Allow to set the gas strategy at the interface layer

nucypher/blockchain/eth/interfaces.py

@@ -280,22 +280,27 @@ class BlockchainInterface:
             self.log.debug('Injecting POA middleware at layer 0')
             self.client.inject_middleware(geth_poa_middleware, layer=0)
 
-        # Gas Price Strategy:
-        # Bundled web3 strategies are too expensive for Infura (it takes ~1 minute to get a price),
-        # so we use external gas price oracles, instead (see #2139)
-        if isinstance(self.client, InfuraClient):
-            gas_strategy = datafeed_fallback_gas_price_strategy
-            self.gas_strategy = 'fast'  # FIXME
-        else:
-            gas_strategy = self.get_gas_strategy(self.gas_strategy)
-        self.client.set_gas_strategy(gas_strategy=gas_strategy)
-        gwei_gas_price = Web3.fromWei(self.client.gas_price_for_transaction(), 'gwei')
-        self.log.debug(f"Currently, our gas strategy returns a gas price of {gwei_gas_price} gwei")
-
         self.client.add_middleware(middleware.time_based_cache_middleware)
         # self.client.add_middleware(middleware.latest_block_based_cache_middleware)
         self.client.add_middleware(middleware.simple_cache_middleware)
 
+        self.set_gas_strategy()
+
+    def set_gas_strategy(self, gas_strategy: Optional[Callable] = None):
+        if gas_strategy:
+            reported_gas_strategy = f"fixed/{gas_strategy.name}"
+        elif isinstance(self.client, InfuraClient):
+            gas_strategy = datafeed_fallback_gas_price_strategy
+            self.gas_strategy = 'fast'
+            reported_gas_strategy = "datafeed/fast"
+        else:
+            reported_gas_strategy = f"web3/{self.gas_strategy}"
+            gas_strategy = self.get_gas_strategy(self.gas_strategy)
+        self.client.set_gas_strategy(gas_strategy=gas_strategy)
+        gwei_gas_price = Web3.fromWei(self.client.gas_price_for_transaction(), 'gwei')
+        self.log.debug(f"Using gas strategy '{reported_gas_strategy}'. "
+                       f"Currently, it returns a gas price of {gwei_gas_price} gwei")
+
     def connect(self):
 
         # Spawn child process

nucypher/utilities/gas_strategies.py

@@ -15,8 +15,7 @@
  along with nucypher.  If not, see <https://www.gnu.org/licenses/>.
 """
 import datetime
-import functools
+from typing import Callable, Optional
-from typing import Callable
 
 from web3 import Web3
 from web3.exceptions import ValidationError
@@ -64,20 +63,24 @@ __RAW_WEB3_GAS_STRATEGIES = {
 }
 
 
-def wrap_web3_gas_strategy(web3_gas_strategy: Callable):
+def wrap_web3_gas_strategy(speed: Optional[str] = None):
     """
     Enriches the web3 exceptions thrown by gas strategies
     """
-    @functools.wraps(web3_gas_strategy)
+    web3_gas_strategy = __RAW_WEB3_GAS_STRATEGIES[speed]
+
     def _wrapper(*args, **kwargs):
         try:
             return web3_gas_strategy(*args, **kwargs)
         except ValidationError as e:
             raise GasStrategyError("Calling the web3 gas strategy failed, probably due to an unsynced chain.") from e
+
+    _wrapper.name = speed
+
     return _wrapper
 
 
-WEB3_GAS_STRATEGIES = {speed: wrap_web3_gas_strategy(strategy) for speed, strategy in __RAW_WEB3_GAS_STRATEGIES.items()}
+WEB3_GAS_STRATEGIES = {speed: wrap_web3_gas_strategy(speed) for speed in __RAW_WEB3_GAS_STRATEGIES}
 
 EXPECTED_CONFIRMATION_TIME_IN_SECONDS = {
     'slow': int(datetime.timedelta(hours=1).total_seconds()),