Feature/reporting 311 add msr asn peers

Ready for merge (pending additional functionality wrt caching and NRENs)

inventory_provider/routes/msr.py

@@ -97,7 +97,7 @@ import threading
 from collections import defaultdict
 from typing import Dict
 
-from flask import Blueprint, Response, request, current_app
+from flask import Blueprint, Response, request, current_app, jsonify
 import jsonschema
 
 from inventory_provider.routes import common
@@ -1173,3 +1173,72 @@ def vpn_proxy():
         peerings = list(_format_peerings(vpnproxy))
         response = json.dumps(peerings)
     return Response(response, mimetype='application/json')
+
+
+@routes.route('/asn-peers', methods=['GET', 'POST'], defaults={'asn': None})
+@routes.route('/asn-peers/<asn>', methods=['GET', 'POST'])
+@common.require_accepts_json
+def asn_peers(asn):
+    """
+    Handler for `/asn-peers`
+
+    This method returns a list of all peers filtered by `group` and `instance`,
+    which can be passed either as URL query parameters or as entries in a
+    POST request with a JSON body that matches this schema:
+    `{
+        "group": "group to filter by",
+        "instance": "instance to filter by"
+    }`
+    Results are returned where all filters given are true, and exact string
+    matches.
+
+    An optional URL parameter can be used to also filter by a specific ASN.
+
+    The response will be formatted according to the following schema:
+
+    .. asjson::
+       inventory_provider.routes.msr.PEERING_LIST_SCHEMA
+
+    :param asn: specific ASN to get peers for
+    :return:
+    """
+    r = common.get_current_redis()
+
+    def _get_filtered_peers_for_asn(asn, group, instance):
+        peers = json.loads(r.get(f'juniper-peerings:peer-asn:{asn}'))
+        
+        def _attribute_filter(peer, name, value):
+            if value is None:
+                return True  # no filter parameter given in request
+            if name not in peer:
+                return False  # no value exists, cannot meet condition
+            return peer[name] == value
+
+        for peer in peers:
+            if _attribute_filter(peer, "group", group) and \
+                    _attribute_filter(peer, "instance", instance):
+                yield peer
+
+    def _get_filtered_peers(nren_asn_map, group, instance):
+        for pair in nren_asn_map:
+            asn = pair['asn']
+            asn_peers = _get_filtered_peers_for_asn(asn, group, instance)
+            for peer in asn_peers:
+                yield peer
+
+    # handle getting parameters regardless of method of input
+    if request.method == 'GET':
+        group = request.args.get('group')
+        instance = request.args.get('instance')
+    else:
+        params = json.loads(request.json)
+        group = params.get('group', None)
+        instance = params.get('instance', None)
+
+    if asn is not None:
+        peers = list(_get_filtered_peers_for_asn(asn, group, instance))
+    else:
+        config = current_app.config['INVENTORY_PROVIDER_CONFIG']
+        nren_asn_map = config['nren-asn-map']
+        peers = list(_get_filtered_peers(nren_asn_map, group, instance))
+    return jsonify(peers)