Since this thing is on the innerwebs I suppose it should have a

[python_utils.git] / thread_utils.py

diff --git a/thread_utils.py b/thread_utils.py
index d8c85f46fbcaed33864d591458c64a1cebeb162d..01755deafc1e7af9189026c2ae233c6146c7d494 100644 (file)
--- a/thread_utils.py
+++ b/thread_utils.py
@@ -1,10 +1,14 @@
 #!/usr/bin/env python3
 
+# © Copyright 2021-2022, Scott Gasch
+
+"""Utilities for dealing with threads + threading."""
+
 import functools
 import logging
 import os
 import threading
-from typing import Callable, Optional, Tuple
+from typing import Any, Callable, Optional, Tuple
 
 # This module is commonly used by others in here and should avoid
 # taking any unnecessary dependencies back on them.
@@ -13,6 +17,19 @@ logger = logging.getLogger(__name__)
 
 
 def current_thread_id() -> str:
+    """Returns a string composed of the parent process' id, the current
+    process' id and the current thread identifier.  The former two are
+    numbers (pids) whereas the latter is a thread id passed during thread
+    creation time.
+
+    >>> ret = current_thread_id()
+    >>> (ppid, pid, tid) = ret.split('/')
+    >>> ppid.isnumeric()
+    True
+    >>> pid.isnumeric()
+    True
+
+    """
     ppid = os.getppid()
     pid = os.getpid()
     tid = threading.current_thread().name
@@ -22,13 +39,33 @@ def current_thread_id() -> str:
 def is_current_thread_main_thread() -> bool:
     """Returns True is the current (calling) thread is the process' main
     thread and False otherwise.
+
+    >>> is_current_thread_main_thread()
+    True
+
+    >>> result = None
+    >>> def thunk():
+    ...     global result
+    ...     result = is_current_thread_main_thread()
+
+    >>> thunk()
+    >>> result
+    True
+
+    >>> import threading
+    >>> thread = threading.Thread(target=thunk)
+    >>> thread.start()
+    >>> thread.join()
+    >>> result
+    False
+
     """
     return threading.current_thread() is threading.main_thread()
 
 
 def background_thread(
-    _funct: Optional[Callable],
-) -> Tuple[threading.Thread, threading.Event]:
+    _funct: Optional[Callable[..., Any]],
+) -> Callable[..., Tuple[threading.Thread, threading.Event]]:
     """A function decorator to create a background thread.
 
     *** Please note: the decorated function must take an shutdown ***
@@ -71,13 +108,13 @@ def background_thread(
                 kwargs=kwa,
             )
             thread.start()
-            logger.debug(f'Started thread {thread.name} tid={thread.ident}')
+            logger.debug('Started thread "%s" tid=%d', thread.name, thread.ident)
             return (thread, should_terminate)
 
         return inner_wrapper
 
     if _funct is None:
-        return wrapper
+        return wrapper  # type: ignore
     else:
         return wrapper(_funct)
 
@@ -130,9 +167,15 @@ def periodically_invoke(
             newargs = (should_terminate, *args)
             thread = threading.Thread(target=helper_thread, args=newargs, kwargs=kwargs)
             thread.start()
-            logger.debug(f'Started thread {thread.name} tid={thread.ident}')
+            logger.debug('Started thread "%s" tid=%d', thread.name, thread.ident)
             return (thread, should_terminate)
 
         return wrapper_repeat
 
     return decorator_repeat
+
+
+if __name__ == '__main__':
+    import doctest
+
+    doctest.testmod()