Logger in SQLiteAckQueue produces UnicodeDecodeError as it tries to print item as a string (Python 2.7)

[sgloutnikov]

I stumbled upon a UnicodeDecodeError: 'ascii' codec can't decode byte... from the logger with certain values in SQLiteAckQueue + Python 2.7. After some investigation, it turns out that the problem lies with log.warning("Can't find item %s from unack cache", item) in combination with from __future__ import unicode_literals on Python 2.7.

Possible solutions:

1. Remove from __future__ import unicode_literals
2. Don't log item at all, but acknowledge the warning.

I am personally more in favor of the second approach as I don't think it is safe to be logging items in this situation. Maybe they contain sensitive information, can be very large, etc.

• Generally how to trigger the exception:

from __future__ import unicode_literals
import logging
import struct

foo = struct.pack("i", 255)
logging.warn("%s", foo)

• Example in SQLiteAckQueue:

q = SQLiteAckQueue('testdata', auto_resume=True)
inflight_map = dict()

# Generate some messages.
q.put('test')
q.put(struct.pack("i", 255))
q.put('test2')

# Publish message over network. Store 'in flight' messages
for id in range(3):
    foo = q.get()
    inflight_map[id] = foo

# Some time passes and no acknowledgement. Republish them.
time.sleep(1)
q.resume_unack_tasks()
for id in range(4, 7):
    foo = q.get()
    inflight_map[id] = foo

# Some more time passes, and server confirms original messages. Acknowledge them.
# _unack_cache now does not contain the items, and triggers the log with the printing of item as a string.
time.sleep(1)
for id in range(3):
    bar = inflight_map[id]
    q.ack(bar)

[peter-wangxu]

@sgloutnikov Agreed with you that should not log the item. I am going to propose a new PR later this week or do you mind send me the mentioned change?