Output values on "Not enough funds" exception

jmclient/jmclient/__init__.py

@@ -7,7 +7,7 @@ from .support import (calc_cj_fee, choose_sweep_orders, choose_orders,
                       rand_weighted_choice, select,
                       select_gradual, select_greedy, select_greediest,
                       get_random_bytes, random_under_max_order_choose,
-                      select_one_utxo)
+                      select_one_utxo, NotEnoughFundsException)
 from .jsonrpc import JsonRpcError, JsonRpcConnectionError, JsonRpc
 from .old_mnemonic import mn_decode, mn_encode
 from .taker import Taker

jmclient/jmclient/support.py

@@ -10,6 +10,14 @@ ORDER_KEYS = ['counterparty', 'oid', 'ordertype', 'minsize', 'maxsize', 'txfee',
 
 log = get_log()
 
+
+class NotEnoughFundsException(RuntimeError):
+
+    def __init__(self, want, has):
+        super().__init__("Not enough funds, " +
+            str(want) + " vs. " + str(has) + ".")
+
+
 """
 Random functions - replacing some NumPy features
 NOTE THESE ARE NEITHER CRYPTOGRAPHICALLY SECURE
@@ -17,7 +25,6 @@ NOR PERFORMANT NOR HIGH PRECISION!
 Only for sampling purposes
 """
 
-
 def get_random_bytes(num_bytes, cryptographically_secure=False):
     if cryptographically_secure:
         # uses os.urandom if available
@@ -78,9 +85,10 @@ def select(unspent, value):
         tv += low[i]["value"]
         i += 1
     if tv < value:
-        raise Exception("Not enough funds")
+        raise NotEnoughFundsException(value, tv)
     return low[:i]
 
+
 def select_gradual(unspent, value):
     """
     UTXO selection algorithm for gradual dust reduction
@@ -94,7 +102,7 @@ def select_gradual(unspent, value):
     lowsum = reduce(lambda x, y: x + y, map(key, low), 0)
     if value > lowsum:
         if len(high) == 0:
-            raise Exception('Not enough funds')
+            raise NotEnoughFundsException(value, lowsum)
         else:
             return [high[0]]
     else:
@@ -129,11 +137,11 @@ def select_greedy(unspent, value):
         if value > 0:  # no, that drops us below the target
             picked += [utxo]  # so we need this one too
             value -= key(utxo)  # 'backtrack' the counter
+    picked_sum = sum(key(u) for u in picked)
     if len(picked) > 0:
-        if len(picked) < len(utxos) or sum(
+        if len(picked) < len(utxos) or picked_sum >= original_value:
-            key(u) for u in picked) >= original_value:
             return picked
-    raise Exception('Not enough funds')  # if all else fails, we do too
+    raise NotEnoughFundsException(original_value, picked_sum)   # if all else fails, we do too
 
 
 def select_greediest(unspent, value):
@@ -149,7 +157,7 @@ def select_greediest(unspent, value):
     lowsum = reduce(lambda x, y: x + y, map(key, low), 0)
     if value > lowsum:
         if len(high) == 0:
-            raise Exception('Not enough funds')
+            raise NotEnoughFundsException(value, lowsum)
         else:
             return [high[0]]
     else:
@@ -159,6 +167,7 @@ def select_greediest(unspent, value):
             end += 1
         return low[0:end]
 
+
 def select_one_utxo(unspent, value):
     key = lambda u: u['value']
     return [random.choice([u for u in unspent if key(u) >= value])]

jmclient/test/test_taker.py

@@ -13,7 +13,8 @@ from base64 import b64encode
 from jmbase import utxostr_to_utxo, hextobin
 from jmclient import load_test_config, jm_single, set_commitment_file,\
     get_commitment_file, SegwitLegacyWallet, Taker, VolatileStorage,\
-    get_network, WalletService, NO_ROUNDING, BTC_P2PKH
+    get_network, WalletService, NO_ROUNDING, BTC_P2PKH,\
+    NotEnoughFundsException
 from taker_test_data import t_utxos_by_mixdepth, t_orderbook,\
     t_maker_response, t_chosen_orders, t_dummy_ext
 from commontest import default_max_cj_fee
@@ -57,7 +58,7 @@ class DummyWallet(SegwitLegacyWallet):
     def select_utxos(self, mixdepth, amount, utxo_filter=None, select_fn=None,
                      maxheight=None, includeaddr=False):
         if amount > self.get_balance_by_mixdepth()[mixdepth]:
-            raise Exception("Not enough funds")
+            raise NotEnoughFundsException(amount, self.get_balance_by_mixdepth()[mixdepth])
         # comment as for get_utxos_by_mixdepth:
         retval = {}
         for k, v in t_utxos_by_mixdepth[mixdepth].items():