Merge pull request #18 from mreiche/bugfix/thread-safety

change() is now thread safe using thread-local Config() class

paf/control.py

@@ -1,24 +1,30 @@
 import dataclasses
+import threading
 from contextlib import contextmanager
 from dataclasses import dataclass
 from time import sleep, time
-from typing import Callable
+from typing import Callable, Optional
 
 from paf.common import Property
 from paf.types import Consumer
 
 
 @dataclass()
-class Config:
+class Config(threading.local):
     retry_count: int = Property.env(Property.PAF_SEQUENCE_RETRY_COUNT)
     wait_after_fail: float = Property.env(Property.PAF_SEQUENCE_WAIT_AFTER_FAIL)
 
 
-__global_config = Config()
+__config = Config()
 
 
-def __get_global_config():
-    return __global_config
+def get_config():
+    return __config
+
+
+def __set_config(config: Config):
+    global __config
+    __config = config
 
 
 class Sequence:
@@ -59,26 +65,26 @@ def change(
     retry_count: int = None,
     wait_after_fail: float = None,
 ):
-    global __global_config
-    config_backup = __global_config
-    config = dataclasses.replace(__global_config)
-    __global_config = config
+    config_backup = get_config()
+    scope_config = dataclasses.replace(config_backup)
+    __set_config(scope_config)
 
     if retry_count is not None:
-        config.retry_count = retry_count
+        scope_config.retry_count = retry_count
 
     if wait_after_fail is not None:
-        config.wait_after_fail = wait_after_fail
+        scope_config.wait_after_fail = wait_after_fail
 
     try:
         yield
     finally:
-        __global_config = config_backup
+        __set_config(config_backup)
 
 
 def retry(action: Callable, on_fail: Consumer[Exception] = None):
-    sequence = Sequence(retry_count=__global_config.retry_count, wait_after_fail=__global_config.wait_after_fail)
-    exception = None
+    config = get_config()
+    sequence = Sequence(retry_count=config.retry_count, wait_after_fail=config.wait_after_fail)
+    exception: Optional[Exception] = None
 
     def _run():
         nonlocal exception

test/test_control.py

@@ -1,20 +1,55 @@
+import asyncio
 import dataclasses
+from time import sleep
 
-from paf.control import change, __get_global_config, retry
+import pytest
 
+from paf.common import Property
+from paf.control import change, get_config, retry
 
-def test_config():
 
-    backup = dataclasses.replace(__get_global_config())
-    assert backup.retry_count != 99
-    assert backup.wait_after_fail != 99
+def test_change():
+
+    backup_config = dataclasses.replace(get_config())
+    assert backup_config.retry_count != 99
+    assert backup_config.wait_after_fail != 99
 
     with change(retry_count=99, wait_after_fail=99):
-        global_config = __get_global_config()
+        global_config = get_config()
         assert global_config.wait_after_fail == 99
         assert global_config.retry_count == 99
         retry(lambda: None)
 
-    global_config = __get_global_config()
-    assert global_config.retry_count == backup.retry_count
-    assert global_config.wait_after_fail == backup.wait_after_fail
+    global_config = get_config()
+    assert global_config.retry_count == backup_config.retry_count
+    assert global_config.wait_after_fail == backup_config.wait_after_fail
+
+
+def change_first():
+    global_config = get_config()
+    assert global_config.retry_count == Property.env(Property.PAF_SEQUENCE_RETRY_COUNT)
+
+    with change(retry_count=0):
+        sleep(0.3)
+        config = get_config()
+        assert config.retry_count == 0
+
+
+def change_second():
+    global_config = get_config()
+    assert global_config.retry_count == Property.env(Property.PAF_SEQUENCE_RETRY_COUNT)
+
+    with change(retry_count=99):
+        sleep(0.1)
+        config = get_config()
+        assert config.retry_count == 99
+
+
+@pytest.mark.asyncio
+async def test_thread_safety():
+    tasks = [
+        asyncio.to_thread(change_first),
+        asyncio.to_thread(change_second)
+    ]
+
+    await asyncio.gather(*tasks)