pst server

kvmd/apps/pst/server.py

@@ -0,0 +1,126 @@
+# ========================================================================== #
+#                                                                            #
+#    KVMD - The main PiKVM daemon.                                           #
+#                                                                            #
+#    Copyright (C) 2018-2022  Maxim Devaev <mdevaev@gmail.com>               #
+#                                                                            #
+#    This program is free software: you can redistribute it and/or modify    #
+#    it under the terms of the GNU General Public License as published by    #
+#    the Free Software Foundation, either version 3 of the License, or       #
+#    (at your option) any later version.                                     #
+#                                                                            #
+#    This program is distributed in the hope that it will be useful,         #
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of          #
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the           #
+#    GNU General Public License for more details.                            #
+#                                                                            #
+#    You should have received a copy of the GNU General Public License       #
+#    along with this program.  If not, see <https://www.gnu.org/licenses/>.  #
+#                                                                            #
+# ========================================================================== #
+
+
+import os
+import asyncio
+
+from typing import List
+from typing import Dict
+
+from aiohttp.web import Request
+from aiohttp.web import WebSocketResponse
+
+from ...logging import get_logger
+
+from ... import aiotools
+from ... import aiohelpers
+
+from ...htserver import exposed_http
+from ...htserver import exposed_ws
+from ...htserver import WsSession
+from ...htserver import HttpServer
+
+
+# =====
+class PstServer(HttpServer):  # pylint: disable=too-many-arguments,too-many-instance-attributes
+    def __init__(  # pylint: disable=too-many-arguments,too-many-locals
+        self,
+        storage_path: str,
+        ro_retries_delay: float,
+        remount_cmd: List[str],
+    ) -> None:
+
+        super().__init__()
+
+        self.__data_path = os.path.join(storage_path, "data")
+        self.__ro_retries_delay = ro_retries_delay
+        self.__remount_cmd = remount_cmd
+
+        self.__notifier = aiotools.AioNotifier()
+
+    # ===== WEBSOCKET
+
+    @exposed_http("GET", "/ws")
+    async def __ws_handler(self, request: Request) -> WebSocketResponse:
+        async with self._ws_session(request) as ws:
+            await ws.send_event("loop", {})
+            return (await self._ws_loop(ws))
+
+    @exposed_ws("ping")
+    async def __ws_ping_handler(self, ws: WsSession, _: Dict) -> None:
+        await ws.send_event("pong", {})
+
+    # ===== SYSTEM STUFF
+
+    async def _init_app(self) -> None:
+        if (await self.__remount_storage(True)):
+            await self.__remount_storage(False)
+        aiotools.create_deadly_task("Controller", self.__controller())
+        self._add_exposed(self)
+
+    async def _on_shutdown(self) -> None:
+        logger = get_logger(0)
+        logger.info("Stopping system tasks ...")
+        await aiotools.stop_all_deadly_tasks()
+        logger.info("Disconnecting clients ...")
+        await self.__broadcast_storage_state(False)
+        await self._close_all_wss()
+        logger.info("On-Shutdown complete")
+
+    async def _on_cleanup(self) -> None:
+        logger = get_logger(0)
+        await self.__remount_storage(False)
+        logger.info("On-Cleanup complete")
+
+    async def _on_ws_opened(self) -> None:
+        await self.__notifier.notify()
+
+    async def _on_ws_closed(self) -> None:
+        await self.__notifier.notify()
+
+    # ===== SYSTEM TASKS
+
+    async def __controller(self) -> None:
+        prev = False
+        while True:
+            cur = self.__has_clients()
+            if not prev and cur:
+                await self.__broadcast_storage_state(await self.__remount_storage(True))
+            elif prev and not cur:
+                while not (await self.__remount_storage(False)):
+                    if self.__has_clients():
+                        continue
+                    await asyncio.sleep(self.__ro_retries_delay)
+            prev = cur
+            await self.__notifier.wait()
+
+    def __has_clients(self) -> bool:
+        return bool(self._get_wss())
+
+    async def __broadcast_storage_state(self, write_allowed: bool) -> None:
+        await self._broadcast_ws_event("storage_state", {
+            "data": {"path": self.__data_path},
+            "write_allowed": write_allowed,
+        })
+
+    async def __remount_storage(self, rw: bool) -> bool:
+        return (await aiohelpers.remount("PST", self.__remount_cmd, rw))