added automatic service selection with one allowed failure

Author: F483

btctxstore/api.py

@@ -19,10 +19,10 @@
 class BtcTxStore():  # TODO use apigen when ported to python 3
     """Bitcoin nulldata output io library."""
 
-    def __init__(self, testnet=False, dryrun=False):
+    def __init__(self, testnet=False, dryrun=False, service="automatic"):
         self.testnet = deserialize.flag(testnet)
         self.dryrun = deserialize.flag(dryrun)
-        self.service = services.select("blockexplorer", testnet=testnet,
+        self.service = services.select(service, testnet=testnet,
                                        dryrun=dryrun)
 
     ###########

btctxstore/services/__init__.py

@@ -5,21 +5,19 @@
 
 from btctxstore.services.insight import Insight
 from btctxstore.services.blockexplorer import BlockExplorer
+from btctxstore.services.automatic import Automatic
 
-
-#from btctxstore.services.blockchaininfo import BlockchainInfo
-# blockchain.info removed because it doesnt accept transaction with OP_RETURN 
-
+_all = {
+    "insight": Insight,
+    "blockexplorer": BlockExplorer,
+}
 
 def select(name, testnet=False, dryrun=False):
-    service_dict = {  # { "name" : (class, testnet_supported), ... }
-        "insight": (Insight, True),
-        "blockexplorer": (BlockExplorer, True),
-        #"blockchain.info": (BlockchainInfo, False),
-    }
-    service_class, testnet_supported = service_dict.get(name, (None, False))
-    if service_class is None:
+    service_class = _all.get(name)
+    if service_class is not None:
+        return service_class(testnet=testnet, dryrun=dryrun)
+    if name != "automatic":
         raise Exception("Service {0} not found!".format(name))
-    if testnet and not testnet_supported:
-        raise Exception("Service {0} does not support testnet!".format(name))
-    return service_class(testnet=testnet, dryrun=dryrun)
+    return Automatic(testnet=testnet, dryrun=dryrun,
+                     service_classes=_all.values())
+    

btctxstore/services/automatic.py

@@ -3,20 +3,73 @@
 # License: MIT (see LICENSE file)
 
 
+import random
+import logging
+from btctxstore.services.interface import BlockchainService
 
-class Insight(BlockchainService):
 
-    def __init__(self, testnet=False, dryrun=False):
-        super(Insight, self).__init__(testnet=testnet, dryrun=dryrun)
+_log = logging.getLogger(__name__)
+
+
+class Automatic(BlockchainService):
+
+    def __init__(self, testnet=False, dryrun=False, service_classes=[]):
+        super(Automatic, self).__init__(testnet=testnet, dryrun=dryrun)
+        if not service_classes:
+            raise ValueError()
+        self.services = []
+        for service_class in service_classes:
+            self.services.append(service_class(testnet=testnet, dryrun=dryrun))
+
+    def _select_service(self):
+        return random.choice(self.services)
+
+    def _select_other_service(self, service):
+        for other_service in self.services:
+            if other_service is not service:
+                return other_service
+        raise Exception("Not enough services!")
 
     def get_tx(self, txid):
-        """TODO doc string"""
-        raise NotImplementedError()
+        service = self._select_service()
+        try:
+            return service.get_tx(txid)
+        except Exception as e:
+            # try only once with another service
+            # if two independant services fail something is wrong
+            # there are also only two working services right now ...
+            name = service.__class__.__name__
+            msg = "Service call to {0} failed: {1}"
+            _log.error(msg.format(name, repr(e)))
+            other_service = self._select_other_service(service)
+            return other_service.get_tx(txid)
 
     def send_tx(self, tx):
-        """TODO doc string"""
-        raise NotImplementedError()
+        service = self._select_service()
+        try:
+            return service.send_tx(tx)
+        except Exception as e:
+            # try only once with another service
+            # if two independant services fail something is wrong
+            # there are also only two working services right now ...
+            name = service.__class__.__name__
+            msg = "Service call to {0} failed: {1}"
+            _log.error(msg.format(name, repr(e)))
+            other_service = self._select_other_service(service)
+            return other_service.send_tx(tx)
+
+    # TODO override spendables_for_addresses in case implementation optimizes
 
     def spendables_for_address(self, bitcoin_address):
-        """TODO doc string"""
-        raise NotImplementedError()
+        service = self._select_service()
+        try:
+            return service.spendables_for_address(bitcoin_address)
+        except Exception as e:
+            # try only once with another service
+            # if two independant services fail something is wrong
+            # there are also only two working services right now ...
+            name = service.__class__.__name__
+            msg = "Service call to {0} failed: {1}"
+            _log.error(msg.format(name, repr(e)))
+            other_service = self._select_other_service(service)
+            return other_service.spendables_for_address(bitcoin_address)

btctxstore/services/blockchaininfo.py

@@ -141,7 +141,6 @@ def test_getutxos(self):
         address = fixtures["wallet"]["address"]
         expected = fixtures["getutxos"]["expected"]
         result = self.api.retrieve_utxos([address])
-        print("RESULT", result)
         self.assertEqual(result, expected)