emrg: daemon single-instance via fixed-port bind exclusivity (rant 2026-08-19T08:05:21)

Agent.md

@@ -118,7 +118,7 @@ Community needs voiced in HN agent-UI discussions map directly to EMRG's design:
 pkill -f "emrg.server"; rm -f ~/.emrg/emrgd.port; python -m emrg
 ```
 
-Python: `uv run pytest tests/ -v` (963) — import check: `uv run python -c "from emrg.client.app import run_client"`
+Python: `uv run pytest tests/ -v` (967) — import check: `uv run python -c "from emrg.client.app import run_client"`
 GUI: `cd emrg/gui && npm test` (260: 45 daemon_client + 19 conn-manager + 22 app-commands + 131 renderer smoke + 16 i18n + 7 integration + 3 commands + 8 build-config + 7 gui-state + 2 tool-group) — syntax: `node --check main.js preload.js daemon_client.js renderer/js/*.js`
 CI: `uv run pytest` (ubuntu + **windows-2025 matrix** — Windows pytest 回归在 PR CI 即失败，v0.2.29 教训 #725) + GUI tests + **actionlint workflow lint** (`rhysd/actionlint@v1.7.12` gate, #444 — workflow 解析错误在 PR CI 即失败，如 `if:` secrets 上下文)
 Re-trigger: `scripts/re-trigger-ci.sh [branch]` (workflow_dispatch, #527 — 替代空 commit 重触发：Actions outage 会整段丢弃 push 事件，dispatch 走 API 路径不受影响)

emrg/_stop_all.py

@@ -58,7 +58,13 @@
 
 # Build stamp printed at the start of every run so the operator can tell at a
 # glance which stop_all.py generation executed (rant 2026-08-17T21:06:31).
-_STOP_ALL_STAMP = "built 2026-08-18 (module-holder enumeration + createfile-probe + taskkill RM + excluded-chain self-exclusion + self-lock guard)"
+_STOP_ALL_STAMP = "built 2026-08-19 (fixed-port daemon shutdown — rant 08:05:21)"
+
+# Fixed daemon port (host rant 2026-08-19T08:05:21): the daemon binds a fixed
+# loopback port as its single-instance admission. This module is pure stdlib
+# (runs standalone inside the installer) so it cannot import emrg.connect —
+# keep in sync with emrg.connect.EMRGD_PORT.
+_EMRGD_PORT = 56031
 
 _EMRG_CLIENT_RE = re.compile(r"-m\s+emrg(\.server)?(\s|$)")
 _APPIMAGE_RE = re.compile(r"EMRG-[\w.\-]*AppImage(\s|$)")
@@ -328,20 +334,23 @@ def stop_daemon() -> None:
  cannot, so we clean it up — the next daemon start re-asserts both files).
  """
  port_path = config_dir() / "emrgd.port"
+ # Fixed-port shutdown (rant 2026-08-19T08:05:21): the daemon always
+ # listens on _EMRGD_PORT; the port file only supplies the auth token. If
+ # the file is missing/stale, fall through to the pid + cmdline paths.
  try:
- port_tok = port_path.read_text(encoding="utf-8").split()
- if len(port_tok) == 2:
- if ws_graceful_shutdown(int(port_tok[0]), port_tok[1]):
- # wait for the daemon to exit + remove its pid file
- # (~10s grace: old stop-emrg.cmd v2 polled emrgd.pid up to
- # 10s; a busy daemon mid-tool-loop needs the full window)
- for _ in range(60):
- pid = _read_pid_file()
- if pid is None or not _pid_alive(pid):
- break
- time.sleep(0.15)
+ text = port_path.read_text(encoding="utf-8").split()
+ token = text[1] if len(text) == 2 else ""
  except (OSError, ValueError):
- pass # port file missing/corrupt → fall through to pid path
+ token = ""
+ if token and ws_graceful_shutdown(_EMRGD_PORT, token):
+ # wait for the daemon to exit + remove its pid file
+ # (~10s grace: old stop-emrg.cmd v2 polled emrgd.pid up to
+ # 10s; a busy daemon mid-tool-loop needs the full window)
+ for _ in range(60):
+ pid = _read_pid_file()
+ if pid is None or not _pid_alive(pid):
+ break
+ time.sleep(0.15)
 
  pid = _read_pid_file()
  if pid is not None and _pid_alive(pid):

emrg/connect.py

@@ -6,8 +6,12 @@
  ws://127.0.0.1:<port> (local, all platforms)
  wss://<host>:<port> (remote, Phase 5 — same protocol + TLS + token)
 
-The daemon writes its dynamic port and auth token to ``~/.emrg/emrgd.port``
-(``port\\n token``, mode 0o600). Clients read that file, connect, and send
+The daemon listens on the fixed port ``127.0.0.1:EMRGD_PORT`` (56031, rant
+2026-08-19T08:05:21 — fixed-port bind exclusivity is the single-instance
+admission) and writes its auth token to ``~/.emrg/emrgd.port``
+(``port\\n token``, mode 0o600). Clients read that file for the token, and
+connect to the fixed port.
+Clients then send
 a first-frame auth message; the daemon confirms with ``auth_ok`` before the
 normal protocol loop. Auth failure raises :class:`AuthError` so callers can
 distinguish it from a transient disconnect (which should be retried).
@@ -32,6 +36,13 @@
 # Port/token file lives at ~/.emrg/emrgd.port (port\n token, mode 0o600)
 CONNECT_ID = "emrgd"
 
+# Fixed daemon port (host rant 2026-08-19T08:05:21): the daemon binds a FIXED
+# loopback port so kernel-level bind exclusivity (EADDRINUSE) is the single-
+# instance admission — no PID file to forge/delete, no race window. The port
+# file still carries the auth token; the port itself is now a constant.
+# Keep in sync with emrg._stop_all._EMRGD_PORT (that module is pure stdlib).
+EMRGD_PORT = 56031
+
 
 class AuthError(Exception):
  """Raised when the daemon rejects the auth handshake.
@@ -49,17 +60,19 @@ def get_server_path() -> str:
 async def connect_to_server():
  """Connect to the emrgd server over WebSocket.
 
- Reads ``~/.emrg/emrgd.port``, connects to ``ws://127.0.0.1:<port>``,
- sends the first-frame auth message and waits for the ``auth_ok``
- confirmation. Returns the connected WebSocket object (single ws — no
+ Reads the auth token from ``~/.emrg/emrgd.port``, connects to the FIXED
+ daemon port ``ws://127.0.0.1:<EMRGD_PORT>`` (rant 2026-08-19T08:05:21 —
+ the port is a constant; the file only carries the token), sends the
+ first-frame auth message and waits for the ``auth_ok`` confirmation.
+ Returns the connected WebSocket object (single ws — no
  ``(reader, writer)`` tuple anymore).
 
  Raises:
  AuthError: auth rejected (bad/missing token, or daemon version mismatch).
  ConnectionRefusedError / OSError / FileNotFoundError: daemon not running.
  """
  port_path = Path(get_server_path())
-port, token = port_path.read_text(encoding="utf-8").split()
+_, token = port_path.read_text(encoding="utf-8").split()
  # proxy=None: loopback connections must never go through a system proxy.
  # websockets 17 defaults proxy=True and reads the OS proxy settings — when a
  # Windows system proxy is enabled (e.g. 10.10.0.28:6501 for HN/Reddit access),
@@ -68,7 +81,7 @@ async def connect_to_server():
  # local daemon, while the Node.js GUI is unaffected (2026-08-14 incident; root
  # cause of continuous emrg-task/emrg-promote-task crashes since 2026-08-13).
  ws = await connect(
- f"ws://127.0.0.1:{port}",
+ f"ws://127.0.0.1:{EMRGD_PORT}",
  proxy=None,
  max_size=16 * 1024 * 1024,
  )
@@ -97,18 +110,15 @@ def cleanup_server() -> None:
 def is_server_running_sync(timeout: float = 2.0) -> bool:
  """Synchronous health-check probe (for client startup).
 
- Uses blocking TCP connect to the port in ``emrgd.port``. Reads only the
- first line (port), never the token — this is a low-cost liveness probe;
- real auth happens on the first frame of a real connection.
+ Blocking TCP connect to the FIXED daemon port ``127.0.0.1:EMRGD_PORT``
+ (rant 2026-08-19T08:05:21). No port-file read: the fixed port is the
+ ground truth, so a missing/stale ``emrgd.port`` never makes the probe
+ report "not running" while a daemon is actually alive (the dual-instance
+ root cause). Real auth happens on the first frame of a real connection.
  """
- port_path = Path(get_server_path())
- try:
- port = int(port_path.read_text(encoding="utf-8").splitlines()[0])
- except (OSError, ValueError, IndexError):
- return False
  sock = None
  try:
- sock = _socket.create_connection(("127.0.0.1", port), timeout=timeout)
+ sock = _socket.create_connection(("127.0.0.1", EMRGD_PORT), timeout=timeout)
  return True
  except (ConnectionRefusedError, OSError):
  return False