Fix semaphore on wrong loop edge case (#83)

* fix: edge case with semaphore attached to wrong loop

* chore: bump version

multicall/call.py

@@ -7,11 +7,11 @@
 from web3 import Web3
 
 from multicall import Signature
-from multicall.constants import Network, w3, ASYNC_SEMAPHORE
+from multicall.constants import Network, w3
 from multicall.exceptions import StateOverrideNotSupported
 from multicall.loggers import setup_logger
-from multicall.utils import (chain_id, get_async_w3, run_in_subprocess,
-                             state_override_supported)
+from multicall.utils import (_get_semaphore, chain_id, get_async_w3,
+                             run_in_subprocess, state_override_supported)
 
 logger = setup_logger(__name__)
 
@@ -112,7 +112,7 @@ async def coroutine(self, args: Optional[Any] = None, _w3: Optional[Web3] = None
         if self.state_override_code and not state_override_supported(_w3):
             raise StateOverrideNotSupported(f'State override is not supported on {Network(chain_id(_w3)).__repr__()[1:-1]}.')
 
-        async with ASYNC_SEMAPHORE:
+        async with _get_semaphore():
             output = await get_async_w3(_w3).eth.call(
                 *await run_in_subprocess(
                     prep_args,

multicall/constants.py

@@ -186,4 +186,4 @@ class Network(IntEnum):
 
 # NOTE: If we run too many async calls at once, we'll have memory issues.
 #       Feel free to increase this with the "MULTICALL_CALL_SEMAPHORE" env var if you know what you're doing.
-ASYNC_SEMAPHORE = asyncio.Semaphore(int(os.environ.get("MULTICALL_CALL_SEMAPHORE", 1000)))
+ASYNC_SEMAPHORE = int(os.environ.get("MULTICALL_CALL_SEMAPHORE", 1000))

multicall/multicall.py

@@ -7,11 +7,10 @@
 from web3 import Web3
 
 from multicall import Call
-from multicall.constants import (ASYNC_SEMAPHORE, GAS_LIMIT,
-                                 MULTICALL2_ADDRESSES, MULTICALL3_ADDRESSES,
-                                 MULTICALL3_BYTECODE, w3)
+from multicall.constants import (GAS_LIMIT, MULTICALL2_ADDRESSES,
+                                 MULTICALL3_ADDRESSES, MULTICALL3_BYTECODE)
 from multicall.loggers import setup_logger
-from multicall.utils import (await_awaitable, chain_id, gather,
+from multicall.utils import (_get_semaphore, await_awaitable, chain_id, gather,
                              run_in_subprocess, state_override_supported)
 
 logger = setup_logger(__name__)
@@ -82,7 +81,7 @@ async def fetch_outputs(self, calls: List[Call], ConnErr_retries: int = 0, id: s
         if calls is None:
             calls = self.calls
 
-        async with ASYNC_SEMAPHORE:
+        async with _get_semaphore():
             try:
                 args = await run_in_subprocess(get_args, calls, self.require_success)
                 if self.require_success is True:

multicall/utils.py

@@ -1,6 +1,7 @@
 
 import asyncio
 from concurrent.futures import ProcessPoolExecutor
+from functools import lru_cache
 from typing import Any, Awaitable, Callable, Coroutine, Dict, Iterable
 
 import eth_retry
@@ -9,7 +10,8 @@
 from web3.eth import AsyncEth
 from web3.providers.async_base import AsyncBaseProvider
 
-from multicall.constants import AIOHTTP_TIMEOUT, NUM_PROCESSES, NO_STATE_OVERRIDE
+from multicall.constants import (AIOHTTP_TIMEOUT, NO_STATE_OVERRIDE,
+                                 NUM_PROCESSES)
 
 chainids: Dict[Web3,int] = {}
 
@@ -94,3 +96,7 @@ def state_override_supported(w3: Web3) -> bool:
     if chain_id(w3) in NO_STATE_OVERRIDE:
         return False
     return True
+
+@lru_cache(maxsize=1)
+def _get_semaphore() -> asyncio.Semaphore:
+    return asyncio.Semaphore()

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "multicall"
-version = "0.7.7"
+version = "0.7.8"
 description = "aggregate results from multiple ethereum contract calls"
 authors = ["banteg"]