Suppress outgoing websocket traffic when pedalboards are loading

modalapi/mod.py

@@ -31,7 +31,7 @@
 
 from blend.snapshot import SnapshotManager
 from modalapi.websocket_bridge import AsyncWebSocketBridge
-from modalapi.ws_protocol import parse_message, LoadingEndMessage, PedalSnapshotMessage, PluginBypassMessage, TransportMessage, AddPluginMessage, ParamSetMessage, MidiMapMessage, WebSocketMessage
+from modalapi.ws_protocol import parse_message, LoadingEndMessage, LoadingStartMessage, PedalSnapshotMessage, PluginBypassMessage, TransportMessage, AddPluginMessage, ParamSetMessage, MidiMapMessage, WebSocketMessage
 from modalapi.pedalboard_monitor import FileChangeMonitor, read_pedalboard_bundle
 
 from pistomp.footswitch import Footswitch
@@ -155,6 +155,9 @@ def __init__(self, audiocard, homedir):
         self.ws_bridge.start()
         logging.info("WebSocket bridge started")
 
+        # Suppress outbound WebSocket messages while a pedalboard change is in flight.
+        self._is_pedalboard_loading: bool = False
+
         # Callback function map.  Key is the user specified name, value is function from this handler
         # Used for calling handler callbacks pointed to by names which may be user set in the config file
         self.callbacks = {"set_mod_tap_tempo": self.set_mod_tap_tempo,
@@ -170,15 +173,12 @@ def __del__(self):
         logging.info("Handler cleanup")
         if self.wifi_manager:
             del self.wifi_manager
-        if self.ws_bridge is not None:
-            self.ws_bridge.stop()
 
     def cleanup(self):
         if self.lcd is not None:
             self.lcd.cleanup()
-        if self.ws_bridge is not None:
-            self.ws_bridge.stop()
-            logging.info("WebSocket bridge stopped")
+        self.ws_bridge.stop()
+        logging.info("WebSocket bridge stopped")
 
     # Container for dynamic data which is unique to the "current" pedalboard
     # The self.current pointed above will point to this object which gets
@@ -480,7 +480,13 @@ def poll_system_info(self):
 
     def _handle_ws_message(self, msg: WebSocketMessage):
         """Handle incoming WebSocket message from MOD-UI"""
-        if isinstance(msg, LoadingEndMessage):
+        if isinstance(msg, LoadingStartMessage):
+            self._is_pedalboard_loading = True
+            cleared = self.ws_bridge.clear_queue()
+            if cleared:
+                logging.debug(f"Cleared {cleared} stale outbound messages on loading_start")
+
+        elif isinstance(msg, LoadingEndMessage):
             logging.debug(f"WebSocket: Pedalboard loading finished, snapshot={msg.snapshot_id}")
             self.next_pedalboard_preset_index = msg.snapshot_id
 
@@ -544,6 +550,7 @@ def poll_modui_changes(self):
 
         # Check for pedalboard change via last.json
         if self.last_json_monitor.check_for_change():
+            self._is_pedalboard_loading = True
             self.lcd.draw_info_message("Loading...")
             mod_bundle = read_pedalboard_bundle(self.last_json_monitor.path)
             if mod_bundle and mod_bundle != self.current.pedalboard.bundle:
@@ -634,6 +641,9 @@ def set_current_pedalboard(self, pedalboard):
         self.load_current_presets()
         self.update_lcd()
 
+        # Resume outbound WebSocket messages now that the new pedalboard is fully set up.
+        self._is_pedalboard_loading = False
+
         # Prepare blend modes if configured (snapshot-based activation)
         try:
             blend_configs = cfg.get('blend_snapshots', []) if cfg else []
@@ -901,7 +911,8 @@ def toggle_plugin_bypass(self):
                         return
             # Non-footswitch plugin: emit only; the inbound echo updates state and LCD.
             target_bypass = not inst.is_bypassed()
-            self.ws_bridge.send_parameter(inst.instance_id, ":bypass", 1.0 if target_bypass else 0.0)
+            if not self._is_pedalboard_loading:
+                self.ws_bridge.send_parameter(inst.instance_id, ":bypass", 1.0 if target_bypass else 0.0)
             self.lcd.draw_plugin_select(inst)  # selection highlight (navigation, not bypass)
 
     #
@@ -1356,7 +1367,8 @@ def parameter_value_change(self, direction, commit_callback):
 
     def parameter_value_commit(self):
         param = self.deep.selected_parameter
-        self.ws_bridge.send_parameter(param.instance_id, param.symbol, param.value)
+        if not self._is_pedalboard_loading:
+            self.ws_bridge.send_parameter(param.instance_id, param.symbol, param.value)
 
     #
     # LCD Stuff

modalapi/modhandler.py

@@ -37,7 +37,7 @@
 import pistomp.settings as Settings
 from blend.snapshot import SnapshotManager
 from modalapi.websocket_bridge import AsyncWebSocketBridge
-from modalapi.ws_protocol import parse_message, LoadingEndMessage, PedalSnapshotMessage, PluginBypassMessage, TransportMessage, AddPluginMessage, ParamSetMessage, MidiMapMessage, WebSocketMessage
+from modalapi.ws_protocol import parse_message, LoadingEndMessage, LoadingStartMessage, PedalSnapshotMessage, PluginBypassMessage, TransportMessage, AddPluginMessage, ParamSetMessage, MidiMapMessage, WebSocketMessage
 from modalapi.pedalboard_monitor import FileChangeMonitor, read_pedalboard_bundle
 
 from pistomp.footswitch import Footswitch
@@ -107,6 +107,9 @@ def __init__(self, audiocard: Audiocard, homedir, data_dir="/home/pistomp/data")
         self.ws_bridge.start()
         logging.info("WebSocket bridge started")
 
+        # Suppress outbound WebSocket messages while a pedalboard change is in flight.
+        self._is_pedalboard_loading = False
+
         # Tuner state
         self._tuner_engine: TunerEngine | None = None
         self._tuner_panel: TunerPanel | None = None
@@ -131,8 +134,6 @@ def __del__(self):
         logging.info("Handler cleanup")
         if self.wifi_manager:
             del self.wifi_manager
-        # ws_bridge.stop() lives in cleanup(), not here — join() in __del__ blows up
-        # during interpreter shutdown on Py 3.14. Daemon thread dies with the process.
 
     def cleanup(self):
         if self._tuner_engine is not None:
@@ -145,9 +146,8 @@ def cleanup(self):
             self._lcd.cleanup()
         if self._hardware is not None:
             self._hardware.cleanup()
-        if self.ws_bridge is not None:
-            self.ws_bridge.stop()
-            logging.info("WebSocket bridge stopped")
+        self.ws_bridge.stop()
+        logging.info("WebSocket bridge stopped")
 
     # Container for dynamic data which is unique to the "current" pedalboard
     # The self.current pointed above will point to this object which gets
@@ -337,7 +337,13 @@ def _handle_blend_mode_snapshot_change(self, new_snapshot_index: int):
 
     def _handle_ws_message(self, msg: WebSocketMessage):
         """Handle incoming WebSocket message from MOD-UI."""
-        if isinstance(msg, LoadingEndMessage):
+        if isinstance(msg, LoadingStartMessage):
+            self._is_pedalboard_loading = True
+            cleared = self.ws_bridge.clear_queue()
+            if cleared:
+                logging.debug(f"Cleared {cleared} stale outbound messages on loading_start")
+
+        elif isinstance(msg, LoadingEndMessage):
             logging.debug(f"WebSocket: Pedalboard loading finished, snapshot={msg.snapshot_id}")
             # Sometimes mod-ui sends us -1 for preset index, but shows 0 anyway ("Default")
             self.next_pedalboard_preset_index = max(0, msg.snapshot_id)
@@ -421,6 +427,7 @@ def poll_modui_changes(self):
 
         # Check for pedalboard change via last.json
         if self.last_json_monitor.check_for_change():
+            self._is_pedalboard_loading = True
             self.lcd.draw_info_message("Loading...")
             mod_bundle = read_pedalboard_bundle(self.last_json_monitor.path)
             if mod_bundle and self.current and mod_bundle != self.current.pedalboard.bundle:
@@ -609,6 +616,9 @@ def set_current_pedalboard(self, pedalboard):
             self.blend_modes = {}
             self.active_blend_mode = None
 
+        # Resume outbound WebSocket messages now that the new pedalboard is fully set up.
+        self._is_pedalboard_loading = False
+
     def bind_current_pedalboard(self):
         # "current" being the pedalboard mod-host says is current
         # The pedalboard data has already been loaded, but this will overlay
@@ -770,7 +780,8 @@ def toggle_plugin_bypass(self, widget, plugin):
             # No echo arrives for WS-initiated bypass. Contrast with footswitches,
             # which send MIDI CC → mod-host internally → feedback → msg_callback.
             value = plugin.toggle_bypass()
-            self.ws_bridge.send_parameter(plugin.instance_id, ":bypass", value)
+            if not self._is_pedalboard_loading:
+                self.ws_bridge.send_parameter(plugin.instance_id, ":bypass", value)
             self.lcd.toggle_plugin(widget, plugin)
 
     def update_lcd_fs(self, footswitch=None, bypass_change=False):
@@ -790,7 +801,8 @@ def parameter_value_commit(self, param, value):
             self.audio_parameter_commit(param.symbol, value)
             return
 
-        self.ws_bridge.send_parameter(param.instance_id, param.symbol, param.value)
+        if not self._is_pedalboard_loading:
+            self.ws_bridge.send_parameter(param.instance_id, param.symbol, param.value)
 
     def parameter_midi_change(self, param, direction):
         if param:

tests/v1/test_plugins.py

@@ -1,3 +1,4 @@
+# pyright: reportAttributeAccessIssue=false
 """Basic v1/v2 (mod.py) coverage for source-of-truth bypass.
 
 Drives Mod.toggle_plugin_bypass directly with a hand-wired handler (no hardware,
@@ -17,6 +18,7 @@ def _make_handler(selected_plugin):
     handler.ws_bridge = FakeWebSocketBridge()
     handler.lcd = MagicMock()
     handler.get_selected_instance = lambda: selected_plugin
+    handler._is_pedalboard_loading = False
     return handler
 
 
@@ -27,6 +29,7 @@ def _make_drain_handler(plugins):
     handler.ws_bridge = FakeWebSocketBridge()
     handler.lcd = MagicMock()
     handler.current = SimpleNamespace(pedalboard=SimpleNamespace(plugins=plugins))
+    handler._is_pedalboard_loading = False
     return handler
 
 
@@ -61,3 +64,27 @@ def test_v1_add_dump_reseeds_bypass_on_reconnect(make_plugin):
     handler.poll_ws_messages()
 
     assert plugin.is_bypassed()
+
+
+def test_v1_outbound_ws_suppressed_during_pedalboard_change(make_plugin):
+    """While a pedalboard change is in flight, outbound param_set messages are dropped."""
+    plugin = make_plugin("fuzz", bypassed=False, has_footswitch=False)
+    handler = _make_handler(plugin)
+    handler.current = SimpleNamespace(pedalboard=SimpleNamespace(plugins=[plugin]))
+    handler._is_pedalboard_loading = True
+
+    handler.toggle_plugin_bypass()
+
+    # mod.py uses emit-only semantics (state unchanged until echo arrives).
+    # The key assertion is that NO ws message was sent while suppressed.
+    assert not plugin.is_bypassed()
+    assert handler.ws_bridge.sent_values_for("fuzz", ":bypass") == []
+
+
+def test_v1_loading_start_suppresses_outbound_ws():
+    """Receiving loading_start from MOD-UI sets the suppression flag."""
+    handler = _make_drain_handler([])
+    assert not getattr(handler, "_is_pedalboard_loading", False)
+    handler.ws_bridge.inject("loading_start 0")
+    handler.poll_ws_messages()
+    assert handler._is_pedalboard_loading is True

tests/v3/test_pedalboards.py

@@ -84,3 +84,58 @@ def get_side_effect(url, **kwargs):
     assert handler.current
     assert handler.current.pedalboard.title == "New Rig"
     snapshot()
+
+
+def test_v3_outbound_ws_suppressed_during_pedalboard_change(v3_system: SystemFixture, make_plugin):
+    """While a pedalboard change is in flight, outbound param_set messages are dropped."""
+    handler = v3_system.handler
+    ws_bridge = v3_system.ws_bridge
+
+    # Start with a loaded pedalboard
+    old_plugin = make_plugin("old_fuzz", category="Distortion", bypassed=False)
+    assert handler.current is not None
+    handler.current.pedalboard.plugins = [old_plugin]
+    handler.lcd.link_data(handler.pedalboard_list, handler.current, handler.hardware.footswitches)
+    handler.lcd.draw_main_panel()
+    widget = next(w for w in handler.lcd.w_plugins if w.object is old_plugin)
+    ws_bridge.sent.clear()
+
+    # Simulate a user tapping the bypass on the old pedalboard while a change is in flight
+    handler._is_pedalboard_loading = True
+    handler.toggle_plugin_bypass(widget, old_plugin)
+
+    # The bypass should flip locally, but NO ws message should be sent
+    assert old_plugin.is_bypassed()
+    assert ws_bridge.sent_values_for("old_fuzz", ":bypass") == []
+
+    # After clearing suppression, sends resume
+    handler._is_pedalboard_loading = False
+    handler.toggle_plugin_bypass(widget, old_plugin)
+    assert not old_plugin.is_bypassed()
+    assert ws_bridge.sent_values_for("old_fuzz", ":bypass") == [0.0]
+
+
+def test_v3_loading_start_suppresses_outbound_ws(v3_system: SystemFixture):
+    """Receiving loading_start from MOD-UI sets the suppression flag."""
+    handler = v3_system.handler
+    ws_bridge = v3_system.ws_bridge
+
+    assert not getattr(handler, "_is_pedalboard_loading", False)
+    ws_bridge.inject("loading_start 0")
+    handler.poll_ws_messages()
+    assert handler._is_pedalboard_loading is True
+
+
+def test_v3_set_current_pedalboard_clears_suppression(v3_system: SystemFixture, make_plugin):
+    """After set_current_pedalboard completes, suppression is cleared so normal operation resumes."""
+    handler = v3_system.handler
+    handler._is_pedalboard_loading = True
+    assert handler.current is not None
+
+    pb = handler.current.pedalboard
+    new_plugin = make_plugin("new_fuzz", category="Distortion", bypassed=False)
+    pb.plugins = [new_plugin]
+
+    handler.set_current_pedalboard(pb)
+
+    assert handler._is_pedalboard_loading is False