proc_stats: add stat callback registration

This allows other components to be register callbacks that will
be executed in the stat update timer. This is useful for methods
that wish to poll subprocess commands, as its desireable to
prevent multiple subprocesses from running simultaneously.

Signed-off-by: Eric Callahan <arksine.code@gmail.com>

moonraker/components/proc_stats.py

@@ -16,6 +16,8 @@ from collections import deque
 # Annotation imports
 from typing import (
     TYPE_CHECKING,
+    Awaitable,
+    Callable,
     Deque,
     Any,
     List,
@@ -27,7 +29,7 @@ if TYPE_CHECKING:
     from confighelper import ConfigHelper
     from websockets import WebRequest, WebsocketManager
     from . import shell_command
-    from .machine import Machine
+    STAT_CALLBACK = Callable[[int], Optional[Awaitable]]
 
 VC_GEN_CMD_FILE = "/usr/bin/vcgencmd"
 STATM_FILE_PATH = "/proc/self/smaps_rollup"
@@ -55,7 +57,6 @@ class ProcStats:
     def __init__(self, config: ConfigHelper) -> None:
         self.server = config.get_server()
         self.event_loop = self.server.get_event_loop()
-        self.machine: Machine = self.server.load_component(config, 'machine')
         self.watchdog = Watchdog(self)
         self.stat_update_timer = self.event_loop.register_timer(
             self._handle_stat_update)
@@ -89,9 +90,13 @@ class ProcStats:
         self.last_net_stats: Dict[str, Dict[str, Any]] = {}
         self.last_cpu_stats: Dict[str, Tuple[int, int]] = {}
         self.cpu_usage: Dict[str, float] = {}
+        self.stat_callbacks: List[STAT_CALLBACK] = []
         self.stat_update_timer.start()
         self.watchdog.start()
 
+    def register_stat_callback(self, callback: STAT_CALLBACK) -> None:
+        self.stat_callbacks.append(callback)
+
     async def _handle_stat_request(self,
                                    web_request: WebRequest
                                    ) -> Dict[str, Any]:
@@ -156,11 +161,7 @@ class ProcStats:
             'system_cpu_usage': self.cpu_usage,
             'websocket_connections': websocket_count
         })
-        self.last_update_time = update_time
-        self.last_proc_time = proc_time
-        self.update_sequence += 1
-        if self.update_sequence == THROTTLE_CHECK_INTERVAL:
-            self.update_sequence = 0
+        if not self.update_sequence % THROTTLE_CHECK_INTERVAL:
             if self.vcgencmd is not None:
                 ts = await self._check_throttled_state()
                 cur_throttled = ts['bits']
@@ -171,8 +172,13 @@ class ProcStats:
                     self.server.send_event("proc_stats:cpu_throttled", ts)
                 self.last_throttled = cur_throttled
                 self.total_throttled |= cur_throttled
-            await self.machine.parse_network_interfaces()
-        await self.machine.update_service_status()
+        for cb in self.stat_callbacks:
+            ret = cb(self.update_sequence)
+            if ret is not None:
+                await ret
+        self.last_update_time = update_time
+        self.last_proc_time = proc_time
+        self.update_sequence += 1
         return eventtime + STAT_UPDATE_TIME
 
     async def _check_throttled_state(self) -> Dict[str, Any]: