decomposer: generate deliverable files for Define the service contract and project architecture for the FastAPI endpoint monitoring service.; Implement the typed monitor CRUD API and concurrency-safe in-memory state according to the service design.; Implement secure on-demand endpoint checks with status updates, latency measurement, robust error handling, and redacted structured logs.; Add operational API endpoints and environment-driven runtime configuration to the monitoring service.; Create automated tests for the monitoring service.; Package the service with Docker and developer documentation.; Validate the complete project.

app/store.py

@@ -1,58 +1,75 @@
 import asyncio
+from dataclasses import dataclass
+from datetime import UTC, datetime
 from uuid import UUID, uuid4
 
-from .models import CheckSnapshot, Monitor, MonitorInput, now
+from app.models import Monitor, MonitorCreate, MonitorUpdate, StatusSnapshot
 
 
-class StoreFullError(Exception):
+@dataclass
-    pass
+class _Record:
+    monitor: Monitor
+    revision: int
 
 
 class MonitorStore:
-    def __init__(self, max_monitors: int) -> None:
+    def __init__(self) -> None:
-        self._items: dict[UUID, Monitor] = {}
         self._lock = asyncio.Lock()
-        self._max = max_monitors
+        self._records: dict[UUID, _Record] = {}
 
-    async def create(self, data: MonitorInput) -> Monitor:
+    async def create(self, data: MonitorCreate) -> Monitor:
+        now = datetime.now(UTC)
+        monitor = Monitor(
+            id=uuid4(), name=data.name, url=data.url, created_at=now,
+            updated_at=now, status=StatusSnapshot(),
+        )
         async with self._lock:
-            if len(self._items) >= self._max:
+            self._records[monitor.id] = _Record(monitor, 0)
-                raise StoreFullError
+        return monitor.model_copy(deep=True)
-            timestamp = now()
-            item = Monitor(id=uuid4(), **data.model_dump(), created_at=timestamp,
-                           updated_at=timestamp, revision=1, status=CheckSnapshot())
-            self._items[item.id] = item
-            return item
 
     async def list(self) -> list[Monitor]:
         async with self._lock:
-            return sorted(self._items.values(), key=lambda item: item.created_at)
+            values = [item.monitor for item in self._records.values()]
+            return [value.model_copy(deep=True) for value in values]
 
     async def get(self, monitor_id: UUID) -> Monitor | None:
         async with self._lock:
-            return self._items.get(monitor_id)
+            record = self._records.get(monitor_id)
+            return record.monitor.model_copy(deep=True) if record else None
 
-    async def replace(self, monitor_id: UUID, data: MonitorInput) -> Monitor | None:
+    async def update(self, monitor_id: UUID, data: MonitorUpdate) -> Monitor | None:
         async with self._lock:
-            old = self._items.get(monitor_id)
+            record = self._records.get(monitor_id)
-            if old is None:
+            if not record:
                 return None
-            item = old.model_copy(update={**data.model_dump(), "updated_at": now(),
+            url_changed = record.monitor.url != data.url
-                                          "revision": old.revision + 1,
+            status = StatusSnapshot() if url_changed else record.monitor.status
-                                          "status": CheckSnapshot()})
+            record.monitor = record.monitor.model_copy(update={
-            self._items[monitor_id] = item
+                "name": data.name, "url": data.url, "updated_at": datetime.now(UTC),
-            return item
+                "status": status,
+            })
+            record.revision += 1
+            return record.monitor.model_copy(deep=True)
 
     async def delete(self, monitor_id: UUID) -> bool:
         async with self._lock:
-            return self._items.pop(monitor_id, None) is not None
+            return self._records.pop(monitor_id, None) is not None
 
-    async def set_status(self, monitor_id: UUID, revision: int,
+    async def begin_check(self, monitor_id: UUID) -> tuple[Monitor, int] | None:
-                         status: CheckSnapshot) -> Monitor | None:
         async with self._lock:
-            old = self._items.get(monitor_id)
+            record = self._records.get(monitor_id)
-            if old is None or old.revision != revision:
+            if not record:
                 return None
-            item = old.model_copy(update={"status": status, "updated_at": now()})
+            return record.monitor.model_copy(deep=True), record.revision
-            self._items[monitor_id] = item
+
-            return item
+    async def finish_check(
+        self, monitor_id: UUID, revision: int, status: StatusSnapshot,
+    ) -> bool:
+        async with self._lock:
+            record = self._records.get(monitor_id)
+            if not record or record.revision != revision:
+                return False
+            record.monitor = record.monitor.model_copy(update={
+                "status": status, "updated_at": datetime.now(UTC),
+            })
+            return True