Rework windows start and stop methods so that command windows dont appear. Stop with signal since we cannot signint.

extensions_built_in/captioner/BaseCaptioner.py

@@ -274,26 +274,21 @@ class BaseCaptioner(BaseExtensionProcess):
         while True:
             try:
                 if self.should_stop():
-                    # Mark and update status (non-blocking; uses existing infra)
+                    if self.is_stopping:
-                    self.is_stopping = True
+                        # maybe_stop() already started the graceful shutdown;
-                    self._run_async_operation(
+                        # a second interrupt would only break its cleanup.
-                        self._update_status("stopped", "Job stopped (remote)")
+                        return
-                    )
-                    # Best-effort flush pending async ops
-                    try:
-                        asyncio.run(self.wait_for_all_async())
-                    except RuntimeError:
-                        pass
-                    # Try to stop DB thread pool quickly
-                    try:
-                        self.thread_pool.shutdown(wait=False, cancel_futures=True)
-                    except TypeError:
-                        self.thread_pool.shutdown(wait=False)
                     print("")
                     print("****************************************************")
                     print("    Stop signal received; terminating process.      ")
                     print("****************************************************")
-                    os.kill(os.getpid(), signal.SIGINT)
+                    # Deliver a real KeyboardInterrupt to the main thread so
+                    # on_error runs the normal shutdown (final DB write, last
+                    # log). os.kill(pid, SIGINT) must not be used here: on
+                    # Windows it is TerminateProcess and kills us instantly.
+                    # Leave the thread pool alone -- on_error still needs it.
+                    signal.raise_signal(signal.SIGINT)
+                    return
                 time.sleep(interval_sec)
             except Exception:
                 time.sleep(interval_sec)
@@ -455,7 +450,11 @@ class BaseCaptioner(BaseExtensionProcess):
         super(BaseCaptioner, self).on_error(e)
         if self.is_ui_captioner:
             try:
-                if not self.is_stopping:
+                if isinstance(e, KeyboardInterrupt):
+                    # SIGINT (UI stop button or ctrl+c) is a stop, not an error
+                    self.is_stopping = True
+                    self.update_status("stopped", "Job stopped")
+                elif not self.is_stopping:
                     self.update_status("error", str(e))
                 asyncio.run(self.wait_for_all_async())
             except Exception as db_err:

extensions_built_in/sd_trainer/DiffusionTrainer.py

@@ -39,7 +39,12 @@ class DiffusionTrainer(SDTrainer):
             # Initialize the status
             self._run_async_operation(self._update_status("running", "Starting"))
             self._stop_watcher_started = False
-            # self.start_stop_watcher(interval_sec=2.0)
+            if os.name == "nt":
+                # On Windows the stop route cannot send us SIGINT from outside
+                # (no console to deliver a Ctrl+C to), so watch the stop flag
+                # and raise the interrupt from inside. On Linux the route
+                # sends a real SIGINT to the pid and this is unnecessary.
+                self.start_stop_watcher(interval_sec=2.0)
     
     def start_stop_watcher(self, interval_sec: float = 5.0):
         """
@@ -60,26 +65,21 @@ class DiffusionTrainer(SDTrainer):
         while True:
             try:
                 if self.should_stop():
-                    # Mark and update status (non-blocking; uses existing infra)
+                    if self.is_stopping:
-                    self.is_stopping = True
+                        # maybe_stop() already started the graceful shutdown;
-                    self._run_async_operation(
+                        # a second interrupt would only break its cleanup.
-                        self._update_status("stopped", "Job stopped (remote)")
+                        return
-                    )
-                    # Best-effort flush pending async ops
-                    try:
-                        asyncio.run(self.wait_for_all_async())
-                    except RuntimeError:
-                        pass
-                    # Try to stop DB thread pool quickly
-                    try:
-                        self.thread_pool.shutdown(wait=False, cancel_futures=True)
-                    except TypeError:
-                        self.thread_pool.shutdown(wait=False)
                     print("")
                     print("****************************************************")
                     print("    Stop signal received; terminating process.      ")
                     print("****************************************************")
-                    os.kill(os.getpid(), signal.SIGINT)
+                    # Deliver a real KeyboardInterrupt to the main thread so
+                    # on_error runs the normal shutdown (final DB write, last
+                    # log). os.kill(pid, SIGINT) must not be used here: on
+                    # Windows it is TerminateProcess and kills us instantly.
+                    # Leave the thread pool alone -- on_error still needs it.
+                    signal.raise_signal(signal.SIGINT)
+                    return
                 time.sleep(interval_sec)
             except Exception:
                 time.sleep(interval_sec)

extensions_built_in/sd_trainer/UITrainer.py

@@ -33,7 +33,12 @@ class UITrainer(SDTrainer):
         # Initialize the status
         self._run_async_operation(self._update_status("running", "Starting"))
         self._stop_watcher_started = False
-        # self.start_stop_watcher(interval_sec=2.0)
+        if os.name == "nt":
+            # On Windows the stop route cannot send us SIGINT from outside
+            # (no console to deliver a Ctrl+C to), so watch the stop flag
+            # and raise the interrupt from inside. On Linux the route
+            # sends a real SIGINT to the pid and this is unnecessary.
+            self.start_stop_watcher(interval_sec=2.0)
     
     def start_stop_watcher(self, interval_sec: float = 5.0):
         """
@@ -52,26 +57,21 @@ class UITrainer(SDTrainer):
         while True:
             try:
                 if self.should_stop():
-                    # Mark and update status (non-blocking; uses existing infra)
+                    if self.is_stopping:
-                    self.is_stopping = True
+                        # maybe_stop() already started the graceful shutdown;
-                    self._run_async_operation(
+                        # a second interrupt would only break its cleanup.
-                        self._update_status("stopped", "Job stopped (remote)")
+                        return
-                    )
-                    # Best-effort flush pending async ops
-                    try:
-                        asyncio.run(self.wait_for_all_async())
-                    except RuntimeError:
-                        pass
-                    # Try to stop DB thread pool quickly
-                    try:
-                        self.thread_pool.shutdown(wait=False, cancel_futures=True)
-                    except TypeError:
-                        self.thread_pool.shutdown(wait=False)
                     print("")
                     print("****************************************************")
                     print("    Stop signal received; terminating process.      ")
                     print("****************************************************")
-                    os.kill(os.getpid(), signal.SIGINT)
+                    # Deliver a real KeyboardInterrupt to the main thread so
+                    # on_error runs the normal shutdown (final DB write, last
+                    # log). os.kill(pid, SIGINT) must not be used here: on
+                    # Windows it is TerminateProcess and kills us instantly.
+                    # Leave the thread pool alone -- on_error still needs it.
+                    signal.raise_signal(signal.SIGINT)
+                    return
                 time.sleep(interval_sec)
             except Exception:
                 time.sleep(interval_sec)
@@ -217,7 +217,12 @@ class UITrainer(SDTrainer):
 
     def on_error(self, e: Exception):
         super(UITrainer, self).on_error(e)
-        if self.accelerator.is_main_process and not self.is_stopping:
+        if isinstance(e, KeyboardInterrupt):
+            # SIGINT (UI stop button or ctrl+c) is a stop, not an error
+            self.is_stopping = True
+            if self.accelerator.is_main_process:
+                self.update_status("stopped", "Job stopped")
+        elif self.accelerator.is_main_process and not self.is_stopping:
             self.update_status("error", str(e))
         self.update_db_key("step", self.last_save_step)
         asyncio.run(self.wait_for_all_async())

run.py

@@ -14,6 +14,13 @@ if "SEED" in os.environ:
         print(f"Invalid SEED value: {os.environ['SEED']}. SEED must be an integer.")
 
 sys.path.insert(0, os.getcwd())
+
+# The UI launches jobs with no console; keep anything we shell out to (torch
+# compiles, HF git downloads) from flashing a console window. Must come before
+# any import that might spawn a subprocess.
+from toolkit.win_console import suppress_child_consoles
+suppress_child_consoles()
+
 # must come before ANY torch or fastai imports
 # import toolkit.cuda_malloc
 

toolkit/win_console.py

@@ -0,0 +1,58 @@
+"""Keep child processes from popping console windows on Windows.
+
+The UI worker launches training jobs with pythonw.exe and DETACHED_PROCESS so
+they survive the UI shutting down (see ui/cron/actions/startJob.ts). That
+leaves the job with no console at all, and Windows hands a brand new console
+-- with a visible window -- to any console program launched from a process
+that has none. MSVC during a torch/triton compile, git during a HF download
+and ffmpeg would each flash a window on the user's desktop.
+
+Defaulting those spawns to CREATE_NO_WINDOW suppresses the flash. This is a
+no-op unless we are on Windows *and* have no console, so running run.py from a
+terminal behaves exactly as it did before.
+"""
+
+import subprocess
+import sys
+
+CREATE_NEW_CONSOLE = 0x00000010
+DETACHED_PROCESS = 0x00000008
+CREATE_NO_WINDOW = 0x08000000
+
+# creationflags is the 14th positional parameter of Popen.__init__ after self.
+_CREATIONFLAGS_POSITION = 14
+
+_patched = False
+
+
+def _has_console():
+    import ctypes
+
+    return bool(ctypes.windll.kernel32.GetConsoleWindow())
+
+
+def suppress_child_consoles():
+    """Make CREATE_NO_WINDOW the default for subprocesses, where it matters."""
+    global _patched
+    if _patched or sys.platform != "win32":
+        return
+    try:
+        if _has_console():
+            return
+    except Exception:
+        # Never let a console tweak take down a training run.
+        return
+
+    original_init = subprocess.Popen.__init__
+
+    def patched_init(self, *args, **kwargs):
+        if len(args) >= _CREATIONFLAGS_POSITION:
+            # Passed positionally; leave the caller's choice alone.
+            return original_init(self, *args, **kwargs)
+        flags = kwargs.get("creationflags", 0)
+        if not flags & (CREATE_NEW_CONSOLE | DETACHED_PROCESS | CREATE_NO_WINDOW):
+            kwargs["creationflags"] = flags | CREATE_NO_WINDOW
+        return original_init(self, *args, **kwargs)
+
+    subprocess.Popen.__init__ = patched_init
+    _patched = True

ui/cron/actions/startJob.ts

@@ -1,10 +1,10 @@
 import prisma from '../prisma';
 import { Job } from '@prisma/client';
-import { spawn } from 'child_process';
+import { spawn, ChildProcess } from 'child_process';
 import path from 'path';
 import fs from 'fs';
 import { TOOLKIT_ROOT, getTrainingFolder, getHFToken } from '../paths';
-import { resolvePythonPath } from '../pythonPath';
+import { resolveDetachedPythonPath } from '../pythonPath';
 const isWindows = process.platform === 'win32';
 
 const appendJobLog = (logPath: string, message: string) => {
@@ -13,6 +13,168 @@ const appendJobLog = (logPath: string, message: string) => {
   });
 };
 
+// Windows only. Launched as `node -e <this>` so the job ends up outside the
+// worker's process tree: `taskkill /T` (the dev script's `concurrently -k`,
+// or any shutdown that kills the tree) walks parent/child links and would take
+// a direct child down with the UI. This relay exits immediately, orphaning the
+// job, and `detached` keeps the job alive once its parent is gone. Its own
+// stdout/stderr are the job log, so the job inherits them as fds 1 and 2.
+// Python failing to launch at all (broken venv, missing interpreter) happens
+// inside the relay, so the relay -- not the worker -- is what sees that error.
+// It reports it two ways: on stderr, which is the job log, and through the pid
+// file, so the worker can put the real reason in the database.
+const RELAY_ERROR_PREFIX = 'error:';
+const WINDOWS_RELAY_SCRIPT = `
+const { spawn } = require('child_process');
+const fs = require('fs');
+const [pidFile, command, ...args] = process.argv.slice(1);
+const child = spawn(command, args, {
+  detached: true,
+  windowsHide: true,
+  stdio: ['ignore', 1, 2],
+});
+child.once('error', error => {
+  process.stderr.write('Error launching job process: ' + error.message + '\\n');
+  try {
+    fs.writeFileSync(pidFile, '${RELAY_ERROR_PREFIX}' + error.message);
+  } catch (e) {
+    process.stderr.write('Could not write job pid file: ' + e.message + '\\n');
+  }
+  process.exit(1);
+});
+if (child.pid) {
+  fs.writeFileSync(pidFile, String(child.pid));
+  child.unref();
+}
+`;
+
+const RELAY_PID_TIMEOUT_MS = 30000;
+
+type RelayResult = { pid: number | null; error?: string };
+
+// The relay exits as soon as it has launched the job, leaving the real pid in
+// pidPath. Without this we would only ever know the (already dead) relay's pid.
+const readRelayPid = (relay: ChildProcess, pidPath: string): Promise<RelayResult> => {
+  return new Promise(resolve => {
+    let settled = false;
+    const finish = (value: RelayResult) => {
+      if (settled) return;
+      settled = true;
+      clearTimeout(timer);
+      resolve(value);
+    };
+
+    const timer = setTimeout(
+      () => finish({ pid: null, error: 'Timed out waiting for the job process to start' }),
+      RELAY_PID_TIMEOUT_MS,
+    );
+
+    relay.once('exit', () => {
+      let contents: string;
+      try {
+        contents = fs.readFileSync(pidPath, 'utf8').trim();
+      } catch {
+        finish({ pid: null, error: 'Job process did not report a pid' });
+        return;
+      }
+
+      if (contents.startsWith(RELAY_ERROR_PREFIX)) {
+        finish({ pid: null, error: contents.slice(RELAY_ERROR_PREFIX.length) });
+        return;
+      }
+
+      const pid = Number(contents);
+      finish(
+        Number.isInteger(pid) && pid > 0
+          ? { pid }
+          : { pid: null, error: 'Job process did not report a usable pid' },
+      );
+    });
+
+    relay.once('error', error => finish({ pid: null, error: error.message }));
+  });
+};
+
+const isProcessAlive = (pid: number): boolean => {
+  try {
+    process.kill(pid, 0);
+    return true;
+  } catch (e: any) {
+    // EPERM means it exists but belongs to someone else, which still counts.
+    return e?.code === 'EPERM';
+  }
+};
+
+// We cannot read an exit code off a process that is not our child, so pull the
+// last thing it said instead -- for a job that dies on startup (bad venv,
+// missing CUDA libs) that traceback line is the whole diagnosis.
+const LOG_TAIL_BYTES = 4096;
+const LOG_TAIL_MAX_CHARS = 300;
+
+const readLogTail = (logPath: string): string | null => {
+  let fd: number | null = null;
+  try {
+    const size = fs.statSync(logPath).size;
+    const length = Math.min(size, LOG_TAIL_BYTES);
+    if (length === 0) return null;
+
+    const buffer = Buffer.alloc(length);
+    fd = fs.openSync(logPath, 'r');
+    fs.readSync(fd, buffer, 0, length, size - length);
+
+    const lines = buffer.toString('utf8').split(/\r?\n/).filter(line => line.trim() !== '');
+    const lastLine = lines[lines.length - 1];
+    if (!lastLine) return null;
+    return lastLine.length > LOG_TAIL_MAX_CHARS ? `${lastLine.slice(-LOG_TAIL_MAX_CHARS)}` : lastLine;
+  } catch {
+    return null;
+  } finally {
+    if (fd !== null) {
+      try {
+        fs.closeSync(fd);
+      } catch {
+        // nothing useful to do if the log handle will not close
+      }
+    }
+  }
+};
+
+// The job is not our child anymore, so there is no 'exit' event to listen for.
+// Poll instead, so a job that dies without updating its own row (OOM kill,
+// hard crash) still gets marked as an error rather than sitting on 'running'.
+const JOB_POLL_INTERVAL_MS = 2000;
+
+const watchDetachedJob = (pid: number, jobID: string, logPath: string) => {
+  const timer = setInterval(() => {
+    if (isProcessAlive(pid)) return;
+    clearInterval(timer);
+
+    // A stopped or completed job writes its own ending (status row + final
+    // log lines) via its KeyboardInterrupt/done handlers -- stay out of the
+    // way. Only a job that vanished while still marked 'running' died without
+    // getting to say anything; record that. There is no exit code to read off
+    // a process that is not our child, so report the last thing it logged.
+    const tail = readLogTail(logPath);
+    const message = tail
+      ? `Job process exited unexpectedly. Last log line: ${tail}`
+      : 'Job process exited unexpectedly.';
+    void prisma.job
+      .updateMany({
+        where: { id: jobID, status: 'running' },
+        data: { status: 'error', info: message, pid: null },
+      })
+      .then(result => {
+        if (result.count > 0) appendJobLog(logPath, `\n${message}\n`);
+      })
+      .catch(updateError => {
+        console.error('Error updating job after process disappeared:', updateError);
+      });
+  }, JOB_POLL_INTERVAL_MS);
+
+  // Never hold the worker open on account of this poll.
+  if (timer.unref) timer.unref();
+};
+
 const startAndWatchJob = (job: Job) => {
   // starts and watches the job asynchronously
   return new Promise<void>(async (resolve, reject) => {
@@ -59,7 +221,7 @@ const startAndWatchJob = (job: Job) => {
     // write the config file
     fs.writeFileSync(configPath, JSON.stringify(jobConfig, null, 2));
 
-    const pythonPath = resolvePythonPath();
+    const pythonPath = resolveDetachedPythonPath();
 
     const runFilePath = path.join(TOOLKIT_ROOT, 'run.py');
     if (!fs.existsSync(runFilePath)) {
@@ -90,6 +252,9 @@ const startAndWatchJob = (job: Job) => {
 
     const args = [runFilePath, configPath];
 
+    // Where the Windows relay reports the job's real pid back to us.
+    const relayPidPath = path.join(trainingFolder, '.job_pid');
+
     let logFd: number | null = null;
     try {
       // Capture errors that occur before run.py can initialize file logging.
@@ -97,14 +262,23 @@ const startAndWatchJob = (job: Job) => {
       let subprocess;
 
       if (isWindows) {
-        // Spawn Python directly on Windows so the process can survive parent exit
+        // Launch through the relay (see WINDOWS_RELAY_SCRIPT) so the job is not
-        subprocess = spawn(pythonPath, args, {
+        // a descendant of this worker and survives the UI being shut down or
+        // tree-killed. The relay spawns the job `detached`, which is what keeps
+        // it alive once the relay exits; that in turn means DETACHED_PROCESS,
+        // so pythonPath is pythonw.exe to avoid Windows handing the job a
+        // console window of its own.
+        try {
+          fs.unlinkSync(relayPidPath);
+        } catch {
+          // no stale pid file to clear
+        }
+        subprocess = spawn(process.execPath, ['-e', WINDOWS_RELAY_SCRIPT, relayPidPath, pythonPath, ...args], {
           env: {
             ...process.env,
             ...additionalEnv,
           },
           cwd: TOOLKIT_ROOT,
-          detached: true,
           windowsHide: true,
           stdio: ['ignore', logFd, logFd], // don't tie stdio to parent; log fd passed as stdout and stderr
         });
@@ -136,6 +310,20 @@ const startAndWatchJob = (job: Job) => {
           });
       });
 
+      let pid: number | null;
+
+      if (isWindows) {
+        // The relay is gone within a few hundred ms; the pid it leaves behind is
+        // the job's. Poll that pid for liveness since we get no 'exit' event.
+        const relayResult = await readRelayPid(subprocess, relayPidPath);
+        if (relayResult.pid == null) {
+          throw new Error(relayResult.error ?? 'Job process did not report a pid');
+        }
+        pid = relayResult.pid;
+        watchDetachedJob(pid, jobID, logPath);
+      } else {
+        pid = subprocess.pid ?? null;
+
         // Record abnormal termination and repair jobs Python could not update itself.
         subprocess.once('exit', (code, signal) => {
           if (code === 0) return;
@@ -152,9 +340,9 @@ const startAndWatchJob = (job: Job) => {
               console.error('Error updating job after abnormal process exit:', updateError);
             });
         });
+      }
 
       // Save the PID to the database and a file for future management (stop/inspect)
-      const pid = subprocess.pid ?? null;
       if (pid != null) {
         await prisma.job.update({
           where: { id: jobID },

ui/cron/pythonPath.ts

@@ -25,3 +25,18 @@ export const resolvePythonPath = (): string => {
 
   return isWindows ? 'python.exe' : 'python3';
 };
+
+// Interpreter for jobs we detach so they outlive the UI. On Windows detaching
+// means DETACHED_PROCESS, and Windows gives any *console* app started that way
+// a fresh console with a visible window. pythonw.exe is the GUI-subsystem
+// build, so it never gets one; stdout/stderr still go to the handles we pass.
+export const resolveDetachedPythonPath = (): string => {
+  const pythonPath = resolvePythonPath();
+  if (!isWindows) return pythonPath;
+
+  // Always take the pythonw next to the interpreter we already resolved, so
+  // both come from the same environment. Falling back to python.exe still
+  // works, it just shows a console window.
+  const pythonwPath = path.join(path.dirname(pythonPath), 'pythonw.exe');
+  return fs.existsSync(pythonwPath) ? pythonwPath : pythonPath;
+};

ui/src/app/api/jobs/[jobID]/stop/route.ts

@@ -6,6 +6,43 @@ import { promisify } from 'util';
 const execAsync = promisify(exec);
 const isWindows = process.platform === 'win32';
 
+// How long a stopping job gets to run its graceful shutdown (KeyboardInterrupt
+// -> on_error -> final DB write) before we assume it is hung and force-kill it.
+const GRACEFUL_STOP_TIMEOUT_MS = 60_000;
+const BACKSTOP_POLL_MS = 2_000;
+
+const isProcessAlive = (pid: number): boolean => {
+  try {
+    process.kill(pid, 0);
+    return true;
+  } catch (e: any) {
+    // EPERM means it exists but belongs to someone else, which still counts.
+    return e?.code === 'EPERM';
+  }
+};
+
+// Windows: the trainer's stop watcher sees the `stop` flag and raises SIGINT
+// inside the process, so the graceful path runs without us sending anything.
+// This backstop only exists for a job that is too hung to notice the flag.
+// Poll (rather than one long timer) so we stop watching the moment the pid
+// dies and never touch a recycled pid.
+const scheduleForceKillBackstop = (pid: number, jobID: string) => {
+  const startedAt = Date.now();
+  const timer = setInterval(() => {
+    if (!isProcessAlive(pid)) {
+      clearInterval(timer);
+      return;
+    }
+    if (Date.now() - startedAt < GRACEFUL_STOP_TIMEOUT_MS) return;
+    clearInterval(timer);
+    console.warn(`Job ${jobID} (pid ${pid}) still alive ${GRACEFUL_STOP_TIMEOUT_MS / 1000}s after stop request, force killing`);
+    execAsync(`taskkill /PID ${pid} /T /F`, { windowsHide: true }).catch(() => {
+      // already gone
+    });
+  }, BACKSTOP_POLL_MS);
+  timer.unref?.();
+};
+
 export async function GET(request: NextRequest, { params }: { params: { jobID: string } }) {
   const { jobID } = await params;
 
@@ -30,9 +67,12 @@ export async function GET(request: NextRequest, { params }: { params: { jobID: s
     console.log(`Attempting to stop job ${jobID} with PID ${job.pid}`);
     try {
       if (isWindows) {
-        // Windows doesn't support SIGINT for arbitrary processes.
+        // No external SIGINT possible on Windows (the job runs under pythonw
-        // Use taskkill with /T (tree) to send a CTRL+C-like termination.
+        // with no console), and none is needed: the `stop` flag written above
-        await execAsync(`taskkill /PID ${job.pid} /T /F`, { windowsHide: true });
+        // is the signal. The trainer's stop watcher polls it and raises
+        // SIGINT in-process, which runs the same KeyboardInterrupt shutdown
+        // as Linux -- final DB write and the closing log lines.
+        scheduleForceKillBackstop(job.pid, jobID);
       } else {
         process.kill(job.pid, 'SIGINT');
       }