The logging_pool module.

1 files changed, 83 insertions, 0 deletions

diff --git a/src/python/_framework/foundation/logging_pool.py b/src/python/_framework/foundation/logging_pool.py
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+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""A thread pool that logs exceptions raised by tasks executed within it."""
+
+import functools
+import logging
+
+from concurrent import futures
+
+
+def _wrap(behavior):
+  """Wraps an arbitrary callable behavior in exception-logging."""
+  @functools.wraps(behavior)
+  def _wrapping(*args, **kwargs):
+    try:
+      return behavior(*args, **kwargs)
+    except Exception as e:
+      logging.exception('Unexpected exception from task run in logging pool!')
+      raise
+  return _wrapping
+
+
+class _LoggingPool(object):
+  """An exception-logging futures.ThreadPoolExecutor-compatible thread pool."""
+
+  def __init__(self, backing_pool):
+    self._backing_pool = backing_pool
+
+  def __enter__(self):
+    return self
+
+  def __exit__(self, exc_type, exc_val, exc_tb):
+    self._backing_pool.shutdown(wait=True)
+
+  def submit(self, fn, *args, **kwargs):
+    return self._backing_pool.submit(_wrap(fn), *args, **kwargs)
+
+  def map(self, func, *iterables, **kwargs):
+    return self._backing_pool.map(
+        _wrap(func), *iterables, timeout=kwargs.get('timeout', None))
+
+  def shutdown(self, wait=True):
+    self._backing_pool.shutdown(wait=wait)
+
+
+def pool(max_workers):
+  """Creates a thread pool that logs exceptions raised by the tasks within it.
+
+  Args:
+    max_workers: The maximum number of worker threads to allow the pool.
+
+  Returns:
+    A futures.ThreadPoolExecutor-compatible thread pool that logs exceptions
+      raised by the tasks executed within it.
+  """
+  return _LoggingPool(futures.ThreadPoolExecutor(max_workers))