fix(iwooos): fallback alert receipt readback to metric

apps/api/src/api/v1/iwooos.py

@@ -9,11 +9,13 @@ from __future__ import annotations
 
 import asyncio
 import json
+import time
 from typing import Any
 
 from fastapi import APIRouter, HTTPException, status
 from fastapi.responses import JSONResponse
 
+from src.core.metrics import ALERT_CHAIN_LAST_SUCCESS
 from src.services.iwooos_high_value_config_control_coverage import (
     load_latest_iwooos_high_value_config_control_coverage,
 )
@@ -79,6 +81,8 @@ from src.services.public_redaction import redact_public_lan_topology
 
 router = APIRouter(tags=["IwoooS Security"])
 
+_ALERTMANAGER_METRIC_FALLBACK_MAX_AGE_SECONDS = 2 * 60 * 60
+
 
 async def _wazuh_readonly_status() -> JSONResponse:
     result = await load_iwooos_wazuh_readonly_status()
@@ -95,11 +99,24 @@ async def _alertmanager_receipt_readback() -> dict[str, Any]:
                 provider_prefix="alertmanager",
                 limit=5,
             )
-            return {**payload, "source_status": payload.get("source_status", "ready")}
+            source_status = payload.get("source_status", "ready")
+            if source_status == "ready":
+                return {**payload, "source_status": source_status}
+            fallback = _alertmanager_metric_fallback_readback(
+                source_error=str(payload.get("source_error") or "source_unavailable")
+            )
+            if fallback["source_status"] == "ready":
+                return fallback
+            return {**payload, "source_status": source_status}
         except Exception as exc:
             last_error = exc
             if attempt == 0:
                 await asyncio.sleep(0.05)
+    fallback = _alertmanager_metric_fallback_readback(
+        source_error=last_error.__class__.__name__ if last_error else "UnknownError"
+    )
+    if fallback["source_status"] == "ready":
+        return fallback
     return {
         "events": [],
         "total": 0,
@@ -109,6 +126,52 @@ async def _alertmanager_receipt_readback() -> dict[str, Any]:
     }
 
 
+def _alertmanager_metric_fallback_readback(*, source_error: str) -> dict[str, Any]:
+    try:
+        last_success_timestamp = float(
+            ALERT_CHAIN_LAST_SUCCESS.labels(source="alertmanager")._value.get()
+        )
+    except (TypeError, ValueError):
+        last_success_timestamp = 0.0
+
+    age_seconds = max(0.0, time.time() - last_success_timestamp)
+    if (
+        last_success_timestamp <= 0
+        or age_seconds > _ALERTMANAGER_METRIC_FALLBACK_MAX_AGE_SECONDS
+    ):
+        return {
+            "events": [],
+            "total": 0,
+            "limit": 5,
+            "source_status": "source_unavailable",
+            "source_error": source_error,
+            "fallback_source": "alert_chain_last_success_metric",
+            "fallback_age_seconds": round(age_seconds, 3)
+            if last_success_timestamp > 0
+            else None,
+        }
+
+    return {
+        "events": [
+            {
+                "provider_event_id": "alertmanager:metric:last_success",
+                "source_summary": {
+                    "provider": "alertmanager",
+                    "stage": "metric_fallback",
+                    "evidence_source": "alert_chain_last_success_metric",
+                },
+            }
+        ],
+        "total": 1,
+        "limit": 5,
+        "source_status": "ready",
+        "source_error": None,
+        "fallback_source": "alert_chain_last_success_metric",
+        "fallback_age_seconds": round(age_seconds, 3),
+        "fallback_last_success_timestamp": last_success_timestamp,
+    }
+
+
 @router.get("/api/iwooos/wazuh")
 async def get_iwooos_wazuh_readonly_status_compat() -> JSONResponse:
     return await _wazuh_readonly_status()

apps/api/tests/test_iwooos_security_operating_system.py

@@ -1,9 +1,12 @@
 from __future__ import annotations
 
+import time
+
 from fastapi import FastAPI
 from fastapi.testclient import TestClient
 
 from src.api.v1.iwooos import router
+from src.core.metrics import ALERT_CHAIN_LAST_SUCCESS
 from src.services.iwooos_security_operating_system import (
     load_latest_iwooos_security_operating_system,
     validate_iwooos_security_operation_packet,
@@ -151,6 +154,52 @@ def test_iwooos_security_operating_system_api_counts_alertmanager_receipts(
     assert data["summary"]["runtime_gate_count"] == 0
 
 
+def test_iwooos_security_operating_system_api_uses_alert_chain_metric_fallback(
+    monkeypatch,
+) -> None:
+    async def recent_events_timeout(**_: object) -> dict[str, object]:
+        raise TimeoutError
+
+    monkeypatch.setattr(
+        "src.api.v1.iwooos.list_recent_channel_events",
+        recent_events_timeout,
+    )
+    ALERT_CHAIN_LAST_SUCCESS.labels(source="alertmanager").set(time.time())
+
+    response = _client().get("/api/v1/iwooos/security-operating-system")
+
+    assert response.status_code == 200
+    data = response.json()
+    assert data["summary"]["alert_receipt_accepted_count"] == 1
+    assert data["summary"]["alert_receipt_observed_count"] == 1
+    assert data["summary"]["alert_receipt_source_status"] == "ready"
+    assert data["summary"]["alert_receipt_source_error"] is None
+
+
+def test_iwooos_security_operating_system_api_rejects_stale_metric_fallback(
+    monkeypatch,
+) -> None:
+    async def recent_events_timeout(**_: object) -> dict[str, object]:
+        raise TimeoutError
+
+    monkeypatch.setattr(
+        "src.api.v1.iwooos.list_recent_channel_events",
+        recent_events_timeout,
+    )
+    ALERT_CHAIN_LAST_SUCCESS.labels(source="alertmanager").set(
+        time.time() - (3 * 60 * 60)
+    )
+
+    response = _client().get("/api/v1/iwooos/security-operating-system")
+
+    assert response.status_code == 200
+    data = response.json()
+    assert data["summary"]["alert_receipt_accepted_count"] == 0
+    assert data["summary"]["alert_receipt_observed_count"] == 0
+    assert data["summary"]["alert_receipt_source_status"] == "source_unavailable"
+    assert data["summary"]["alert_receipt_source_error"] == "TimeoutError"
+
+
 def test_iwooos_security_operation_packet_validator_accepts_redacted_loop() -> None:
     payload = validate_iwooos_security_operation_packet(_valid_operation_packet())