blob: e58477c9afa49671d96a72b52f1daae51ca4cced [file] [log] [blame]
Matteo Scandolo56879722017-05-17 21:39:54 -07001import os
2import sys
3import yaml
4import requests
5import default
6from pykwalify.core import Core as PyKwalify
7
8DEFAULT_CONFIG_FILE = "/opt/xos/config.yaml"
9INITIALIZED = False
10CONFIG = {}
11
12class Config:
13 """
14 XOS Configuration APIs
15 """
16
17 @staticmethod
18 def init(config_file=DEFAULT_CONFIG_FILE):
19 global INITIALIZED
20 global CONFIG
21 # the config module can be initialized only one
22 if INITIALIZED:
23 raise Exception('[XOS-Config] Module already initialized')
24 INITIALIZED = True
25
26 # if XOS-CONFIG is defined override the config_file
27 if os.environ.get('XOS-CONFIG'):
28 config_file = os.environ['XOS-CONFIG']
29
30 # if a -C parameter is set in the cli override the config_file
31 # FIXME shouldn't this stay in whatever module call this one? and then just pass the file to the init method
32 if Config.get_cli_param(sys.argv):
33 config_file = Config.get_cli_param(sys.argv)
34
35 CONFIG = Config.read_config(config_file)
36
37 @staticmethod
38 def clear():
39 global INITIALIZED
40 INITIALIZED = False
41
42 @staticmethod
43 def validate_config_format(config_file):
44 schema = os.path.abspath(os.path.dirname(os.path.realpath(__file__)) + '/config-schema.yaml')
45 c = PyKwalify(source_file=config_file, schema_files=[schema])
46 c.validate(raise_exception=True)
47
48 @staticmethod
49 def get_cli_param(args):
50 last = None
51 for arg in args:
52 if last == '-C':
53 return arg
54 last = arg
55
56 @staticmethod
57 def read_config(config_file):
58 """
59 Read the configuration file and return a dictionary
60 :param config_file: string
61 :return: dict
62 """
63 if not os.path.exists(config_file):
64 raise Exception('[XOS-Config] Config file not found at: %s' % config_file)
65
66 try:
67 Config.validate_config_format(config_file)
68 except Exception, e:
69 raise Exception('[XOS-Config] The config format is wrong: %s' % e.msg)
70
71 with open(config_file, 'r') as stream:
72 return yaml.safe_load(stream)
73
74 @staticmethod
75 def get(query):
76 """
77 Read a parameter from the config
78 :param query: a dot separated selector for configuration options (eg: database.username)
79 :return: the requested parameter in any format the parameter is specified
80 """
81 global INITIALIZED
82 global CONFIG
83
84 if not INITIALIZED:
85 raise Exception('[XOS-Config] Module has not been initialized')
86
87 val = Config.get_param(query, CONFIG)
88 if not val:
89 val = Config.get_param(query, default.DEFAULT_VALUES)
90 if not val:
91 raise Exception('[XOS-Config] Config does not have a value (or a default) parameter %s' % query)
92 return val
93
94 @staticmethod
95 def get_param(query, config):
96 """
97 Search for a parameter in config's first level, other call get_nested_param
98 :param query: a dot separated selector for configuration options (eg: database.username)
99 :param config: the config source to read from (can be the config file or the defaults)
100 :return: the requested parameter in any format the parameter is specified
101 """
102 keys = query.split('.')
103 if len(keys) == 1:
104 key = keys[0]
105 if not config.has_key(key):
106 return None
107 return config[key]
108 else:
109 return Config.get_nested_param(keys, config)
110
111 @staticmethod
112 def get_nested_param(keys, config):
113 """
114
115 :param keys: a list of descending selector
116 :param config: the config source to read from (can be the config file or the defaults)
117 :return: the requested parameter in any format the parameter is specified
118 """
119 param = config
120 for k in keys:
121 if not param.has_key(k):
122 return None
123 param = param[k]
124 return param
125
126 @staticmethod
127 def get_service_list():
128 """
129 Query registrator to get the list of services
130 NOTE: we assume that consul is a valid URL
131 :return: a list of service names
132 """
133 service_dict = requests.get('http://consul:8500/v1/catalog/services').json()
134 service_list = []
135 for s in service_dict:
136 service_list.append(s)
137 return service_list
138
139 @staticmethod
140 def get_service_info(service_name):
141 """
142 Query registrator to get the details about a service
143 NOTE: we assume that consul is a valid URL
144 :param service_name: the name of the service, can be retrieved from get_service_list
145 :return: the informations about a service
146 """
147 response = requests.get('http://consul:8500/v1/catalog/service/%s' % service_name)
148 if not response.ok:
149 raise Exception('[XOS-Config] Registrator is down')
150 service = response.json()
151 if not service or len(service) == 0:
152 raise Exception('[XOS-Config] The service missing-service looking for does not exist')
153 return {
154 'name': service[0]['ServiceName'],
155 'url': service[0]['ServiceAddress'],
156 'port': service[0]['ServicePort']
157 }
158
159 @staticmethod
160 def get_service_endpoint(service_name):
161 """
162 Query registrator to get the details about a service and return the endpoint in for of a string
163 :param service_name: the name of the service, can be retrieved from get_service_list
164 :return: the endpoint of the service
165 """
166 service = Config.get_service_info(service_name)
167 return 'http://%s:%s' % (service['url'], service['port'])
168
169# NOTE is this needed if this package is not meant to be execute from the CLI?
170if __name__ == '__main__':
171 config = Config()
172 config.init()