🚧 Web UI

src/wago_sim/cli.py

@@ -38,7 +38,7 @@ from pathlib import Path
 
 import yaml
 
-from .app import build_app
+from .app import WebUIConfig, build_app
 from .modules import ChannelMismatch, ModuleUnknown
 from .scenario.dsl import load_node_modules, load_yaml, validate_scenario
 from .scenario.engine import ScenarioEngine, ScenarioError
@@ -47,6 +47,49 @@ from .scenario.report import result_summary, write_csv, write_jsonl
 log = logging.getLogger("wago_sim.cli")
 
 
+async def start_webui(app, cfg: WebUIConfig):
+    """Start the web UI's Uvicorn server on the running event loop.
+
+    Runs on the same loop as the Modbus TCP server (spec §10.3) so UI
+    writes and Modbus requests never race on the datastore. The socket
+    is bound eagerly so 'port in use' surfaces as a clean CLI error.
+    """
+    import uvicorn
+
+    from .webui.app import build_webui
+
+    fastapi_app = build_webui(
+        app, user=cfg.user, password=cfg.password, readonly=cfg.readonly
+    )
+    # Bind eagerly: a taken port raises OSError here (clean CLI error)
+    # instead of failing asynchronously inside the uvicorn task.
+    try:
+        prebound = await asyncio.get_running_loop().create_server(
+            lambda: None, "0.0.0.0", cfg.port
+        )
+    except OSError as exc:
+        _fail(f"cannot bind web UI port {cfg.port}: {exc.strerror or exc}")
+    prebound.close()
+    await prebound.wait_closed()
+    config = uvicorn.Config(
+        fastapi_app, host="0.0.0.0", port=cfg.port, log_level="warning"
+    )
+    server = uvicorn.Server(config)
+    # serve() blocks; run it as a task so _serve keeps its stop-event wait
+    task = asyncio.create_task(server.serve())
+    # poll until the server reports started (or fails) so startup errors
+    # surface here as a clean CLI error
+    for _ in range(100):  # up to ~2 s
+        if server.started or task.done():
+            break
+        await asyncio.sleep(0.02)
+    if not server.started:
+        task.cancel()
+        _fail(f"web UI failed to start on port {cfg.port}")
+    server._serve_task = task  # keep a ref for graceful shutdown
+    return server
+
+
 def _build_logger(verbose: bool) -> None:
     # Stream logs unbuffered & single-line so they work in docker/systemd
     logging.basicConfig(
@@ -137,8 +180,23 @@ def _prepare_report_path(path: str, option: str) -> Path:
 async def _serve(args: argparse.Namespace) -> int:
     node_config = _load_yaml_file(args.node, "node config")
     modules = load_node_modules(node_config)
-    app = build_app(modules=modules, host=args.host, port=args.port)
+    web_cfg = None
+    if args.web:
+        web_cfg = WebUIConfig(
+            enabled=True,
+            port=args.web_port,
+            user=_env("WAGO_SIM_WEB_USER", "admin"),
+            password=_env("WAGO_SIM_WEB_PASSWORD", "simu"),
+            readonly=_env_flag("WAGO_SIM_WEB_READONLY"),
+        )
+    app = build_app(modules=modules, host=args.host, port=args.port, web=web_cfg,
+                    node_config_path=args.node)
     await app.server.start()
+    web_server = None
+    if web_cfg is not None:
+        web_server = await start_webui(app, web_cfg)
+        print(f"Web UI on http://{'127.0.0.1' if args.host == '0.0.0.0' else args.host}"
+              f":{web_cfg.port} (user: {web_cfg.user})")
     print(f"Simulating WAGO 750-362 with {len(modules)} modules "
           f"on {args.host}:{args.port} (Ctrl+C to stop)")
 
@@ -157,6 +215,14 @@ async def _serve(args: argparse.Namespace) -> int:
     except asyncio.CancelledError:
         pass  # SIGINT via asyncio.run's handler
     finally:
+        if web_server is not None:
+            task = getattr(web_server, "_serve_task", None)
+            web_server.should_exit = True
+            if task is not None:
+                try:
+                    await asyncio.wait_for(task, timeout=5.0)
+                except (asyncio.TimeoutError, asyncio.CancelledError):
+                    task.cancel()
         await app.server.stop()
     return 0
 
@@ -242,6 +308,16 @@ def main(argv: list[str] | None = None) -> int:
         "--port", type=_port_type, default=_env_port("WAGO_SIM_PORT", 502),
         help="listen port 1-65535 (or env: WAGO_SIM_PORT)",
     )
+    serve.add_argument(
+        "--web", action=argparse.BooleanOptionalAction,
+        default=not _env_flag("WAGO_SIM_NO_WEB"),
+        help="serve the web UI alongside Modbus (default: on; --no-web disables; "
+             "env WAGO_SIM_NO_WEB=1)",
+    )
+    serve.add_argument(
+        "--web-port", type=_port_type, default=_env_port("WAGO_SIM_WEB_PORT", 8080),
+        help="web UI port (or env: WAGO_SIM_WEB_PORT; default 8080)",
+    )
     serve.set_defaults(func=_serve)
 
     runp = sub.add_parser("run", help="run a scenario headless (no server)")