monitors loader: add get monitors to load function

Author: GabrielSalla

src/components/monitors_loader/monitors_loader.py

@@ -212,6 +212,32 @@ async def _disable_monitors_without_code_modules() -> None:
     await do_concurrently(*[_disable_monitor(monitor) for monitor in monitors_to_disable])
 
 
+async def _get_monitors_to_load(
+    last_load_time: datetime | None,
+) -> tuple[dict[int, Monitor], list[CodeModule]]:
+    """Get all the monitors that need to be loaded"""
+    # Get all enabled monitors
+    loaded_monitors = await Monitor.get_all(Monitor.enabled.is_(True))
+    monitors = {monitor.id: monitor for monitor in loaded_monitors}
+
+    # Get all code modules that were updated since the last load time
+    # Add a time delta to have some room for code modules that updated right before the last load
+    updated_code_modules = await CodeModule.get_updated_code_modules(
+        monitors_ids=list(monitors.keys()),
+        reference_timestamp=last_load_time,
+        time_delta=timedelta(seconds=15),
+    )
+    code_modules = [code_module for code_module in updated_code_modules]
+
+    # Add monitors that are enabled but aren't in the registry
+    registry_monitors_ids = set(registry.get_monitors_ids())
+    pending_monitors = registry_monitors_ids - set(monitors.keys())
+    if len(pending_monitors) > 0:
+        code_modules.extend(await CodeModule.get_all(CodeModule.monitor_id.in_(pending_monitors)))
+
+    return monitors, code_modules
+
+
 async def _load_monitors() -> None:
     """Load all enabled monitors from the database and add them to the registry. If any of the
     monitor's modules fails to load, the monitor will not be added to the registry"""

tests/components/monitors_loader/test_monitors_loader.py

@@ -594,6 +594,60 @@ async def test_disable_monitors_without_code_modules_no_monitors_to_disable(mock
     disable_monitor_spy.assert_not_called()
 
 
+async def test_get_monitors_to_load(clear_database):
+    """'_get_monitors_to_load' should return only the updated monitors"""
+    await databases.execute_application(
+        'insert into "Monitors"(id, name, enabled) values'
+        "(9999123, 'monitor_1', true),"
+        "(9999456, 'internal.monitor_2', true),"
+        "(9999457, 'disabled_monitor', false);"
+    )
+    await databases.execute_application(
+        'insert into "CodeModules"(monitor_id, code, registered_at) values'
+        "(9999123, 'def get_value(): return 10', '2025-01-10 00:00'),"
+        "(9999456, 'def get_value(): return 11', '2025-01-20 00:00'),"
+        "(9999457, 'def get_value(): return 12', '2025-01-30 00:00');"
+    )
+
+    monitors, code_modules = await monitors_loader._get_monitors_to_load(
+        datetime(2025, 1, 15, tzinfo=timezone.utc)
+    )
+
+    assert len(monitors) == 2
+    assert monitors[9999123].name == "monitor_1"
+    assert monitors[9999456].name == "internal.monitor_2"
+    assert len(code_modules) == 1
+    assert code_modules[0].monitor_id == 9999456
+
+
+async def test_get_monitors_to_load_enabled_not_in_registry(clear_database):
+    """'_get_monitors_to_load' should return enabled monitors that are not in the registry"""
+    await databases.execute_application(
+        'insert into "Monitors"(id, name, enabled) values'
+        "(9999123, 'monitor_1', true),"
+        "(9999456, 'internal.monitor_2', true),"
+        "(9999457, 'disabled_monitor', false);"
+    )
+    await databases.execute_application(
+        'insert into "CodeModules"(monitor_id, code) values'
+        "(9999123, 'def get_value(): return 10', '2025-01-10 00:00'),"
+        "(9999456, 'def get_value(): return 11', '2025-01-20 00:00'),"
+        "(9999457, 'def get_value(): return 12', '2025-01-30 00:00');"
+    )
+
+    registry._monitors = {9999456: {"module": ModuleType}}
+
+    monitors, code_modules = await monitors_loader._get_monitors_to_load(
+        datetime(2025, 1, 15, tzinfo=timezone.utc)
+    )
+
+    assert len(monitors) == 2
+    assert monitors[9999123].name == "monitor_1"
+    assert monitors[9999456].name == "internal.monitor_2"
+    assert len(code_modules) == 2
+    assert {code_module.monitor_id for code_module in code_modules} == {9999123, 9999456}
+
+
 async def test_load_monitors(clear_database):
     """'_load_monitors' should load all enabled monitors from the database and add them to the
     registry"""