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# ================================================================================
# Copyright (c) 2017-2018 AT&T Intellectual Property. All rights reserved.
# ================================================================================
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ============LICENSE_END=========================================================
#
# ECOMP is a trademark and service mark of AT&T Intellectual Property.
import json
import requests
import os
import logging
root = logging.getLogger()
logger = root.getChild(__name__)
def _get_uri_from_consul(consul_url, name):
"""
Call consul's catalog
TODO: currently assumes there is only one service with this HOSTNAME
"""
url = "{0}/v1/catalog/service/{1}".format(consul_url, name)
logger.debug("Trying to lookup service: {0}".format(url))
res = requests.get(url)
try:
res.raise_for_status()
services = res.json()
return "http://{0}:{1}".format(services[0]["ServiceAddress"], services[0]["ServicePort"])
except Exception as e:
logger.error("Exception occured when querying Consul: either could not hit {0} or no service registered. Error code: {1}, Error Text: {2}".format(url, res.status_code, res.text))
return None
def _get_envs():
"""
Returns HOSTNAME, CONSUL_HOST, CONFIG_BINDING_SERVICE or crashes for caller to deal with
"""
HOSTNAME = os.environ["HOSTNAME"]
CONSUL_HOST = os.environ["CONSUL_HOST"]
return HOSTNAME, CONSUL_HOST
#Public
def get_config():
"""
This call does not raise an exception if Consul or the CBS cannot complete the request.
It logs an error and returns {} if the config is not bindable.
It could be a temporary network outage. Call me again later.
It will raise an exception if the necessary env parameters were not set because that is irrecoverable.
This function is called in my /heatlhcheck, so this will be caught early.
"""
config = {}
HOSTNAME, CONSUL_HOST = _get_envs()
#not sure how I as the component developer is supposed to know consul port
consul_url = "http://{0}:8500".format(CONSUL_HOST)
#get the CBS URL. Would not need the following hoorahrah if we had DNS.
cbs_url = _get_uri_from_consul(consul_url, "config_binding_service")
if cbs_url is None:
logger.error("Cannot bind config at this time, cbs is unreachable")
else:
#get my config
my_config_endpoint = "{0}/service_component/{1}".format(cbs_url, HOSTNAME)
res = requests.get(my_config_endpoint)
try:
res.raise_for_status()
config = res.json()
logger.info("get_config returned the following configuration: {0}".format(json.dumps(config)))
except:
logger.error("in get_config, the config binding service endpoint {0} blew up on me. Error code: {1}, Error text: {2}".format(my_config_endpoint, res.status_code, res.text))
return config
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