new file mode 100644
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+"""
+Misc. utils and helper functions
+"""
+
+import asyncio
+import traceback
+import sys
+from typing import (
+ Any,
+ Coroutine,
+ TypeVar,
+)
+
+
+T = TypeVar('T')
+
+
+def create_task(coro: Coroutine[Any, Any, T]) -> 'asyncio.Future[T]':
+ """
+ Python 3.6-compatible create_task() wrapper.
+ """
+ if hasattr(asyncio, 'create_task'):
+ # Python 3.7+
+ return asyncio.create_task(coro)
+
+ # Python 3.6
+ return asyncio.ensure_future(coro)
+
+
+async def wait_closed(writer: asyncio.StreamWriter) -> None:
+ """
+ Python 3.6-compatible StreamWriter.wait_closed() wrapper.
+ """
+ if hasattr(writer, 'wait_closed'):
+ # Python 3.7+
+ await writer.wait_closed()
+ else:
+ # Python 3.6
+ transport = writer.transport
+ assert isinstance(transport, asyncio.WriteTransport)
+
+ while not transport.is_closing():
+ await asyncio.sleep(0.0)
+ while transport.get_write_buffer_size() > 0:
+ await asyncio.sleep(0.0)
+
+
+def asyncio_run(coro: Coroutine[Any, Any, T]) -> T:
+ """
+ Python 3.6-compatible asyncio.run() wrapper.
+ """
+ # Python 3.7+
+ if hasattr(asyncio, 'run'):
+ return asyncio.run(coro)
+
+ # Python 3.6
+ loop = asyncio.get_event_loop()
+ ret = loop.run_until_complete(coro)
+ loop.close()
+
+ return ret
+
+
+def pretty_traceback() -> str:
+ """
+ Print the current traceback, but indented to provide visual distinction.
+
+ This is useful for printing a traceback within a traceback for
+ debugging purposes when encapsulating errors to deliver them up the
+ stack; when those errors are printed, this helps provide a nice
+ visual grouping to quickly identify the parts of the error that
+ belong to the inner exception.
+
+ :returns: A string, formatted something like the following::
+
+ | Traceback (most recent call last):
+ | File "foobar.py", line 42, in arbitrary_example
+ | foo.baz()
+ | ArbitraryError: [Errno 42] Something bad happened!
+
+ """
+ exc_lines = []
+ for chunk in traceback.format_exception(*sys.exc_info()):
+ for line in chunk.split("\n"):
+ if line:
+ exc_lines.append(f" | {line}")
+ return "\n".join(exc_lines)
Nothing too interesting design-wise here; mostly asyncio-related helpers designed to make writing Python 3.6-compliant code a little nicer to read. Signed-off-by: John Snow <jsnow@redhat.com> --- util.py | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 util.py