| 1 | #!/usr/bin/env python |
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| 2 | # -*- coding: utf-8 -*- |
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| 3 | """ |
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| 4 | Read from configuration files easily without hurting performances |
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| 5 | |
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| 6 | USAGE: |
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| 7 | During development you can load a config file either in .ini or .json |
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| 8 | format (by default app/private/appconfig.ini or app/private/appconfig.json) |
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| 9 | The result is a dict holding the configured values. Passing reload=True |
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| 10 | is meant only for development: in production, leave reload to False and all |
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| 11 | values will be cached |
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| 12 | |
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| 13 | from gluon.contrib.appconfig import AppConfig |
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| 14 | myconfig = AppConfig(path_to_configfile, reload=False) |
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| 15 | |
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| 16 | print myconfig['db']['uri'] |
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| 17 | |
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| 18 | The returned dict can walk with "dot notation" an arbitrarely nested dict |
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| 19 | |
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| 20 | print myconfig.take('db.uri') |
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| 21 | |
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| 22 | You can even pass a cast function, i.e. |
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| 23 | |
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| 24 | print myconfig.take('auth.expiration', cast=int) |
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| 25 | |
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| 26 | Once the value has been fetched (and casted) it won't change until the process |
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| 27 | is restarted (or reload=True is passed). |
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| 28 | |
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| 29 | """ |
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| 30 | import os |
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| 31 | import json |
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| 32 | from gluon._compat import thread, configparser |
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| 33 | from gluon.globals import current |
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| 34 | |
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| 35 | locker = thread.allocate_lock() |
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| 36 | |
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| 37 | def AppConfig(*args, **vars): |
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| 38 | |
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| 39 | locker.acquire() |
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| 40 | reload_ = vars.pop('reload', False) |
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| 41 | try: |
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| 42 | instance_name = 'AppConfig_' + current.request.application |
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| 43 | if reload_ or not hasattr(AppConfig, instance_name): |
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| 44 | setattr(AppConfig, instance_name, AppConfigLoader(*args, **vars)) |
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| 45 | return getattr(AppConfig, instance_name).settings |
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| 46 | finally: |
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| 47 | locker.release() |
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| 48 | |
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| 49 | |
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| 50 | class AppConfigDict(dict): |
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| 51 | """ |
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| 52 | dict that has a .take() method to fetch nested values and puts |
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| 53 | them into cache |
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| 54 | """ |
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| 55 | |
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| 56 | def __init__(self, *args, **kwargs): |
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| 57 | dict.__init__(self, *args, **kwargs) |
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| 58 | self.int_cache = {} |
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| 59 | |
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| 60 | def get(self, path, default=None): |
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| 61 | try: |
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| 62 | value = self.take(path).strip() |
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| 63 | if value.lower() in ('none','null',''): |
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| 64 | return None |
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| 65 | elif value.lower() == 'true': |
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| 66 | return True |
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| 67 | elif value.lower() == 'false': |
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| 68 | return False |
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| 69 | elif value.isdigit() or (value[0]=='-' and value[1:].isdigit()): |
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| 70 | return int(value) |
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| 71 | elif ',' in value: |
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| 72 | return map(lambda x:x.strip(),value.split(',')) |
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| 73 | else: |
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| 74 | try: |
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| 75 | return float(value) |
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| 76 | except: |
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| 77 | return value |
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| 78 | except: |
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| 79 | return default |
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| 80 | |
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| 81 | def take(self, path, cast=None): |
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| 82 | parts = path.split('.') |
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| 83 | if path in self.int_cache: |
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| 84 | return self.int_cache[path] |
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| 85 | value = self |
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| 86 | walking = [] |
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| 87 | for part in parts: |
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| 88 | if part not in value: |
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| 89 | raise BaseException("%s not in config [%s]" % |
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| 90 | (part, '-->'.join(walking))) |
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| 91 | value = value[part] |
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| 92 | walking.append(part) |
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| 93 | if cast is None: |
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| 94 | self.int_cache[path] = value |
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| 95 | else: |
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| 96 | try: |
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| 97 | value = cast(value) |
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| 98 | self.int_cache[path] = value |
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| 99 | except (ValueError, TypeError): |
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| 100 | raise BaseException("%s can't be converted to %s" % |
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| 101 | (value, cast)) |
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| 102 | return value |
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| 103 | |
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| 104 | |
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| 105 | class AppConfigLoader(object): |
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| 106 | |
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| 107 | def __init__(self, configfile=None): |
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| 108 | if not configfile: |
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| 109 | priv_folder = os.path.join(current.request.folder, 'private') |
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| 110 | configfile = os.path.join(priv_folder, 'appconfig.ini') |
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| 111 | if not os.path.isfile(configfile): |
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| 112 | configfile = os.path.join(priv_folder, 'appconfig.json') |
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| 113 | if not os.path.isfile(configfile): |
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| 114 | configfile = None |
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| 115 | if not configfile or not os.path.isfile(configfile): |
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| 116 | raise BaseException("Config file not found") |
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| 117 | self.file = configfile |
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| 118 | self.ctype = os.path.splitext(configfile)[1][1:] |
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| 119 | self.settings = None |
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| 120 | self.read_config() |
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| 121 | |
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| 122 | def read_config_ini(self): |
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| 123 | config = configparser.SafeConfigParser() |
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| 124 | config.read(self.file) |
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| 125 | settings = {} |
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| 126 | for section in config.sections(): |
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| 127 | settings[section] = {} |
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| 128 | for option in config.options(section): |
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| 129 | settings[section][option] = config.get(section, option) |
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| 130 | self.settings = AppConfigDict(settings) |
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| 131 | |
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| 132 | def read_config_json(self): |
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| 133 | with open(self.file, 'r') as c: |
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| 134 | self.settings = AppConfigDict(json.load(c)) |
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| 135 | |
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| 136 | def read_config(self): |
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| 137 | if self.settings is None: |
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| 138 | try: |
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| 139 | getattr(self, 'read_config_' + self.ctype)() |
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| 140 | except AttributeError: |
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| 141 | raise BaseException("Unsupported config file format") |
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| 142 | return self.settings |
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