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Diffstat (limited to 'config_binding_service/client.py')
| -rw-r--r-- | config_binding_service/client.py | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/config_binding_service/client.py b/config_binding_service/client.py new file mode 100644 index 0000000..02354ee --- /dev/null +++ b/config_binding_service/client.py @@ -0,0 +1,181 @@ +# ============LICENSE_START======================================================= +# org.onap.dcae +# ================================================================================ +# Copyright (c) 2017 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 re +import requests +import copy +import base64 +import json +import six +from config_binding_service import get_consul_uri, get_logger +from functools import partial, reduce + +_logger = get_logger(__name__) +CONSUL = get_consul_uri() + +template_match_rels = re.compile("\{{2}([^\}\{]*)\}{2}") +template_match_dmaap = re.compile("<{2}([^><]*)>{2}") + +### +# Cusom Exception +### +class CantGetConfig(Exception): + def __init__(self, code, response): + self.code = code + self.response = response +### +# Private Functions +### +def _consul_get_key(key): + """ + Try to fetch a key from Consul. + No error checking here, let caller deal with it + """ + _logger.info("Fetching {0}".format(key)) + response = requests.get("{0}/v1/kv/{1}".format(CONSUL, key)) + response.raise_for_status() + D = json.loads(response.text)[0] + return json.loads(base64.b64decode(D["Value"]).decode("utf-8")) + +def _get_config_rels_dmaap(service_component_name): + try: + config = _consul_get_key(service_component_name) #not ok if no config + except requests.exceptions.HTTPError as e: + #might be a 404, or could be not even able to reach consul (503?), bubble up the requests error + raise CantGetConfig(e.response.status_code, e.response.text) + + rels = [] + dmaap = {} + try: #Not all nodes have relationships, so catch the error here and return [] if so + rels = _consul_get_key("{0}:rel".format(service_component_name)) + except requests.exceptions.HTTPError: #ok if no rels key, might just have dmaap key + pass + try: + dmaap = _consul_get_key("{0}:dmaap".format(service_component_name)) + except requests.exceptions.HTTPError: #ok if no dmaap key + pass + return config, rels, dmaap + +def _get_connection_info_from_consul(service_component_name): + """ + Call consul's catalog + TODO: currently assumes there is only one service + + TODO: WARNING: FIXTHIS: CALLINTHENATIONALARMY: + This tries to determine that a service_component_name is a cdap application by inspecting service_component_name and name munging. However, this would force all CDAP applications to have cdap_app in their name. A much better way to do this is to do some kind of catalog_lookup here, OR MAYBE change this API so that the component_type is passed in somehow. THis is a gaping TODO. + """ + _logger.info("Retrieving connection information for {0}".format(service_component_name)) + res = requests.get("{0}/v1/catalog/service/{1}".format(CONSUL, service_component_name)) + res.raise_for_status() + services = res.json() + if services == []: + _logger.info("Warning: config and rels keys were both valid, but there is no component named {0} registered in Consul!".format(service_component_name)) + return None #later will get filtered out + else: + ip = services[0]["ServiceAddress"] + port = services[0]["ServicePort"] + if "cdap_app" in service_component_name: + redirectish_url = "http://{0}:{1}/application/{2}".format(ip, port, service_component_name) + _logger.info("component is a CDAP application; trying the broker redirect on {0}".format(redirectish_url)) + r = requests.get(redirectish_url) + r.raise_for_status() + details = r.json() + # Pick out the details to expose to the component developers. These keys come from the broker API + return { key: details[key] for key in ["connectionurl", "serviceendpoints"] } + else: + return "{0}:{1}".format(ip, port) + +def _replace_rels_template(rels, template_identifier): + """ + The magic. Replaces a template identifier {{...}} with the entrie(s) from the rels keys + NOTE: There was a discussion over whether the CBS should treat {{}} as invalid. Mike asked that + it resolve to the empty list. So, it does resolve it to empty list. + """ + returnl = [] + for r in rels: + if template_identifier in r and template_identifier is not "": + returnl.append(r) + #returnl now contains a list of DNS names (possible empty), now resolve them (or not if they are not regustered) + return list(filter(lambda x: x is not None, map(_get_connection_info_from_consul, returnl))) + +def _replace_dmaap_template(dmaap, template_identifier): + """ + This one liner could have been just put inline in the caller but maybe this will get more complex in future + Talked to Mike, default value if key is not found in dmaap key should be {} + """ + return {} if (template_identifier not in dmaap or template_identifier == "<<>>") else dmaap[template_identifier] + +def _replace_value(v, rels, dmaap): + """ + Takes a value v that was some value in the templatized configuration, determines whether it needs replacement (either {{}} or <<>>), and if so, replaces it. + Otherwise just returns v + + implementation notes: + - the split below sees if we have v = x,y,z... so we can support {{x,y,z,....}} + - the lambda is because we can't fold operators in Python, wanted fold(+, L) where + when applied to lists in python is list concatenation + """ + if isinstance(v, six.string_types): #do not try to replace anything that is not a string + match_on_rels = re.match(template_match_rels, v) + if match_on_rels: + template_identifier = match_on_rels.groups()[0].strip() #now holds just x,.. of {{x,...}} + rtpartial = partial(_replace_rels_template, rels) + return reduce(lambda a,b: a+b, map(rtpartial, template_identifier.split(",")), []) + match_on_dmaap = re.match(template_match_dmaap, v) + if match_on_dmaap: + template_identifier = match_on_dmaap.groups()[0].strip() + """ + Here is what Mike said: + 1) want simple replacement of "<< >>" with dmaap key value + 2) never need to support <<f1,f2>> whereas we do support {{sct1,sct2}} + The consequence is that if you give the CBS a dmaap key like {"foo" : {...}} you are going to get back {...}, but rels always returns [...]. + So now component developers have to possible handle dicts and [], and we have to communicate that to them + """ + return _replace_dmaap_template(dmaap, template_identifier) + return v #was not a match or was not a string, return value as is + +def _recurse(config, rels, dmaap): + for key in config: + v = config[key] + if isinstance(v, list): + replacement = [_recurse(item, rels, dmaap) for item in v] + elif isinstance(v,dict): + replacement = _recurse(v, rels, dmaap) + else: + replacement = _replace_value(config[key], rels, dmaap) + config[key] = replacement + return config + +######### +# PUBLIC API +######### +def resolve(service_component_name): + """ + Return the bound config of service_component_name + """ + config, rels, dmaap = _get_config_rels_dmaap(service_component_name) + _logger.info("Fetching {0}: config={1}, rels={2}".format(service_component_name, json.dumps(config), rels)) + return _recurse(config, rels, dmaap) + +def resolve_override(config, rels=[], dmaap={}): + """ + Explicitly take in a config, rels, dmaap and try to resolve it. + Useful for testing where you dont want to put the test values in consul + """ + #use deepcopy to make sure that config is not touched + return _recurse(copy.deepcopy(config), rels, dmaap) |