Antoon Pardon wrote:
I have some in house code for which I am considering replacing the
logging code with something that uses the logging module.
However there is one thing the in-house log code does, that seems
difficult to do with the logging module, provide some context. The
in-house handlers give the possibilty to specify the number of lines of
context the hander can provide.
So the following code:
Logger(fl = stderr, level = warning, context = 2)
log(INFO, line 1)
log(INFO, line 2)
log(INFO, line 3)
log(INFO, line 4)
log(WARNING, line 5)
Will sent something like the following lines to stderr:
INFO: line 3
INFO: line 4
WARNING: line 5
I tried the code below, but that produced the same
as the ordinary StreamHandler.
class ContextStreamHandler (StreamHandler):
def __init__(self, stream=None, context = 5):
self.recqueue = deque([], context)
StreamHandler.__init__(self, stream)
#__init__
def handle(self, record):
print(CONTEXT HANDLER)
rv = self.filter(record)
if rv:
self.acquire()
try:
for rec in self.recqueue:
self.emit(rec)
self.recqueue.clear()
self.emit(record)
finally:
self.release
else:
self.recqueue.append(record)
return rv
#handle
#ContextStreamHandler
It turns out the logic of the above is correct. The problem is that the
handler has to see the INFO-level records while the filter() method has to
reject them. The following configuration seems to achieve that:
import logging
from collections import deque
class ContextStreamHandler(logging.StreamHandler):
def __init__(self, stream=None, context=5):
self.record_queue = deque([], context + 1)
logging.StreamHandler.__init__(self, stream)
def handle(self, record):
rv = self.filter(record)
self.record_queue.append(record)
if rv:
self.acquire()
try:
for record in self.record_queue:
self.emit(record)
self.record_queue.clear()
finally:
self.release()
return rv
class LevelFilter(logging.Filter):
def __init__(self, level, name=):
logging.Filter.__init__(self, name)
self._filter_level = level
def filter(self, record):
return record.levelno = self._filter_level
if __name__ == __main__:
root = logging.getLogger()
root.setLevel(logging.INFO)
handler = ContextStreamHandler(context=2)
handler.addFilter(LevelFilter(logging.WARN))
root.addHandler(handler)
for i in range(20):
if i % 5:
root.info(message #%d % i)
else:
root.warn(MESSAGE #%d % i)
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