Problem: Event stream api crashing (#2173)

Solution: Fix Exchange initialization

bigchaindb/tendermint/commands.py

@@ -35,8 +35,6 @@ BANNER = """
 def start():
     # Exchange object for event stream api
     exchange = Exchange()
-    p_exchange = Process(name='exchange', target=exchange.run)
-    p_exchange.start()
 
     # start the web api
     app_server = server.create_server(
@@ -61,6 +59,9 @@ def start():
                                  args=(exchange.get_publisher_queue(),))
     p_websocket_client.start()
 
+    p_exchange = Process(name='exchange', target=exchange.run)
+    p_exchange.start()
+
     # We need to import this after spawning the web server
     # because import ABCIServer will monkeypatch all sockets
     # for gevent.

bigchaindb/web/websocket_server.py

@@ -96,9 +96,9 @@ class Dispatcher:
             elif event.type == EventTypes.BLOCK_VALID:
                 block = event.data
 
-                for tx in block['block']['transactions']:
+                for tx in block['transactions']:
                     asset_id = tx['id'] if tx['operation'] == 'CREATE' else tx['asset']['id']
-                    data = {'block_id': block['id'],
+                    data = {'height': block['height'],
                             'asset_id': asset_id,
                             'transaction_id': tx['id']}
                     str_buffer.append(json.dumps(data))

tests/web/test_websocket_server.py

@@ -121,23 +121,29 @@ def test_websocket_string_event(test_client, loop):
 def test_websocket_block_event(b, _block, test_client, loop):
     from bigchaindb import events
     from bigchaindb.web.websocket_server import init_app, POISON_PILL, EVENTS_ENDPOINT
+    from bigchaindb.models import Transaction
+    from bigchaindb.common import crypto
+
+    user_priv, user_pub = crypto.generate_key_pair()
+    tx = Transaction.create([user_pub], [([user_pub], 1)])
+    tx = tx.sign([user_priv])
 
     event_source = asyncio.Queue(loop=loop)
     app = init_app(event_source, loop=loop)
     client = yield from test_client(app)
     ws = yield from client.ws_connect(EVENTS_ENDPOINT)
-    block = _block.to_dict()
+    block = {'height': 1, 'transactions': [tx.to_dict()]}
     block_event = events.Event(events.EventTypes.BLOCK_VALID, block)
 
     yield from event_source.put(block_event)
 
-    for tx in block['block']['transactions']:
+    for tx in block['transactions']:
         result = yield from ws.receive()
         json_result = json.loads(result.data)
         assert json_result['transaction_id'] == tx['id']
         # Since the transactions are all CREATEs, asset id == transaction id
         assert json_result['asset_id'] == tx['id']
-        assert json_result['block_id'] == block['id']
+        assert json_result['height'] == block['height']
 
     yield from event_source.put(POISON_PILL)