Implement Monlet MVP stack and UI updates

server/monlet_server/metrics.py

@@ -0,0 +1,54 @@
+from prometheus_client import CollectorRegistry, Counter, Gauge, Histogram, generate_latest
+from prometheus_client.exposition import CONTENT_TYPE_LATEST
+
+REGISTRY = CollectorRegistry()
+
+heartbeats_total = Counter(
+    "monlet_server_heartbeats_total",
+    "Total heartbeats received.",
+    ["result"],
+    registry=REGISTRY,
+)
+events_total = Counter(
+    "monlet_server_events_total",
+    "Total events ingested.",
+    ["result"],
+    registry=REGISTRY,
+)
+incidents_opened_total = Counter(
+    "monlet_server_incidents_opened_total",
+    "Total incidents opened.",
+    registry=REGISTRY,
+)
+incidents_resolved_total = Counter(
+    "monlet_server_incidents_resolved_total",
+    "Total incidents resolved.",
+    registry=REGISTRY,
+)
+agents_gauge = Gauge(
+    "monlet_server_agents",
+    "Agents by status.",
+    ["status"],
+    registry=REGISTRY,
+)
+open_incidents_gauge = Gauge(
+    "monlet_server_open_incidents",
+    "Number of open incidents.",
+    registry=REGISTRY,
+)
+notifications_total = Counter(
+    "monlet_server_notifications_total",
+    "Notification delivery attempts by notifier and result.",
+    ["notifier", "result"],
+    registry=REGISTRY,
+)
+request_duration = Histogram(
+    "monlet_server_request_duration_seconds",
+    "Request duration seconds.",
+    ["path"],
+    registry=REGISTRY,
+)
+
+
+def render() -> tuple[bytes, str]:
+    return generate_latest(REGISTRY), CONTENT_TYPE_LATEST