vtnhbrb

gistfile1.txt

from typing import Callable

from prometheus_client import Counter, Histogram, generate_latest
from time import time
from flask import request, Response


REQUEST_COUNT = Counter(
    "http_requests_total",
    "Total HTTP requests",
    ["method", "endpoint", "http_status"],
)

REQUEST_LATENCY = Histogram(
    "http_request_duration_seconds",
    "HTTP request latency in seconds",
    ["method", "endpoint", "http_status"],
)


METRICS_LABELS = {}


ENDPOINT_MATCHER: list[tuple[Callable[[str], bool], str]] = [
    (lambda s: s.startswith("/api/v1/dashboard/"), "dashboard"),
    (lambda s: s.startswith("/api/v1/chart/"), "chart"),
    (lambda s: s.startswith("/api/v1/slice/"), "slice"),
    (lambda s: "/explore/" in s, "explore"),
]


def get_metric_label(rule):
    for matcher, label in ENDPOINT_MATCHER:
        if matcher(rule):
            return label
        return None


class MetricsMiddleware:
    def __init__(self, app):
        self.app = app

        @self.app.route("/metrics")
        def metrics():
            return Response(generate_latest(), mimetype="text/plain")

        @self.app.before_request
        def start_timer():
            request._start_time = time()

        @self.app.after_request
        def record_metrics(response):
            start = getattr(request, "_start_time", None)
            rule_obj = getattr(request, "url_rule", None)
            label = get_metric_label(rule_obj.rule)

            if start and label:
                latency = time() - start
                REQUEST_LATENCY.labels(request.method, label, str(response.status_code)).observe(latency)
                REQUEST_COUNT.labels(request.method, label, str(response.status_code)).inc()

            return response