Trace Retrieval: new traces: inform semantic-linking; expose rest get

transaction-hub-in/trace-retrieval-microservice/app/configs/swagger.yml

@@ -32,7 +32,7 @@ paths:
 
   /trace:
     post:
-        operationId: "rest.blockchain_trace.receive"
+        operationId: "rest.blockchain_trace.post"
         tags:
           - "Blockchain Trace"
         summary: "Add a new blockchain trace to SMART"
@@ -49,6 +49,18 @@ paths:
             description: "Successful operation"
           400:
             description: "Invalid input"
+    get:
+        operationId: "rest.blockchain_trace.get"
+        tags:
+          - "Blockchain Trace"
+        summary: "Get blockchain traces"
+        description: "Returns all blockchain traces in the database"
+        parameters: []
+        responses:
+          200:
+            description: "Successful operation"
+            schema:
+              $ref: "#/definitions/BlockchainTrace"
               
 definitions:
   BlockchainTrace:

transaction-hub-in/trace-retrieval-microservice/app/db/MongoRepository.py

@@ -17,8 +17,8 @@ class MongoRepository:
     def insert_trace(self, content: dict):
         self._collection.insert_one(content)
 
-    def get_traces(self, selection: dict = {}):
-        return self._collection.find(selection)
+    def get_traces(self, selection: dict = {}, projection: dict = {'_': 0}) -> pymongo.cursor.Cursor:
+        return self._collection.find(selection, projection)
 
     def close_connection(self):
         self._mongo_client.close()

transaction-hub-in/trace-retrieval-microservice/app/messaging/MessageHandler.py

 from db.MongoRepository import MongoRepository
+from messaging.MessageSender import MessageSender
 import json
 
 import logging
@@ -6,9 +7,16 @@ LOGGER = logging.getLogger(__name__)
 
 class MessageHandler:
     _mongo_repo = None
+    _message_sender = None
 
     def __init__(self):
         self._mongo_repo = MongoRepository()
+        self._init_message_sender()
+
+    def _init_message_sender(self):
+        self._message_sender = MessageSender()
+        self._message_sender.connect()
+        self._message_sender.create_exchange('inhub', 'direct')
 
     def handle_generic(self, body):
         LOGGER.info(f"Received message: {body}")
@@ -31,3 +39,7 @@ class MessageHandler:
             
     def handle_blockchain_transaction(self, transaction):
         self._mongo_repo.insert_trace(transaction)
+        
+        # inform semantic linking microservice
+        msg = {'type': 'new-traces-available'}
+        self._message_sender.send('datahub', json.dumps(msg), 'semantic-linking')

transaction-hub-in/trace-retrieval-microservice/app/rest/blockchain_trace.py

 from flask import request, Response
+from db.MongoRepository import MongoRepository
 
-def receive():
+mongo_repo = MongoRepository()
+
+def post():
     return Response(status=501)
+
+def get():
+    return list(mongo_repo.get_traces(projection={'_id': 0}))
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