feat: traefik scrape task (delta tracking, DB write, record_metric)

plugins/traefik/scheduler.py

@@ -0,0 +1,97 @@
+# plugins/traefik/scheduler.py
+from __future__ import annotations
+import logging
+import time
+from typing import TYPE_CHECKING
+
+from fablednetmon.core.scheduler import ScheduledTask
+
+if TYPE_CHECKING:
+    from quart import Quart
+
+logger = logging.getLogger(__name__)
+
+# Module-level state: previous scrape data for delta computation
+_prev_metrics: dict = {}
+_prev_time: float = 0.0
+
+
+def make_scrape_task(app: "Quart") -> ScheduledTask:
+    """Return a ScheduledTask that scrapes Traefik metrics on the configured interval."""
+    interval = app.config["PLUGINS"]["traefik"]["scrape_interval_seconds"]
+
+    async def scrape() -> None:
+        await _do_scrape(app)
+
+    return ScheduledTask(
+        name="traefik_scrape",
+        coro_factory=scrape,
+        interval_seconds=int(interval),
+        run_on_startup=True,
+    )
+
+
+async def _do_scrape(app: "Quart") -> None:
+    """Fetch Traefik metrics, write to DB, and emit plugin_metrics."""
+    global _prev_metrics, _prev_time
+
+    from datetime import datetime, timezone
+    from plugins.traefik.models import TraefikMetric
+    from plugins.traefik.scraper import fetch_metrics, compute_router_metrics
+    from fablednetmon.core.alerts import record_metric
+
+    metrics_url: str = app.config["PLUGINS"]["traefik"]["metrics_url"]
+
+    try:
+        current = await fetch_metrics(metrics_url)
+    except Exception:
+        logger.exception("Traefik scrape failed (url=%s)", metrics_url)
+        return
+
+    now = time.monotonic()
+    elapsed = now - _prev_time if _prev_time else 60.0
+    router_metrics = compute_router_metrics(current, _prev_metrics or None, elapsed)
+
+    _prev_metrics = current
+    _prev_time = now
+
+    if not router_metrics:
+        logger.debug("Traefik scrape: no router metrics found")
+        return
+
+    scraped_at = datetime.now(timezone.utc)
+
+    async with app.db_sessionmaker() as session:
+        async with session.begin():
+            for router_name, metrics in router_metrics.items():
+                # Write to traefik_metrics history table
+                row = TraefikMetric(
+                    router_name=router_name,
+                    scraped_at=scraped_at,
+                    request_rate=metrics["request_rate"],
+                    error_rate_4xx_pct=metrics["error_rate_4xx_pct"],
+                    error_rate_5xx_pct=metrics["error_rate_5xx_pct"],
+                    latency_p50_ms=metrics["latency_p50_ms"],
+                    latency_p95_ms=metrics["latency_p95_ms"],
+                    latency_p99_ms=metrics["latency_p99_ms"],
+                )
+                session.add(row)
+
+                # Emit plugin_metrics for alert rules
+                for metric_name, value in [
+                    ("request_rate", metrics["request_rate"]),
+                    ("error_rate_4xx_pct", metrics["error_rate_4xx_pct"]),
+                    ("error_rate_5xx_pct", metrics["error_rate_5xx_pct"]),
+                    ("latency_p50_ms", metrics["latency_p50_ms"]),
+                    ("latency_p95_ms", metrics["latency_p95_ms"]),
+                    ("latency_p99_ms", metrics["latency_p99_ms"]),
+                ]:
+                    await record_metric(
+                        session=session,
+                        source_module="traefik",
+                        resource_name=router_name,
+                        metric_name=metric_name,
+                        value=value,
+                    )
+
+    logger.debug("Traefik scrape: wrote metrics for %d router(s)", len(router_metrics))