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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 os
import logging
import requests
LOGGER = logging.getLogger().getChild(__name__)
class ENVsMissing(Exception):
"""
Exception to represent critical ENVs are missing
"""
pass
#########
# HELPERS
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)
res.raise_for_status()
services = res.json()
return "http://{0}:{1}".format(services[0]["ServiceAddress"], services[0]["ServicePort"])
def _get_envs():
"""
Returns hostname, consul_host.
If the necessary ENVs are not found, this is fatal, and raises an exception.
"""
try:
hostname = os.environ["HOSTNAME"] # this is the name of the component itself
consul_host = os.environ["CONSUL_HOST"] # this is the host of consul itself
cbs_name = os.environ["CONFIG_BINDING_SERVICE"] # this is the name under which the CBS is registered in Consul.
except KeyError as e:
raise ENVsMissing("Required ENV Variable {0} missing".format(e))
return hostname, consul_host, cbs_name
def _get_path(path):
"""
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, cbs_name = _get_envs()
# not sure how I as the component developer is supposed to know consul port
consul_url = "http://{0}:8500".format(consul_host)
try:
# get my config
cbs_url = _get_uri_from_consul(consul_url, cbs_name)
my_config_endpoint = "{0}/{1}/{2}".format(cbs_url, path, hostname)
res = requests.get(my_config_endpoint)
res.raise_for_status()
config = res.json()
LOGGER.info("get_config returned the following configuration: {0}".format(
json.dumps(config)))
except requests.exceptions.HTTPError:
LOGGER.error("in get_config, the config binding service endpoint %s was not reachable. Error code: %d, Error text: %s", my_config_endpoint, res.status_code, res.text)
except Exception as exc:
LOGGER.exception(exc)
return config
#########
# Public
def get_all():
"""
Hit the CBS service_component_all endpoint
"""
return _get_path("service_component_all")
def get_config():
"""
Hit the CBS service_component endpoint
"""
return _get_path("service_component")
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