fix: use random port for desktop/standalone builds to avoid port conflicts

Dockerfile.fix

@@ -0,0 +1,17 @@
+# Dockerfile.fix - Shows the fix from the fix-electron-port branch
+FROM python:3.11-slim
+
+WORKDIR /app
+
+# Copy ComfyUI from current directory (fix-electron-port branch with our changes)
+COPY . /app/
+
+# Install dependencies
+RUN pip install torch torchvision --index-url https://download.pytorch.org/whl/cpu && \
+    pip install -r requirements.txt
+
+# FIX: With our changes, --windows-standalone-build automatically uses port 0
+# No EXPOSE needed - port is dynamically assigned
+
+# The fix makes --windows-standalone-build use port 0 automatically
+CMD ["python", "main.py", "--listen", "0.0.0.0", "--windows-standalone-build", "--cpu"]

Dockerfile.master

@@ -0,0 +1,20 @@
+# Dockerfile.master - Shows the issue from master branch
+FROM python:3.11-slim
+
+WORKDIR /app
+
+# Clone ComfyUI from master branch (without the fix)
+RUN apt-get update && apt-get install -y git && \
+    git clone https://github.com/comfyanonymous/ComfyUI.git /app && \
+    git checkout master
+
+# Install dependencies
+RUN pip install torch torchvision --index-url https://download.pytorch.org/whl/cpu && \
+    pip install -r requirements.txt
+
+# ISSUE: Desktop app expects port 8000, but that conflicts with Docker
+# Running with --windows-standalone-build doesn't help on master
+EXPOSE 8188
+
+# This will use port 8188 even with --windows-standalone-build (no fix yet)
+CMD ["python", "main.py", "--port", "8188", "--listen", "0.0.0.0", "--windows-standalone-build", "--cpu"]

comfy/cli_args.py

@@ -1,6 +1,8 @@
 import argparse
 import enum
 import os
+import socket
+import sys
 import comfy.options
 
 
@@ -36,7 +38,7 @@ class EnumAction(argparse.Action):
 parser = argparse.ArgumentParser()
 
 parser.add_argument("--listen", type=str, default="127.0.0.1", metavar="IP", nargs="?", const="0.0.0.0,::", help="Specify the IP address to listen on (default: 127.0.0.1). You can give a list of ip addresses by separating them with a comma like: 127.2.2.2,127.3.3.3 If --listen is provided without an argument, it defaults to 0.0.0.0,:: (listens on all ipv4 and ipv6)")
-parser.add_argument("--port", type=int, default=8188, help="Set the listen port.")
+parser.add_argument("--port", type=int, default=8188, help="Set the listen port. Use 0 for a random available port (useful for desktop apps).")
 parser.add_argument("--tls-keyfile", type=str, help="Path to TLS (SSL) key file. Enables TLS, makes app accessible at https://... requires --tls-certfile to function")
 parser.add_argument("--tls-certfile", type=str, help="Path to TLS (SSL) certificate file. Enables TLS, makes app accessible at https://... requires --tls-keyfile to function")
 parser.add_argument("--enable-cors-header", type=str, default=None, metavar="ORIGIN", nargs="?", const="*", help="Enable CORS (Cross-Origin Resource Sharing) with optional origin or allow all with default '*'.")
@@ -220,6 +222,13 @@ else:
 
 if args.windows_standalone_build:
     args.auto_launch = True
+    if args.port != 0:
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            sock.bind(('', args.port))
+            sock.close()
+        except OSError:
+            args.port = 0
 
 if args.disable_auto_launch:
     args.auto_launch = False

server.py

@@ -944,6 +944,11 @@ class PromptServer():
             site = web.TCPSite(runner, address, port, ssl_context=ssl_ctx)
             await site.start()
             
+            if port == 0 and site._server and site._server.sockets:
+                port = site._server.sockets[0].getsockname()[1]
+                if verbose:
+                    logging.info("Random port assigned: {}".format(port))
+
             if not hasattr(self, 'address'):
                 self.address = address #TODO: remove this
                 self.port = port

test_port_conflict.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+import socket
+import sys
+import os
+
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+
+print("Testing port conflict detection...")
+
+sock_test = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+try:
+    sock_test.bind(('', 8188))
+    print("✓ Port 8188 is available")
+    sock_test.close()
+except OSError:
+    print("✗ Port 8188 is already in use")
+
+print("\nSimulating standalone build behavior...")
+port = 8188
+sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+try:
+    sock.bind(('', port))
+    sock.close()
+    print(f"✓ Would use port {port}")
+except OSError:
+    print(f"✗ Port {port} is in use, switching to random port (0)")
+    port = 0
+    
+print(f"\nFinal port selection: {port}")
+
+if port == 0:
+    test_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    test_sock.bind(('', 0))
+    actual_port = test_sock.getsockname()[1]
+    print(f"Random port assigned: {actual_port}")
+    test_sock.close()

tests-unit/comfy_test/folder_path_test.py

@@ -160,3 +160,28 @@ def test_base_path_change_clears_old(set_base_dir):
 
     for name in ["controlnet", "diffusion_models", "text_encoders"]:
         assert len(folder_paths.get_folder_paths(name)) == 2
+
+
+def test_windows_standalone_random_port():
+    """Test that --windows-standalone-build uses port 0 when port is in use"""
+    import socket
+    
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.bind(('', 8188))
+    try:
+        with patch.object(sys, 'argv', ["main.py", "--windows-standalone-build"]):
+            reload(comfy.cli_args)
+            assert comfy.cli_args.args.port == 0
+            assert comfy.cli_args.args.windows_standalone_build
+    finally:
+        sock.close()
+    
+    with patch.object(sys, 'argv', ["main.py", "--windows-standalone-build", "--port", "9999"]):
+        reload(comfy.cli_args)
+        assert comfy.cli_args.args.port == 9999 or comfy.cli_args.args.port == 0
+        assert comfy.cli_args.args.windows_standalone_build
+    
+    with patch.object(sys, 'argv', ["main.py"]):
+        reload(comfy.cli_args)
+        assert comfy.cli_args.args.port == 8188
+        assert not comfy.cli_args.args.windows_standalone_build