cpython/Lib/logging/config.py

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# Copyright 2001-2007 by Vinay Sajip. All Rights Reserved.
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#
# Permission to use, copy, modify, and distribute this software and its
# documentation for any purpose and without fee is hereby granted,
# provided that the above copyright notice appear in all copies and that
# both that copyright notice and this permission notice appear in
# supporting documentation, and that the name of Vinay Sajip
# not be used in advertising or publicity pertaining to distribution
# of the software without specific, written prior permission.
# VINAY SAJIP DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
# ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
# VINAY SAJIP BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
# ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
# IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""
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Configuration functions for the logging package for Python. The core package
is based on PEP 282 and comments thereto in comp.lang.python, and influenced
by Apache's log4j system.
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Should work under Python versions >= 1.5.2, except that source line
information is not available unless 'sys._getframe()' is.
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Copyright (C) 2001-2007 Vinay Sajip. All Rights Reserved.
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To use, simply 'import logging' and log away!
"""
import sys, logging, logging.handlers, string, socket, struct, os, traceback, types
try:
import thread
import threading
except ImportError:
thread = None
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from SocketServer import ThreadingTCPServer, StreamRequestHandler
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DEFAULT_LOGGING_CONFIG_PORT = 9030
if sys.platform == "win32":
RESET_ERROR = 10054 #WSAECONNRESET
else:
RESET_ERROR = 104 #ECONNRESET
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#
# The following code implements a socket listener for on-the-fly
# reconfiguration of logging.
#
# _listener holds the server object doing the listening
_listener = None
def fileConfig(fname, defaults=None, disable_existing_loggers=1):
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"""
Read the logging configuration from a ConfigParser-format file.
This can be called several times from an application, allowing an end user
the ability to select from various pre-canned configurations (if the
developer provides a mechanism to present the choices and load the chosen
configuration).
In versions of ConfigParser which have the readfp method [typically
shipped in 2.x versions of Python], you can pass in a file-like object
rather than a filename, in which case the file-like object will be read
using readfp.
"""
import ConfigParser
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cp = ConfigParser.ConfigParser(defaults)
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if hasattr(cp, 'readfp') and hasattr(fname, 'readline'):
cp.readfp(fname)
else:
cp.read(fname)
formatters = _create_formatters(cp)
# critical section
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logging._acquireLock()
try:
logging._handlers.clear()
del logging._handlerList[:]
# Handlers add themselves to logging._handlers
handlers = _install_handlers(cp, formatters)
_install_loggers(cp, handlers, disable_existing_loggers)
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finally:
logging._releaseLock()
def _resolve(name):
"""Resolve a dotted name to a global object."""
name = string.split(name, '.')
used = name.pop(0)
found = __import__(used)
for n in name:
used = used + '.' + n
try:
found = getattr(found, n)
except AttributeError:
__import__(used)
found = getattr(found, n)
return found
def _create_formatters(cp):
"""Create and return formatters"""
flist = cp.get("formatters", "keys")
if not len(flist):
return {}
flist = string.split(flist, ",")
formatters = {}
for form in flist:
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sectname = "formatter_%s" % string.strip(form)
opts = cp.options(sectname)
if "format" in opts:
fs = cp.get(sectname, "format", 1)
else:
fs = None
if "datefmt" in opts:
dfs = cp.get(sectname, "datefmt", 1)
else:
dfs = None
c = logging.Formatter
if "class" in opts:
class_name = cp.get(sectname, "class")
if class_name:
c = _resolve(class_name)
f = c(fs, dfs)
formatters[form] = f
return formatters
def _install_handlers(cp, formatters):
"""Install and return handlers"""
hlist = cp.get("handlers", "keys")
if not len(hlist):
return {}
hlist = string.split(hlist, ",")
handlers = {}
fixups = [] #for inter-handler references
for hand in hlist:
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sectname = "handler_%s" % string.strip(hand)
klass = cp.get(sectname, "class")
opts = cp.options(sectname)
if "formatter" in opts:
fmt = cp.get(sectname, "formatter")
else:
fmt = ""
try:
klass = eval(klass, vars(logging))
except (AttributeError, NameError):
klass = _resolve(klass)
args = cp.get(sectname, "args")
args = eval(args, vars(logging))
h = apply(klass, args)
if "level" in opts:
level = cp.get(sectname, "level")
h.setLevel(logging._levelNames[level])
if len(fmt):
h.setFormatter(formatters[fmt])
if issubclass(klass, logging.handlers.MemoryHandler):
if "target" in opts:
target = cp.get(sectname,"target")
else:
target = ""
if len(target): #the target handler may not be loaded yet, so keep for later...
fixups.append((h, target))
handlers[hand] = h
#now all handlers are loaded, fixup inter-handler references...
for h, t in fixups:
h.setTarget(handlers[t])
return handlers
def _install_loggers(cp, handlers, disable_existing_loggers):
"""Create and install loggers"""
# configure the root first
llist = cp.get("loggers", "keys")
llist = string.split(llist, ",")
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llist = map(lambda x: string.strip(x), llist)
llist.remove("root")
sectname = "logger_root"
root = logging.root
log = root
opts = cp.options(sectname)
if "level" in opts:
level = cp.get(sectname, "level")
log.setLevel(logging._levelNames[level])
for h in root.handlers[:]:
root.removeHandler(h)
hlist = cp.get(sectname, "handlers")
if len(hlist):
hlist = string.split(hlist, ",")
for hand in hlist:
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log.addHandler(handlers[string.strip(hand)])
#and now the others...
#we don't want to lose the existing loggers,
#since other threads may have pointers to them.
#existing is set to contain all existing loggers,
#and as we go through the new configuration we
#remove any which are configured. At the end,
#what's left in existing is the set of loggers
#which were in the previous configuration but
#which are not in the new configuration.
existing = root.manager.loggerDict.keys()
#The list needs to be sorted so that we can
#avoid disabling child loggers of explicitly
#named loggers. With a sorted list it is easier
#to find the child loggers.
existing.sort()
#We'll keep the list of existing loggers
#which are children of named loggers here...
child_loggers = []
#now set up the new ones...
for log in llist:
sectname = "logger_%s" % log
qn = cp.get(sectname, "qualname")
opts = cp.options(sectname)
if "propagate" in opts:
propagate = cp.getint(sectname, "propagate")
else:
propagate = 1
logger = logging.getLogger(qn)
if qn in existing:
i = existing.index(qn)
prefixed = qn + "."
pflen = len(prefixed)
num_existing = len(existing)
i = i + 1 # look at the entry after qn
while (i < num_existing) and (existing[i][:pflen] == prefixed):
child_loggers.append(existing[i])
i = i + 1
existing.remove(qn)
if "level" in opts:
level = cp.get(sectname, "level")
logger.setLevel(logging._levelNames[level])
for h in logger.handlers[:]:
logger.removeHandler(h)
logger.propagate = propagate
logger.disabled = 0
hlist = cp.get(sectname, "handlers")
if len(hlist):
hlist = string.split(hlist, ",")
for hand in hlist:
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logger.addHandler(handlers[string.strip(hand)])
#Disable any old loggers. There's no point deleting
#them as other threads may continue to hold references
#and by disabling them, you stop them doing any logging.
#However, don't disable children of named loggers, as that's
#probably not what was intended by the user.
for log in existing:
logger = root.manager.loggerDict[log]
if log in child_loggers:
logger.level = logging.NOTSET
logger.handlers = []
logger.propagate = 1
elif disable_existing_loggers:
logger.disabled = 1
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def listen(port=DEFAULT_LOGGING_CONFIG_PORT):
"""
Start up a socket server on the specified port, and listen for new
configurations.
These will be sent as a file suitable for processing by fileConfig().
Returns a Thread object on which you can call start() to start the server,
and which you can join() when appropriate. To stop the server, call
stopListening().
"""
if not thread:
raise NotImplementedError, "listen() needs threading to work"
class ConfigStreamHandler(StreamRequestHandler):
"""
Handler for a logging configuration request.
It expects a completely new logging configuration and uses fileConfig
to install it.
"""
def handle(self):
"""
Handle a request.
Each request is expected to be a 4-byte length, packed using
struct.pack(">L", n), followed by the config file.
Uses fileConfig() to do the grunt work.
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"""
import tempfile
try:
conn = self.connection
chunk = conn.recv(4)
if len(chunk) == 4:
slen = struct.unpack(">L", chunk)[0]
chunk = self.connection.recv(slen)
while len(chunk) < slen:
chunk = chunk + conn.recv(slen - len(chunk))
#Apply new configuration. We'd like to be able to
#create a StringIO and pass that in, but unfortunately
#1.5.2 ConfigParser does not support reading file
#objects, only actual files. So we create a temporary
#file and remove it later.
file = tempfile.mktemp(".ini")
f = open(file, "w")
f.write(chunk)
f.close()
try:
fileConfig(file)
except (KeyboardInterrupt, SystemExit):
raise
except:
traceback.print_exc()
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os.remove(file)
except socket.error, e:
if type(e.args) != types.TupleType:
raise
else:
errcode = e.args[0]
if errcode != RESET_ERROR:
raise
class ConfigSocketReceiver(ThreadingTCPServer):
"""
A simple TCP socket-based logging config receiver.
"""
allow_reuse_address = 1
def __init__(self, host='localhost', port=DEFAULT_LOGGING_CONFIG_PORT,
handler=None):
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ThreadingTCPServer.__init__(self, (host, port), handler)
logging._acquireLock()
self.abort = 0
logging._releaseLock()
self.timeout = 1
def serve_until_stopped(self):
import select
abort = 0
while not abort:
rd, wr, ex = select.select([self.socket.fileno()],
[], [],
self.timeout)
if rd:
self.handle_request()
logging._acquireLock()
abort = self.abort
logging._releaseLock()
def serve(rcvr, hdlr, port):
server = rcvr(port=port, handler=hdlr)
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global _listener
logging._acquireLock()
_listener = server
logging._releaseLock()
server.serve_until_stopped()
return threading.Thread(target=serve,
args=(ConfigSocketReceiver,
ConfigStreamHandler, port))
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def stopListening():
"""
Stop the listening server which was created with a call to listen().
"""
global _listener
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if _listener:
logging._acquireLock()
_listener.abort = 1
_listener = None
logging._releaseLock()