diff options
| -rw-r--r-- | python/qemu/aqmp/util.py | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/python/qemu/aqmp/util.py b/python/qemu/aqmp/util.py index 5b8f968..52a1532 100644 --- a/python/qemu/aqmp/util.py +++ b/python/qemu/aqmp/util.py @@ -4,10 +4,15 @@ Miscellaneous Utilities This module provides asyncio utilities and compatibility wrappers for Python 3.6 to provide some features that otherwise become available in Python 3.7+. + +Various logging and debugging utilities are also provided, such as +`exception_summary()` and `pretty_traceback()`, used primarily for +adding information into the logging stream. """ import asyncio import sys +import traceback from typing import ( Any, Coroutine, @@ -140,3 +145,54 @@ async def wait_closed(writer: asyncio.StreamWriter) -> None: while sock.fileno() != -1: await asyncio.sleep(0) + + +# ---------------------------- +# Section: Logging & Debugging +# ---------------------------- + + +def exception_summary(exc: BaseException) -> str: + """ + Return a summary string of an arbitrary exception. + + It will be of the form "ExceptionType: Error Message", if the error + string is non-empty, and just "ExceptionType" otherwise. + """ + name = type(exc).__qualname__ + smod = type(exc).__module__ + if smod not in ("__main__", "builtins"): + name = smod + '.' + name + + error = str(exc) + if error: + return f"{name}: {error}" + return name + + +def pretty_traceback(prefix: str = " | ") -> str: + """ + Formats the current traceback, 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. + + :param prefix: The prefix to append to each line of the traceback. + :return: 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! + """ + output = "".join(traceback.format_exception(*sys.exc_info())) + + exc_lines = [] + for line in output.split('\n'): + exc_lines.append(prefix + line) + + # The last line is always empty, omit it + return "\n".join(exc_lines[:-1]) |