Intial commit of CBS to ONAP

Change-Id: I2082544efc59476ac8de0dc39c899f968c3847bd
Signed-off-by: Tommy Carpenter <tommy@research.att.com>
Issue-Id: DCAEGEN2-47

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)