Problem: The commit mode behaves incorrectly. (#2510)

* Problem: The commit mode behaves incorrectly.

Solution: Parse the Tendermint response properly. The functionality was disabled in https://github.com/bigchaindb/bigchaindb/pull/2235/files#diff-c6511560546a7dc577e7e647b5bfdaceL68 and was not fixed since then.

* Add a test case for the sync mode.

* Do not strictly expect deliver_tx in the response.

* Fix post_mock in web/test_transactions.py.

* Check for the error field first.

bigchaindb/lib.py

@@ -56,9 +56,10 @@ def __init__(self, connection=None):
                 A connection to the database.
         """
         config_utils.autoconfigure()
+        self.mode_commit = 'broadcast_tx_commit'
         self.mode_list = ('broadcast_tx_async',
                           'broadcast_tx_sync',
-                          'broadcast_tx_commit')
+                          self.mode_commit)
         self.tendermint_host = bigchaindb.config['tendermint']['host']
         self.tendermint_port = bigchaindb.config['tendermint']['port']
         self.endpoint = 'http://{}:{}/'.format(self.tendermint_host, self.tendermint_port)
@@ -96,29 +97,23 @@ def write_transaction(self, transaction, mode):
 
     def _process_post_response(self, response, mode):
         logger.debug(response)
-        if response.get('error') is not None:
-            return (500, 'Internal error')
+
+        error = response.get('error')
+        if error:
+            return (500, error)
+
+        result = response['result']
+        if mode == self.mode_commit:
+            check_tx_code = result.get('check_tx', {}).get('code', 0)
+            deliver_tx_code = result.get('deliver_tx', {}).get('code', 0)
+            error_code = check_tx_code or deliver_tx_code
+        else:
+            error_code = result.get('code', 0)
+
+        if error_code:
+            return (500, 'Transaction validation failed')
 
         return (202, '')
-        # result = response['result']
-        # if mode == self.mode_list[2]:
-        #     return self._process_commit_mode_response(result)
-        # else:
-        #     status_code = result['code']
-        #     return self._process_status_code(status_code,
-        #                                      'Error while processing transaction')
-
-    # def _process_commit_mode_response(self, result):
-    #     check_tx_status_code = result['check_tx']['code']
-    #     if check_tx_status_code == 0:
-    #         deliver_tx_status_code = result['deliver_tx']['code']
-    #         return self._process_status_code(deliver_tx_status_code,
-    #                                          'Error while commiting the transaction')
-    #     else:
-    #         return (500, 'Error while validating the transaction')
-
-    def process_status_code(self, status_code, failure_msg):
-        return (202, '') if status_code == 0 else (500, failure_msg)
 
     def store_bulk_transactions(self, transactions):
         txns = []

tests/tendermint/test_integration.py

@@ -130,12 +130,13 @@ def test_post_transaction_responses(tendermint_ws_url, b):
     code, message = b.write_transaction(tx_transfer, 'broadcast_tx_commit')
     assert code == 202
 
-    # NOTE: DOESN'T WORK (double spend)
-    # Tendermint crashes with error: Unexpected result type
-    # carly = generate_key_pair()
-    # double_spend = Transaction.transfer(tx.to_inputs(),
-    #                                     [([carly.public_key], 1)],
-    #                                     asset_id=tx.id)\
-    #                           .sign([alice.private_key])
-    # code, message = b.write_transaction(double_spend, 'broadcast_tx_commit')
-    # assert code == 500
+    carly = generate_key_pair()
+    double_spend = Transaction.transfer(
+        tx.to_inputs(),
+        [([carly.public_key], 1)],
+        asset_id=tx.id,
+    ).sign([alice.private_key])
+    for mode in ('broadcast_tx_sync', 'broadcast_tx_commit'):
+        code, message = b.write_transaction(double_spend, mode)
+        assert code == 500
+        assert message == 'Transaction validation failed'

tests/web/test_transactions.py

@@ -416,6 +416,12 @@ def should_not_be_called():
 def test_post_transaction_valid_modes(mock_post, client, mode):
     from bigchaindb.models import Transaction
     from bigchaindb.common.crypto import generate_key_pair
+
+    def _mock_post(*args, **kwargs):
+        return Mock(json=Mock(return_value={'result': {'code': 0}}))
+
+    mock_post.side_effect = _mock_post
+
     alice = generate_key_pair()
     tx = Transaction.create([alice.public_key],
                             [([alice.public_key], 1)],