autoforward: never send to a Kraken address that is about to expire

src/autoforward.py

@@ -239,23 +239,32 @@ def get_new_kraken_address(asset: Literal['btc', 'ltc', 'xmr', 'zec']) -> str:
         'method': sym_to_name[asset]
     }
 
+    # Kraken returns its newest unused address until a deposit lands on it,
+    # so one left unused by a failed pass keeps coming back until it expires.
+    def valid(addr) -> bool:
+        expires = int(addr.get('expiretm') or 0)  # 0: never
+        return not expires or expires - time() >= env.KRAKEN_ADDRESS_MIN_VALIDITY
+
     result = util.kraken_request('/0/private/DepositAddresses', payload)
 
-    first_new_address = next((addr for addr in result if addr.get('new', False)), None)
+    first_new_address = next((addr for addr in result if addr.get('new', False) and valid(addr)), None)
     if first_new_address:
         return first_new_address['address']
     elif env.DRY_RUN and result:
         # Creating addresses is a write on the Kraken account; a dry run
         # reuses an existing one.
-        return result[0]['address']
+        existing = next((addr for addr in result if valid(addr)), None)
+        if existing:
+            return existing['address']
     else:
         payload['new'] = True
         result = util.kraken_request('/0/private/DepositAddresses', payload)
-        first_new_address = next((addr for addr in result if addr.get('new', False)), None)
+        first_new_address = next((addr for addr in result if addr.get('new', False) and valid(addr)), None)
         if first_new_address:
             return first_new_address['address']
 
-    raise Exception(f'Kraken did not return a new address: {json.dumps(result, indent=2)}')
+    raise Exception(f'Kraken returned no {asset} address that is new and expires more than '
+                    f'{env.KRAKEN_ADDRESS_MIN_VALIDITY}s from now: {json.dumps(result, indent=2)}')
 
 def attempt_electrum_autoforward(coin: ElectrumCoin):
     coin_upper = coin.upper()

src/env.py

@@ -93,6 +93,9 @@ def _csv(name: str, default: str) -> list[str]:
 
 KRAKEN_API_KEY = os.getenv('KRAKEN_API_KEY', '')
 KRAKEN_API_SECRET = os.getenv('KRAKEN_API_SECRET', '')
+# Seconds a Kraken deposit address must stay valid (`expiretm`) to be sent
+# to: a deposit landing after expiry may be lost or cost a recovery fee.
+KRAKEN_ADDRESS_MIN_VALIDITY = int(os.getenv('KRAKEN_ADDRESS_MIN_VALIDITY', '86400'))
 
 MAX_NETWORK_FEE_PERCENT = float(os.getenv('MAX_NETWORK_FEE_PERCENT', '5'))
 MAX_SLIPPAGE_PERCENT = float(os.getenv('MAX_SLIPPAGE_PERCENT', '0.5'))

tests/test_dry_run.py

@@ -18,6 +18,7 @@
 import json
 import os
 import sys
+import time
 import unittest
 from unittest import mock
 
@@ -44,8 +45,10 @@ def raise_for_status(self):
 class Backends:
     """Canned answers for exactly the calls the forward/sale paths make."""
 
-    def __init__(self, utxos=None, tip=1000, zcash_ready=True, zcash_empty_pools=()):
+    def __init__(self, utxos=None, tip=1000, zcash_ready=True, zcash_empty_pools=(), kraken_address_expires_in=None):
         self.sent = []
+        # Seconds until Kraken's deposit addresses expire (`expiretm`); None: never.
+        self.kraken_address_expires_in = kraken_address_expires_in
         self.zcash_ready = zcash_ready
         self.zcash_empty_pools = zcash_empty_pools
         # One mature output by default; tests of selection pass their own.
@@ -134,7 +137,9 @@ def monero(self, method, params):
     def kraken(self, path, data):
         if path.startswith('/0/private/DepositAddresses'):
             address = 't1krakenaddress' if data.get('asset') == 'zec' else 'kraken-address'
-            return [{'address': address, 'new': bool(data.get('new'))}]
+            expires = self.kraken_address_expires_in
+            expiretm = '0' if expires is None else str(int(time.time()) + expires)
+            return [{'address': address, 'expiretm': expiretm, 'new': bool(data.get('new'))}]
         if path.startswith('/0/public/AssetPairs'):
             wanted = data.get('pair')
             if wanted and not any(wanted in (pair_id, p['altname']) for pair_id, p in self.PAIRS.items()):
@@ -313,6 +318,25 @@ def test_mweb_is_pegged_out_to_an_ltc_change_address_not_sent_to_kraken(self):
                       [p for b, method, p in backends.sent if method == 'listaddresses'])
 
 
+class KrakenAddressExpiry(unittest.TestCase):
+    def test_never_forwards_to_an_address_about_to_expire(self):
+        # Kraken hands back its newest unused address until a deposit lands
+        # on it, so an address left unused by a failed pass keeps coming back
+        # until it expires; a deposit to an expired address may be lost.
+        backends = Backends(kraken_address_expires_in=3600)
+        with mock.patch('requests.post', backends.post), mock.patch('requests.get', backends.get):
+            module = load('autoforward', dry_run=False, kraken_key=True)
+            with self.assertRaisesRegex(Exception, 'expires'):
+                module.attempt_electrum_autoforward('btc')
+        self.assertEqual(backends.fund_moving(), ['kraken new deposit address'])
+
+    def test_forwards_to_an_address_valid_past_the_margin(self):
+        backends = Backends(kraken_address_expires_in=7 * 86400)
+        with mock.patch('requests.post', backends.post), mock.patch('requests.get', backends.get):
+            load('autoforward', dry_run=False, kraken_key=True).attempt_electrum_autoforward('btc')
+        self.assertIn('electrum broadcast', backends.fund_moving())
+
+
 class BackendFailures(unittest.TestCase):
     def test_electrum_restart_reloads_the_wallet(self):
         # A restarted Electrum daemon answers 'wallet not loaded' until