feat(isolation): execution engine integration for isolated workers

Wires isolation into ComfyUI's execution pipeline: child process startup
in main.py, isolated node dispatch in execution.py with boundary cleanup,
graph notification, quiescence waits, and RPC event loop coordination.
Integrates with master's try/finally and RAM pressure structures.

execution.py

@@ -1,7 +1,9 @@
 import copy
+import gc
 import heapq
 import inspect
 import logging
+import os
 import sys
 import threading
 import time
@@ -42,6 +44,8 @@ from comfy_api.internal import _ComfyNodeInternal, _NodeOutputInternal, first_re
 from comfy_api.latest import io, _io
 from comfy_execution.cache_provider import _has_cache_providers, _get_cache_providers, _logger as _cache_logger
 
+_AIMDO_VBAR_RESET_UNAVAILABLE_LOGGED = False
+
 
 class ExecutionResult(Enum):
     SUCCESS = 0
@@ -262,7 +266,18 @@ async def _async_map_node_over_list(prompt_id, unique_id, obj, input_data_all, f
                 pre_execute_cb(index)
             # V3
             if isinstance(obj, _ComfyNodeInternal) or (is_class(obj) and issubclass(obj, _ComfyNodeInternal)):
-                # if is just a class, then assign no state, just create clone
+                # Check for isolated node - skip validation and class cloning
+                if hasattr(obj, "_pyisolate_extension"):
+                    # Isolated Node: The stub is just a proxy; real validation happens in child process
+                    if v3_data is not None:
+                        inputs = _io.build_nested_inputs(inputs, v3_data)
+                        # Inject hidden inputs so they're available in the isolated child process
+                        inputs.update(v3_data.get("hidden_inputs", {}))
+                    f = getattr(obj, func)
+                # Standard V3 Node (Existing Logic)
+
+                else:
+                    # if is just a class, then assign no resources or state, just create clone
                     if is_class(obj):
                         type_obj = obj
                         obj.VALIDATE_CLASS()
@@ -537,7 +552,17 @@ async def execute(server, dynprompt, caches, current_item, extra_data, executed,
                     if args.verbose == "DEBUG":
                         comfy_aimdo.control.analyze()
                     comfy.model_management.reset_cast_buffers()
+                    vbar_lib = getattr(comfy_aimdo.model_vbar, "lib", None)
+                    if vbar_lib is not None:
                         comfy_aimdo.model_vbar.vbars_reset_watermark_limits()
+                    else:
+                        global _AIMDO_VBAR_RESET_UNAVAILABLE_LOGGED
+                        if not _AIMDO_VBAR_RESET_UNAVAILABLE_LOGGED:
+                            logging.warning(
+                                "DynamicVRAM backend unavailable for watermark reset; "
+                                "skipping vbar reset for this process."
+                            )
+                            _AIMDO_VBAR_RESET_UNAVAILABLE_LOGGED = True
 
             if has_pending_tasks:
                 pending_async_nodes[unique_id] = output_data
@@ -546,6 +571,14 @@ async def execute(server, dynprompt, caches, current_item, extra_data, executed,
                     tasks = [x for x in output_data if isinstance(x, asyncio.Task)]
                     await asyncio.gather(*tasks, return_exceptions=True)
                     unblock()
+
+                # Keep isolation node execution deterministic by default, but allow
+                # opt-out for diagnostics.
+                isolation_sequential = os.environ.get("COMFY_ISOLATE_SEQUENTIAL", "1").lower() in ("1", "true", "yes")
+                if args.use_process_isolation and isolation_sequential:
+                    await await_completion()
+                    return await execute(server, dynprompt, caches, current_item, extra_data, executed, prompt_id, execution_list, pending_subgraph_results, pending_async_nodes, ui_outputs)
+
                 asyncio.create_task(await_completion())
                 return (ExecutionResult.PENDING, None, None)
         if len(output_ui) > 0:
@@ -657,6 +690,46 @@ class PromptExecutor:
         self.status_messages = []
         self.success = True
 
+    async def _notify_execution_graph_safe(self, class_types: set[str], *, fail_loud: bool = False) -> None:
+        if not args.use_process_isolation:
+            return
+        try:
+            from comfy.isolation import notify_execution_graph
+            await notify_execution_graph(class_types, caches=self.caches.all)
+        except Exception:
+            if fail_loud:
+                raise
+            logging.debug("][ EX:notify_execution_graph failed", exc_info=True)
+
+    async def _flush_running_extensions_transport_state_safe(self) -> None:
+        if not args.use_process_isolation:
+            return
+        try:
+            from comfy.isolation import flush_running_extensions_transport_state
+            await flush_running_extensions_transport_state()
+        except Exception:
+            logging.debug("][ EX:flush_running_extensions_transport_state failed", exc_info=True)
+
+    async def _wait_model_patcher_quiescence_safe(
+        self,
+        *,
+        fail_loud: bool = False,
+        timeout_ms: int = 120000,
+        marker: str = "EX:wait_model_patcher_idle",
+    ) -> None:
+        if not args.use_process_isolation:
+            return
+        try:
+            from comfy.isolation import wait_for_model_patcher_quiescence
+
+            await wait_for_model_patcher_quiescence(
+                timeout_ms=timeout_ms, fail_loud=fail_loud, marker=marker
+            )
+        except Exception:
+            if fail_loud:
+                raise
+            logging.debug("][ EX:wait_model_patcher_quiescence failed", exc_info=True)
+
     def add_message(self, event, data: dict, broadcast: bool):
         data = {
             **data,
@@ -711,6 +784,18 @@ class PromptExecutor:
         asyncio.run(self.execute_async(prompt, prompt_id, extra_data, execute_outputs))
 
     async def execute_async(self, prompt, prompt_id, extra_data={}, execute_outputs=[]):
+        if args.use_process_isolation:
+            # Update RPC event loops for all isolated extensions.
+            # This is critical for serial workflow execution - each asyncio.run() creates
+            # a new event loop, and RPC instances must be updated to use it.
+            try:
+                from comfy.isolation import update_rpc_event_loops
+                update_rpc_event_loops()
+            except ImportError:
+                pass  # Isolation not available
+            except Exception as e:
+                logging.getLogger(__name__).warning(f"Failed to update RPC event loops: {e}")
+
         set_preview_method(extra_data.get("preview_method"))
 
         nodes.interrupt_processing(False)
@@ -723,6 +808,25 @@ class PromptExecutor:
         self.status_messages = []
         self.add_message("execution_start", { "prompt_id": prompt_id}, broadcast=False)
 
+        if args.use_process_isolation:
+            try:
+                # Boundary cleanup runs at the start of the next workflow in
+                # isolation mode, matching non-isolated "next prompt" timing.
+                self.caches = CacheSet(cache_type=self.cache_type, cache_args=self.cache_args)
+                await self._wait_model_patcher_quiescence_safe(
+                    fail_loud=False,
+                    timeout_ms=120000,
+                    marker="EX:boundary_cleanup_wait_idle",
+                )
+                await self._flush_running_extensions_transport_state_safe()
+                comfy.model_management.unload_all_models()
+                comfy.model_management.cleanup_models_gc()
+                comfy.model_management.cleanup_models()
+                gc.collect()
+                comfy.model_management.soft_empty_cache()
+            except Exception:
+                logging.debug("][ EX:isolation_boundary_cleanup_start failed", exc_info=True)
+
         self._notify_prompt_lifecycle("start", prompt_id)
         ram_headroom = int(self.cache_args["ram"] * (1024 ** 3))
         ram_release_callback = self.caches.outputs.ram_release if self.cache_type == CacheType.RAM_PRESSURE else None
@@ -760,6 +864,18 @@ class PromptExecutor:
                 for node_id in list(execute_outputs):
                     execution_list.add_node(node_id)
 
+                if args.use_process_isolation:
+                    pending_class_types = set()
+                    for node_id in execution_list.pendingNodes.keys():
+                        class_type = dynamic_prompt.get_node(node_id)["class_type"]
+                        pending_class_types.add(class_type)
+                    await self._wait_model_patcher_quiescence_safe(
+                        fail_loud=True,
+                        timeout_ms=120000,
+                        marker="EX:notify_graph_wait_idle",
+                    )
+                    await self._notify_execution_graph_safe(pending_class_types, fail_loud=True)
+
                 while not execution_list.is_empty():
                     node_id, error, ex = await execution_list.stage_node_execution()
                     if error is not None:

main.py

@@ -1,7 +1,21 @@
+import os
+import sys
+
+IS_PYISOLATE_CHILD = os.environ.get("PYISOLATE_CHILD") == "1"
+
+if __name__ == "__main__" and IS_PYISOLATE_CHILD:
+    del os.environ["PYISOLATE_CHILD"]
+    IS_PYISOLATE_CHILD = False
+
+CURRENT_DIR = os.path.dirname(os.path.realpath(__file__))
+if CURRENT_DIR not in sys.path:
+    sys.path.insert(0, CURRENT_DIR)
+
+IS_PRIMARY_PROCESS = (not IS_PYISOLATE_CHILD) and __name__ == "__main__"
+
 import comfy.options
 comfy.options.enable_args_parsing()
 
-import os
 import importlib.util
 import shutil
 import importlib.metadata
@@ -12,7 +26,7 @@ from app.logger import setup_logger
 from app.assets.seeder import asset_seeder
 from app.assets.services import register_output_files
 import itertools
-import utils.extra_config
+import utils.extra_config  # noqa: F401
 from utils.mime_types import init_mime_types
 import faulthandler
 import logging
@@ -22,11 +36,44 @@ from comfy_execution.utils import get_executing_context
 from comfy_api import feature_flags
 from app.database.db import init_db, dependencies_available
 
-if __name__ == "__main__":
+import comfy_aimdo.control
-    #NOTE: These do not do anything on core ComfyUI, they are for custom nodes.
+
+if enables_dynamic_vram():
+    if not comfy_aimdo.control.init():
+        logging.warning(
+            "DynamicVRAM requested, but comfy-aimdo failed to initialize early. "
+            "Will fall back to legacy model loading if device init fails."
+        )
+
+if '--use-process-isolation' in sys.argv:
+    from comfy.isolation import initialize_proxies
+    initialize_proxies()
+
+    # Explicitly register the ComfyUI adapter for pyisolate (v1.0 architecture)
+    try:
+        import pyisolate
+        from comfy.isolation.adapter import ComfyUIAdapter
+        pyisolate.register_adapter(ComfyUIAdapter())
+        logging.info("PyIsolate adapter registered: comfyui")
+    except ImportError:
+        logging.warning("PyIsolate not installed or version too old for explicit registration")
+    except Exception as e:
+        logging.error(f"Failed to register PyIsolate adapter: {e}")
+
+    if not IS_PYISOLATE_CHILD:
+        if 'PYTORCH_CUDA_ALLOC_CONF' not in os.environ:
+            os.environ['PYTORCH_CUDA_ALLOC_CONF'] = 'backend:native'
+
+if not IS_PYISOLATE_CHILD:
+    from comfy_execution.progress import get_progress_state
+    from comfy_execution.utils import get_executing_context
+    from comfy_api import feature_flags
+
+if IS_PRIMARY_PROCESS:
     os.environ['HF_HUB_DISABLE_TELEMETRY'] = '1'
     os.environ['DO_NOT_TRACK'] = '1'
 
+if not IS_PYISOLATE_CHILD:
     setup_logger(log_level=args.verbose, use_stdout=args.log_stdout)
 
 faulthandler.enable(file=sys.stderr, all_threads=False)
@@ -93,14 +140,15 @@ if args.enable_manager:
 
 
 def apply_custom_paths():
+    from utils import extra_config  # Deferred import - spawn re-runs main.py
     # extra model paths
     extra_model_paths_config_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), "extra_model_paths.yaml")
     if os.path.isfile(extra_model_paths_config_path):
-        utils.extra_config.load_extra_path_config(extra_model_paths_config_path)
+        extra_config.load_extra_path_config(extra_model_paths_config_path)
 
     if args.extra_model_paths_config:
         for config_path in itertools.chain(*args.extra_model_paths_config):
-            utils.extra_config.load_extra_path_config(config_path)
+            extra_config.load_extra_path_config(config_path)
 
     # --output-directory, --input-directory, --user-directory
     if args.output_directory:
@@ -175,12 +223,14 @@ def execute_prestartup_script():
             logging.info("{:6.1f} seconds{}: {}".format(n[0], import_message, n[1]))
     logging.info("")
 
+if not IS_PYISOLATE_CHILD:
     apply_custom_paths()
     init_mime_types()
 
-if args.enable_manager:
+if args.enable_manager and not IS_PYISOLATE_CHILD:
     comfyui_manager.prestartup()
 
+if not IS_PYISOLATE_CHILD:
     execute_prestartup_script()
 
 
@@ -192,9 +242,9 @@ import gc
 if 'torch' in sys.modules:
     logging.warning("WARNING: Potential Error in code: Torch already imported, torch should never be imported before this point.")
 
-
 import comfy.utils
 
+if not IS_PYISOLATE_CHILD:
     import execution
     import server
     from protocol import BinaryEventTypes
@@ -462,6 +512,10 @@ def start_comfyui(asyncio_loop=None):
         asyncio.set_event_loop(asyncio_loop)
     prompt_server = server.PromptServer(asyncio_loop)
 
+    if args.use_process_isolation:
+        from comfy.isolation import start_isolation_loading_early
+        start_isolation_loading_early(asyncio_loop)
+
     if args.enable_manager and not args.disable_manager_ui:
         comfyui_manager.start()
 
@@ -506,6 +560,7 @@ def start_comfyui(asyncio_loop=None):
 if __name__ == "__main__":
     # Running directly, just start ComfyUI.
     logging.info("Python version: {}".format(sys.version))
+    if not IS_PYISOLATE_CHILD:
         logging.info("ComfyUI version: {}".format(comfyui_version.__version__))
         for package in ("comfy-aimdo", "comfy-kitchen"):
             try: