Add asset-based monitor setup

backend/app/api/monitors.py

@@ -4,14 +4,42 @@ from fastapi import APIRouter, Depends, HTTPException
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
+from app.api.credentials import SNMP_CREDENTIAL_TYPE
 from app.auth.dependencies import get_current_user, require_role
 from app.db.session import get_db
-from app.models import AlertRule, Asset, CheckResult, Incident, Monitor, User
-from app.schemas.core import CheckResultRead, MonitorCreate, MonitorRead, MonitorUpdate, PingMonitorCreate, TcpMonitorCreate, WebsiteMonitorCreate
+from app.models import AlertRule, Asset, CheckResult, Credential, Incident, Monitor, User
+from app.schemas.core import (
+    CheckResultRead,
+    MonitorCreate,
+    MonitorRead,
+    MonitorUpdate,
+    PingMonitorCreate,
+    SnmpMonitorsCreate,
+    TcpMonitorCreate,
+    WebsiteMonitorCreate,
+)
 
 router = APIRouter(prefix="/monitors", tags=["monitors"])
 
 
+def _get_asset_or_404(db: Session, asset_id: int) -> Asset:
+    asset = db.get(Asset, asset_id)
+    if asset is None:
+        raise HTTPException(status_code=404, detail="Asset not found")
+    return asset
+
+
+def _resolve_asset_id(db: Session, asset_id: int | None, create_asset: bool, asset: Asset) -> int | None:
+    if asset_id is not None:
+        _get_asset_or_404(db, asset_id)
+        return asset_id
+    if not create_asset:
+        return None
+    db.add(asset)
+    db.flush()
+    return asset.id
+
+
 @router.get("", response_model=list[MonitorRead])
 def list_monitors(_: User = Depends(get_current_user), db: Session = Depends(get_db)) -> list[Monitor]:
     return list(db.scalars(select(Monitor).order_by(Monitor.name)).all())
@@ -23,6 +51,8 @@ def create_monitor(
     _: User = Depends(require_role("admin")),
     db: Session = Depends(get_db),
 ) -> Monitor:
+    if payload.asset_id is not None:
+        _get_asset_or_404(db, payload.asset_id)
     monitor = Monitor(**payload.model_dump())
     db.add(monitor)
     db.commit()
@@ -36,12 +66,12 @@ def create_website_monitor(
     _: User = Depends(require_role("admin")),
     db: Session = Depends(get_db),
 ) -> Monitor:
-    asset_id: int | None = None
-    if payload.create_asset:
-        asset = Asset(name=payload.name, asset_type="website", address=payload.url, status="unknown", extra={})
-        db.add(asset)
-        db.flush()
-        asset_id = asset.id
+    asset_id = _resolve_asset_id(
+        db,
+        payload.asset_id,
+        payload.create_asset,
+        Asset(name=payload.name, asset_type="website", address=payload.url, status="unknown", extra={}),
+    )
 
     monitor = Monitor(
         asset_id=asset_id,
@@ -86,12 +116,12 @@ def create_ping_monitor(
     _: User = Depends(require_role("admin")),
     db: Session = Depends(get_db),
 ) -> Monitor:
-    asset_id: int | None = None
-    if payload.create_asset:
-        asset = Asset(name=payload.name, asset_type="host", address=payload.host, status="unknown", extra={})
-        db.add(asset)
-        db.flush()
-        asset_id = asset.id
+    asset_id = _resolve_asset_id(
+        db,
+        payload.asset_id,
+        payload.create_asset,
+        Asset(name=payload.name, asset_type="host", address=payload.host, status="unknown", extra={}),
+    )
 
     monitor = Monitor(
         asset_id=asset_id,
@@ -129,13 +159,13 @@ def create_tcp_monitor(
     _: User = Depends(require_role("admin")),
     db: Session = Depends(get_db),
 ) -> Monitor:
-    asset_id: int | None = None
     target = f"{payload.host}:{payload.port}"
-    if payload.create_asset:
-        asset = Asset(name=payload.name, asset_type="tcp_service", address=target, status="unknown", extra={})
-        db.add(asset)
-        db.flush()
-        asset_id = asset.id
+    asset_id = _resolve_asset_id(
+        db,
+        payload.asset_id,
+        payload.create_asset,
+        Asset(name=payload.name, asset_type="tcp_service", address=target, status="unknown", extra={}),
+    )
 
     monitor = Monitor(
         asset_id=asset_id,
@@ -167,6 +197,44 @@ def create_tcp_monitor(
     return monitor
 
 
+@router.post("/snmp/from-discovery", response_model=list[MonitorRead])
+def create_snmp_monitors_from_discovery(
+    payload: SnmpMonitorsCreate,
+    _: User = Depends(require_role("admin")),
+    db: Session = Depends(get_db),
+) -> list[Monitor]:
+    asset = _get_asset_or_404(db, payload.asset_id)
+    profile = db.get(Credential, payload.credential_profile_id)
+    if profile is None or profile.credential_type != SNMP_CREDENTIAL_TYPE:
+        raise HTTPException(status_code=404, detail="SNMP credential profile not found")
+
+    monitors: list[Monitor] = []
+    for item in payload.selected_items:
+        monitor = Monitor(
+            asset_id=asset.id,
+            name=f"{asset.name} {item.label}",
+            monitor_type="snmp",
+            target=payload.host,
+            config={
+                "credential_profile_id": payload.credential_profile_id,
+                "item_id": item.item_id,
+                "item_type": item.item_type,
+                "group": item.group,
+                "label": item.label,
+                "unit": item.unit,
+            },
+            interval_seconds=payload.interval_seconds,
+            status="unknown",
+        )
+        db.add(monitor)
+        monitors.append(monitor)
+
+    db.commit()
+    for monitor in monitors:
+        db.refresh(monitor)
+    return monitors
+
+
 @router.get("/{monitor_id}", response_model=MonitorRead)
 def get_monitor(monitor_id: int, _: User = Depends(get_current_user), db: Session = Depends(get_db)) -> Monitor:
     monitor = db.get(Monitor, monitor_id)