith("/api/v1/download/"):
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path = "/api/v1/download/{id}"
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http_requests_total.labels(
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method=request.method,
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path=path,
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status=str(response.status_code),
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).inc()
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return response
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def get_metrics() -> Response:
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body = generate_latest()
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return Response(content=body, media_type=CONTENT_TYPE_LATEST)
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