unsloth/studio/backend/run.py
Daniel Han 1daaa5cbb4
Let a decode failure degrade instead of escaping a fail-closed helper (#7487)
* Let a decode failure degrade instead of escaping a fail-closed helper

Pinning utf-8 makes a read that used to return mojibake on Windows raise
instead. 33 of those reads sit under a handler catching OSError or
json.JSONDecodeError but not UnicodeDecodeError, which subclasses
ValueError, so a corrupt file would now escape a helper written to return
a default. Adds UnicodeDecodeError to those tuples only.

* Treat an undecodable install lock as stale instead of retrying forever
2026-07-27 03:26:08 -07:00

2007 lines
77 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-only
# Copyright 2026-present the Unsloth AI Inc. team. All rights reserved. See /studio/LICENSE.AGPL-3.0
"""Run script for Unsloth UI Backend.
Self-contained; can be moved to any directory.
"""
import os
import sys
import time
from pathlib import Path
from typing import Optional, Tuple
def _fix_torch_cuda_ld_path():
"""Prepend torch's bundled CUDA libs to LD_LIBRARY_PATH.
PyTorch wheels ship their own CUDA runtime (libcudart, libcublas, ...) in
``site-packages/nvidia/*/lib``. On Linux the dynamic linker reads
LD_LIBRARY_PATH before the RUNPATH baked into torch's .so files, so a
pre-existing LD_LIBRARY_PATH pointing at a different system CUDA (e.g.
/usr/local/cuda-13/lib64 from conda or a Docker base image) shadows torch's
libs and triggers "undefined symbol" errors when torch is imported. Detect
torch's lib dirs (without importing torch) and prepend them. Returns True if
LD_LIBRARY_PATH was changed.
"""
if sys.platform != "linux":
return False
ld_path = os.environ.get("LD_LIBRARY_PATH", "")
if not ld_path:
return False
try:
import importlib.util
spec = importlib.util.find_spec("torch")
if not spec or not spec.origin:
return False
torch_dir = os.path.dirname(spec.origin)
site_pkgs = os.path.dirname(torch_dir)
nvidia_dir = os.path.join(site_pkgs, "nvidia")
lib_dirs = []
torch_lib = os.path.join(torch_dir, "lib")
if os.path.isdir(torch_lib):
lib_dirs.append(torch_lib)
if os.path.isdir(nvidia_dir):
for sub in sorted(os.listdir(nvidia_dir)):
lib = os.path.join(nvidia_dir, sub, "lib")
if os.path.isdir(lib):
lib_dirs.append(lib)
if not lib_dirs:
return False
existing = ld_path.split(":")
if existing[: len(lib_dirs)] == lib_dirs:
return False # already at the front, nothing to do
torch_set = set(lib_dirs)
cleaned = [p for p in existing if p not in torch_set]
os.environ["LD_LIBRARY_PATH"] = ":".join(lib_dirs + cleaned)
return True
except Exception:
return False
_LD_FIXED_SENTINEL = "_UNSLOTH_STUDIO_LD_FIXED"
def _maybe_reexec_for_cuda_ld_path():
"""Re-exec once so the dynamic linker sees the corrected LD_LIBRARY_PATH.
LD_LIBRARY_PATH is read at process start, so editing os.environ in-process
cannot fix the running interpreter; a single re-exec is required. Call only
from a true entry point (the ``if __name__ == "__main__"`` block), never at
import time, because os.execv replaces the whole process (an embedder such
as Colab that does ``from run import run_server`` must not be re-exec'd).
"""
if _LD_FIXED_SENTINEL in os.environ:
return
if not _fix_torch_cuda_ld_path():
return
os.environ[_LD_FIXED_SENTINEL] = "1"
argv = getattr(sys, "orig_argv", None) or [sys.executable, *sys.argv]
os.execv(sys.executable, argv)
# Suppress C-level dependency warnings globally (e.g. SwigPyPacked).
os.environ["PYTHONWARNINGS"] = "ignore"
# Add the backend dir to sys.path early so local modules import.
backend_dir = Path(__file__).parent
if str(backend_dir) not in sys.path:
sys.path.insert(0, str(backend_dir))
from utils.cpu_threads import configure_cpu_threads
try:
configure_cpu_threads()
except ValueError as exc:
configured = os.environ.get("UNSLOTH_CPU_THREADS")
raise SystemExit(f"Error: Invalid UNSLOTH_CPU_THREADS value {configured!r}: {exc}") from None
# Anaconda/conda-forge Python: seed platform._sys_version_cache before imports
# that trigger attrs -> rich -> structlog -> platform crash.
# See: https://github.com/python/cpython/issues/102396
import _platform_compat # noqa: F401
from loggers import get_logger
from startup_banner import print_studio_access_banner, print_studio_stop_hint
logger = get_logger(__name__)
DISABLE_PUBLIC_CHECK_ENV = "UNSLOTH_STUDIO_DISABLE_PUBLIC_CHECK"
def public_check_disabled() -> bool:
"""True when the operator has turned off the third-party startup lookups.
On a wildcard bind Unsloth asks ifconfig.me for the public IP and check-host.net
whether the port is reachable. Both are useful for sharing a Studio but both tell
an outside service this machine is running one, which lab and privacy-sensitive
deployments do not want (#7307 Problem 8). Set the var to opt out.
"""
return os.environ.get(DISABLE_PUBLIC_CHECK_ENV, "").strip().lower() in {"1", "true", "yes"}
def _resolve_external_ip() -> str:
"""Resolve the machine's external IP address.
Tries, in order:
1. GCE metadata server (instant on Google Cloud VMs)
2. ifconfig.me (anywhere with internet, skipped by UNSLOTH_STUDIO_DISABLE_PUBLIC_CHECK)
3. LAN IP via UDP socket trick (fallback)
"""
import urllib.request
import socket
# 1. GCE metadata server (<10ms on GCE, times out fast elsewhere).
try:
req = urllib.request.Request(
"http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/access-configs/0/external-ip",
headers = {"Metadata-Flavor": "Google"},
)
with urllib.request.urlopen(req, timeout = 1) as resp:
ip = resp.read().decode().strip()
if ip:
return ip
except Exception:
pass
# 2. Public IP service. Third-party, so skippable; the LAN address below still works.
if not public_check_disabled():
try:
with urllib.request.urlopen("https://ifconfig.me", timeout = 3) as resp:
ip = resp.read().decode().strip()
if ip:
return ip
except Exception:
pass
# 3. Fallback: LAN IP via UDP socket trick
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.connect(("8.8.8.8", 80))
ip = s.getsockname()[0]
s.close()
return ip
except Exception:
return "0.0.0.0"
def _install_uvicorn_startup_log_rewrite(bind_host: str, display_host: str) -> None:
"""Rewrite Uvicorn's startup log line: swap wildcard bind for the
externally-reachable address, use our Mac-aware stop hint, and rename the
prefix to "Unsloth Studio running on"."""
import logging
import re
rewrite_host = (
bind_host in ("0.0.0.0", "::") and bool(display_host) and display_host != bind_host
)
new_suffix = "(To stop: press Ctrl+C -- on macOS, Control+C not Command+C)"
old_suffix_re = re.compile(r"\(Press CTRL\+C to quit\)")
old_prefix = "Uvicorn running on "
new_prefix = "Unsloth Studio running on "
def _rewrite(text: str) -> str:
if text.startswith(old_prefix):
text = new_prefix + text[len(old_prefix) :]
return old_suffix_re.sub(new_suffix, text)
class _UvicornStartupRewrite(logging.Filter):
def filter(self, record: logging.LogRecord) -> bool:
try:
msg = record.msg if isinstance(record.msg, str) else ""
if (
msg.startswith(old_prefix)
and isinstance(record.args, tuple)
and len(record.args) >= 3
):
if rewrite_host and record.args[1] == bind_host:
record.args = (
record.args[0],
display_host,
record.args[2],
*record.args[3:],
)
record.msg = _rewrite(msg)
cmsg = getattr(record, "color_message", None)
if isinstance(cmsg, str):
record.color_message = _rewrite(cmsg)
except Exception:
pass
return True
f = _UvicornStartupRewrite()
for name in ("uvicorn", "uvicorn.error"):
logging.getLogger(name).addFilter(f)
def _local_port_open(
host: str,
port: int,
timeout: float = 1.0,
) -> bool:
"""True iff a TCP connection to (host, port) succeeds within timeout."""
import socket
try:
with socket.create_connection((host, port), timeout = timeout):
return True
except OSError:
return False
def _working_local_url(port: int) -> "str | None":
"""A working loopback URL on this machine, or None if neither 127.0.0.1 nor
::1 responds. Fallback when external reachability fails."""
if _local_port_open("127.0.0.1", port):
return f"http://127.0.0.1:{port}"
if _local_port_open("::1", port):
return f"http://[::1]:{port}"
return None
def _localhost_ipv6_mismatch_url(bind_host: str, port: int) -> "str | None":
"""Return the IPv4 loopback URL when localhost won't reach 127.0.0.1.
Local Unsloth binds to 127.0.0.1. Where localhost resolves to IPv6 only (::1),
http://localhost:<port> fails (or hits a different process on ::1) even though
http://127.0.0.1:<port> works. Return the IPv4 URL for the caller to surface.
"""
import socket
if bind_host != "127.0.0.1" or not port or port <= 0:
return None
ipv4_url = f"http://127.0.0.1:{port}"
# Only warn once Unsloth is confirmed answering on IPv4 loopback.
if _working_local_url(port) != ipv4_url:
return None
try:
addr_info = socket.getaddrinfo("localhost", port, socket.AF_UNSPEC, socket.SOCK_STREAM)
except Exception:
return None
if not addr_info:
return None
has_ipv4_loopback = False
has_ipv6_loopback = False
for family, _, _, _, sockaddr in addr_info:
if family == socket.AF_INET and sockaddr and sockaddr[0] == "127.0.0.1":
has_ipv4_loopback = True
elif family == socket.AF_INET6 and sockaddr:
host = sockaddr[0].split("%", 1)[0]
if host == "::1":
has_ipv6_loopback = True
# A connection to ::1 is NOT evidence Unsloth is reachable there: Unsloth binds
# 127.0.0.1 only, so anything on ::1 is a different process. Dual-stack
# localhost is fine (browsers fall back to 127.0.0.1), so only the IPv6-only
# case strands the user.
if has_ipv6_loopback and not has_ipv4_loopback:
return ipv4_url
return None
def _stdout_color_ok() -> bool:
"""Whether to emit ANSI color codes on stdout. Mirrors startup_banner."""
if os.environ.get("NO_COLOR", "").strip():
return False
if os.environ.get("FORCE_COLOR", "").strip():
return True
try:
return sys.stdout.isatty()
except (AttributeError, OSError, ValueError):
return False
def _print_localhost_ipv6_mismatch_warning(local_url: str, port: int) -> None:
"""Warn that localhost points at ::1 while Unsloth is bound to 127.0.0.1."""
use_color = _stdout_color_ok()
warn_c = "\033[38;5;215;1m" if use_color else ""
reset = "\033[0m" if use_color else ""
print(
f"{warn_c} Warning: localhost resolves to IPv6 (::1), but Unsloth "
f"Studio is listening on 127.0.0.1 only. Open {local_url} instead of "
f"http://localhost:{port}.{reset}",
flush = True,
)
def _verify_global_reachability(display_host: str, port: int) -> None:
"""Probe check-host.net to confirm display_host:port is reachable from the
public internet. Synchronous so output lands between the banner URLs and the
stop hint. Bounded at ~15s; failures swallowed (verifier failing != Unsloth
failing). Only meaningful for a wildcard bind, and skipped entirely by
UNSLOTH_STUDIO_DISABLE_PUBLIC_CHECK."""
global _public_reachable
# Reset to "unknown" each run; set True/False only when the probe decides.
_public_reachable = None
import ipaddress
import json
import time
import urllib.error
import urllib.parse
import urllib.request
if not display_host or display_host in ("0.0.0.0", "::"):
return
use_color = _stdout_color_ok()
dim = "\033[38;5;245m" if use_color else ""
ok_c = "\033[38;5;120;1m" if use_color else ""
err_c = "\033[38;5;203;1m" if use_color else ""
warn_c = "\033[38;5;215;1m" if use_color else ""
local_url_c = "\033[38;5;108;1m" if use_color else "" # matches banner's URL color
reset = "\033[0m" if use_color else ""
url = f"http://{_url_host(display_host)}:{port}"
# Private/loopback/link-local addresses aren't globally routable.
try:
addr = ipaddress.ip_address(display_host)
if addr.is_loopback or addr.is_private or addr.is_link_local:
_public_reachable = False
print(
f"{dim} Note: {display_host} is a private/LAN address -- "
f"reachable on this network only, not from the public internet."
f"{reset}",
flush = True,
)
return
except ValueError:
# Not an IP literal; probe by hostname.
pass
# The probe hands display_host:port to a third party and asks it to connect.
if public_check_disabled():
logger.debug("Skipping the check-host.net probe (%s).", DISABLE_PUBLIC_CHECK_ENV)
return
try:
qs = urllib.parse.urlencode({"host": f"{display_host}:{port}", "max_nodes": 3})
req = urllib.request.Request(
f"https://check-host.net/check-tcp?{qs}",
headers = {
"Accept": "application/json",
"User-Agent": "unsloth-studio-reachability/1",
},
)
with urllib.request.urlopen(req, timeout = 5) as resp:
init = json.loads(resp.read().decode("utf-8", errors = "replace"))
req_id = init.get("request_id")
if not req_id:
return
results = {}
deadline = time.monotonic() + 15.0
poll_req = urllib.request.Request(
f"https://check-host.net/check-result/{req_id}",
headers = {
"Accept": "application/json",
"User-Agent": "unsloth-studio-reachability/1",
},
)
while time.monotonic() < deadline:
time.sleep(1.5)
try:
with urllib.request.urlopen(poll_req, timeout = 5) as resp:
results = json.loads(resp.read().decode("utf-8", errors = "replace"))
except Exception:
continue
if results and all(v is not None for v in results.values()):
break
# Two decisive nodes is enough; stop early.
decisive = [
v
for v in results.values()
if isinstance(v, list)
and v
and isinstance(v[0], dict)
and ("time" in v[0] or "error" in v[0])
]
if len(decisive) >= 2:
break
ok_nodes = err_nodes = 0
for v in results.values():
if not isinstance(v, list) or not v or not isinstance(v[0], dict):
continue
if "time" in v[0]:
ok_nodes += 1
elif "error" in v[0]:
err_nodes += 1
total = ok_nodes + err_nodes
print("", flush = True)
if ok_nodes:
_public_reachable = True
print(
f"{ok_c} Reachability check: {url}/ is reachable from the "
f"public internet ({ok_nodes}/{total} probe nodes connected).{reset}",
flush = True,
)
elif err_nodes:
_public_reachable = False
print(
f"{err_c} Reachability check: {url}/ is NOT reachable from "
f"the public internet ({err_nodes}/{total} probe nodes failed).{reset}",
flush = True,
)
print(
f"{dim} Usually a cloud firewall (AWS security group, "
f"GCP firewall / Azure NSG rule) or home router isn't "
f"allowing inbound TCP {port}.{reset}",
flush = True,
)
print(
f"{dim} No firewall change needed -- SSH local-forward "
f"from your own computer:{reset}",
flush = True,
)
print(
f"{dim} ssh -L {port}:localhost:{port} <user>@{display_host}{reset}",
flush = True,
)
print(
f"{dim} then open http://localhost:{port}/ in your browser.{reset}",
flush = True,
)
# Only offer the local URL if loopback answers.
local_url = _working_local_url(port)
if local_url:
print(
f"{local_url_c} You can access Unsloth Studio locally "
f"in the meantime: {local_url}{reset}",
flush = True,
)
else:
print(
f"{warn_c} Reachability check: probe nodes did not respond "
f"in time -- could not verify {url}/.{reset}",
flush = True,
)
except urllib.error.URLError:
# Outbound HTTPS blocked; skip.
pass
except Exception:
pass
def _display_host_for_bind(host: str) -> str:
return _resolve_external_ip() if host in ("0.0.0.0", "::") else host
def _loopback_bind_host_for(host: str) -> str:
return "::1" if host == "::" else "127.0.0.1"
def _url_host(host: str) -> str:
return (
f"[{host}]" if ":" in host and not (host.startswith("[") and host.endswith("]")) else host
)
def _tool_policy_notice(host: str, secure: bool, enable_tools: "Optional[bool]") -> str:
"""One-line tool-policy summary for the plain-server startup banner, so a
network-reachable launch is never silent about code execution."""
if enable_tools is False:
return "Server-side tools are DISABLED (--disable-tools)."
state = (
"ENABLED (--enable-tools)"
if enable_tools
else "ENABLED by default (per-request setting honored)"
)
if secure:
return (
f"Server-side tools are {state}, reachable via the authenticated "
"Cloudflare HTTPS tunnel. Anyone with the API key can run code on "
"this machine. Do not share the API key. Pass --disable-tools to turn off."
)
from utils.host_policy import is_external_host
if host in ("0.0.0.0", "::") or is_external_host(host):
return (
f"Server-side tools are {state} and this port is network-reachable. "
"Anyone who can reach it with the API key can run code on this "
"machine. Do not share the API key. Pass --disable-tools to turn off."
)
return f"Server-side tools are {state} for loopback. Pass --disable-tools to turn off."
def _emit_tool_policy_notice(host: str, secure: bool, enable_tools: "Optional[bool]") -> None:
print(_tool_policy_notice(host, secure, enable_tools), flush = True)
def _emit_secure_startup_output(port: int, enable_tools: "Optional[bool]" = None) -> None:
"""Secure-mode banner: only the Cloudflare link (loopback has no public raw URL)."""
print("")
print("🦥 Unsloth Studio is running (secure)")
print("" * 52)
_print_cloudflare_line(secure = True)
print(f" On this machine only: http://127.0.0.1:{port}/")
print("" * 52)
_emit_tool_policy_notice("127.0.0.1", True, enable_tools)
print_studio_stop_hint()
def _emit_startup_output(
host: str,
port: int,
display_host: str,
secure: bool = False,
enable_tools: "Optional[bool]" = None,
) -> None:
"""Print the access banner, post-startup warnings, the tool-policy notice,
then a single stop hint. Extracted from ``_run`` so the wiring is testable."""
if secure:
_emit_secure_startup_output(port, enable_tools)
return
wildcard_bind = host in ("0.0.0.0", "::")
localhost_mismatch_url = _localhost_ipv6_mismatch_url(host, port)
print_studio_access_banner(
port = port,
bind_host = host,
display_host = display_host,
include_stop_hint = False,
)
if localhost_mismatch_url:
_print_localhost_ipv6_mismatch_warning(localhost_mismatch_url, port)
elif wildcard_bind:
_verify_global_reachability(display_host, port)
_print_cloudflare_line(loopback_host = _loopback_bind_host_for(host))
_emit_tool_policy_notice(host, False, enable_tools)
print_studio_stop_hint()
def _print_cloudflare_line(secure: bool = False, loopback_host: str = "127.0.0.1") -> None:
"""Print Cloudflare tunnel state for startup banners."""
from startup_banner import stdout_supports_color
accent = "\033[38;5;150;1m"
warn = "\033[38;5;215;1m"
reset = "\033[0m"
color = stdout_supports_color()
def _emit(text: str, style: str = "") -> None:
print(f"{style}{text}{reset}" if (color and style) else text)
if _cloudflare_url:
if _public_reachable is False:
_emit(f" Use the secure link access via Cloudflare instead: {_cloudflare_url}", accent)
else:
_emit(f" Secure link access via Cloudflare: {_cloudflare_url}", accent)
if not secure:
if _public_reachable is True:
_emit(
" Cloudflare tunnel: ON. This Cloudflare URL is PUBLIC, and the "
"raw port is also publicly reachable. --no-cloudflare disables "
f"only the Cloudflare URL; bind {loopback_host} or close firewall "
"access to keep Unsloth private.",
warn,
)
else:
_emit(
" Cloudflare tunnel: ON. This is a PUBLIC internet URL: anyone "
"who has it can reach this Unsloth. Relaunch with --no-cloudflare "
f"to disable the Cloudflare URL; bind {loopback_host} or close "
"firewall access to keep Unsloth private.",
warn,
)
return
if _cloudflare_requested:
if _public_reachable is True:
_emit(
" Cloudflare tunnel: requested but failed to start. The raw port is "
"still reachable from the public internet (see the reachability check "
"above): anyone who can reach it can access this Unsloth.",
warn,
)
elif _public_reachable is False:
_emit(
" Cloudflare tunnel: requested but failed to start. Unsloth is reachable "
"on your local network only (no public link).",
warn,
)
else:
_emit(
" Cloudflare tunnel: requested but failed to start. There is no "
"Cloudflare public link. Raw port reachability was not verified; "
f"bind {loopback_host} or close firewall access to keep Unsloth private.",
warn,
)
elif _cloudflare_flag:
if _public_reachable is True:
_emit(
" Cloudflare tunnel: OFF for this mode. The raw port is still "
"reachable from the public internet (see the reachability check above): "
"anyone who can reach it can access this Unsloth.",
warn,
)
elif _public_reachable is False:
_emit(
" Cloudflare tunnel: OFF for this mode. Unsloth is reachable on your "
"local network only (no public link)."
)
else:
_emit(
" Cloudflare tunnel: OFF for this mode. There is no Cloudflare public "
"link. Raw port reachability was not verified; "
f"bind {loopback_host} or close firewall access to keep Unsloth private.",
warn,
)
elif _cloudflare_flag is False or _cloudflare_flag is None:
# None = off by default (no flag); False = explicit --no-cloudflare.
_reason = "default" if _cloudflare_flag is None else "--no-cloudflare"
if _public_reachable is True:
_emit(
f" Cloudflare tunnel: OFF ({_reason}). The raw port is still "
"reachable from the public internet (see the reachability check above): "
"pass --cloudflare to also expose a public Cloudflare HTTPS link, or "
f"bind {loopback_host} to keep Unsloth private.",
warn,
)
elif _public_reachable is False:
_emit(
f" Cloudflare tunnel: OFF ({_reason}). Unsloth is reachable on your "
"local network only. Pass --cloudflare to expose a public "
"Cloudflare HTTPS link."
)
else:
_emit(
f" Cloudflare tunnel: OFF ({_reason}). There is no Cloudflare "
"public link. Raw port reachability was not verified; pass --cloudflare "
"to expose a public Cloudflare HTTPS link, or "
f"bind {loopback_host} or close firewall access to keep Unsloth private.",
warn,
)
def _get_pid_on_port(port: int) -> "tuple[int, str] | None":
"""Return (pid, process_name) listening on *port*, or None.
Uses psutil when available, else None so callers can still report the conflict
without process details.
"""
try:
import psutil
except ImportError:
return None
try:
for conn in psutil.net_connections(kind = "tcp"):
if conn.status == "LISTEN" and conn.laddr.port == port:
if conn.pid is None:
return None
try:
proc = psutil.Process(conn.pid)
return (conn.pid, proc.name())
except (psutil.NoSuchProcess, psutil.AccessDenied):
return (conn.pid, "<unknown>")
except (psutil.AccessDenied, OSError) as e:
# net_connections() needs elevated privileges on some platforms.
logger.debug("Failed to scan network connections for port %s: %s", port, e)
return None
def _is_port_free(host: str, port: int) -> bool:
"""Check if a port is available for binding.
For a ``0.0.0.0`` wildcard host, also check whether anything is listening on
``127.0.0.1`` (and ``::1`` when IPv6 exists): an SSH tunnel may hold loopback
while the wildcard bind succeeds, making Unsloth unreachable via ``localhost``.
"""
import socket
# 1. Can we bind to the requested address? getaddrinfo resolves both
# IPv4 and IPv6 to the right address family.
try:
addr_info = socket.getaddrinfo(host, port, socket.AF_UNSPEC, socket.SOCK_STREAM)
family, socktype, proto, _, sockaddr = addr_info[0]
with socket.socket(family, socktype, proto) as s:
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(sockaddr)
except OSError:
return False
# 2. On a wildcard bind, verify localhost isn't already claimed by another
# process (e.g. an SSH -L tunnel); a successful connect means it is.
if host in ("0.0.0.0", "::"):
for loopback, family in [
("127.0.0.1", socket.AF_INET),
("::1", socket.AF_INET6),
]:
try:
with socket.socket(family, socket.SOCK_STREAM) as s:
s.settimeout(1)
if s.connect_ex((loopback, port)) == 0:
# Port is taken on loopback.
return False
except OSError:
# IPv6 disabled or other OS-level restriction -- skip.
continue
return True
def _find_free_port(
host: str,
start: int,
max_attempts: int = 20,
) -> int:
"""Find a free port from `start`, trying up to max_attempts ports."""
for offset in range(max_attempts):
candidate = start + offset
if _is_port_free(host, candidate):
return candidate
raise RuntimeError(f"Could not find a free port in range {start}-{start + max_attempts - 1}")
from utils.paths.storage_roots import studio_root as _studio_root
_PID_FILE = _studio_root() / "studio.pid"
# Direct backend launches bypass the CLI's env re-export; do it here for
# real custom roots so unsloth-zoo's import-time LLAMA_CPP_DEFAULT_DIR
# picks up the custom build. Skip legacy-default to avoid flipping
# default-mode installs into env-override.
try:
_LEGACY_STUDIO_ROOT = (Path.home() / ".unsloth" / "studio").resolve()
except (OSError, ValueError):
_LEGACY_STUDIO_ROOT = Path.home() / ".unsloth" / "studio"
try:
_STUDIO_ROOT_RESOLVED = _studio_root().resolve()
except (OSError, ValueError):
_STUDIO_ROOT_RESOLVED = _studio_root()
if _STUDIO_ROOT_RESOLVED != _LEGACY_STUDIO_ROOT:
if not os.environ.get("UNSLOTH_STUDIO_HOME"):
os.environ["UNSLOTH_STUDIO_HOME"] = str(_STUDIO_ROOT_RESOLVED)
if not os.environ.get("UNSLOTH_LLAMA_CPP_PATH"):
os.environ["UNSLOTH_LLAMA_CPP_PATH"] = str(_STUDIO_ROOT_RESOLVED / "llama.cpp")
# The studio bundles unsloth_zoo; declare unsloth present (as `import unsloth`
# does) so its lazy submodule imports (export, hardware, mlx) and the
# DiffusionGemma runner never trip the install guard on a clean install.
os.environ.setdefault("UNSLOTH_IS_PRESENT", "1")
def _write_pid_file():
"""Write the current process PID to the studio PID file."""
try:
_PID_FILE.parent.mkdir(parents = True, exist_ok = True)
_PID_FILE.write_text(str(os.getpid()), encoding = "utf-8")
except OSError:
pass
def _remove_pid_file():
"""Remove the PID file if it belongs to this process."""
try:
if _PID_FILE.is_file():
stored = _PID_FILE.read_text(encoding = "utf-8").strip()
if stored == str(os.getpid()):
_PID_FILE.unlink(missing_ok = True)
except (OSError, UnicodeDecodeError):
pass
def _graceful_shutdown(server = None):
"""Shut down all subprocess backends and the uvicorn server.
Called from signal handlers to clean up children before exit. Critical on
Windows where atexit handlers are unreliable after Ctrl+C.
"""
_remove_pid_file()
logger.info("Graceful shutdown initiated -- cleaning up subprocesses...")
# 1. Shut down uvicorn (releases the listening socket).
if server is not None:
server.should_exit = True
# 2. Clean up inference subprocess (if instantiated).
try:
from core.inference.orchestrator import _inference_backend
if _inference_backend is not None:
_inference_backend._shutdown_subprocess(timeout = 5.0)
except Exception as e:
logger.warning("Error shutting down inference subprocess: %s", e)
# 3. Clean up export subprocess (if instantiated).
try:
from core.export.orchestrator import _export_backend
if _export_backend is not None:
_export_backend._shutdown_subprocess(timeout = 5.0)
except Exception as e:
logger.warning("Error shutting down export subprocess: %s", e)
# 4. Clean up training subprocess (if active).
try:
from core.training.training import _training_backend
if _training_backend is not None:
_training_backend.force_terminate()
except Exception as e:
logger.warning("Error shutting down training subprocess: %s", e)
# 5. Kill llama-server subprocess (if loaded).
try:
from routes.inference import _llama_cpp_backend
if _llama_cpp_backend is not None:
_llama_cpp_backend._kill_process()
except Exception as e:
logger.warning("Error shutting down llama-server: %s", e)
# 6. Stop the Cloudflare tunnel (if started).
try:
from cloudflare_tunnel import stop_studio_tunnel
stop_studio_tunnel()
except Exception as e:
logger.warning("Error stopping Cloudflare tunnel: %s", e)
# 7. Backstop sweep for any adopted child the steps above missed.
try:
from utils.process_lifetime import terminate_all
terminate_all()
except Exception as e:
logger.warning("Error in process-lifetime sweep: %s", e)
logger.info("All subprocesses cleaned up")
# Bound the join so a stuck uvicorn shutdown cannot hang the terminal.
_SERVER_SHUTDOWN_JOIN_TIMEOUT = 5.0
def _flush_standard_streams() -> None:
for stream in (sys.stdout, sys.stderr):
try:
stream.flush()
except Exception:
pass
def _wait_for_server_shutdown(timeout: Optional[float] = _SERVER_SHUTDOWN_JOIN_TIMEOUT) -> None:
"""Join the uvicorn thread so the prompt returns only after its shutdown logs
flush. Skip the self-join when called from the server thread."""
import threading
thread = _server_thread
if thread is None or thread is threading.current_thread():
_flush_standard_streams()
return
thread.join(timeout = timeout)
if thread.is_alive():
logger.warning("Timed out waiting for uvicorn server thread to stop")
_flush_standard_streams()
# The uvicorn server instance -- set by run_server(), used by callers
# that tell the server to exit (e.g. signal handlers).
_server = None
_server_thread = None
# Shutdown event -- wakes the main loop on signal.
_shutdown_event = None
# trycloudflare.com URL for wildcard binds (set by run_server, read by the banner);
# None when there is no tunnel (loopback, disabled, or a silently-ignored failure).
_cloudflare_url = None
# Public reachability from the last _verify_global_reachability run, read by the
# Cloudflare banner line. True when the public ip:port probe confirmed reachable,
# False when it confirmed NOT reachable, None when the probe did not run or could
# not decide (timeout, blocked, private address).
_public_reachable = None
_cloudflare_requested = False
# Opt-in tri-state (mirrors the CLI): None = off by default, True = on,
# False = explicit --no-cloudflare. run_server overwrites it before the banner.
_cloudflare_flag = None
_DEFAULT_FRONTEND_PATH = Path(__file__).resolve().parent.parent / "frontend" / "dist"
def _iter_frontend_fallback_candidates() -> "list[Path]":
"""Yield `studio/frontend/dist` paths to try when the default is missing.
Covers PATH-shadowed binaries whose __file__ resolves into a site-packages
tree with no vite build (e.g. plain `pip install unsloth`).
"""
import ast
import re
out: list[Path] = []
home_str = (
os.environ.get("UNSLOTH_STUDIO_HOME")
or os.environ.get("STUDIO_HOME")
or str(Path.home() / ".unsloth" / "studio")
)
venv_dir = Path(home_str).expanduser() / "unsloth_studio"
# Installer venv site-packages.
for pattern in (
"lib/python*/site-packages/studio/frontend/dist",
"Lib/site-packages/studio/frontend/dist",
):
out.extend(venv_dir.glob(pattern))
# Editable source roots referenced from the installer venv.
for sp_pattern in ("lib/python*/site-packages", "Lib/site-packages"):
for sp in venv_dir.glob(sp_pattern):
for finder in sp.glob("__editable___*_finder.py"):
try:
src = finder.read_text(encoding = "utf-8")
except (OSError, UnicodeDecodeError):
continue
# Tolerate single/multi-line dict literals; [^}]* rejects nested
# dicts, which the setuptools editable template never emits.
m = re.search(r"^MAPPING\s*(?::[^=]*)?=\s*(\{[^}]*\})", src, re.M | re.S)
if not m:
continue
try:
mapping = ast.literal_eval(m.group(1))
except (SyntaxError, ValueError):
continue
# literal_eval can return a set/list/None if `{...}` isn't a dict.
if not isinstance(mapping, dict):
continue
studio_pkg = mapping.get("studio")
if studio_pkg:
out.append(Path(studio_pkg) / "frontend" / "dist")
return out
def _resolve_frontend_path(frontend_path: Path) -> tuple[Optional[Path], list[Path]]:
"""Pick a frontend dir that contains `index.html`.
Returns (chosen, attempted). `chosen` is None if nothing servable was found;
`attempted` is the ordered list for diagnostics.
"""
attempted: list[Path] = []
seen: set[Path] = set()
def _try(p: Path) -> bool:
try:
key = p.resolve()
except OSError:
key = p
if key in seen:
return False
seen.add(key)
attempted.append(p)
return (p / "index.html").is_file()
if _try(Path(frontend_path)):
return attempted[-1], attempted
for alt in _iter_frontend_fallback_candidates():
if _try(alt):
return attempted[-1], attempted
return None, attempted
class _TeeStream:
"""Mirror writes to the original stream and a session log file.
Console behavior is unchanged (writes/returns delegate to the original
stream; Tauri's structured-stdout protocol and isatty probes see exactly
what they saw before). The file copy is best-effort: a full disk or a
closed handle must never break the console."""
def __init__(self, stream, log_fh):
self._stream = stream
self._log_fh = log_fh
def write(self, data):
try:
self._log_fh.write(data)
except Exception:
pass
return self._stream.write(data)
def flush(self):
try:
self._log_fh.flush()
except Exception:
pass
try:
self._stream.flush()
except Exception:
pass
def close(self):
# We do NOT own the console stream (it is the terminal / Jupyter kernel
# stream we wrapped), so closing the tee must never take the server down.
# Flush the log copy, then forward close() to the wrapped stream
# best-effort: on Colab that stream is an ipykernel OutStream whose
# close() can raise (see _harden_console_close / ipython/ipykernel#867).
try:
self._log_fh.flush()
except Exception:
pass
try:
self._stream.close()
except Exception:
pass
def __getattr__(self, name):
return getattr(self._stream, name)
_WATCH_FD_THREAD_ATTR = "watch_fd_thread"
def _is_missing_watch_fd_thread(exc):
"""True only for ipython/ipykernel#867's missing-``watch_fd_thread`` error.
``AttributeError.name`` exists from Python 3.10; the message carries the
attribute name on every version (possibly with a "Did you mean" tail), so
check both and let every other AttributeError through.
"""
if getattr(exc, "name", None) == _WATCH_FD_THREAD_ATTR:
return True
return _WATCH_FD_THREAD_ATTR in str(exc)
def _harden_console_close(stream):
"""Stop a displaced console stream's close() from aborting Studio startup.
``_setup_server_disk_logging`` replaces ``sys.stdout``/``sys.stderr`` with a
tee. That changes the object identity of the console stream, so a third-party
logging handler that captured the ORIGINAL stream (notably Colab's ``absl``
logging handler, whose ``close()`` skips ``sys.stdout``/``sys.stderr`` but not
a stream that is no longer either) treats it as an ordinary stream and calls
``close()`` on it during logging teardown -- ``uvicorn.Config()`` ->
``logging.config.dictConfig()`` -> ``logging.shutdown()``.
A Jupyter/Colab ``ipykernel`` ``OutStream`` created with ``watchfd=False``
(the Colab default, and every in-process kernel) never gains a
``watch_fd_thread``, yet the ``OutStream.close()`` shipped in the affected
ipykernel versions joins that thread unconditionally and raises
``AttributeError: 'OutStream' object has no attribute 'watch_fd_thread'``
(ipython/ipykernel#867). That AttributeError propagates out of
``uvicorn.Config(...)`` and aborts startup ("Unsloth Studio failed to start").
Wrap the stream's ``close()`` in a transparent pass-through that swallows
ONLY that specific teardown AttributeError. A healthy close() (a real console
stream, or an OutStream with fd-watching on) runs to completion exactly as
before and any other error still propagates, so nothing changes off Colab. A
stream whose ``close`` cannot be reassigned keeps its original close().
"""
try:
_orig_close = stream.close
except Exception:
return
def _safe_close(*args, **kwargs):
try:
return _orig_close(*args, **kwargs)
except AttributeError as exc:
if not _is_missing_watch_fd_thread(exc):
# A real teardown failure; never hide it.
raise
# ipython/ipykernel#867: watchfd=False OutStream.close() joins a
# thread that was never created. Nothing to clean up; keep going.
return None
try:
stream.close = _safe_close
except (AttributeError, TypeError):
# A stream that forbids setting instance attributes; leave it as-is.
pass
def _setup_server_disk_logging():
"""Tee stdout/stderr to ~/.unsloth/studio/logs/server/ and aim
faulthandler at the same file so hard crashes (access violations /
SIGSEGV in the GPU runtime) leave a stack trace on disk.
Also exports PYTHONFAULTHANDLER=1 so child Python processes (training
workers) dump native-crash stacks to their captured stderr. Keeps the
newest 20 session logs. Opt out with UNSLOTH_STUDIO_NO_FILE_LOG=1.
Returns the log path, or None when disabled/unavailable.
"""
if os.environ.get("UNSLOTH_STUDIO_NO_FILE_LOG") == "1":
return None
try:
from utils.paths import studio_root
log_dir = Path(studio_root()) / "logs" / "server"
except Exception:
home = (
os.environ.get("UNSLOTH_STUDIO_HOME")
or os.environ.get("STUDIO_HOME")
or os.path.join(os.path.expanduser("~"), ".unsloth", "studio")
)
log_dir = Path(home) / "logs" / "server"
try:
log_dir.mkdir(parents = True, exist_ok = True)
stamp = time.strftime("%Y%m%d-%H%M%S")
log_path = log_dir / f"server-{stamp}-pid{os.getpid()}.log"
# Line-buffered so the tail survives a hard kill; errors="replace"
# so a console encoding quirk can never take the server down.
log_fh = open(log_path, "w", encoding = "utf-8", errors = "replace", buffering = 1)
except Exception:
return None
import faulthandler
try:
faulthandler.enable(file = log_fh, all_threads = True)
except Exception:
pass
# Children (training workers) inherit: their native-crash stacks land on
# the stderr the server already captures.
os.environ.setdefault("PYTHONFAULTHANDLER", "1")
# Replacing the console streams orphans them from third-party "is this the
# live console?" checks, so guard their close() first (ipython/ipykernel#867).
_harden_console_close(sys.stdout)
_harden_console_close(sys.stderr)
sys.stdout = _TeeStream(sys.stdout, log_fh)
sys.stderr = _TeeStream(sys.stderr, log_fh)
# Best-effort retention: keep the newest 20 session logs.
try:
logs = sorted(log_dir.glob("server-*.log"), key = lambda p: p.stat().st_mtime)
for old in logs[:-20]:
old.unlink(missing_ok = True)
except Exception:
pass
return log_path
def _cloudflare_tunnel_should_start(
*, cloudflare: bool, host: str, secure: bool, api_only: bool, is_colab: bool
) -> bool:
"""Whether to start the Cloudflare tunnel. --secure exposes only the tunnel
(loopback bind), so it tunnels even api-only (headless secure API serving);
otherwise tunnel wildcard binds, never api-only (Tauri) or Colab."""
if is_colab or not cloudflare:
return False
if secure:
return True
return host in ("0.0.0.0", "::") and not api_only
def _stream_isatty(stream) -> bool:
"""isatty() that treats broken streams as non-interactive.
isatty() can raise under service wrappers (closed stdin -> ValueError;
sys.stdin None in Windows GUI -> AttributeError); such a stream can't host a
prompt, which is a fallback, not an error.
"""
try:
return stream.isatty()
except (AttributeError, ValueError):
return False
def _terminal_password_gate(
*,
tunnel_will_start: bool,
host: str,
secure: bool,
api_only: bool,
frontend_served: bool,
is_colab: bool = False,
) -> Tuple[bool, bool]:
"""Force a terminal password change before the public tunnel goes up.
When the tunnel is about to publish Unsloth and the seeded admin password was
never changed, ask for a new one (masked, confirmed) before any public URL
exists. The CLI normally does this before re-exec'ing the backend; this is
the backstop for direct `python run.py` launches and older-CLI installs.
Must run BEFORE the uvicorn socket binds: on a wildcard bind the served HTML
injects the bootstrap credential, so a pre-gate listener would hand the
default password to anyone reaching the raw port while the operator types.
Returns (proceed, drop_bootstrap_injection):
proceed False -> abort the launch (interactive refusal, or a headless
public launch nothing would protect); fail closed.
drop_bootstrap_injection True -> caller must null
app.state.bootstrap_password: the password just changed (stale), or a
public URL is about to serve the default credential and must not leak it.
Without a usable terminal the prompt is skipped: proceed if the bootstrap
deadline (armed later) will protect the launch; if even that is disabled
(api-only, timeout 0) nothing protects it, so refuse. NOT wrapped in a broad
try/except: an auth storage failure must abort rather than expose the default.
"""
if not tunnel_will_start:
return True, False
from auth import hashing as _auth_hashing
from auth import storage as _auth_storage
from auth.bootstrap_timeout import (
bootstrap_timeout_seconds,
should_arm_bootstrap_timeout,
)
from auth.terminal_prompt import (
prompt_for_password_change,
should_prompt_password_change,
)
_admin = _auth_storage.DEFAULT_ADMIN_USERNAME
# Gate can run before lifespan: seed the admin row here (idempotent).
_auth_storage.ensure_default_admin()
requires_change = _auth_storage.requires_password_change(_admin)
if not requires_change:
return True, False
if not should_prompt_password_change(
tunnel_will_start = tunnel_will_start,
requires_change = requires_change,
stdin_isatty = _stream_isatty(sys.stdin),
stderr_isatty = _stream_isatty(sys.stderr),
):
# No terminal: only proceed if the bootstrap deadline will arm; api-only
# and TIMEOUT=0 never arm it, leaving the default credential public.
deadline_arms = should_arm_bootstrap_timeout(
host = host,
secure = secure,
api_only = api_only,
frontend_served = frontend_served,
is_colab = is_colab,
requires_change = True,
timeout_seconds = bootstrap_timeout_seconds(),
)
if not deadline_arms:
print(
"Refusing to publish Unsloth on a public Cloudflare URL: the "
"default admin password was never changed, no terminal is "
"attached to change it here, and the bootstrap shutdown "
"deadline does not apply to this launch (api-only, or "
"UNSLOTH_STUDIO_BOOTSTRAP_TIMEOUT=0). Change the password "
"first (run `unsloth studio` locally and log in, or re-run "
"with a terminal attached), then retry.",
file = sys.stderr,
flush = True,
)
return False, False
# The public page won't auto-fill the bootstrap credential (suppressed
# below) and the seeded file may already be gone, so point recovery at a
# terminal-attached run / reset-password instead of reading it from disk.
print(
" WARNING: the default admin password is still active while "
"Unsloth is about to be published on a public Cloudflare URL, and "
"no terminal is attached to change it here. The public page will "
"NOT auto-fill the bootstrap credential. Set a new password by "
"running `unsloth studio` locally with a terminal attached, or "
"`unsloth studio reset-password`. Unsloth shuts down after the "
"bootstrap deadline (UNSLOTH_STUDIO_BOOTSTRAP_TIMEOUT, default 1h) "
"unless the password is changed.",
file = sys.stderr,
flush = True,
)
# Never serve the default credential in HTML over a public URL.
return True, True
def _is_current_password(candidate: str) -> bool:
record = _auth_storage.get_user_and_secret(_admin)
if record is None:
return False
salt, pwd_hash, _jwt_secret, _must_change = record
return _auth_hashing.verify_password(candidate, salt, pwd_hash)
def _apply_change(new_password: str) -> None:
# Same effects as routes/auth.py change_password: rehash, rotate the JWT
# secret, revoke refresh tokens in the SAME transaction.
_auth_storage.update_password(_admin, new_password, revoke_refresh_tokens = True)
changed = prompt_for_password_change(
min_length = _auth_storage.MIN_PASSWORD_LENGTH,
is_current_password = _is_current_password,
apply_change = _apply_change,
out = sys.stderr,
)
return (True, True) if changed else (False, False)
def _apply_supplied_password(password_value: "Optional[str]") -> None:
"""Non-interactively set the INITIAL admin password before the socket binds,
for a direct ``python run.py`` launch (the CLI does this in its own parent).
Value comes from --password / UNSLOTH_STUDIO_PASSWORD / stdin.
Only ever sets the FIRST password: an already-set one is a hard error, an
invalid value fails closed. NOT wrapped in a broad try/except: an auth
storage failure must abort rather than expose the default credential.
"""
from auth import hashing as _auth_hashing
from auth import storage as _auth_storage
from auth.terminal_prompt import SUPPLIED_PASSWORD_ENV, resolve_supplied_password
supplied = resolve_supplied_password(password_value)
# Strip the env var once read so child subprocesses (cloudflared, llama-server,
# code-exec tools) can't inherit the plaintext via /proc/PID/environ. Mirrors
# the CLI. Unconditional: strips a leftover value even when a literal --password won.
os.environ.pop(SUPPLIED_PASSWORD_ENV, None)
if not supplied:
return
_admin = _auth_storage.DEFAULT_ADMIN_USERNAME
_auth_storage.ensure_default_admin()
if not _auth_storage.requires_password_change(_admin):
print(
"Error: an Unsloth admin password is already set; --password only sets "
"the initial password. Run `unsloth studio reset-password` first.",
file = sys.stderr,
flush = True,
)
sys.exit(1)
def _is_current_password(candidate: str) -> bool:
record = _auth_storage.get_user_and_secret(_admin)
if record is None:
return False
salt, pwd_hash, _jwt_secret, _must_change = record
return _auth_hashing.verify_password(candidate, salt, pwd_hash)
if len(supplied) < _auth_storage.MIN_PASSWORD_LENGTH:
print(
f"Error: password must be at least {_auth_storage.MIN_PASSWORD_LENGTH} "
"characters; not starting.",
file = sys.stderr,
flush = True,
)
sys.exit(1)
if any(ch.isspace() for ch in supplied):
print(
"Error: password cannot contain spaces; not starting.",
file = sys.stderr,
flush = True,
)
sys.exit(1)
if _is_current_password(supplied):
print(
"Error: the new password must differ from the current bootstrap "
"password; not starting.",
file = sys.stderr,
flush = True,
)
sys.exit(1)
_auth_storage.update_password(_admin, supplied, revoke_refresh_tokens = True)
print(f"Password updated for '{_admin}'.", file = sys.stderr, flush = True)
def _apply_cli_tool_policy(enable_tools: "Optional[bool]") -> None:
"""Honor an explicit --enable-tools/--disable-tools; None leaves the policy
unset (tools default on, per-request enable_tools honored). Host is never
inspected here."""
if enable_tools is None:
return
from state.tool_policy import set_tool_policy
set_tool_policy(enable_tools)
def run_server(
host: str = "127.0.0.1",
port: int = 8888,
frontend_path: Path = _DEFAULT_FRONTEND_PATH,
silent: bool = False,
api_only: bool = False,
llama_parallel_slots: int = 1,
cloudflare: "Optional[bool]" = None,
secure: bool = False,
enable_tools: "Optional[bool]" = None,
password: "Optional[str]" = None,
emit_tauri_port: bool = True,
):
"""
Start the FastAPI server.
Args:
host: Host to bind to
port: Port to bind to (auto-increments if in use)
frontend_path: Path to frontend build directory (optional)
silent: Suppress startup messages
api_only: API server only, no frontend (for Tauri desktop app)
llama_parallel_slots: parallel slots for llama-server
cloudflare: opt in to the public Cloudflare HTTPS tunnel for a wildcard
bind. Tri-state: None (unset) and False both mean off; True enables it.
--secure implies it (True) and rejects an explicit False.
enable_tools: explicit --enable-tools/--disable-tools policy; None leaves
the default (tools on, per-request enable_tools honored)
emit_tauri_port: print the machine-readable TAURI_PORT line the desktop
app parses from stdout; the headless `run --api-only` path turns it
off so it does not pollute the documented URL/API-key banner
Note:
Signal handlers are NOT registered here so embedders (e.g. Colab) keep
their own interrupt semantics; standalone callers register them after.
"""
global _server, _server_thread, _shutdown_event
boot_started = time.perf_counter()
logger.info("run_server startup begin api_only=%s host=%s port=%s", api_only, host, port)
# Reap every child if the parent dies abnormally (terminal close, Task
# Manager kill, SIGKILL); must run before any child can spawn.
from utils.process_lifetime import initialize_parent_lifetime
initialize_parent_lifetime()
# --secure exposes ONLY the Cloudflare link: reject --secure --no-cloudflare,
# then force a loopback bind so the raw port is never public (even -H 0.0.0.0).
# Otherwise keep the tri-state so the banner distinguishes "off by default"
# from an explicit --no-cloudflare.
if secure:
if cloudflare is False:
raise SystemExit(
"--secure requires the Cloudflare tunnel; do not combine it with --no-cloudflare."
)
cloudflare = True
host = "127.0.0.1"
# `unsloth studio run` installs its own resolved policy and passes None here.
_apply_cli_tool_policy(enable_tools)
# Windows cp1252 can't encode emoji; reconfigure stdout to UTF-8.
if sys.platform == "win32" and hasattr(sys.stdout, "reconfigure"):
try:
sys.stdout.reconfigure(encoding = "utf-8", errors = "replace")
except Exception:
pass
# Persist a session log + native-crash stacks BEFORE importing main, so
# even import-time failures leave evidence on disk. Field report: Unsloth
# "terminates without a warning" -- a native crash in the GPU runtime
# kills the process with no Python traceback, and a desktop-shortcut
# console closes before anything can be read. Console-only logging made
# that undiagnosable.
_session_log = _setup_server_disk_logging()
if _session_log is not None and not silent:
print(f"Session log: {_session_log}")
# Set env vars BEFORE importing main so CORS middleware picks them up.
# secure api-only is a remote server behind Cloudflare, so it keeps the
# any-origin CORS profile; plain api-only stays locked to the Tauri app.
if api_only:
os.environ["UNSLOTH_API_ONLY"] = "1"
if secure:
os.environ["UNSLOTH_SECURE"] = "1"
import asyncio
# nest_asyncio is for Colab/IPython, where the main thread already runs a loop
# the blocking waits below would collide with. Apply it only with a loop running
# (a plain CLI start has nothing to nest) and only on Python <= 3.13: on 3.14+
# its global Task patch leaves asyncio.current_task() None (tracking moved into
# C), which also breaks the background uvicorn loop and 500s every request. It
# is archived upstream, so no 3.14 fix is coming; skip it there.
if sys.version_info < (3, 14):
try:
asyncio.get_running_loop()
except RuntimeError:
pass
else:
import nest_asyncio
nest_asyncio.apply()
from threading import Thread, Event
import uvicorn
# `from main import app` below loads torch/unsloth/transformers (~2 min cold,
# silent), so print a flushed heads-up (piped stdout is block-buffered).
if not silent:
print(
"Loading Unsloth Studio, please wait... (this can take a few minutes)",
flush = True,
)
print(" - loading PyTorch, Unsloth and Transformers...", flush = True)
import_started = time.perf_counter()
from main import app, setup_frontend, _IS_COLAB
logger.info(
"Imported FastAPI app in %.1fms",
(time.perf_counter() - import_started) * 1000,
)
if not silent:
print(" - Starting server...", flush = True)
from utils.paths import ensure_studio_directories
# Allow local stdio MCP servers on a loopback bind (the user's own machine),
# but never on Colab, which is a hosted VM reachable through its proxy. The
# gate reads the env var at request time, so this need not precede the import.
from utils.host_policy import apply_stdio_mcp_loopback_default
apply_stdio_mcp_loopback_default(host, is_colab = _IS_COLAB)
# Create all standard directories on startup.
ensure_studio_directories()
logger.info(
"Ensured Unsloth directories in %.1fms",
(time.perf_counter() - boot_started) * 1000,
)
# Auto-find a free port if the requested one is in use.
if not _is_port_free(host, port):
original_port = port
blocker = _get_pid_on_port(port)
port = _find_free_port(host, port + 1)
if not silent:
print("")
print("=" * 50)
if blocker:
pid, name = blocker
print(f"Port {original_port} is already in use by {name} (PID {pid}).")
else:
print(f"Port {original_port} is already in use.")
print(f"Unsloth Studio will use port {port} instead.")
print(f"Open http://localhost:{port} in your browser.")
print("=" * 50)
print("")
# Setup frontend (skip in api-only). Falls back through alternate locations if
# the default lacks a built dist; errors loudly rather than 404 on `/`.
if frontend_path and not api_only:
chosen, attempted = _resolve_frontend_path(Path(frontend_path))
if chosen is not None and setup_frontend(app, chosen):
if not silent:
# Resolve so logs show an absolute path for support.
try:
display = chosen.resolve()
except OSError:
display = chosen
print(f"[OK] Frontend loaded from {display}")
else:
home_str = (
os.environ.get("UNSLOTH_STUDIO_HOME")
or os.environ.get("STUDIO_HOME")
or str(Path.home() / ".unsloth" / "studio")
)
# Windows shim: $STUDIO_HOME/bin/unsloth.exe; Linux/macOS venv binary:
# $STUDIO_HOME/unsloth_studio/bin/unsloth.
home = Path(home_str).expanduser()
if sys.platform == "win32":
installer_bin = home / "bin" / "unsloth.exe"
else:
installer_bin = home / "unsloth_studio" / "bin" / "unsloth"
tried_lines = "\n".join(f" - {p}" for p in attempted) or " (none)"
raise SystemExit(
"[ERROR] Unsloth frontend build not found.\n"
f"Tried:\n{tried_lines}\n"
"\n"
"Likely cause: another 'unsloth' on PATH is shadowing the "
"installer's binary and points at a site-packages tree with "
"no built dist.\n"
"\n"
"Fix one of:\n"
f" - run the installer's binary directly: {installer_bin} studio\n"
" - pass --frontend <path/to/studio/frontend/dist>\n"
" - pass --api-only to skip serving the web UI\n"
" - reinstall: curl -fsSL https://unsloth.ai/install.sh | sh"
)
# Resolve once; shared by the log rewrite and banner.
display_host = _display_host_for_bind(host)
_install_uvicorn_startup_log_rewrite(host, display_host)
logger.info(
"run_server pre-uvicorn setup completed in %.1fms",
(time.perf_counter() - boot_started) * 1000,
)
ready_event = Event()
startup_failed = Event()
startup_errors = []
class _ReadyServer(uvicorn.Server):
async def startup(self, *args, **kwargs):
await super().startup(*args, **kwargs)
if getattr(self, "started", False) and not self.should_exit:
logger.info(
"Uvicorn startup hook completed in %.1fms",
(time.perf_counter() - boot_started) * 1000,
)
ready_event.set()
# server_header=False suppresses uvicorn's "Server: uvicorn"; SecurityHeadersMiddleware sets its own.
config_kwargs = dict(
host = host,
port = port,
log_level = "info",
access_log = False,
server_header = False,
)
# Colab only: trust X-Forwarded-* from Colab's reverse proxy so the app sees
# the real https origin. forwarded_allow_ips="*" is safe in Colab's
# single-user sandbox but too lax for local/standalone, so leave uvicorn's
# loopback-only default elsewhere.
if _IS_COLAB:
config_kwargs["proxy_headers"] = True
config_kwargs["forwarded_allow_ips"] = "*"
config = uvicorn.Config(app, **config_kwargs)
_server = _ReadyServer(config)
_shutdown_event = Event()
# Expose the actual bound port so handlers build loopback URLs at the real
# backend, not whatever a proxy/tunnel exposed. For ephemeral binds (port==0)
# leave it unset so handlers fall back to the request scope / base_url.
app.state.server_port = port if port and port > 0 else None
# Direct (non-tunnel) base for the API panel; resolve wildcard binds to the LAN IP.
if port and port > 0:
_direct_host = _display_host_for_bind(host)
app.state.server_url = f"http://{_url_host(_direct_host)}:{port}"
else:
app.state.server_url = None
app.state.secure = secure
app.state.llama_parallel_slots = llama_parallel_slots
# Expose a shutdown callable before the server accepts requests so
# /api/shutdown is ready as soon as readiness publishes.
def _trigger_shutdown():
_graceful_shutdown(_server)
if _shutdown_event is not None:
_shutdown_event.set()
app.state.trigger_shutdown = _trigger_shutdown
# A supplied --password / UNSLOTH_STUDIO_PASSWORD / stdin sets the initial
# admin password before the gate and socket bind (direct `python run.py`;
# the CLI applies it in its own parent).
_apply_supplied_password(password)
# Never publish with the seeded default password active: prompt first (or
# warn / fail closed headless; see _terminal_password_gate). Runs BEFORE the
# socket binds so a pre-gate listener can't hand out the injected credential.
_pw_proceed, _pw_drop_bootstrap = _terminal_password_gate(
tunnel_will_start = _cloudflare_tunnel_should_start(
cloudflare = cloudflare,
host = host,
secure = secure,
api_only = api_only,
is_colab = _IS_COLAB,
),
host = host,
secure = secure,
api_only = api_only,
frontend_served = bool(frontend_path) and not api_only,
is_colab = _IS_COLAB,
)
if not _pw_proceed:
print(
"Not starting Unsloth; set a new admin password first, or launch "
"without --secure/--cloudflare.",
file = sys.stderr,
flush = True,
)
sys.exit(1)
if _pw_drop_bootstrap:
# Password just changed (stale) or a public URL is about to serve the
# default credential: don't leak it in the HTML. Lifespan runs AFTER this
# and re-reads the bootstrap password, so the flag (not a plain None)
# makes it skip that re-read.
app.state.suppress_bootstrap_injection = True
app.state.bootstrap_password = None
# Run server in a daemon thread with explicit new_event_loop() +
# run_until_complete() (not asyncio.run) so nest_asyncio's patches don't
# interfere when Colab/IPython already runs a loop on the main thread.
def _run():
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
try:
loop.run_until_complete(_server.serve())
except BaseException as exc:
startup_errors.append(exc)
startup_failed.set()
finally:
loop.close()
if not ready_event.is_set():
startup_failed.set()
thread = Thread(target = _run, daemon = True)
_server_thread = thread
thread.start()
# Wait until uvicorn finishes lifespan startup and binds sockets, or until it
# exits/fails first. No deadline: a slow but live startup stays in progress.
try:
while not ready_event.is_set():
if startup_failed.is_set() or not thread.is_alive():
if startup_errors:
raise RuntimeError(
"Uvicorn server failed before startup completed"
) from startup_errors[0]
raise RuntimeError("Uvicorn server exited before startup completed")
ready_event.wait(timeout = 0.1)
except KeyboardInterrupt:
_graceful_shutdown(_server)
_shutdown_event.set()
raise
logger.info(
"run_server uvicorn ready after %.1fms",
(time.perf_counter() - boot_started) * 1000,
)
_write_pid_file()
import atexit
atexit.register(_remove_pid_file)
from utils.process_lifetime import terminate_all
atexit.register(terminate_all)
# Output port for Tauri (api-only), only after sockets bind and startup done.
# The headless `run --api-only` path opts out so it does not leak this line.
if api_only and emit_tauri_port:
print(f"TAURI_PORT={port}", flush = True)
# Free trycloudflare.com tunnel for wildcard binds (the raw ip:port is often
# unreachable). Started pre-banner and even when silent so the CLI banner can
# read app.state.cloudflare_url; torn down by _graceful_shutdown.
global _cloudflare_url, _cloudflare_requested, _cloudflare_flag
_cloudflare_url = None
_cloudflare_flag = cloudflare
app.state.cloudflare_url = None
_cloudflare_enabled = _cloudflare_tunnel_should_start(
cloudflare = cloudflare,
host = host,
secure = secure,
api_only = api_only,
is_colab = _IS_COLAB,
)
_cloudflare_requested = _cloudflare_enabled
if _cloudflare_enabled:
try: # best-effort: any failure must not block startup
from cloudflare_tunnel import start_studio_tunnel, stop_studio_tunnel
_cloudflare_url = start_studio_tunnel(port)
app.state.cloudflare_url = _cloudflare_url
# Backstop: tear the tunnel down even on an abnormal exit that bypasses
# _graceful_shutdown (e.g. an exception after startup -> sys.exit). Idempotent.
atexit.register(stop_studio_tunnel)
except Exception as e:
logger.debug("Cloudflare tunnel skipped: %s", e)
# --secure fails closed: no tunnel means no public link, so exit rather than
# silently fall back to a raw port.
if secure and not _cloudflare_url:
print(
"A secure Cloudflare link is not allowed, use --no-secure which provides a 0.0.0.0 link",
file = sys.stderr,
flush = True,
)
_graceful_shutdown(_server)
sys.exit(1)
# Time-box a freshly-exposed web UI: if nobody changes the seeded admin
# password within the deadline (default 1h), shut down rather than leave an
# unsecured public instance running. No-op for loopback, --api-only, Colab,
# an already-changed password, or UNSLOTH_STUDIO_BOOTSTRAP_TIMEOUT=0.
try:
from auth import storage as _auth_storage
from auth.bootstrap_timeout import (
arm_bootstrap_timeout,
bootstrap_timeout_seconds,
should_arm_bootstrap_timeout,
)
_bootstrap_timeout = bootstrap_timeout_seconds()
if should_arm_bootstrap_timeout(
host = host,
secure = secure,
api_only = api_only,
frontend_served = bool(frontend_path) and not api_only,
is_colab = _IS_COLAB,
requires_change = _auth_storage.requires_password_change(
_auth_storage.DEFAULT_ADMIN_USERNAME
),
timeout_seconds = _bootstrap_timeout,
):
arm_bootstrap_timeout(
_auth_storage,
_trigger_shutdown,
timeout_seconds = _bootstrap_timeout,
logger = logger,
)
logger.info(
"Unsloth will shut down in %ds unless the default admin password is changed.",
_bootstrap_timeout,
)
except Exception as e: # best-effort: never block startup on the timeout
logger.warning("Bootstrap timeout not armed: %s", e)
if not silent:
_emit_startup_output(host, port, display_host, secure = secure, enable_tools = enable_tools)
return app
# Mirror unsloth_cli/commands/studio.py's _PARALLEL_*. Default 1 is for direct
# backend launches; `unsloth studio run` always passes its own value (4).
_PARALLEL_MIN = 1
_PARALLEL_MAX = 64
_PARALLEL_DEFAULT_PLAIN = 1
def _build_arg_parser():
"""Build the backend CLI argument parser.
Extracted from the __main__ block so the flag wiring (notably the
--secure/--no-secure polarity and its --not-secure alias) stays unit-testable.
"""
import argparse
parser = argparse.ArgumentParser(description = "Run Unsloth UI Backend server")
parser.add_argument(
"--host",
default = "127.0.0.1",
help = "Host to bind to (default: 127.0.0.1; use 0.0.0.0 for network/cloud access)",
)
parser.add_argument(
"--password",
default = None,
help = "Set the INITIAL admin password non-interactively (headless), only when "
"none is set yet. Also reads UNSLOTH_STUDIO_PASSWORD, or --password - for stdin. "
"A literal value is visible in the process list. Rotate later via "
"`unsloth studio reset-password`.",
)
parser.add_argument("--port", type = int, default = 8888, help = "Port to bind to")
parser.add_argument(
"--frontend",
type = str,
default = _DEFAULT_FRONTEND_PATH,
help = "Path to frontend build",
)
parser.add_argument("--silent", action = "store_true", help = "Suppress output")
parser.add_argument(
"--api-only",
action = "store_true",
help = "API server only, no frontend (for Tauri)",
)
parser.add_argument(
"--cloudflare",
action = argparse.BooleanOptionalAction,
default = None,
help = "Expose Unsloth on a PUBLIC internet URL via a free Cloudflare HTTPS "
"tunnel, for non-api-only wildcard binds (0.0.0.0 or ::). Off by default; "
"pass --cloudflare to enable it (--secure implies it), --no-cloudflare to "
"force it off. It does not change a raw wildcard bind. If the admin "
"password was never changed, Unsloth asks for a new one in the terminal "
"before publishing the URL.",
)
parser.add_argument(
"--secure",
action = argparse.BooleanOptionalAction,
default = False,
help = "Expose ONLY a Cloudflare HTTPS link: bind localhost and fail closed "
"if the tunnel can't start. Without it, --no-secure also serves the raw "
"0.0.0.0 port, which is reachable from anywhere on the network. If the "
"admin password was never changed, Unsloth asks for a new one in the "
"terminal before publishing the URL.",
)
# Back-compat: accept --not-secure as a hidden alias for --no-secure.
parser.add_argument(
"--not-secure",
dest = "secure",
action = "store_false",
default = argparse.SUPPRESS,
help = argparse.SUPPRESS,
)
# Tri-state tool policy: no flag -> None (tools on, per-request honored);
# --enable-tools/--disable-tools force on/off.
parser.add_argument(
"--enable-tools",
dest = "enable_tools",
action = "store_true",
default = None,
help = "Force server-side tools (web search, code execution) on for "
"every request. Default: on for every bind, per-request setting honored.",
)
parser.add_argument(
"--disable-tools",
dest = "enable_tools",
action = "store_false",
default = None,
help = "Force server-side tools off for every request.",
)
parser.add_argument(
"--disable-dns-pinning",
action = "store_true",
help = "Allow hostname-based web fetches for enterprise proxies. WARNING: weakens "
"DNS-rebinding protection; hostname and redirect validation remain enabled.",
)
parser.add_argument(
"--parallel",
"--n-parallel",
type = int,
default = _PARALLEL_DEFAULT_PLAIN,
help = (
f"llama-server parallel decode slots ({_PARALLEL_MIN}..{_PARALLEL_MAX}). "
f"Default {_PARALLEL_DEFAULT_PLAIN}; `unsloth studio run` uses 4."
),
)
return parser
# For direct execution (also invoked by CLI via os.execvp / subprocess).
if __name__ == "__main__":
# Correct a conflicting system CUDA on LD_LIBRARY_PATH before torch is
# imported (below, via run_server). Re-execs once on Linux so the dynamic
# linker uses torch's bundled CUDA libs; no-op on other platforms, when
# LD_LIBRARY_PATH is unset or already correct, or after the single re-exec.
_maybe_reexec_for_cuda_ld_path()
import signal
import traceback
# Ensure stderr handles Unicode on Windows (non-ASCII path tracebacks).
if sys.platform == "win32" and hasattr(sys.stderr, "reconfigure"):
try:
sys.stderr.reconfigure(encoding = "utf-8", errors = "replace")
except Exception:
pass
parser = _build_arg_parser()
args = parser.parse_args()
if not _PARALLEL_MIN <= args.parallel <= _PARALLEL_MAX:
parser.error(f"--parallel must be between {_PARALLEL_MIN} and {_PARALLEL_MAX}")
if args.secure and args.cloudflare is False:
parser.error(
"--secure requires the Cloudflare tunnel; do not combine it with --no-cloudflare"
)
if args.disable_dns_pinning:
os.environ["UNSLOTH_STUDIO_DISABLE_DNS_PINNING"] = "1"
else:
os.environ.setdefault("UNSLOTH_STUDIO_DISABLE_DNS_PINNING", "0")
kwargs = dict(
host = args.host,
port = args.port,
silent = args.silent,
api_only = args.api_only,
llama_parallel_slots = args.parallel,
cloudflare = args.cloudflare,
secure = args.secure,
enable_tools = args.enable_tools,
password = args.password,
)
if args.frontend is not None:
kwargs["frontend_path"] = Path(args.frontend)
try:
run_server(**kwargs)
except Exception:
sys.stderr.write("\n")
sys.stderr.write("=" * 60 + "\n")
sys.stderr.write("ERROR: Unsloth Studio failed to start.\n")
sys.stderr.write("=" * 60 + "\n")
traceback.print_exc(file = sys.stderr)
sys.stderr.write("\n")
sys.stderr.write("If a package is missing, try re-running: unsloth studio setup\n")
sys.stderr.flush()
sys.exit(1)
# Signal handler -- ensures subprocess cleanup on Ctrl+C.
def _signal_handler(signum, frame):
# Restore defaults so a second signal force-quits if shutdown stalls.
signal.signal(signal.SIGINT, signal.SIG_DFL)
signal.signal(signal.SIGTERM, signal.SIG_DFL)
if hasattr(signal, "SIGBREAK"):
signal.signal(signal.SIGBREAK, signal.SIG_DFL)
_graceful_shutdown(_server)
_shutdown_event.set()
signal.signal(signal.SIGINT, _signal_handler)
signal.signal(signal.SIGTERM, _signal_handler)
# On Windows, some terminals send SIGBREAK for Ctrl+C / Ctrl+Break.
if hasattr(signal, "SIGBREAK"):
signal.signal(signal.SIGBREAK, _signal_handler)
# Keep running until shutdown signal. Event.wait() without a timeout blocks at
# the C level on Linux, preventing SIGINT delivery; a short timeout in a loop
# lets the interpreter process pending signals.
while not _shutdown_event.is_set():
_shutdown_event.wait(timeout = 1)
_wait_for_server_shutdown()