add a fairly basic file locking mechanism with src/LockFile.py
closes #96
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parent
0331b763ff
commit
2c19bdb949
4 changed files with 57 additions and 6 deletions
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@ -36,7 +36,7 @@ class ListLambdaPollHook(PollHook.PollHook):
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class Bot(object):
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def __init__(self, directory, args, cache, config, database, events,
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exports, log, modules, timers):
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exports, log, modules, timers, lock_file):
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self.directory = directory
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self.args = args
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self.cache = cache
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@ -71,6 +71,7 @@ class Bot(object):
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self._poll_timeouts = [] # typing.List[PollHook]
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self._poll_timeouts.append(self._timers)
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self._poll_timeouts.append(self.cache)
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self._poll_timeouts.append(lock_file)
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self._poll_timeouts.append(ListLambdaPollHook(
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lambda: self.servers.values(),
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40
src/LockFile.py
Normal file
40
src/LockFile.py
Normal file
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@ -0,0 +1,40 @@
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import datetime, os
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from src import PollHook, utils
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EXPIRATION = 60 # 1 minute
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class LockFile(PollHook.PollHook):
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def __init__(self, database_location: str):
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self._database_location = database_location
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self._lock_location = "%s.lock" % database_location
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self._next_lock = None
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def available(self):
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now = utils.datetime_utcnow()
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if os.path.exists(self._lock_location):
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with open(self._lock_location, "r") as lock_file:
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timestamp_str = lock_file.read().strip().split(" ", 1)[0]
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timestamp = utils.iso8601_parse(timestamp_str)
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if (now-timestamp).total_seconds() < EXPIRATION:
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return False
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return True
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def lock(self):
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with open(self._lock_location, "w") as lock_file:
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last_lock = utils.datetime_utcnow()
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lock_file.write("%s" % utils.iso8601_format(last_lock))
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self._next_lock = last_lock+datetime.timedelta(
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seconds=EXPIRATION/2)
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def next(self):
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return max(0, (self._next_lock-utils.datetime_utcnow()).total_seconds())
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def call(self):
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if self.next() == 0:
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self.lock()
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def unlock(self):
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if os.path.isfile(self._lock_location):
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os.remove(self._lock_location)
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@ -15,6 +15,9 @@ ISO8601_FORMAT_TZ = "%z"
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DATETIME_HUMAN = "%Y/%m/%d %H:%M:%S"
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def datetime_utcnow() -> datetime.datetime:
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return datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc)
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def iso8601_format(dt: datetime.datetime, milliseconds: bool=False) -> str:
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dt_format = dt.strftime(ISO8601_FORMAT_DT)
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tz_format = dt.strftime(ISO8601_FORMAT_TZ)
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@ -25,8 +28,7 @@ def iso8601_format(dt: datetime.datetime, milliseconds: bool=False) -> str:
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return "%s%s%s" % (dt_format, ms_format, tz_format)
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def iso8601_format_now(milliseconds: bool=False) -> str:
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now = datetime.datetime.utcnow().replace(tzinfo=datetime.timezone.utc)
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return iso8601_format(now, milliseconds=milliseconds)
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return iso8601_format(datetime_utcnow(), milliseconds=milliseconds)
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def iso8601_parse(s: str, microseconds: bool=False) -> datetime.datetime:
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fmt = ISO8601_PARSE_MICROSECONDS if microseconds else ISO8601_PARSE
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return datetime.datetime.strptime(s, fmt)
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14
start.py
14
start.py
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@ -6,9 +6,9 @@ if sys.version_info < (3, 6):
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sys.stderr.write("BitBot requires python 3.6.0 or later\n")
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sys.exit(1)
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import argparse, faulthandler, os, platform, time
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import atexit, argparse, faulthandler, os, platform, time
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from src import Cache, Config, Database, EventManager, Exports, IRCBot
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from src import Logging, ModuleManager, Timers, utils
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from src import LockFile, Logging, ModuleManager, Timers, utils
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faulthandler.enable()
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@ -65,6 +65,14 @@ log = Logging.Log(not args.no_logging, log_level, args.log_dir)
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log.info("Starting BitBot %s (Python v%s)",
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[IRCBot.VERSION, platform.python_version()])
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lock_file = LockFile.LockFile(args.database)
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if not lock_file.available():
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log.critical("Database is locked. Is BitBot already running?")
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sys.exit(1)
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atexit.register(lock_file.unlock)
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lock_file.lock()
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database = Database.Database(log, args.database)
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if args.remove_server:
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@ -98,7 +106,7 @@ modules = ModuleManager.ModuleManager(events, exports, timers, config, log,
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module_directories)
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bot = IRCBot.Bot(directory, args, cache, config, database, events,
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exports, log, modules, timers)
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exports, log, modules, timers, lock_file)
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if args.module:
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definition = modules.find_module(args.module)
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