Mercurial > templog
view py/utils.py @ 279:6848907f85be
fix missing on_time variable
author | Matt Johnston <matt@ucc.asn.au> |
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date | Sat, 28 Nov 2015 08:42:33 +0800 |
parents | af924d27140f |
children | 02aff9ff8d24 |
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import os import sys import ctypes import time import select import logging import binascii import json import datetime import collections D = logging.debug L = logging.info W = logging.warning E = logging.error DEFAULT_TRIES = 3 READLINE_SELECT_TIMEOUT = 1 def EX(msg, *args, **kwargs): kwargs['exc_info'] = True logging.error(msg, *args, **kwargs) clock_gettime = None no_clock_gettime = True def monotonic_time(): global clock_gettime global no_clock_gettime if no_clock_gettime: return time.time() class timespec(ctypes.Structure): _fields_ = [ ('tv_sec', ctypes.c_long), ('tv_nsec', ctypes.c_long) ] if not clock_gettime: try: librt = ctypes.CDLL('librt.so.0', use_errno=True) clock_gettime = librt.clock_gettime clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)] except: W("No clock_gettime(), using fake fallback.") no_clock_gettime = True return time.time() t = timespec() CLOCK_MONOTONIC = 1 # see <linux/time.h> if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0: errno_ = ctypes.get_errno() raise OSError(errno_, os.strerror(errno_)) return t.tv_sec + t.tv_nsec * 1e-9 # decorator, tries a number of times, returns None on failure, sleeps between # Must be used as "@retry()" if arguments are defaulted def retry(retries=DEFAULT_TRIES, try_time = 1): def inner(func): def new_f(*args, **kwargs): for i in range(retries): d = func(*args, **kwargs) if d is not None: return d time.sleep(try_time) return None new_f.__name__ = func.__name__ return new_f return inner def readline(sock): timeout = READLINE_SELECT_TIMEOUT buf = '' while True: (rlist, wlist, xlist) = select.select([sock], [], [], timeout) if sock not in rlist: # hit timeout return None c = sock.recv(1) if c == '': # lightblue timeout return None if c == '\r': continue buf += c if c == '\n': return buf # from http://blog.stalkr.net/2011/04/pctf-2011-32-thats-no-bluetooth.html def crc16(buff, crc = 0, poly = 0x8408): l = len(buff) i = 0 while i < l: ch = ord(buff[i]) uc = 0 while uc < 8: if (crc & 1) ^ (ch & 1): crc = (crc >> 1) ^ poly else: crc >>= 1 ch >>= 1 uc += 1 i += 1 return crc def cheap_daemon(): L("Daemonising.") sys.stdout.flush() sys.stderr.flush() out = file('/dev/null', 'a+') os.dup2(out.fileno(), sys.stdout.fileno()) os.dup2(out.fileno(), sys.stderr.fileno()) try: pid = os.fork() if pid > 0: sys.exit(0) except OSError as e: E("Bad fork()") sys.exit(1) os.setsid() try: pid = os.fork() if pid > 0: sys.exit(0) except OSError as e: E("Bad fork()") sys.exit(1) def uptime(): try: return float(open('/proc/uptime', 'r').read().split(' ', 1)[0]) except Exception as e: return -1 def json_load_round_float(s, **args): return json.loads(s,parse_float = lambda f: round(float(f), 2), **args) class NotTooOften(object): """ prevents things happening more than once per limit. Isn't monotonic, good enough for logging. eg self.logfailure = NotTooOften(180) # 3 minutes ... if self.logfailure(): L("blah") """ def __init__(self, limit): """ limit is a delay in seconds or TimeDelta """ if type(limit) is datetime.timedelta: self.limit = limit else: self.limit = datetime.timedelta(seconds=limit) # must be positive assert self.limit > datetime.timedelta(0) self.last = datetime.datetime(10, 1, 1) def __call__(self): if datetime.datetime.now() - self.last > self.limit: self.last = datetime.datetime.now() return True def log(self, msg): """ calls L(msg) if it isn't too often, otherwise D(msg) """ if self(): L(msg + " (log interval %s)" % str(self.limit)) else: D(msg) Period = collections.namedtuple('Period', 'start end') class StepIntegrator(object): """ Takes on/off events and a monotonically increasing timefn. Returns the integral of (now-limittime, now) over those events. >>> s = StepIntegrator(lambda: t, 40) >>> t = 1 >>> s.turn(1) >>> t = 10 >>> s.turn(0) >>> t = 20 >>> s.turn(1) >>> t = 30 >>> print(s.integrate()) 19 >>> s.turn(0) >>> print(s.integrate()) 19 >>> t = 35 >>> print(s.integrate()) 19 >>> t = 42 >>> print(s.integrate()) 18 >>> t = 52 >>> print(s.integrate()) 10 >>> t = 69 >>> print(s.integrate()) 1 >>> t = 70 >>> print(s.integrate()) 0 >>> t = 170 >>> print(s.integrate()) 0 """ def __init__(self, timefn, limittime): # _on_periods is a list of [period]. End is None if still on self._on_periods = [] self._timefn = timefn self._limittime = limittime def set_limit(self, limittime): if self._limittime == limittime: return self._limittime = limittime self._trim() def turn(self, value): if not self._on_periods: if value: self._on_periods.append(Period(self._timefn(), None)) return # state hasn't changed on_now = (self._on_periods[-1].end is None) if value == on_now: return if value: self._on_periods.append(Period(self._timefn(), None)) else: self._on_periods[-1] = self._on_periods[-1]._replace(end = self._timefn()) def _trim(self): begin = self._timefn() - self._limittime # shortcut, first start is after begin if not self._on_periods or self._on_periods[0].start >= begin: return new_periods = [] for s, e in self._on_periods: if s == e: continue elif s >= begin: new_periods.append(Period(s,e)) elif e is not None and e < begin: continue else: new_periods.append(Period(begin, e)) self._on_periods = new_periods def integrate(self): self._trim() tot = 0 for s, e in self._on_periods: if e is None: e = self._timefn() tot += (e-s) return tot