Mercurial > templog
annotate py/utils.py @ 261:c3600a9fa747
merge long polling
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Tue, 09 Jun 2015 23:39:22 +0800 |
| parents | 26eee8591f61 |
| children | 78c542f03030 |
| rev | line source |
|---|---|
| 141 | 1 import os |
| 2 import sys | |
| 3 #import ctypes | |
| 4 import time | |
| 5 import select | |
| 6 import logging | |
|
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0a1b642e3086
long polling config updates
Matt Johnston <matt@ucc.asn.au>
parents:
230
diff
changeset
|
7 import binascii |
| 259 | 8 import json |
| 141 | 9 |
|
149
d686b111dab4
working better. logging works properly, cleanup fridge.off() happens.
Matt Johnston <matt@ucc.asn.au>
parents:
145
diff
changeset
|
10 D = logging.debug |
| 141 | 11 L = logging.info |
| 12 W = logging.warning | |
| 13 E = logging.error | |
| 14 | |
| 15 DEFAULT_TRIES = 3 | |
| 16 READLINE_SELECT_TIMEOUT = 1 | |
| 17 | |
| 144 | 18 def EX(msg, *args, **kwargs): |
| 19 kwargs['exc_info'] = True | |
| 20 logging.error(msg, *args, **kwargs) | |
| 21 | |
| 141 | 22 clock_gettime = None |
| 23 no_clock_gettime = True | |
| 24 def monotonic_time(): | |
| 25 global clock_gettime | |
| 26 global no_clock_gettime | |
| 27 if no_clock_gettime: | |
| 28 return time.time() | |
| 29 | |
| 30 class timespec(ctypes.Structure): | |
| 31 _fields_ = [ | |
| 32 ('tv_sec', ctypes.c_long), | |
| 33 ('tv_nsec', ctypes.c_long) | |
| 34 ] | |
| 35 if not clock_gettime: | |
| 36 try: | |
| 37 librt = ctypes.CDLL('librt.so.0', use_errno=True) | |
| 38 clock_gettime = librt.clock_gettime | |
| 39 clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)] | |
| 40 except: | |
| 41 W("No clock_gettime(), using fake fallback.") | |
| 42 no_clock_gettime = True | |
| 43 return time.time() | |
| 44 | |
| 45 t = timespec() | |
| 46 CLOCK_MONOTONIC = 1 # see <linux/time.h> | |
| 47 | |
| 48 if clock_gettime(CLOCK_MONOTONIC, ctypes.pointer(t)) != 0: | |
| 49 errno_ = ctypes.get_errno() | |
| 50 raise OSError(errno_, os.strerror(errno_)) | |
| 51 return t.tv_sec + t.tv_nsec * 1e-9 | |
| 52 | |
| 53 # decorator, tries a number of times, returns None on failure, sleeps between | |
| 54 # Must be used as "@retry()" if arguments are defaulted | |
| 55 def retry(retries=DEFAULT_TRIES, try_time = 1): | |
| 56 def inner(func): | |
| 57 def new_f(*args, **kwargs): | |
| 58 for i in range(retries): | |
| 59 d = func(*args, **kwargs) | |
| 60 if d is not None: | |
| 61 return d | |
| 62 time.sleep(try_time) | |
| 63 return None | |
| 64 | |
| 230 | 65 new_f.__name__ = func.__name__ |
| 141 | 66 return new_f |
| 67 return inner | |
| 68 | |
| 69 def readline(sock): | |
| 70 timeout = READLINE_SELECT_TIMEOUT | |
| 71 buf = '' | |
| 72 while True: | |
| 73 (rlist, wlist, xlist) = select.select([sock], [], [], timeout) | |
| 74 if sock not in rlist: | |
| 75 # hit timeout | |
| 76 return None | |
| 77 | |
| 78 c = sock.recv(1) | |
| 79 if c == '': | |
| 80 # lightblue timeout | |
| 81 return None | |
| 82 if c == '\r': | |
| 83 continue | |
| 84 | |
| 85 buf += c | |
| 86 if c == '\n': | |
| 87 return buf | |
| 88 | |
| 89 # from http://blog.stalkr.net/2011/04/pctf-2011-32-thats-no-bluetooth.html | |
| 90 def crc16(buff, crc = 0, poly = 0x8408): | |
| 91 l = len(buff) | |
| 92 i = 0 | |
| 93 while i < l: | |
| 94 ch = ord(buff[i]) | |
| 95 uc = 0 | |
| 96 while uc < 8: | |
| 97 if (crc & 1) ^ (ch & 1): | |
| 98 crc = (crc >> 1) ^ poly | |
| 99 else: | |
| 100 crc >>= 1 | |
| 101 ch >>= 1 | |
| 102 uc += 1 | |
| 103 i += 1 | |
| 104 return crc | |
| 105 | |
| 106 def cheap_daemon(): | |
| 107 L("Daemonising.") | |
| 108 sys.stdout.flush() | |
| 109 sys.stderr.flush() | |
| 110 out = file('/dev/null', 'a+') | |
| 111 os.dup2(out.fileno(), sys.stdout.fileno()) | |
| 112 os.dup2(out.fileno(), sys.stderr.fileno()) | |
| 113 | |
| 114 try: | |
| 115 pid = os.fork() | |
| 116 if pid > 0: | |
| 117 sys.exit(0) | |
| 230 | 118 except OSError as e: |
| 141 | 119 E("Bad fork()") |
| 120 sys.exit(1) | |
| 121 | |
| 122 os.setsid() | |
| 123 | |
| 124 try: | |
| 125 pid = os.fork() | |
| 126 if pid > 0: | |
| 127 sys.exit(0) | |
| 230 | 128 except OSError as e: |
| 141 | 129 E("Bad fork()") |
| 130 sys.exit(1) | |
| 131 | |
| 145 | 132 def uptime(): |
| 133 try: | |
| 134 return float(open('/proc/uptime', 'r').read().split(' ', 1)[0]) | |
| 230 | 135 except Exception as e: |
| 145 | 136 return -1 |
| 141 | 137 |
| 259 | 138 |
| 139 def json_load_round_float(s, **args): | |
| 140 return json.loads(s,parse_float = lambda f: round(float(f), 2), **args) |