Merge JoinMarket-Org/joinmarket-clientserver#1478: Refactor: Add `get_wallet_rescan_status()` instead of `getwalletinfo()` for `bci`

e31e839c1d Add get_wallet_rescan_status() instead of getwalletinfo() for bci (Kristaps Kaupe)

Pull request description:

  Noticed this when tried to rebase #1462 after merging of #1477. #1461 added public `getwalletinfo()` method to `BitcoinCoreInterface`, which was used by code outside of `jmclient/jmclient/blockchaininterface.py`. This is bad approach, as it relies on Bitcoin Core RPC `getwalletinfo` returned `dict`, which contains a lots of different stuff too, could lead to more problems in future introducing other blockchain interface classes. Let's instead have generic method returning just wallet rescan status. Also it now returns `Tuple[bool, Optional[Decimal]]` with rescan status percentage, if rescan is in progress, although that's not used by any other code for now.

ACKs for top commit:
  AdamISZ:
    utACK e31e839c1d , very much agree with the thinking here.

Tree-SHA512: 2d8c9b8157847e713838099d0f62dfcd5321c9498cf8453a9087407e2cd9c32906739c8e71460fc6ac6426662d2ac501261080fea08388d928933f788bda9a8d

jmclient/jmclient/blockchaininterface.py

@@ -4,7 +4,7 @@ import ast
 import random
 import sys
 import time
-from typing import Optional
+from typing import Optional, Tuple
 from decimal import Decimal
 import binascii
 from twisted.internet import reactor, task
@@ -56,6 +56,11 @@ class BlockchainInterface(object):
         required for inclusion in the next N blocks.
 	'''
 
+    @abc.abstractmethod
+    def get_wallet_rescan_status(self) -> Tuple[bool, Optional[Decimal]]:
+        """Returns pair of True/False is wallet currently rescanning and
+        Optional[Decimal] with current rescan progress status."""
+
     def import_addresses_if_needed(self, addresses, wallet_name):
         """import addresses to the underlying blockchain interface if needed
         returns True if the sync call needs to do a system exit"""
@@ -99,7 +104,7 @@ class BitcoinCoreInterface(BlockchainInterface):
             if not wallet_name in loaded_wallets:
                 self._rpc("loadwallet", [wallet_name])
             # We only support legacy wallets currently
-            wallet_info = self._rpc("getwalletinfo", [])
+            wallet_info = self._getwalletinfo()
             if "descriptors" in wallet_info and wallet_info["descriptors"]:
                 raise Exception(
                     "JoinMarket currently does not support Bitcoin Core "
@@ -146,12 +151,21 @@ class BitcoinCoreInterface(BlockchainInterface):
             log.error("Failure of RPC connection to Bitcoin Core. "
                       "Rescanning process not started.")
 
-    def getwalletinfo(self) -> dict:
+    def _getwalletinfo(self) -> dict:
         """ Returns detailed about currently loaded (see `loadwallet`
         call in __init__) Bitcoin Core wallet.
         """
         return self._rpc("getwalletinfo", [])
 
+    def get_wallet_rescan_status(self) -> Tuple[bool, Optional[Decimal]]:
+        winfo = self._getwalletinfo()
+        if "scanning" in winfo and winfo["scanning"]:
+            # If not 'false', it contains info that looks like:
+            # {'duration': 1, 'progress': Decimal('0.04665404082350701')}
+            return True, winfo["scanning"]["progress"]
+        else:
+            return False, None
+
     def _rpc(self, method, args):
         """ Returns the result of an rpc call to the Bitcoin Core RPC API.
         If the connection is permanently or unrecognizably broken, None

jmclient/jmclient/wallet_rpc.py

@@ -641,11 +641,7 @@ class JMWalletDaemon(Service):
 
             if self.services["wallet"]:
                 if self.services["wallet"].isRunning():
-                    winfo = self.services["wallet"].get_backend_walletinfo()
-                    if "scanning" in winfo and winfo["scanning"]:
-                        # Note that if not 'false', it contains info
-                        # that looks like: {'duration': 1, 'progress': Decimal('0.04665404082350701')}
-                        rescanning = True
+                    rescanning, _ = self.services["wallet"].get_backend_wallet_rescan_status()
                     wallet_name = self.wallet_name
                     # At this point if an `auth_header` is present, it has been checked
                     # by the call to `check_cookie_if_present` above.

jmclient/jmclient/wallet_service.py

@@ -4,7 +4,7 @@ import collections
 import itertools
 import time
 import sys
-from typing import Optional
+from typing import Optional, Tuple
 from decimal import Decimal
 from copy import deepcopy
 from twisted.internet import reactor
@@ -733,11 +733,8 @@ class WalletService(Service):
     def rescanblockchain(self, start_height: int, end_height: Optional[int] = None) -> None:
         self.bci.rescanblockchain(start_height, end_height)
 
-    def get_backend_walletinfo(self) -> dict:
-        """ 'Backend' wallet means the Bitcoin Core wallet,
-        which will always be loaded if self.bci is init-ed.
-        """
-        return self.bci.getwalletinfo()
+    def get_backend_wallet_rescan_status(self) -> Tuple[bool, Optional[Decimal]]:
+        return self.bci.get_wallet_rescan_status()
 
     def get_transaction_block_height(self, tx):
         """ Given a CTransaction object tx, return