handlers.py

xen虚拟机源代码安装包

# Copyright 2001-2004 by Vinay Sajip. All Rights Reserved.
#
# 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.

"""
Additional handlers 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.

Should work under Python versions >= 1.5.2, except that source line
information is not available unless 'sys._getframe()' is.

Copyright (C) 2001-2004 Vinay Sajip. All Rights Reserved.

To use, simply 'import logging' and log away!
"""

import sys, logging, socket, types, os, string, cPickle, struct, time

from SocketServer import ThreadingTCPServer, StreamRequestHandler

#
# Some constants...
#

DEFAULT_TCP_LOGGING_PORT    = 9020
DEFAULT_UDP_LOGGING_PORT    = 9021
DEFAULT_HTTP_LOGGING_PORT   = 9022
DEFAULT_SOAP_LOGGING_PORT   = 9023
SYSLOG_UDP_PORT             = 514


class RotatingFileHandler(logging.FileHandler):
    def __init__(self, filename, mode="a", maxBytes=0, backupCount=0):
        """
        Open the specified file and use it as the stream for logging.

        By default, the file grows indefinitely. You can specify particular
        values of maxBytes and backupCount to allow the file to rollover at
        a predetermined size.

        Rollover occurs whenever the current log file is nearly maxBytes in
        length. If backupCount is >= 1, the system will successively create
        new files with the same pathname as the base file, but with extensions
        ".1", ".2" etc. appended to it. For example, with a backupCount of 5
        and a base file name of "app.log", you would get "app.log",
        "app.log.1", "app.log.2", ... through to "app.log.5". The file being
        written to is always "app.log" - when it gets filled up, it is closed
        and renamed to "app.log.1", and if files "app.log.1", "app.log.2" etc.
        exist, then they are renamed to "app.log.2", "app.log.3" etc.
        respectively.

        If maxBytes is zero, rollover never occurs.
        """
        logging.FileHandler.__init__(self, filename, mode)
        self.maxBytes = maxBytes
        self.backupCount = backupCount
        if maxBytes > 0:
            self.mode = "a"

    def doRollover(self):
        """
        Do a rollover, as described in __init__().
        """

        self.stream.close()
        if self.backupCount > 0:
            for i in range(self.backupCount - 1, 0, -1):
                sfn = "%s.%d" % (self.baseFilename, i)
                dfn = "%s.%d" % (self.baseFilename, i + 1)
                if os.path.exists(sfn):
                    #print "%s -> %s" % (sfn, dfn)
                    if os.path.exists(dfn):
                        os.remove(dfn)
                    os.rename(sfn, dfn)
            dfn = self.baseFilename + ".1"
            if os.path.exists(dfn):
                os.remove(dfn)
            os.rename(self.baseFilename, dfn)
            #print "%s -> %s" % (self.baseFilename, dfn)
        self.stream = open(self.baseFilename, "w")

    def emit(self, record):
        """
        Emit a record.

        Output the record to the file, catering for rollover as described
        in doRollover().
        """
        if self.maxBytes > 0:                   # are we rolling over?
            msg = "%s\n" % self.format(record)
            self.stream.seek(0, 2)  #due to non-posix-compliant Windows feature
            if self.stream.tell() + len(msg) >= self.maxBytes:
                self.doRollover()
        logging.FileHandler.emit(self, record)


class SocketHandler(logging.Handler):
    """
    A handler class which writes logging records, in pickle format, to
    a streaming socket. The socket is kept open across logging calls.
    If the peer resets it, an attempt is made to reconnect on the next call.
    The pickle which is sent is that of the LogRecord's attribute dictionary
    (__dict__), so that the receiver does not need to have the logging module
    installed in order to process the logging event.

    To unpickle the record at the receiving end into a LogRecord, use the
    makeLogRecord function.
    """

    def __init__(self, host, port):
        """
        Initializes the handler with a specific host address and port.

        The attribute 'closeOnError' is set to 1 - which means that if
        a socket error occurs, the socket is silently closed and then
        reopened on the next logging call.
        """
        logging.Handler.__init__(self)
        self.host = host
        self.port = port
        self.sock = None
        self.closeOnError = 0
        self.retryTime = None
        #
        # Exponential backoff parameters.
        #
        self.retryStart = 1.0
        self.retryMax = 30.0
        self.retryFactor = 2.0

    def makeSocket(self):
        """
        A factory method which allows subclasses to define the precise
        type of socket they want.
        """
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        s.connect((self.host, self.port))
        return s

    def createSocket(self):
        """
        Try to create a socket, using an exponential backoff with
        a max retry time. Thanks to Robert Olson for the original patch
        (SF #815911) which has been slightly refactored.
        """
        now = time.time()
        # Either retryTime is None, in which case this
        # is the first time back after a disconnect, or
        # we've waited long enough.
        if self.retryTime is None:
          attempt = 1
        else:
          attempt = (now >= self.retryTime)
        if attempt:
            try:
                self.sock = self.makeSocket()
                self.retryTime = None # next time, no delay before trying
            except:
                #Creation failed, so set the retry time and return.
                if self.retryTime is None:
                    self.retryPeriod = self.retryStart
                else:
                    self.retryPeriod = self.retryPeriod * self.retryFactor
                    if self.retryPeriod > self.retryMax:
                        self.retryPeriod = self.retryMax
                self.retryTime = now + self.retryPeriod

    def send(self, s):
        """
        Send a pickled string to the socket.

        This function allows for partial sends which can happen when the
        network is busy.
        """
        if self.sock is None:
            self.createSocket()
        #self.sock can be None either because we haven't reached the retry
        #time yet, or because we have reached the retry time and retried,
        #but are still unable to connect.
        if self.sock:
            try:
                if hasattr(self.sock, "sendall"):
                    self.sock.sendall(s)
                else:
                    sentsofar = 0
                    left = len(s)
                    while left > 0:
                        sent = self.sock.send(s[sentsofar:])
                        sentsofar = sentsofar + sent
                        left = left - sent
            except socket.error:
                self.sock.close()
                self.sock = None  # so we can call createSocket next time

    def makePickle(self, record):
        """
        Pickles the record in binary format with a length prefix, and
        returns it ready for transmission across the socket.
        """
        ei = record.exc_info
        if ei:
          dummy = self.format(record) # just to get traceback text into record.exc_text
          record.exc_info = None  # to avoid Unpickleable error
        s = cPickle.dumps(record.__dict__, 1)
        if ei:
          record.exc_info = ei  # for next handler
        slen = struct.pack(">L", len(s))
        return slen + s

    def handleError(self, record):
        """
        Handle an error during logging.

        An error has occurred during logging. Most likely cause -
        connection lost. Close the socket so that we can retry on the
        next event.
        """
        if self.closeOnError and self.sock:
            self.sock.close()
            self.sock = None        #try to reconnect next time
        else:
            logging.Handler.handleError(self, record)

    def emit(self, record):
        """
        Emit a record.

        Pickles the record and writes it to the socket in binary format.
        If there is an error with the socket, silently drop the packet.
        If there was a problem with the socket, re-establishes the
        socket.
        """
        try:
            s = self.makePickle(record)
            self.send(s)
        except:
            self.handleError(record)

    def close(self):
        """
        Closes the socket.
        """
        if self.sock:
            self.sock.close()
            self.sock = None
        logging.Handler.close(self)

class DatagramHandler(SocketHandler):
    """
    A handler class which writes logging records, in pickle format, to
    a datagram socket.  The pickle which is sent is that of the LogRecord's
    attribute dictionary (__dict__), so that the receiver does not need to
    have the logging module installed in order to process the logging event.

    To unpickle the record at the receiving end into a LogRecord, use the
    makeLogRecord function.

    """
    def __init__(self, host, port):
        """
        Initializes the handler with a specific host address and port.
        """
        SocketHandler.__init__(self, host, port)
        self.closeOnError = 0

    def makeSocket(self):
        """
        The factory method of SocketHandler is here overridden to create
        a UDP socket (SOCK_DGRAM).
        """
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        return s

    def send(self, s):
        """
        Send a pickled string to a socket.

        This function no longer allows for partial sends which can happen
        when the network is busy - UDP does not guarantee delivery and
        can deliver packets out of sequence.
        """
        self.sock.sendto(s, (self.host, self.port))

class SysLogHandler(logging.Handler):
    """
    A handler class which sends formatted logging records to a syslog
    server. Based on Sam Rushing's syslog module:
    http://www.nightmare.com/squirl/python-ext/misc/syslog.py
    Contributed by Nicolas Untz (after which minor refactoring changes
    have been made).
    """

    # from <linux/sys/syslog.h>:
    # ======================================================================
    # priorities/facilities are encoded into a single 32-bit quantity, where
    # the bottom 3 bits are the priority (0-7) and the top 28 bits are the
    # facility (0-big number). Both the priorities and the facilities map
    # roughly one-to-one to strings in the syslogd(8) source code.  This
    # mapping is included in this file.
    #
    # priorities (these are ordered)

    LOG_EMERG     = 0       #  system is unusable
    LOG_ALERT     = 1       #  action must be taken immediately
    LOG_CRIT      = 2       #  critical conditions
    LOG_ERR       = 3       #  error conditions
    LOG_WARNING   = 4       #  warning conditions
    LOG_NOTICE    = 5       #  normal but significant condition
    LOG_INFO      = 6       #  informational
    LOG_DEBUG     = 7       #  debug-level messages

    #  facility codes
    LOG_KERN      = 0       #  kernel messages
    LOG_USER      = 1       #  random user-level messages
    LOG_MAIL      = 2       #  mail system
    LOG_DAEMON    = 3       #  system daemons
    LOG_AUTH      = 4       #  security/authorization messages
    LOG_SYSLOG    = 5       #  messages generated internally by syslogd
    LOG_LPR       = 6       #  line printer subsystem
    LOG_NEWS      = 7       #  network news subsystem
    LOG_UUCP      = 8       #  UUCP subsystem
    LOG_CRON      = 9       #  clock daemon
    LOG_AUTHPRIV  = 10  #  security/authorization messages (private)

    #  other codes through 15 reserved for system use
    LOG_LOCAL0    = 16      #  reserved for local use
    LOG_LOCAL1    = 17      #  reserved for local use
    LOG_LOCAL2    = 18      #  reserved for local use
    LOG_LOCAL3    = 19      #  reserved for local use
    LOG_LOCAL4    = 20      #  reserved for local use
    LOG_LOCAL5    = 21      #  reserved for local use
    LOG_LOCAL6    = 22      #  reserved for local use
    LOG_LOCAL7    = 23      #  reserved for local use

    priority_names = {
        "alert":    LOG_ALERT,
        "crit":     LOG_CRIT,
        "critical": LOG_CRIT,
        "debug":    LOG_DEBUG,
        "emerg":    LOG_EMERG,
        "err":      LOG_ERR,
        "error":    LOG_ERR,        #  DEPRECATED
        "info":     LOG_INFO,
        "notice":   LOG_NOTICE,
        "panic":    LOG_EMERG,      #  DEPRECATED
        "warn":     LOG_WARNING,    #  DEPRECATED
        "warning":  LOG_WARNING,
        }

    facility_names = {
        "auth":     LOG_AUTH,
        "authpriv": LOG_AUTHPRIV,
        "cron":     LOG_CRON,
        "daemon":   LOG_DAEMON,
        "kern":     LOG_KERN,
        "lpr":      LOG_LPR,
        "mail":     LOG_MAIL,
        "news":     LOG_NEWS,
        "security": LOG_AUTH,       #  DEPRECATED
        "syslog":   LOG_SYSLOG,
        "user":     LOG_USER,
        "uucp":     LOG_UUCP,
        "local0":   LOG_LOCAL0,
        "local1":   LOG_LOCAL1,
        "local2":   LOG_LOCAL2,
        "local3":   LOG_LOCAL3,
        "local4":   LOG_LOCAL4,
        "local5":   LOG_LOCAL5,
        "local6":   LOG_LOCAL6,
        "local7":   LOG_LOCAL7,
        }

    def __init__(self, address=('localhost', SYSLOG_UDP_PORT), facility=LOG_USER):
        """
        Initialize a handler.

        If address is specified as a string, UNIX socket is used.
        If facility is not specified, LOG_USER is used.
        """
        logging.Handler.__init__(self)