Signed-off-by: John Snow <js...@redhat.com>
---
python/qemu/aqmp/__init__.py | 7 +++
python/qemu/aqmp/error.py | 97 ++++++++++++++++++++++++++++++++++++
2 files changed, 104 insertions(+)
create mode 100644 python/qemu/aqmp/error.py
diff --git a/python/qemu/aqmp/__init__.py b/python/qemu/aqmp/__init__.py
index 4c713b3ccf..8e955d784d 100644
--- a/python/qemu/aqmp/__init__.py
+++ b/python/qemu/aqmp/__init__.py
@@ -21,7 +21,14 @@
# This work is licensed under the terms of the GNU GPL, version 2. See
# the COPYING file in the top-level directory.
+from .error import AQMPError, MultiException
+
# The order of these fields impact the Sphinx documentation order.
__all__ = (
+ # Exceptions
+ 'AQMPError',
+
+ # Niche topics
+ 'MultiException',
)
diff --git a/python/qemu/aqmp/error.py b/python/qemu/aqmp/error.py
new file mode 100644
index 0000000000..126f77bb5c
--- /dev/null
+++ b/python/qemu/aqmp/error.py
@@ -0,0 +1,97 @@
+"""
+AQMP Error Classes
+
+This package seeks to provide semantic error classes that are intended
+to be used directly by clients when they would like to handle particular
+semantic failures (e.g. "failed to connect") without needing to know the
+enumeration of possible reasons for that failure.
+
+AQMPError serves as the ancestor for *almost* all exceptions raised by
+this package, and is suitable for use in handling semantic errors from
+this library. In most cases, individual public methods will attempt to
+catch and re-encapsulate various exceptions to provide a semantic
+error-handling interface.
+
+.. caution::
+
+ The only exception that is not an `AQMPError` is
+ `MultiException`. It is special, and used to encapsulate one-or-more
+ exceptions of an arbitrary kind; this exception MAY be raised on
+ `disconnect()` when there are two or more exceptions from the AQMP
+ event loop to report back to the caller.
+
+ Every pain has been taken to prevent this circumstance but in
+ certain cases these exceptions may occasionally be (unfortunately)
+ visible. See `MultiException` and `AsyncProtocol.disconnect()` for
+ more details.
+
+
+.. admonition:: AQMP Exception Hierarchy Reference
+
+ | `Exception`
+ | +-- `MultiException`
+ | +-- `AQMPError`
+ | +-- `ConnectError`
+ | +-- `StateError`
+ | +-- `ExecInterruptedError`
+ | +-- `ExecuteError`
+ | +-- `ListenerError`
+ | +-- `ProtocolError`
+ | +-- `DeserializationError`
+ | +-- `UnexpectedTypeError`
+ | +-- `ServerParseError`
+ | +-- `BadReplyError`
+ | +-- `GreetingError`
+ | +-- `NegotiationError`
+"""
+
+from typing import Iterable, Iterator, List
+
+
+class AQMPError(Exception):
+ """Abstract error class for all errors originating from this package."""
+
+
+class ProtocolError(AQMPError):
+ """
+ Abstract error class for protocol failures.
+
+ Semantically, these errors are generally the fault of either the
+ protocol server or as a result of a bug in this this library.
+
+ :param error_message: Human-readable string describing the error.
+ """
+ def __init__(self, error_message: str):
+ super().__init__(error_message)
+ #: Human-readable error message, without any prefix.
+ self.error_message: str = error_message
+
+
+class MultiException(Exception):
+ """
+ Used for multiplexing exceptions.
+
+ This exception is used in the case that errors were encountered in both the
+ Reader and Writer tasks, and we must raise more than one.
+
+ PEP 0654 seeks to remedy this clunky infrastructure, but it will not be
+ available for quite some time -- possibly Python 3.11 or even later.
+
+ :param exceptions: An iterable of `BaseException` objects.
+ """
+ def __init__(self, exceptions: Iterable[BaseException]):
+ super().__init__(exceptions)
+ self._exceptions: List[BaseException] = list(exceptions)
+
+ def __str__(self) -> str:
+ ret = "------------------------------\n"
+ ret += "Multiple Exceptions occurred:\n"
+ ret += "\n"
+ for i, exc in enumerate(self._exceptions):
+ ret += f"{i}) {str(exc)}\n"
+ ret += "\n"
+ ret += "-----------------------------\n"
+ return ret
+
+ def __iter__(self) -> Iterator[BaseException]:
+ return iter(self._exceptions)
--
2.31.1
