Mercurial > templog
view py/params.py @ 258:03e540c3ec24
fix server side long polling
author | Matt Johnston <matt@ucc.asn.au> |
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date | Tue, 09 Jun 2015 23:29:11 +0800 |
parents | 0a1b642e3086 |
children | 26eee8591f61 |
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# -*- coding: utf-8 -*- import collections import json import signal import io import tempfile import config from utils import W,L,E,EX import utils _FIELD_DEFAULTS = { 'fridge_setpoint': 16, 'fridge_difference': 0.2, 'overshoot_delay': 720, # 12 minutes 'overshoot_factor': 1, # ÂșC 'disabled': False, 'nowort': False, 'fridge_range_lower': 3, 'fridge_range_upper': 3, } class Params(dict): class Error(Exception): pass def __init__(self): self.update(_FIELD_DEFAULTS) self._epoch = None def __getattr__(self, k): return self[k] def __setattr__(self, k, v): # fail if we set a bad value self[k] self[k] = v def _do_load(self, f): try: u = json.load(f) except Exception as e: raise self.Error(e) for k in u: if k.startswith('_'): continue if k not in self: raise self.Error("Unknown parameter %s=%s in file '%s'" % (str(k), str(u[k]), getattr(f, 'name', '???'))) self.update(u) self._epoch = utils.hexnonce() L("Loaded parameters") L(self.save_string()) def load(self, f = None): if f: return self._do_load(f) else: with open(config.PARAMS_FILE, 'r') as f: try: return self._do_load(f) except IOError as e: W("Missing parameter file, using defaults. %s" % str(e)) return def get_epoch(self): return self._epoch def receive(self, params, epoch): """ updates parameters from the server. does some validation, writes config file to disk. Returns True on success, False failure """ if epoch != self._epoch: return def same_type(a, b): ta = type(a) tb = type(b) if ta == int: ta = float if tb == int: tb = float return ta == tb if self.keys() != new_params.keys(): diff = self.keys() ^ new_params.keys() E("Mismatching params, %s" % str(diff)) return False for k, v in new_params.items(): if not same_type(v, self[k]): E("Bad type for %s" % k) return False dir = os.path.dirname(config.PARAMS_FILE) try: t = tempfile.NamedTemporaryFile(prefix='config', dir = dir, delete = False) t.write(json.dumps(new_params, sort_keys=True, indent=4)+'\n') name = t.name t.close() os.rename(name, config.PARAMS_FILE) return True except Exception as e: E("Problem: %s" % e) return False def save_string(self): return json.dumps(self, sort_keys=True, indent=4)