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{"repo": "samschott/maestral", "pull_number": 146, "instance_id": "samschott__maestral-146", "issue_numbers": "", "base_commit": "9bc149fd9a478de4d6082208c9ffca31b1d7f508", "patch": "diff --git a/maestral/cli.py b/maestral/cli.py\n--- a/maestral/cli.py\n+++ b/maestral/cli.py\n@@ -445,16 +445,10 @@ def gui(config_name):\n def start(config_name: str, foreground: bool, verbose: bool):\n \"\"\"Starts the Maestral daemon.\"\"\"\n \n- from maestral.daemon import get_maestral_pid, get_maestral_proxy\n+ from maestral.daemon import get_maestral_proxy\n from maestral.daemon import (start_maestral_daemon_thread, threads,\n start_maestral_daemon_process, Start)\n \n- # do nothing if already running\n- if get_maestral_pid(config_name):\n- click.echo('Maestral daemon is already running.')\n- return\n-\n- # start daemon\n click.echo('Starting Maestral...', nl=False)\n \n if foreground:\n@@ -464,6 +458,9 @@ def start(config_name: str, foreground: bool, verbose: bool):\n \n if res == Start.Ok:\n click.echo('\\rStarting Maestral... ' + OK)\n+ elif res == Start.AlreadyRunning:\n+ click.echo('\\rStarting Maestral... Already running.')\n+ return\n else:\n click.echo('\\rStarting Maestral... ' + FAILED)\n click.echo('Please check logs for more information.')\n@@ -841,14 +838,14 @@ def rebuild_index(config_name: str):\n @main.command(help_priority=16)\n def configs():\n \"\"\"Lists all configured Dropbox accounts.\"\"\"\n- from maestral.daemon import get_maestral_pid\n+ from maestral.daemon import is_running\n \n # clean up stale configs\n config_names = list_configs()\n \n for name in config_names:\n dbid = MaestralConfig(name).get('account', 'account_id')\n- if dbid == '' and not get_maestral_pid(name):\n+ if dbid == '' and not is_running(name):\n remove_configuration(name)\n \n # display remaining configs\n@@ -1132,4 +1129,4 @@ def notify_snooze(config_name: str, minutes: int):\n click.echo(f'Notifications snoozed for {minutes} min. '\n 'Set snooze to 0 to reset.')\n else:\n- click.echo(f'Notifications enabled.')\n+ click.echo('Notifications enabled.')\ndiff --git a/maestral/daemon.py b/maestral/daemon.py\n--- a/maestral/daemon.py\n+++ b/maestral/daemon.py\n@@ -16,16 +16,22 @@\n import signal\n import traceback\n import enum\n+import subprocess\n+import threading\n+import fcntl\n+import struct\n+import tempfile\n \n # external imports\n import Pyro5.errors\n from Pyro5.api import Daemon, Proxy, expose, oneway\n from Pyro5.serializers import SerpentSerializer\n-from lockfile.pidlockfile import PIDLockFile, AlreadyLocked\n+from fasteners import InterProcessLock\n \n # local imports\n from maestral.errors import SYNC_ERRORS, FATAL_ERRORS\n from maestral.constants import IS_FROZEN\n+from maestral.utils.appdirs import get_runtime_path\n \n \n threads = dict()\n@@ -76,6 +82,151 @@ def serpent_deserialize_api_error(class_name, d):\n )\n \n \n+# ==== interprocess locking ==============================================================\n+\n+def _get_lockdata():\n+\n+ try:\n+ os.O_LARGEFILE\n+ except AttributeError:\n+ start_len = 'll'\n+ else:\n+ start_len = 'qq'\n+\n+ if (sys.platform.startswith(('netbsd', 'freebsd', 'openbsd'))\n+ or sys.platform == 'darwin'):\n+ if struct.calcsize('l') == 8:\n+ off_t = 'l'\n+ pid_t = 'i'\n+ else:\n+ off_t = 'lxxxx'\n+ pid_t = 'l'\n+\n+ fmt = off_t + off_t + pid_t + 'hh'\n+ pid_index = 2\n+ lockdata = struct.pack(fmt, 0, 0, 0, fcntl.F_WRLCK, 0)\n+ # elif sys.platform.startswith('gnukfreebsd'):\n+ # fmt = 'qqihhi'\n+ # pid_index = 2\n+ # lockdata = struct.pack(fmt, 0, 0, 0, fcntl.F_WRLCK, 0, 0)\n+ # elif sys.platform in ('hp-uxB', 'unixware7'):\n+ # fmt = 'hhlllii'\n+ # pid_index = 2\n+ # lockdata = struct.pack(fmt, fcntl.F_WRLCK, 0, 0, 0, 0, 0, 0)\n+ elif sys.platform.startswith('linux'):\n+ fmt = 'hh' + start_len + 'ih'\n+ pid_index = 4\n+ lockdata = struct.pack(fmt, fcntl.F_WRLCK, 0, 0, 0, 0, 0)\n+ else:\n+ raise RuntimeError(f'Unsupported platform {sys.platform}')\n+\n+ return lockdata, fmt, pid_index\n+\n+\n+class Lock:\n+ \"\"\"\n+ A inter-process and inter-thread lock. This reuses uses code from oslo.concurrency\n+ but provides non-blocking acquire. Use the :meth:`singleton` class method to retrieve\n+ an existing instance for thread-safe usage.\n+ \"\"\"\n+\n+ _instances = dict()\n+ _singleton_lock = threading.Lock()\n+\n+ @classmethod\n+ def singleton(cls, name, lock_path=None):\n+\n+ with cls._singleton_lock:\n+ try:\n+ instance = cls._instances[name]\n+ except KeyError:\n+ instance = cls(name, lock_path)\n+ cls._instances[name] = instance\n+\n+ return instance\n+\n+ def __init__(self, name, lock_path=None):\n+\n+ self.name = name\n+ dirname = lock_path or tempfile.gettempdir()\n+ lock_path = os.path.join(dirname, name)\n+\n+ self._internal_lock = threading.Semaphore()\n+ self._external_lock = InterProcessLock(lock_path)\n+\n+ self._lock = threading.RLock()\n+\n+ def acquire(self):\n+ \"\"\"\n+ Attempts to acquire the given lock.\n+\n+ :returns: Whether or not the acquisition succeeded.\n+ :rtype: bool\n+ \"\"\"\n+\n+ with self._lock:\n+ locked_internal = self._internal_lock.acquire(blocking=False)\n+\n+ if not locked_internal:\n+ return False\n+\n+ try:\n+ locked_external = self._external_lock.acquire(blocking=False)\n+ except Exception:\n+ self._internal_lock.release()\n+ raise\n+ else:\n+\n+ if locked_external:\n+ return True\n+ else:\n+ self._internal_lock.release()\n+ return False\n+\n+ def release(self):\n+ \"\"\"Release the previously acquired lock.\"\"\"\n+ with self._lock:\n+ self._external_lock.release()\n+ self._internal_lock.release()\n+\n+ def locked(self):\n+ \"\"\"Checks if the lock is currently held by any thread or process.\"\"\"\n+ with self._lock:\n+ gotten = self.acquire()\n+ if gotten:\n+ self.release()\n+ return not gotten\n+\n+ def locking_pid(self):\n+ \"\"\"\n+ Returns the PID of the process which currently holds the lock or None.\n+\n+ :returns: The PID of the process which currently holds the lock or None.\n+ :rtype: int\n+ \"\"\"\n+\n+ with self._lock:\n+\n+ if self._external_lock.acquired:\n+ return os.getpid()\n+\n+ try:\n+ # don't close again in case we are the locking process\n+ self._external_lock._do_open()\n+ lockdata, fmt, pid_index = _get_lockdata()\n+ lockdata = fcntl.fcntl(self._external_lock.lockfile,\n+ fcntl.F_GETLK, lockdata)\n+\n+ lockdata_list = struct.unpack(fmt, lockdata)\n+ pid = lockdata_list[pid_index]\n+\n+ if pid > 0:\n+ return pid\n+\n+ except OSError:\n+ pass\n+\n+\n # ==== helpers for daemon management =====================================================\n \n def _escape_spaces(string):\n@@ -93,12 +244,15 @@ def _send_term(pid):\n pass\n \n \n-def _process_exists(pid):\n- try:\n- os.kill(pid, signal.SIG_DFL)\n- return True\n- except ProcessLookupError:\n- return False\n+class MaestralLock:\n+ \"\"\"\n+ A inter-process and inter-thread lock for Maestral.\n+ \"\"\"\n+\n+ def __new__(cls, config_name):\n+ name = f'{config_name}.lock'\n+ path = get_runtime_path('maestral')\n+ return Lock.singleton(name, path)\n \n \n def sockpath_for_config(config_name):\n@@ -106,28 +260,11 @@ def sockpath_for_config(config_name):\n Returns the unix socket location to be used for the config. This should default to\n the apps runtime directory + '/maestral/CONFIG_NAME.sock'.\n \"\"\"\n- from maestral.utils.appdirs import get_runtime_path\n- return get_runtime_path('maestral', config_name + '.sock')\n-\n-\n-def pidpath_for_config(config_name):\n- from maestral.utils.appdirs import get_runtime_path\n- return get_runtime_path('maestral', config_name + '.pid')\n-\n+ return get_runtime_path('maestral', f'{config_name}.sock')\n \n-def is_pidfile_stale(pidfile):\n- \"\"\"\n- Determine whether a PID file is stale. Returns ``True`` if the PID file is stale,\n- ``False`` otherwise. The PID file is stale if its contents are valid but do not\n- match the PID of a currently-running process.\n- \"\"\"\n- result = False\n \n- pid = pidfile.read_pid()\n- if pid:\n- return not _process_exists(pid)\n- else:\n- return result\n+def lockpath_for_config(config_name):\n+ return get_runtime_path('maestral', f'{config_name}.lock')\n \n \n def get_maestral_pid(config_name):\n@@ -139,39 +276,28 @@ def get_maestral_pid(config_name):\n :rtype: int\n \"\"\"\n \n- lockfile = PIDLockFile(pidpath_for_config(config_name))\n- pid = lockfile.read_pid()\n-\n- if pid and not is_pidfile_stale(lockfile):\n- return pid\n- else:\n- lockfile.break_lock()\n+ return MaestralLock(config_name).locking_pid()\n \n \n-def _wait_for_startup(config_name, timeout=8):\n- \"\"\"Waits for the daemon to start and verifies Pyro communication. Returns ``Start.Ok``\n- if startup and communication succeeds within timeout, ``Start.Failed`` otherwise.\"\"\"\n- t0 = time.time()\n- pid = None\n+def is_running(config_name):\n+ \"\"\"\n+ Checks if a daemon is currently running.\n \n- while not pid and time.time() - t0 < timeout / 2:\n- pid = get_maestral_pid(config_name)\n- time.sleep(0.2)\n+ :param str config_name: The name of the Maestral configuration.\n+ :returns: Whether the daemon is running.\n+ :rtype: bool\n+ \"\"\"\n \n- if pid:\n- return _check_pyro_communication(config_name, timeout=int(timeout / 2))\n- else:\n- return Start.Failed\n+ return MaestralLock(config_name).locked()\n \n \n-def _check_pyro_communication(config_name, timeout=4):\n+def _wait_for_startup(config_name, timeout=8):\n \"\"\"Checks if we can communicate with the maestral daemon. Returns ``Start.Ok`` if\n communication succeeds within timeout, ``Start.Failed`` otherwise.\"\"\"\n \n sock_name = sockpath_for_config(config_name)\n maestral_daemon = Proxy(URI.format(_escape_spaces(config_name), './u:' + sock_name))\n \n- # wait until we can communicate with daemon, timeout after :param:`timeout`\n while timeout > 0:\n try:\n maestral_daemon._pyroBind()\n@@ -189,36 +315,30 @@ def _check_pyro_communication(config_name, timeout=4):\n \n def start_maestral_daemon(config_name='maestral', log_to_stdout=False):\n \"\"\"\n+ Starts the Maestral daemon with event loop in the current thread. Startup is race\n+ free: there will never be two daemons running for the same config.\n+\n Wraps :class:`main.Maestral` as Pyro daemon object, creates a new instance and starts\n Pyro's event loop to listen for requests on a unix domain socket. This call will block\n until the event loop shuts down.\n \n- This command will return silently if the daemon is already running.\n-\n :param str config_name: The name of the Maestral configuration to use.\n :param bool log_to_stdout: If ``True``, write logs to stdout. Defaults to ``False``.\n+ :raises: :class:`RuntimeError` if a daemon for the given ``config_name`` is already\n+ running.\n \"\"\"\n import threading\n from maestral.main import Maestral\n \n- sock_name = sockpath_for_config(config_name)\n- pid_name = pidpath_for_config(config_name)\n-\n- lockfile = PIDLockFile(pid_name)\n+ sockpath = sockpath_for_config(config_name)\n \n if threading.current_thread() is threading.main_thread():\n signal.signal(signal.SIGTERM, _sigterm_handler)\n \n # acquire PID lock file\n-\n- try:\n- lockfile.acquire(timeout=0.5)\n- except AlreadyLocked:\n- if is_pidfile_stale(lockfile):\n- lockfile.break_lock()\n- lockfile.acquire()\n- else:\n- return\n+ lock = MaestralLock(config_name)\n+ if not lock.acquire():\n+ raise RuntimeError('Maestral daemon is already running')\n \n # Nice ourselves to give other processes priority. We will likely only\n # have significant CPU usage in case of many concurrent downloads.\n@@ -227,7 +347,7 @@ def start_maestral_daemon(config_name='maestral', log_to_stdout=False):\n try:\n # clean up old socket\n try:\n- os.remove(sock_name)\n+ os.remove(sockpath)\n except FileNotFoundError:\n pass\n \n@@ -243,7 +363,7 @@ def start_maestral_daemon(config_name='maestral', log_to_stdout=False):\n \n m = ExposedMaestral(config_name, log_to_stdout=log_to_stdout)\n \n- with Daemon(unixsocket=sock_name) as daemon:\n+ with Daemon(unixsocket=sockpath) as daemon:\n daemon.register(m, f'maestral.{_escape_spaces(config_name)}')\n daemon.requestLoop(loopCondition=m._loop_condition)\n \n@@ -252,24 +372,24 @@ def start_maestral_daemon(config_name='maestral', log_to_stdout=False):\n except (KeyboardInterrupt, SystemExit):\n sys.exit(0)\n finally:\n- lockfile.release()\n+ lock.release()\n \n \n def start_maestral_daemon_thread(config_name='maestral', log_to_stdout=False):\n \"\"\"\n- Starts the Maestral daemon in a thread (by calling :func:`start_maestral_daemon`).\n+ Starts the Maestral daemon in a new thread by calling :func:`start_maestral_daemon`.\n+ Startup is race free: there will never be two daemons running for the same config.\n \n :param str config_name: The name of the Maestral configuration to use.\n :param bool log_to_stdout: If ``True``, write logs to stdout. Defaults to ``False``.\n :returns: ``Start.Ok`` if successful, ``Start.AlreadyRunning`` if the daemon was\n- already running or ``Start.Failed`` if startup failed.\n+ already running or ``Start.Failed`` if startup failed. It is possible that\n+ Start.Ok is returned instead of Start.AlreadyRunning in case of a race.\n \"\"\"\n \n- if config_name in threads and threads[config_name].is_alive():\n+ if is_running(config_name):\n return Start.AlreadyRunning\n \n- import threading\n-\n t = threading.Thread(\n target=start_maestral_daemon,\n args=(config_name, log_to_stdout),\n@@ -288,17 +408,18 @@ def start_maestral_daemon_thread(config_name='maestral', log_to_stdout=False):\n \n def start_maestral_daemon_process(config_name='maestral', log_to_stdout=False):\n \"\"\"\n- Starts the Maestral daemon in a separate process by calling\n- :func:`start_maestral_daemon`.\n+ Starts the Maestral daemon in a new process by calling :func:`start_maestral_daemon`.\n+ Startup is race free: there will never be two daemons running for the same config.\n \n- This function assumes that ``sys.executable`` points to the Python executable. In\n- case of a frozen app, the executable must take the command line argument\n- ``--frozen-daemon to start`` a daemon process which is *not syncing*, .i.e., just run\n- :meth:`start_maestral_daemon`. This is currently supported through the\n- constole_script entry points of both `maestral` and `maestral_qt`.\n+ This function assumes that ``sys.executable`` points to the Python executable or a\n+ frozen executable. In case of a frozen executable, the executable must take the\n+ command line argument ``--frozen-daemon to start`` to start a daemon process which is\n+ *not syncing*, .i.e., just run :meth:`start_maestral_daemon`. This is currently\n+ supported through the console_script entry points of both `maestral` and\n+ `maestral_qt`.\n \n Starting a detached daemon process is difficult from a standalone executable since\n- the typical double-fork magic may fail on macOS and we do not have acccess to a\n+ the typical double-fork magic may fail on macOS and we do not have access to a\n standalone Python interpreter to spawn a subprocess. Our approach mimics the \"freeze\n support\" implemented by the multiprocessing module but fully detaches the spawned\n process.\n@@ -306,18 +427,19 @@ def start_maestral_daemon_process(config_name='maestral', log_to_stdout=False):\n :param str config_name: The name of the Maestral configuration to use.\n :param bool log_to_stdout: If ``True``, write logs to stdout. Defaults to ``False``.\n :returns: ``Start.Ok`` if successful, ``Start.AlreadyRunning`` if the daemon was\n- already running or ``Start.Failed`` if startup failed.\n+ already running or ``Start.Failed`` if startup failed. It is possible that\n+ Start.Ok is returned instead of Start.AlreadyRunning in case of a race.\n \"\"\"\n- import subprocess\n+\n+ if is_running(config_name):\n+ return Start.AlreadyRunning\n+\n from shlex import quote\n import multiprocessing as mp\n \n # use nested Popen and multiprocessing.Process to effectively create double fork\n # see Unix 'double-fork magic'\n \n- if get_maestral_pid(config_name):\n- return Start.AlreadyRunning\n-\n if IS_FROZEN:\n \n def target():\n@@ -347,48 +469,49 @@ def target():\n def stop_maestral_daemon_process(config_name='maestral', timeout=10):\n \"\"\"Stops a maestral daemon process by finding its PID and shutting it down.\n \n- This function first tries to shut down Maestral gracefully. If this fails, it will\n- send SIGTERM. If that fails as well, it will send SIGKILL to the process.\n+ This function first tries to shut down Maestral gracefully. If this fails and we know\n+ its PID, it will send SIGTERM. If that fails as well, it will send SIGKILL to the\n+ process.\n \n :param str config_name: The name of the Maestral configuration to use.\n :param float timeout: Number of sec to wait for daemon to shut down before killing it.\n- :returns: ``Exit.Ok`` if successful, ``Exit.Killed`` if killed and ``Exit.NotRunning``\n- if the daemon was not running.\n+ :returns: ``Exit.Ok`` if successful, ``Exit.Killed`` if killed, ``Exit.NotRunning`` if\n+ the daemon was not running and ``Exit.Failed`` if killing the process failed\n+ because we could not retrieve its PID.\n \"\"\"\n \n- lockfile = PIDLockFile(pidpath_for_config(config_name))\n- pid = lockfile.read_pid()\n+ if not is_running(config_name):\n+ return Exit.NotRunning\n \n- try:\n- if not pid or not _process_exists(pid):\n- return Exit.NotRunning\n+ pid = get_maestral_pid(config_name)\n \n- try:\n- with MaestralProxy(config_name) as m:\n- m.stop_sync()\n- m.shutdown_pyro_daemon()\n- except Pyro5.errors.CommunicationError:\n+ try:\n+ with MaestralProxy(config_name) as m:\n+ m.stop_sync()\n+ m.shutdown_pyro_daemon()\n+ except Pyro5.errors.CommunicationError:\n+ if pid:\n _send_term(pid)\n- finally:\n- while timeout > 0:\n- if not _process_exists(pid):\n- return Exit.Ok\n- else:\n- time.sleep(0.2)\n- timeout -= 0.2\n+ finally:\n+ while timeout > 0:\n+ if not is_running(config_name):\n+ return Exit.Ok\n+ else:\n+ time.sleep(0.2)\n+ timeout -= 0.2\n \n- # send SIGTERM after timeout and delete PID file\n- _send_term(pid)\n+ # send SIGTERM after timeout and delete PID file\n+ _send_term(pid)\n \n- time.sleep(1)\n+ time.sleep(1)\n \n- if not _process_exists(pid):\n- return Exit.Ok\n- else:\n- os.kill(pid, signal.SIGKILL)\n- return Exit.Killed\n- finally:\n- lockfile.break_lock()\n+ if not is_running(config_name):\n+ return Exit.Ok\n+ elif pid:\n+ os.kill(pid, signal.SIGKILL)\n+ return Exit.Killed\n+ else:\n+ return Exit.Failed\n \n \n def stop_maestral_daemon_thread(config_name='maestral', timeout=10):\n@@ -400,11 +523,7 @@ def stop_maestral_daemon_thread(config_name='maestral', timeout=10):\n ``Exit.Failed`` if it could not be stopped within timeout.\n \"\"\"\n \n- lockfile = PIDLockFile(pidpath_for_config(config_name))\n- t = threads[config_name]\n-\n- if not t.is_alive():\n- lockfile.break_lock()\n+ if not is_running(config_name):\n return Exit.NotRunning\n \n # tell maestral daemon to shut down\n@@ -416,11 +535,11 @@ def stop_maestral_daemon_thread(config_name='maestral', timeout=10):\n return Exit.Failed\n \n # wait for maestral to carry out shutdown\n+ t = threads.get(config_name)\n t.join(timeout=timeout)\n if t.is_alive():\n return Exit.Failed\n else:\n- del threads[config_name]\n return Exit.Ok\n \n \n@@ -436,9 +555,7 @@ def get_maestral_proxy(config_name='maestral', fallback=False):\n ``fallback`` is ``False``.\n \"\"\"\n \n- pid = get_maestral_pid(config_name)\n-\n- if pid:\n+ if is_running(config_name):\n sock_name = sockpath_for_config(config_name)\n \n sys.excepthook = Pyro5.errors.excepthook\ndiff --git a/setup.py b/setup.py\n--- a/setup.py\n+++ b/setup.py\n@@ -1,35 +1,11 @@\n # -*- coding: utf-8 -*-\n \n # system imports\n-import sys\n-import os.path as osp\n from setuptools import setup, find_packages\n import importlib.util\n \n # local imports (must not depend on 3rd party packages)\n from maestral import __version__, __author__, __url__\n-from maestral.utils.appdirs import get_runtime_path\n-from maestral.config.base import list_configs\n-\n-\n-# abort install if there are running daemons\n-running_daemons = []\n-\n-for config in list_configs():\n- pid_file = get_runtime_path('maestral', config + '.pid')\n- if osp.exists(pid_file):\n- running_daemons.append(config)\n-\n-if running_daemons:\n- sys.stderr.write(f\"\"\"\n-Maestral daemons with the following configs are running:\n-\n-{', '.join(running_daemons)}\n-\n-Please stop the daemons before updating to ensure a clean upgrade\n-of config files and compatibility been the CLI and daemon.\n- \"\"\")\n- sys.exit(1)\n \n \n # proceed with actual install\n@@ -42,7 +18,7 @@\n 'jeepney;sys_platform==\"linux\"',\n 'keyring>=19.0.0',\n 'keyrings.alt>=3.1.0',\n- 'lockfile>=0.12.0',\n+ 'fasteners',\n 'packaging',\n 'pathspec>=0.5.8',\n 'Pyro5>=5.7',\n", "test_patch": "", "problem_statement": "", "hints_text": "", "created_at": "2020-05-14T10:37:40Z"}
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