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authorJohn Snow <jsnow@redhat.com>2021-09-15 12:29:36 -0400
committerJohn Snow <jsnow@redhat.com>2021-09-27 12:10:29 -0400
commit50e533061f30e69d618643c9513b6797019023d1 (patch)
tree0d70aa0a0ed091700cacfd832870f9c8167340f7
parentc1408345af0fd5b2e7a286743b4678bc70fe5051 (diff)
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python/aqmp: add logging to AsyncProtocol
Give the connection and the reader/writer tasks nicknames, and add logging statements throughout. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 20210915162955.333025-9-jsnow@redhat.com Signed-off-by: John Snow <jsnow@redhat.com>
-rw-r--r--python/qemu/aqmp/protocol.py82
1 files changed, 73 insertions, 9 deletions
diff --git a/python/qemu/aqmp/protocol.py b/python/qemu/aqmp/protocol.py
index 1946085..1dfd128 100644
--- a/python/qemu/aqmp/protocol.py
+++ b/python/qemu/aqmp/protocol.py
@@ -14,6 +14,7 @@ import asyncio
from asyncio import StreamReader, StreamWriter
from enum import Enum
from functools import wraps
+import logging
from ssl import SSLContext
from typing import (
Any,
@@ -32,8 +33,10 @@ from .error import AQMPError
from .util import (
bottom_half,
create_task,
+ exception_summary,
flush,
is_closing,
+ pretty_traceback,
upper_half,
wait_closed,
)
@@ -174,14 +177,28 @@ 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
@@ -205,6 +222,14 @@ class AsyncProtocol(Generic[T]):
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."""
@@ -246,6 +271,7 @@ class AsyncProtocol(Generic[T]):
:raise Exception: When the reader or writer terminate unexpectedly.
"""
+ self.logger.debug("disconnect() called.")
self._schedule_disconnect()
await self._wait_disconnect()
@@ -273,6 +299,8 @@ class AsyncProtocol(Generic[T]):
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()
@@ -312,8 +340,15 @@ class AsyncProtocol(Generic[T]):
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):
@@ -363,12 +398,16 @@ class AsyncProtocol(Generic[T]):
: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:
"""
@@ -382,8 +421,8 @@ class AsyncProtocol(Generic[T]):
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)
@@ -410,6 +449,7 @@ class AsyncProtocol(Generic[T]):
"""
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
@@ -492,30 +532,39 @@ class AsyncProtocol(Generic[T]):
# Try to flush the writer, if possible:
if not error_pathway:
await self._bh_flush_writer()
- except:
+ except BaseException as err:
error_pathway = True
+ emsg = "Failed to flush the writer"
+ self.logger.error("%s: %s", emsg, exception_summary(err))
+ self.logger.debug("%s:\n%s\n", emsg, pretty_traceback())
raise
finally:
# Cancel any still-running tasks:
if self._writer_task is not None and not self._writer_task.done():
+ self.logger.debug("Cancelling writer task.")
self._writer_task.cancel()
if self._reader_task is not None and not self._reader_task.done():
+ self.logger.debug("Cancelling reader task.")
self._reader_task.cancel()
# Close out the tasks entirely (Won't raise):
if tasks:
+ self.logger.debug("Waiting for tasks to complete ...")
await asyncio.wait(tasks)
# Lastly, close the stream itself. (May raise):
await self._bh_close_stream(error_pathway)
+ self.logger.debug("Disconnected.")
@bottom_half
async def _bh_flush_writer(self) -> None:
if not self._writer_task:
return
+ 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)
@bottom_half
@@ -525,8 +574,10 @@ class AsyncProtocol(Generic[T]):
return
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: # pylint: disable=broad-except
@@ -541,13 +592,18 @@ class AsyncProtocol(Generic[T]):
# just trust that the Exception we already have is the
# better one to present to the user, even if we don't
# genuinely *know* the relationship between the two.
- pass
+ self.logger.debug(
+ "Discarding Exception from wait_closed:\n%s\n",
+ pretty_traceback(),
+ )
else:
# Oops, this is a brand-new error!
raise
+ finally:
+ self.logger.debug("StreamWriter closed.")
@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.
@@ -555,16 +611,24 @@ class AsyncProtocol(Generic[T]):
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: