Mercurial > templog
annotate py/utils.py @ 508:32f77e42f9c2
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| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Sun, 30 Mar 2014 20:35:30 +0800 |
| parents | fe729664a5e6 |
| children | 185621f47040 |
| rev | line source |
|---|---|
| 439 | 1 import os |
| 2 import sys | |
| 3 #import ctypes | |
| 4 import time | |
| 5 import select | |
| 6 import logging | |
| 7 | |
|
448
fe729664a5e6
working better. logging works properly, cleanup fridge.off() happens.
Matt Johnston <matt@ucc.asn.au>
parents:
444
diff
changeset
|
8 D = logging.debug |
| 439 | 9 L = logging.info |
| 10 W = logging.warning | |
| 11 E = logging.error | |
| 12 | |
| 13 DEFAULT_TRIES = 3 | |
| 14 READLINE_SELECT_TIMEOUT = 1 | |
| 15 | |
| 443 | 16 def EX(msg, *args, **kwargs): |
| 17 kwargs['exc_info'] = True | |
| 18 logging.error(msg, *args, **kwargs) | |
| 19 | |
| 439 | 20 clock_gettime = None |
| 21 no_clock_gettime = True | |
| 22 def monotonic_time(): | |
| 23 global clock_gettime | |
| 24 global no_clock_gettime | |
| 25 if no_clock_gettime: | |
| 26 return time.time() | |
| 27 | |
| 28 class timespec(ctypes.Structure): | |
| 29 _fields_ = [ | |
| 30 ('tv_sec', ctypes.c_long), | |
| 31 ('tv_nsec', ctypes.c_long) | |
| 32 ] | |
| 33 if not clock_gettime: | |
| 34 try: | |
| 35 librt = ctypes.CDLL('librt.so.0', use_errno=True) | |
| 36 clock_gettime = librt.clock_gettime | |
| 37 clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)] | |
| 38 except: | |
| 39 W("No clock_gettime(), using fake fallback.") | |
| 40 no_clock_gettime = True | |
| 41 return time.time() | |
| 42 | |
| 43 t = timespec() | |
| 44 CLOCK_MONOTONIC = 1 # see <linux/time.h> | |
| 45 | |
| 46 if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0: | |
| 47 errno_ = ctypes.get_errno() | |
| 48 raise OSError(errno_, os.strerror(errno_)) | |
| 49 return t.tv_sec + t.tv_nsec * 1e-9 | |
| 50 | |
| 51 # decorator, tries a number of times, returns None on failure, sleeps between | |
| 52 # Must be used as "@retry()" if arguments are defaulted | |
| 53 def retry(retries=DEFAULT_TRIES, try_time = 1): | |
| 54 def inner(func): | |
| 55 def new_f(*args, **kwargs): | |
| 56 for i in range(retries): | |
| 57 d = func(*args, **kwargs) | |
| 58 if d is not None: | |
| 59 return d | |
| 60 time.sleep(try_time) | |
| 61 return None | |
| 62 | |
| 63 new_f.func_name = func.func_name | |
| 64 return new_f | |
| 65 return inner | |
| 66 | |
| 67 def readline(sock): | |
| 68 timeout = READLINE_SELECT_TIMEOUT | |
| 69 buf = '' | |
| 70 while True: | |
| 71 (rlist, wlist, xlist) = select.select([sock], [], [], timeout) | |
| 72 if sock not in rlist: | |
| 73 # hit timeout | |
| 74 return None | |
| 75 | |
| 76 c = sock.recv(1) | |
| 77 if c == '': | |
| 78 # lightblue timeout | |
| 79 return None | |
| 80 if c == '\r': | |
| 81 continue | |
| 82 | |
| 83 buf += c | |
| 84 if c == '\n': | |
| 85 return buf | |
| 86 | |
| 87 # from http://blog.stalkr.net/2011/04/pctf-2011-32-thats-no-bluetooth.html | |
| 88 def crc16(buff, crc = 0, poly = 0x8408): | |
| 89 l = len(buff) | |
| 90 i = 0 | |
| 91 while i < l: | |
| 92 ch = ord(buff[i]) | |
| 93 uc = 0 | |
| 94 while uc < 8: | |
| 95 if (crc & 1) ^ (ch & 1): | |
| 96 crc = (crc >> 1) ^ poly | |
| 97 else: | |
| 98 crc >>= 1 | |
| 99 ch >>= 1 | |
| 100 uc += 1 | |
| 101 i += 1 | |
| 102 return crc | |
| 103 | |
| 104 def cheap_daemon(): | |
| 105 L("Daemonising.") | |
| 106 sys.stdout.flush() | |
| 107 sys.stderr.flush() | |
| 108 out = file('/dev/null', 'a+') | |
| 109 os.dup2(out.fileno(), sys.stdout.fileno()) | |
| 110 os.dup2(out.fileno(), sys.stderr.fileno()) | |
| 111 | |
| 112 try: | |
| 113 pid = os.fork() | |
| 114 if pid > 0: | |
| 115 sys.exit(0) | |
| 116 except OSError, e: | |
| 117 E("Bad fork()") | |
| 118 sys.exit(1) | |
| 119 | |
| 120 os.setsid() | |
| 121 | |
| 122 try: | |
| 123 pid = os.fork() | |
| 124 if pid > 0: | |
| 125 sys.exit(0) | |
| 126 except OSError, e: | |
| 127 E("Bad fork()") | |
| 128 sys.exit(1) | |
| 129 | |
| 444 | 130 def uptime(): |
| 131 try: | |
| 132 return float(open('/proc/uptime', 'r').read().split(' ', 1)[0]) | |
| 133 except Exception, e: | |
| 134 return -1 | |
| 439 | 135 |