Python3 Migrate

venv/lib/python3.7/site-packages/pykka/debug.py

@@ -0,0 +1,67 @@
+from __future__ import absolute_import
+
+import logging
+import sys
+import threading
+import traceback
+
+
+logger = logging.getLogger('pykka')
+
+
+__all__ = ['log_thread_tracebacks']
+
+
+def log_thread_tracebacks(*args, **kwargs):
+    """Logs at :attr:`logging.CRITICAL` level a traceback for each running
+    thread.
+
+    This can be a convenient tool for debugging deadlocks.
+
+    The function accepts any arguments so that it can easily be used as e.g. a
+    signal handler, but it does not use the arguments for anything.
+
+    To use this function as a signal handler, setup logging with a
+    :attr:`logging.CRITICAL` threshold or lower and make your main thread
+    register this with the :mod:`signal` module::
+
+        import logging
+        import signal
+
+        import pykka.debug
+
+        logging.basicConfig(level=logging.DEBUG)
+        signal.signal(signal.SIGUSR1, pykka.debug.log_thread_tracebacks)
+
+    If your application deadlocks, send the `SIGUSR1` signal to the process::
+
+        kill -SIGUSR1 <pid of your process>
+
+    Signal handler caveats:
+
+    - The function *must* be registered as a signal handler by your main
+      thread. If not, :func:`signal.signal` will raise a :exc:`ValueError`.
+
+    - All signals in Python are handled by the main thread. Thus, the signal
+      will only be handled, and the tracebacks logged, if your main thread is
+      available to do some work. Making your main thread idle using
+      :func:`time.sleep` is OK. The signal will awaken your main thread.
+      Blocking your main thread on e.g. :func:`queue.Queue.get` or
+      :meth:`pykka.Future.get` will break signal handling, and thus you won't
+      be able to signal your process to print the thread tracebacks.
+
+    The morale is: setup signals using your main thread, start your actors,
+    then let your main thread relax for the rest of your application's life
+    cycle.
+
+    .. versionadded:: 1.1
+    """
+
+    thread_names = dict((t.ident, t.name) for t in threading.enumerate())
+
+    for ident, frame in sys._current_frames().items():
+        name = thread_names.get(ident, '?')
+        stack = ''.join(traceback.format_stack(frame))
+        logger.critical(
+            'Current state of {} (ident: {}):\n{}'.format(name, ident, stack)
+        )