Mercurial > templog
annotate py/utils.py @ 551:9499bd2f344b
long polling config updates
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Mon, 08 Jun 2015 22:29:46 +0800 |
| parents | 5201f441bf4a |
| children | 26eee8591f61 |
| rev | line source |
|---|---|
| 439 | 1 import os |
| 2 import sys | |
| 3 #import ctypes | |
| 4 import time | |
| 5 import select | |
| 6 import logging | |
|
551
9499bd2f344b
long polling config updates
Matt Johnston <matt@ucc.asn.au>
parents:
529
diff
changeset
|
7 import binascii |
| 439 | 8 |
|
448
fe729664a5e6
working better. logging works properly, cleanup fridge.off() happens.
Matt Johnston <matt@ucc.asn.au>
parents:
444
diff
changeset
|
9 D = logging.debug |
| 439 | 10 L = logging.info |
| 11 W = logging.warning | |
| 12 E = logging.error | |
| 13 | |
| 14 DEFAULT_TRIES = 3 | |
| 15 READLINE_SELECT_TIMEOUT = 1 | |
| 16 | |
| 443 | 17 def EX(msg, *args, **kwargs): |
| 18 kwargs['exc_info'] = True | |
| 19 logging.error(msg, *args, **kwargs) | |
| 20 | |
| 439 | 21 clock_gettime = None |
| 22 no_clock_gettime = True | |
| 23 def monotonic_time(): | |
| 24 global clock_gettime | |
| 25 global no_clock_gettime | |
| 26 if no_clock_gettime: | |
| 27 return time.time() | |
| 28 | |
| 29 class timespec(ctypes.Structure): | |
| 30 _fields_ = [ | |
| 31 ('tv_sec', ctypes.c_long), | |
| 32 ('tv_nsec', ctypes.c_long) | |
| 33 ] | |
| 34 if not clock_gettime: | |
| 35 try: | |
| 36 librt = ctypes.CDLL('librt.so.0', use_errno=True) | |
| 37 clock_gettime = librt.clock_gettime | |
| 38 clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)] | |
| 39 except: | |
| 40 W("No clock_gettime(), using fake fallback.") | |
| 41 no_clock_gettime = True | |
| 42 return time.time() | |
| 43 | |
| 44 t = timespec() | |
| 45 CLOCK_MONOTONIC = 1 # see <linux/time.h> | |
| 46 | |
| 47 if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0: | |
| 48 errno_ = ctypes.get_errno() | |
| 49 raise OSError(errno_, os.strerror(errno_)) | |
| 50 return t.tv_sec + t.tv_nsec * 1e-9 | |
| 51 | |
| 52 # decorator, tries a number of times, returns None on failure, sleeps between | |
| 53 # Must be used as "@retry()" if arguments are defaulted | |
| 54 def retry(retries=DEFAULT_TRIES, try_time = 1): | |
| 55 def inner(func): | |
| 56 def new_f(*args, **kwargs): | |
| 57 for i in range(retries): | |
| 58 d = func(*args, **kwargs) | |
| 59 if d is not None: | |
| 60 return d | |
| 61 time.sleep(try_time) | |
| 62 return None | |
| 63 | |
| 529 | 64 new_f.__name__ = func.__name__ |
| 439 | 65 return new_f |
| 66 return inner | |
| 67 | |
| 68 def readline(sock): | |
| 69 timeout = READLINE_SELECT_TIMEOUT | |
| 70 buf = '' | |
| 71 while True: | |
| 72 (rlist, wlist, xlist) = select.select([sock], [], [], timeout) | |
| 73 if sock not in rlist: | |
| 74 # hit timeout | |
| 75 return None | |
| 76 | |
| 77 c = sock.recv(1) | |
| 78 if c == '': | |
| 79 # lightblue timeout | |
| 80 return None | |
| 81 if c == '\r': | |
| 82 continue | |
| 83 | |
| 84 buf += c | |
| 85 if c == '\n': | |
| 86 return buf | |
| 87 | |
| 88 # from http://blog.stalkr.net/2011/04/pctf-2011-32-thats-no-bluetooth.html | |
| 89 def crc16(buff, crc = 0, poly = 0x8408): | |
| 90 l = len(buff) | |
| 91 i = 0 | |
| 92 while i < l: | |
| 93 ch = ord(buff[i]) | |
| 94 uc = 0 | |
| 95 while uc < 8: | |
| 96 if (crc & 1) ^ (ch & 1): | |
| 97 crc = (crc >> 1) ^ poly | |
| 98 else: | |
| 99 crc >>= 1 | |
| 100 ch >>= 1 | |
| 101 uc += 1 | |
| 102 i += 1 | |
| 103 return crc | |
| 104 | |
| 105 def cheap_daemon(): | |
| 106 L("Daemonising.") | |
| 107 sys.stdout.flush() | |
| 108 sys.stderr.flush() | |
| 109 out = file('/dev/null', 'a+') | |
| 110 os.dup2(out.fileno(), sys.stdout.fileno()) | |
| 111 os.dup2(out.fileno(), sys.stderr.fileno()) | |
| 112 | |
| 113 try: | |
| 114 pid = os.fork() | |
| 115 if pid > 0: | |
| 116 sys.exit(0) | |
| 529 | 117 except OSError as e: |
| 439 | 118 E("Bad fork()") |
| 119 sys.exit(1) | |
| 120 | |
| 121 os.setsid() | |
| 122 | |
| 123 try: | |
| 124 pid = os.fork() | |
| 125 if pid > 0: | |
| 126 sys.exit(0) | |
| 529 | 127 except OSError as e: |
| 439 | 128 E("Bad fork()") |
| 129 sys.exit(1) | |
| 130 | |
| 444 | 131 def uptime(): |
| 132 try: | |
| 133 return float(open('/proc/uptime', 'r').read().split(' ', 1)[0]) | |
| 529 | 134 except Exception as e: |
| 444 | 135 return -1 |
| 439 | 136 |
|
551
9499bd2f344b
long polling config updates
Matt Johnston <matt@ucc.asn.au>
parents:
529
diff
changeset
|
137 def hexnonce(): |
|
9499bd2f344b
long polling config updates
Matt Johnston <matt@ucc.asn.au>
parents:
529
diff
changeset
|
138 return binascii.hexlify(os.urandom(120)) |