Give the connection and the reader/writer tasks nicknames, and add
logging statements throughout.
Signed-off-by: John Snow <js...@redhat.com>
---
python/qemu/aqmp/protocol.py | 71 ++++++++++++++++++++++++++++++++----
1 file changed, 64 insertions(+), 7 deletions(-)
diff --git a/python/qemu/aqmp/protocol.py b/python/qemu/aqmp/protocol.py
index 247b60c31a6..f9295546cda 100644
--- a/python/qemu/aqmp/protocol.py
+++ b/python/qemu/aqmp/protocol.py
@@ -14,6 +14,7 @@
from asyncio import StreamReader, StreamWriter
from enum import Enum
from functools import wraps
+import logging
from ssl import SSLContext
from typing import (
Any,
@@ -31,8 +32,10 @@
from .util import (
bottom_half,
create_task,
+ exception_summary,
flush,
is_closing,
+ pretty_traceback,
upper_half,
wait_closed,
)
@@ -173,14 +176,28 @@ class AsyncProtocol(Generic[T]):
can be written after the super() call.
- `_on_message`:
Actions to be performed when a message is received.
+
+ :param name:
+ Name used for logging messages, if any. By default, messages
+ will log to 'qemu.aqmp.protocol', but each individual connection
+ can be given its own logger by giving it a name; messages will
+ then log to 'qemu.aqmp.protocol.${name}'.
"""
# pylint: disable=too-many-instance-attributes
+ #: Logger object for debugging messages from this connection.
+ logger = logging.getLogger(__name__)
+
# -------------------------
# Section: Public interface
# -------------------------
- def __init__(self) -> None:
+ def __init__(self, name: Optional[str] = None) -> None:
+ #: The nickname for this connection, if any.
+ self.name: Optional[str] = name
+ if self.name is not None:
+ self.logger = self.logger.getChild(self.name)
+
# stream I/O
self._reader: Optional[StreamReader] = None
self._writer: Optional[StreamWriter] = None
@@ -207,6 +224,14 @@ def __init__(self) -> None:
self._runstate = Runstate.IDLE
self._runstate_changed: Optional[asyncio.Event] = None
+ def __repr__(self) -> str:
+ cls_name = type(self).__name__
+ tokens = []
+ if self.name is not None:
+ tokens.append(f"name={self.name!r}")
+ tokens.append(f"runstate={self.runstate.name}")
+ return f"<{cls_name} {' '.join(tokens)}>"
+
@property # @upper_half
def runstate(self) -> Runstate:
"""The current `Runstate` of the connection."""
@@ -275,6 +300,8 @@ def _set_state(self, state: Runstate) -> None:
if state == self._runstate:
return
+ self.logger.debug("Transitioning from '%s' to '%s'.",
+ str(self._runstate), str(state))
self._runstate = state
self._runstate_event.set()
self._runstate_event.clear()
@@ -314,8 +341,15 @@ async def _new_session(self,
except BaseException as err:
emsg = f"Failed to establish {phase}"
- # Reset from CONNECTING back to IDLE.
- await self.disconnect()
+ self.logger.error("%s: %s", emsg, exception_summary(err))
+ self.logger.debug("%s:\n%s\n", emsg, pretty_traceback())
+ try:
+ # Reset from CONNECTING back to IDLE.
+ await self.disconnect()
+ except:
+ emsg = "Unexpected bottom half exception"
+ self.logger.critical("%s:\n%s\n", emsg, pretty_traceback())
+ raise
# NB: CancelledError is not a BaseException before Python 3.8
if isinstance(err, asyncio.CancelledError):
@@ -365,12 +399,16 @@ async def _do_connect(self, address: Union[str,
Tuple[str, int]],
:raise OSError: For stream-related errors.
"""
+ self.logger.debug("Connecting to %s ...", address)
+
if isinstance(address, tuple):
connect = asyncio.open_connection(address[0], address[1], ssl=ssl)
else:
connect = asyncio.open_unix_connection(path=address, ssl=ssl)
self._reader, self._writer = await connect
+ self.logger.debug("Connected.")
+
@upper_half
async def _establish_session(self) -> None:
"""
@@ -384,8 +422,8 @@ async def _establish_session(self) -> None:
self._outgoing = asyncio.Queue()
- reader_coro = self._bh_loop_forever(self._bh_recv_message)
- writer_coro = self._bh_loop_forever(self._bh_send_message)
+ reader_coro = self._bh_loop_forever(self._bh_recv_message, 'Reader')
+ writer_coro = self._bh_loop_forever(self._bh_send_message, 'Writer')
self._reader_task = create_task(reader_coro)
self._writer_task = create_task(writer_coro)
@@ -412,6 +450,7 @@ def _schedule_disconnect(self) -> None:
"""
if not self._dc_task:
self._set_state(Runstate.DISCONNECTING)
+ self.logger.debug("Scheduling disconnect.")
self._dc_task = create_task(self._bh_disconnect())
@upper_half
@@ -497,8 +536,10 @@ def _exception(
# This implicitly closes the reader, too.
if self._writer:
if not is_closing(self._writer):
+ self.logger.debug("Closing StreamWriter.")
self._writer.close()
+ self.logger.debug("Waiting for StreamWriter to close ...")
try:
await wait_closed(self._writer)
except Exception as err: # pylint: disable=broad-except
@@ -509,6 +550,10 @@ def _exception(
self._reader_task, self._writer_task))):
raise
+ self.logger.debug("StreamWriter closed.")
+
+ self.logger.debug("Disconnected.")
+
@bottom_half
async def _bh_stop_writer(self, force: bool = False) -> None:
if not self._writer_task or self._writer_task.done():
@@ -516,10 +561,13 @@ async def _bh_stop_writer(self, force: bool = False) ->
None:
# If we're not in a hurry, drain the outbound queue.
if not force:
+ self.logger.debug("Draining the outbound queue ...")
await self._outgoing.join()
if self._writer is not None:
+ self.logger.debug("Flushing the StreamWriter ...")
await flush(self._writer)
+ self.logger.debug("Cancelling writer task ...")
self._writer_task.cancel()
# Waits for the writer to finish but does NOT raise its exception.
await asyncio.wait((self._writer_task,))
@@ -529,12 +577,13 @@ async def _bh_stop_reader(self) -> None:
if not self._reader_task or self._reader_task.done():
return
+ self.logger.debug("Cancelling reader task ...")
self._reader_task.cancel()
# Waits for the reader to finish but does NOT raise its exception.
await asyncio.wait((self._reader_task,))
@bottom_half
- async def _bh_loop_forever(self, async_fn: _TaskFN) -> None:
+ async def _bh_loop_forever(self, async_fn: _TaskFN, name: str) -> None:
"""
Run one of the bottom-half methods in a loop forever.
@@ -542,16 +591,24 @@ async def _bh_loop_forever(self, async_fn: _TaskFN) ->
None:
disconnect that will terminate the entire loop.
:param async_fn: The bottom-half method to run in a loop.
+ :param name: The name of this task, used for logging.
"""
try:
while True:
await async_fn()
except asyncio.CancelledError:
# We have been cancelled by _bh_disconnect, exit gracefully.
+ self.logger.debug("Task.%s: cancelled.", name)
return
- except BaseException:
+ except BaseException as err:
+ self.logger.error("Task.%s: %s",
+ name, exception_summary(err))
+ self.logger.debug("Task.%s: failure:\n%s\n",
+ name, pretty_traceback())
self._schedule_disconnect()
raise
+ finally:
+ self.logger.debug("Task.%s: exiting.", name)
@bottom_half
async def _bh_send_message(self) -> None:
--
2.31.1
