Bridge voronFDM to Moonraker only once Moonraker has identified Klipper

scripts/wsrelay/relay.py

@@ -13,8 +13,10 @@
 # that read voronFDM's stdout and injected the print.start the display was not sending; it was retired
 # once the display's own print flow was repaired, and nothing has replaced it.
 import asyncio
+import json
 import tornado.web, tornado.websocket, tornado.ioloop
 from tornado.websocket import websocket_connect
+from tornado.httpclient import AsyncHTTPClient
 import logging
 logging.basicConfig(level=logging.INFO, format="%(asctime)s wsrelay %(message)s")
 UP = "ws://127.0.0.1:7125/websocket"
@@ -26,14 +28,53 @@
 # cycle plus its ~15 s of panel initialisation. Turning it away once is therefore expensive, and holding
 # it for a few seconds costs nothing. This also removes the only reason the boot ordering had to be
 # exact, which is what made it safe to look at that at all.
-UP_WAIT = 60
+# ... and wait for Moonraker to have IDENTIFIED KLIPPER, not merely to be listening. Between "Websocket
+# Opened" and the end of its Klippy handshake Moonraker has not registered the printer.* methods yet, and
+# answers them with "Method not found". That window is milliseconds on an idle host and seconds on a
+# loaded one -- and voronFDM, told "Method not found" for its subscribe and its first gcode, answers with
+# printer.firmware_restart. Measured 2026-09-05 on the dev printer, a boot with the post-update setup
+# running in the background: Moonraker listening at 64 s, voronFDM's requests refused at 65-66 s, two
+# FIRMWARE_RESTARTs at 66.7 s and 66.9 s, Klipper back at 82 s, the panel some 40 s later than it
+# needed to be. So the bridge is only made once /server/info reports a klippy_state other than
+# "startup" or "disconnected" -- ready, error and shutdown all count, because an error is exactly what
+# the panel must be allowed to show. The cap is the same UP_WAIT: past it the bridge is made regardless,
+# so a Klipper that never comes up still cannot take the display with it.
+UP_WAIT = 120
+INFO = "http://127.0.0.1:7125/server/info"
+SETTLED = ("ready", "error", "shutdown")
+
+async def klippy_settled(deadline):
+    """Wait until Moonraker reports Klipper identified (state in SETTLED) or the deadline passes.
+    Returns (state, last) -- state None means the deadline won."""
+    loop = tornado.ioloop.IOLoop.current()
+    client = AsyncHTTPClient()
+    last = "?"
+    while True:
+        try:
+            resp = await client.fetch(INFO, request_timeout=3)
+            state = json.loads(resp.body)["result"].get("klippy_state", "?")
+            if state in SETTLED:
+                return state, last
+            last = "klippy_state=" + str(state)
+        except Exception as e:
+            last = str(e)
+        if loop.time() >= deadline:
+            return None, last
+        await asyncio.sleep(1)
 
 class Relay(tornado.websocket.WebSocketHandler):
     def check_origin(self, origin): return True
     async def open(self, *a):
         self.up = None; self.alive = True
         loop = tornado.ioloop.IOLoop.current()
         deadline = loop.time() + UP_WAIT
+        state, last = await klippy_settled(deadline)
+        if not self.alive:
+            return
+        if state is None:
+            logging.info("klippy not identified after %ss (last: %s) -- bridging anyway", UP_WAIT, last)
+        else:
+            logging.info("klippy %s -- bridging", state)
         tries = 0
         last = "?"
         while self.alive: