1 files changed, 244 insertions, 0 deletions
diff --git a/app/backends/servers.py b/app/backends/servers.py
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+++ b/app/backends/servers.py
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+"""Start and stop TTS backend servers from the TUI hub.
+
+Each backend's ``detect()`` returns a list of ``ServerSpec`` — the exact argv
+(absolute binaries in the managed venv, no shell activation needed) and the
+URL to probe for readiness. This module turns those specs into running
+processes: ``start`` spawns the server, streams its output to
+``app/logs/<name>-server.log``, records its pid, and polls the URL until it
+accepts connections (model loads are slow, so the timeout is generous);
+``stop`` terminates the process group the hub started.
+
+Everything here runs in the plain console tail after the curses TUI returns
+(matching the wizards' build/pip streaming), so progress and log tails appear
+normally. Pid/log files live under ``app/logs/`` which is already gitignored.
+"""
+
+import os
+import signal
+import subprocess
+import sys
+import time
+from pathlib import Path
+from typing import List
+
+from backends import common
+from backends.common import APP_DIR
+
+LOG_DIR = APP_DIR / "logs"
+
+# How long to wait for a server to accept connections on its URL. First-time
+# model loads (especially qwen-tts / faster-qwen3-tts pulling weights into
+# VRAM) can take minutes, so this is deliberately generous.
+SERVER_START_TIMEOUT = 600
+
+# Grace period after SIGTERM before escalating to SIGKILL (POSIX).
+STOP_GRACE_SECONDS = 10
+
+
+def _log_path(name: str) -> Path:
+    return LOG_DIR / f"{name}-server.log"
+
+
+def _pid_path(name: str) -> Path:
+    return LOG_DIR / f"{name}-server.pid"
+
+
+def _tail_log(name: str, lines: int = 20) -> None:
+    """Print the last LINES of the server's log (best-effort)."""
+    path = _log_path(name)
+    try:
+        text = path.read_text(encoding="utf-8", errors="replace")
+    except OSError:
+        return
+    tail = "\n".join(text.splitlines()[-lines:])
+    if tail:
+        print(f"--- last {lines} lines of {path} ---")
+        print(tail)
+        print("---")
+
+
+def _pid_alive(pid: int) -> bool:
+    """True when a process with PID is still running (POSIX signal-0 probe)."""
+    if sys.platform == "win32":
+        try:
+            import ctypes
+            kernel32 = ctypes.windll.kernel32  # type: ignore[attr-defined]
+            PROCESS_QUERY_LIMITED_INFORMATION = 0x1000
+            handle = kernel32.OpenProcess(
+                PROCESS_QUERY_LIMITED_INFORMATION, False, pid)
+            if not handle:
+                return False
+            kernel32.CloseHandle(handle)
+            return True
+        except OSError:
+            return False
+    try:
+        os.kill(pid, 0)
+    except ProcessLookupError:
+        return False
+    except PermissionError:
+        return True
+    return True
+
+
+def _kill_pid(pid: int) -> bool:
+    """Terminate PID (and its process group on POSIX). Returns True when dead."""
+    if sys.platform == "win32":
+        try:
+            os.kill(pid, signal.SIGTERM)
+        except (ProcessLookupError, PermissionError, OSError):
+            return not _pid_alive(pid)
+        for _ in range(int(STOP_GRACE_SECONDS * 10)):
+            if not _pid_alive(pid):
+                return True
+            time.sleep(0.1)
+        try:
+            os.kill(pid, signal.SIGTERM)
+        except OSError:
+            pass
+        return not _pid_alive(pid)
+    # POSIX: kill the whole process group (started with start_new_session=True).
+    try:
+        pgid = os.getpgid(pid)
+    except ProcessLookupError:
+        return True
+    try:
+        os.killpg(pgid, signal.SIGTERM)
+    except ProcessLookupError:
+        return True
+    except PermissionError:
+        return False
+    for _ in range(int(STOP_GRACE_SECONDS * 10)):
+        try:
+            os.killpg(pgid, 0)
+        except ProcessLookupError:
+            return True
+        except PermissionError:
+            return False
+        time.sleep(0.1)
+    try:
+        os.killpg(pgid, signal.SIGKILL)
+    except (ProcessLookupError, PermissionError):
+        pass
+    return True
+
+
+def start(spec) -> bool:
+    """Start the server described by SPEC (a ``backends.ServerSpec``).
+
+    Spawns its argv with stdout/stderr to ``logs/<name>-server.log``, records
+    the pid, and polls ``common.server_running(spec.url)`` until it accepts
+    connections or ``SERVER_START_TIMEOUT`` elapses. Returns True when the
+    server is up; on timeout or early exit, prints the log tail and returns
+    False. A no-op (True) when the server is already running.
+    """
+    argv: List[str] = list(spec.argv)
+    exe = Path(argv[0])
+    if not exe.exists():
+        print(f"[ERROR] server executable not found: {exe}")
+        print("        run 'Set up a backend' for "
+              f"{spec.name!r} first.")
+        return False
+    if common.server_running(spec.url):
+        print(f"[INFO] {spec.name} server already running on {spec.url}")
+        return True
+
+    LOG_DIR.mkdir(parents=True, exist_ok=True)
+    pid_file = _pid_path(spec.name)
+    if pid_file.exists():
+        try:
+            pid_file.unlink()
+        except OSError:
+            pass
+
+    print(f"[INFO] starting {spec.name} server: "
+          + " ".join(str(a) for a in argv))
+    log_handle = _log_path(spec.name).open("w", encoding="utf-8")
+    popen_kwargs = {"stdout": log_handle, "stderr": subprocess.STDOUT}
+    if sys.platform == "win32":
+        popen_kwargs["creationflags"] = \
+            subprocess.CREATE_NEW_PROCESS_GROUP  # type: ignore[attr-defined]
+    else:
+        popen_kwargs["start_new_session"] = True
+    try:
+        proc = subprocess.Popen(argv, **popen_kwargs)
+    except OSError as exc:
+        print(f"[ERROR] could not start server: {exc}")
+        log_handle.close()
+        return False
+
+    pid_file.write_text(str(proc.pid), encoding="utf-8")
+    print(f"[INFO] pid {proc.pid}; logs: {_log_path(spec.name)}")
+
+    deadline = time.time() + SERVER_START_TIMEOUT
+    while time.time() < deadline:
+        if proc.poll() is not None:
+            print(f"[ERROR] {spec.name} server exited with code "
+                  f"{proc.returncode}")
+            _tail_log(spec.name)
+            try:
+                pid_file.unlink()
+            except OSError:
+                pass
+            return False
+        if common.server_running(spec.url):
+            print(f"[OK] {spec.name} server is up on {spec.url}")
+            return True
+        time.sleep(1)
+    print(f"[ERROR] {spec.name} server did not start within "
+          f"{SERVER_START_TIMEOUT}s")
+    _tail_log(spec.name)
+    # Leave the pid file in place so stop() can kill it (it may still load).
+    return False
+
+
+def stop(name: str) -> bool:
+    """Stop a server previously started by ``start`` (identified by pid file).
+
+    Returns True when the process was terminated (or already gone). Returns
+    False when there is no pid file — the server was not started by this tool,
+    so the user must stop it manually (e.g. close its terminal).
+    """
+    pid_file = _pid_path(name)
+    if not pid_file.exists():
+        print(f"[INFO] no pid file for '{name}' "
+              "(not started by this tool — stop it manually)")
+        return False
+    try:
+        pid = int(pid_file.read_text(encoding="utf-8").strip())
+    except (OSError, ValueError):
+        print(f"[WARNING] could not read pid file {pid_file}; removing it")
+        try:
+            pid_file.unlink()
+        except OSError:
+            pass
+        return False
+    if not _pid_alive(pid):
+        print(f"[INFO] {name} server (pid {pid}) already stopped")
+        try:
+            pid_file.unlink()
+        except OSError:
+            pass
+        return True
+    print(f"[INFO] stopping {name} server (pid {pid})...")
+    killed = _kill_pid(pid)
+    if killed:
+        print(f"[OK] {name} server stopped")
+    else:
+        print(f"[WARNING] could not stop pid {pid}; stop it manually")
+    try:
+        pid_file.unlink()
+    except OSError:
+        pass
+    return killed
+
+
+def pid_for(name: str):
+    """Return the recorded pid for NAME, or None when no pid file exists."""
+    pid_file = _pid_path(name)
+    if not pid_file.exists():
+        return None
+    try:
+        return int(pid_file.read_text(encoding="utf-8").strip())
+    except (OSError, ValueError):
+        return None