"""Module with helper classes and functions for daemons"""
+import asyncore
+import asynchat
+import collections
+import grp
import os
-import select
+import pwd
import signal
-import errno
import logging
+import sched
+import time
+import socket
+import select
+import sys
from ganeti import utils
from ganeti import constants
+from ganeti import errors
+from ganeti import netutils
-class Mainloop(object):
- """Generic mainloop for daemons
+_DEFAULT_RUN_USER = "root"
+_DEFAULT_RUN_GROUP = "root"
+
+
+class SchedulerBreakout(Exception):
+ """Exception used to get out of the scheduler loop
"""
- def __init__(self):
- """Constructs a new Mainloop instance.
+
+
+def AsyncoreDelayFunction(timeout):
+ """Asyncore-compatible scheduler delay function.
+
+ This is a delay function for sched that, rather than actually sleeping,
+ executes asyncore events happening in the meantime.
+
+ After an event has occurred, rather than returning, it raises a
+ SchedulerBreakout exception, which will force the current scheduler.run()
+ invocation to terminate, so that we can also check for signals. The main loop
+ will then call the scheduler run again, which will allow it to actually
+ process any due events.
+
+ This is needed because scheduler.run() doesn't support a count=..., as
+ asyncore loop, and the scheduler module documents throwing exceptions from
+ inside the delay function as an allowed usage model.
+
+ """
+ asyncore.loop(timeout=timeout, count=1, use_poll=True)
+ raise SchedulerBreakout()
+
+
+class AsyncoreScheduler(sched.scheduler):
+ """Event scheduler integrated with asyncore
+
+ """
+ def __init__(self, timefunc):
+ sched.scheduler.__init__(self, timefunc, AsyncoreDelayFunction)
+
+
+class GanetiBaseAsyncoreDispatcher(asyncore.dispatcher):
+ """Base Ganeti Asyncore Dispacher
+
+ """
+ # this method is overriding an asyncore.dispatcher method
+ def handle_error(self):
+ """Log an error in handling any request, and proceed.
"""
- self._io_wait = {}
- self._io_wait_add = []
- self._io_wait_remove = []
- self._signal_wait = []
+ logging.exception("Error while handling asyncore request")
- def Run(self, handle_sigchld=True, handle_sigterm=True, stop_on_empty=False):
- """Runs the mainloop.
+ # this method is overriding an asyncore.dispatcher method
+ def writable(self):
+ """Most of the time we don't want to check for writability.
+
+ """
+ return False
+
+
+def FormatAddress(family, address):
+ """Format a client's address
- @type handle_sigchld: bool
- @param handle_sigchld: Whether to install handler for SIGCHLD
- @type handle_sigterm: bool
- @param handle_sigterm: Whether to install handler for SIGTERM
- @type stop_on_empty: bool
- @param stop_on_empty: Whether to stop mainloop once all I/O waiters
- unregistered
+ @type family: integer
+ @param family: socket family (one of socket.AF_*)
+ @type address: family specific (usually tuple)
+ @param address: address, as reported by this class
+
+ """
+ if family == socket.AF_INET and len(address) == 2:
+ return "%s:%d" % address
+ elif family == socket.AF_UNIX and len(address) == 3:
+ return "pid=%s, uid=%s, gid=%s" % address
+ else:
+ return str(address)
+
+
+class AsyncStreamServer(GanetiBaseAsyncoreDispatcher):
+ """A stream server to use with asyncore.
+
+ Each request is accepted, and then dispatched to a separate asyncore
+ dispatcher to handle.
+
+ """
+
+ _REQUEST_QUEUE_SIZE = 5
+
+ def __init__(self, family, address):
+ """Constructor for AsyncUnixStreamSocket
+
+ @type family: integer
+ @param family: socket family (one of socket.AF_*)
+ @type address: address family dependent
+ @param address: address to bind the socket to
"""
- poller = select.poll()
+ GanetiBaseAsyncoreDispatcher.__init__(self)
+ self.family = family
+ self.create_socket(self.family, socket.SOCK_STREAM)
+ self.set_reuse_addr()
+ self.bind(address)
+ self.listen(self._REQUEST_QUEUE_SIZE)
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_accept(self):
+ """Accept a new client connection.
+
+ Creates a new instance of the handler class, which will use asyncore to
+ serve the client.
- # Setup signal handlers
- if handle_sigchld:
- sigchld_handler = utils.SignalHandler([signal.SIGCHLD])
+ """
+ accept_result = utils.IgnoreSignals(self.accept)
+ if accept_result is not None:
+ connected_socket, client_address = accept_result
+ if self.family == socket.AF_UNIX:
+ # override the client address, as for unix sockets nothing meaningful
+ # is passed in from accept anyway
+ client_address = netutils.GetSocketCredentials(connected_socket)
+ logging.info("Accepted connection from %s",
+ FormatAddress(self.family, client_address))
+ self.handle_connection(connected_socket, client_address)
+
+ def handle_connection(self, connected_socket, client_address):
+ """Handle an already accepted connection.
+
+ """
+ raise NotImplementedError
+
+
+class AsyncTerminatedMessageStream(asynchat.async_chat):
+ """A terminator separated message stream asyncore module.
+
+ Handles a stream connection receiving messages terminated by a defined
+ separator. For each complete message handle_message is called.
+
+ """
+ def __init__(self, connected_socket, peer_address, terminator, family,
+ unhandled_limit):
+ """AsyncTerminatedMessageStream constructor.
+
+ @type connected_socket: socket.socket
+ @param connected_socket: connected stream socket to receive messages from
+ @param peer_address: family-specific peer address
+ @type terminator: string
+ @param terminator: terminator separating messages in the stream
+ @type family: integer
+ @param family: socket family
+ @type unhandled_limit: integer or None
+ @param unhandled_limit: maximum unanswered messages
+
+ """
+ # python 2.4/2.5 uses conn=... while 2.6 has sock=... we have to cheat by
+ # using a positional argument rather than a keyword one.
+ asynchat.async_chat.__init__(self, connected_socket)
+ self.connected_socket = connected_socket
+ # on python 2.4 there is no "family" attribute for the socket class
+ # FIXME: when we move to python 2.5 or above remove the family parameter
+ #self.family = self.connected_socket.family
+ self.family = family
+ self.peer_address = peer_address
+ self.terminator = terminator
+ self.unhandled_limit = unhandled_limit
+ self.set_terminator(terminator)
+ self.ibuffer = []
+ self.receive_count = 0
+ self.send_count = 0
+ self.oqueue = collections.deque()
+ self.iqueue = collections.deque()
+
+ # this method is overriding an asynchat.async_chat method
+ def collect_incoming_data(self, data):
+ self.ibuffer.append(data)
+
+ def _can_handle_message(self):
+ return (self.unhandled_limit is None or
+ (self.receive_count < self.send_count + self.unhandled_limit) and
+ not self.iqueue)
+
+ # this method is overriding an asynchat.async_chat method
+ def found_terminator(self):
+ message = "".join(self.ibuffer)
+ self.ibuffer = []
+ message_id = self.receive_count
+ # We need to increase the receive_count after checking if the message can
+ # be handled, but before calling handle_message
+ can_handle = self._can_handle_message()
+ self.receive_count += 1
+ if can_handle:
+ self.handle_message(message, message_id)
else:
- sigchld_handler = None
- try:
- if handle_sigterm:
- sigterm_handler = utils.SignalHandler([signal.SIGTERM])
+ self.iqueue.append((message, message_id))
+
+ def handle_message(self, message, message_id):
+ """Handle a terminated message.
+
+ @type message: string
+ @param message: message to handle
+ @type message_id: integer
+ @param message_id: stream's message sequence number
+
+ """
+ pass
+ # TODO: move this method to raise NotImplementedError
+ # raise NotImplementedError
+
+ def send_message(self, message):
+ """Send a message to the remote peer. This function is thread-safe.
+
+ @type message: string
+ @param message: message to send, without the terminator
+
+ @warning: If calling this function from a thread different than the one
+ performing the main asyncore loop, remember that you have to wake that one
+ up.
+
+ """
+ # If we just append the message we received to the output queue, this
+ # function can be safely called by multiple threads at the same time, and
+ # we don't need locking, since deques are thread safe. handle_write in the
+ # asyncore thread will handle the next input message if there are any
+ # enqueued.
+ self.oqueue.append(message)
+
+ # this method is overriding an asyncore.dispatcher method
+ def readable(self):
+ # read from the socket if we can handle the next requests
+ return self._can_handle_message() and asynchat.async_chat.readable(self)
+
+ # this method is overriding an asyncore.dispatcher method
+ def writable(self):
+ # the output queue may become full just after we called writable. This only
+ # works if we know we'll have something else waking us up from the select,
+ # in such case, anyway.
+ return asynchat.async_chat.writable(self) or self.oqueue
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_write(self):
+ if self.oqueue:
+ # if we have data in the output queue, then send_message was called.
+ # this means we can process one more message from the input queue, if
+ # there are any.
+ data = self.oqueue.popleft()
+ self.push(data + self.terminator)
+ self.send_count += 1
+ if self.iqueue:
+ self.handle_message(*self.iqueue.popleft())
+ self.initiate_send()
+
+ def close_log(self):
+ logging.info("Closing connection from %s",
+ FormatAddress(self.family, self.peer_address))
+ self.close()
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_expt(self):
+ self.close_log()
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_error(self):
+ """Log an error in handling any request, and proceed.
+
+ """
+ logging.exception("Error while handling asyncore request")
+ self.close_log()
+
+
+class AsyncUDPSocket(GanetiBaseAsyncoreDispatcher):
+ """An improved asyncore udp socket.
+
+ """
+ def __init__(self, family):
+ """Constructor for AsyncUDPSocket
+
+ """
+ GanetiBaseAsyncoreDispatcher.__init__(self)
+ self._out_queue = []
+ self._family = family
+ self.create_socket(family, socket.SOCK_DGRAM)
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_connect(self):
+ # Python thinks that the first udp message from a source qualifies as a
+ # "connect" and further ones are part of the same connection. We beg to
+ # differ and treat all messages equally.
+ pass
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_read(self):
+ recv_result = utils.IgnoreSignals(self.recvfrom,
+ constants.MAX_UDP_DATA_SIZE)
+ if recv_result is not None:
+ payload, address = recv_result
+ if self._family == socket.AF_INET6:
+ # we ignore 'flow info' and 'scope id' as we don't need them
+ ip, port, _, _ = address
else:
- sigterm_handler = None
-
- try:
- running = True
-
- # Start actual main loop
- while running:
- # Entries could be added again afterwards, hence removing first
- if self._io_wait_remove:
- for fd in self._io_wait_remove:
- try:
- poller.unregister(fd)
- except KeyError:
- pass
- try:
- del self._io_wait[fd]
- except KeyError:
- pass
- self._io_wait_remove = []
-
- # Add new entries
- if self._io_wait_add:
- for (owner, fd, conditions) in self._io_wait_add:
- self._io_wait[fd] = owner
- poller.register(fd, conditions)
- self._io_wait_add = []
-
- # Stop if nothing is listening anymore
- if stop_on_empty and not (self._io_wait):
- break
-
- # Wait for I/O events
- try:
- io_events = poller.poll(None)
- except select.error, err:
- # EINTR can happen when signals are sent
- if err.args and err.args[0] in (errno.EINTR,):
- io_events = None
- else:
- raise
-
- if io_events:
- # Check for I/O events
- for (evfd, evcond) in io_events:
- owner = self._io_wait.get(evfd, None)
- if owner:
- owner.OnIO(evfd, evcond)
-
- # Check whether signal was raised
- if sigchld_handler and sigchld_handler.called:
- self._CallSignalWaiters(signal.SIGCHLD)
- sigchld_handler.Clear()
-
- if sigterm_handler and sigterm_handler.called:
- self._CallSignalWaiters(signal.SIGTERM)
- running = False
- sigterm_handler.Clear()
- finally:
- # Restore signal handlers
- if sigterm_handler:
- sigterm_handler.Reset()
- finally:
- if sigchld_handler:
- sigchld_handler.Reset()
+ ip, port = address
- def _CallSignalWaiters(self, signum):
- """Calls all signal waiters for a certain signal.
+ self.handle_datagram(payload, ip, port)
- @type signum: int
- @param signum: Signal number
+ def handle_datagram(self, payload, ip, port):
+ """Handle an already read udp datagram
"""
- for owner in self._signal_wait:
- owner.OnSignal(signal.SIGCHLD)
+ raise NotImplementedError
+
+ # this method is overriding an asyncore.dispatcher method
+ def writable(self):
+ # We should check whether we can write to the socket only if we have
+ # something scheduled to be written
+ return bool(self._out_queue)
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_write(self):
+ if not self._out_queue:
+ logging.error("handle_write called with empty output queue")
+ return
+ (ip, port, payload) = self._out_queue[0]
+ utils.IgnoreSignals(self.sendto, payload, 0, (ip, port))
+ self._out_queue.pop(0)
+
+ def enqueue_send(self, ip, port, payload):
+ """Enqueue a datagram to be sent when possible
- def RegisterIO(self, owner, fd, condition):
- """Registers a receiver for I/O notifications
+ """
+ if len(payload) > constants.MAX_UDP_DATA_SIZE:
+ raise errors.UdpDataSizeError('Packet too big: %s > %s' % (len(payload),
+ constants.MAX_UDP_DATA_SIZE))
+ self._out_queue.append((ip, port, payload))
- The receiver must support a "OnIO(self, fd, conditions)" function.
+ def process_next_packet(self, timeout=0):
+ """Process the next datagram, waiting for it if necessary.
- @type owner: instance
- @param owner: Receiver
- @type fd: int
- @param fd: File descriptor
- @type condition: int
- @param condition: ORed field of conditions to be notified
- (see select module)
+ @type timeout: float
+ @param timeout: how long to wait for data
+ @rtype: boolean
+ @return: True if some data has been handled, False otherwise
"""
- # select.Poller also supports file() like objects, but we don't.
- assert isinstance(fd, (int, long)), \
- "Only integers are supported for file descriptors"
+ result = utils.WaitForFdCondition(self, select.POLLIN, timeout)
+ if result is not None and result & select.POLLIN:
+ self.handle_read()
+ return True
+ else:
+ return False
+
+
+class AsyncAwaker(GanetiBaseAsyncoreDispatcher):
+ """A way to notify the asyncore loop that something is going on.
- self._io_wait_add.append((owner, fd, condition))
+ If an asyncore daemon is multithreaded when a thread tries to push some data
+ to a socket, the main loop handling asynchronous requests might be sleeping
+ waiting on a select(). To avoid this it can create an instance of the
+ AsyncAwaker, which other threads can use to wake it up.
- def UnregisterIO(self, fd):
- """Unregister a file descriptor.
+ """
+ def __init__(self, signal_fn=None):
+ """Constructor for AsyncAwaker
- It'll be unregistered the next time the mainloop checks for it.
+ @type signal_fn: function
+ @param signal_fn: function to call when awaken
- @type fd: int
- @param fd: File descriptor
+ """
+ GanetiBaseAsyncoreDispatcher.__init__(self)
+ assert signal_fn == None or callable(signal_fn)
+ (self.in_socket, self.out_socket) = socket.socketpair(socket.AF_UNIX,
+ socket.SOCK_STREAM)
+ self.in_socket.setblocking(0)
+ self.in_socket.shutdown(socket.SHUT_WR)
+ self.out_socket.shutdown(socket.SHUT_RD)
+ self.set_socket(self.in_socket)
+ self.need_signal = True
+ self.signal_fn = signal_fn
+ self.connected = True
+
+ # this method is overriding an asyncore.dispatcher method
+ def handle_read(self):
+ utils.IgnoreSignals(self.recv, 4096)
+ if self.signal_fn:
+ self.signal_fn()
+ self.need_signal = True
+
+ # this method is overriding an asyncore.dispatcher method
+ def close(self):
+ asyncore.dispatcher.close(self)
+ self.out_socket.close()
+
+ def signal(self):
+ """Signal the asyncore main loop.
+
+ Any data we send here will be ignored, but it will cause the select() call
+ to return.
"""
- # select.Poller also supports file() like objects, but we don't.
- assert isinstance(fd, (int, long)), \
- "Only integers are supported for file descriptors"
+ # Yes, there is a race condition here. No, we don't care, at worst we're
+ # sending more than one wakeup token, which doesn't harm at all.
+ if self.need_signal:
+ self.need_signal = False
+ self.out_socket.send("\0")
- self._io_wait_remove.append(fd)
+
+class Mainloop(object):
+ """Generic mainloop for daemons
+
+ @ivar scheduler: A sched.scheduler object, which can be used to register
+ timed events
+
+ """
+ def __init__(self):
+ """Constructs a new Mainloop instance.
+
+ """
+ self._signal_wait = []
+ self.scheduler = AsyncoreScheduler(time.time)
+
+ @utils.SignalHandled([signal.SIGCHLD])
+ @utils.SignalHandled([signal.SIGTERM])
+ @utils.SignalHandled([signal.SIGINT])
+ def Run(self, signal_handlers=None):
+ """Runs the mainloop.
+
+ @type signal_handlers: dict
+ @param signal_handlers: signal->L{utils.SignalHandler} passed by decorator
+
+ """
+ assert isinstance(signal_handlers, dict) and \
+ len(signal_handlers) > 0, \
+ "Broken SignalHandled decorator"
+ running = True
+ # Start actual main loop
+ while running:
+ if not self.scheduler.empty():
+ try:
+ self.scheduler.run()
+ except SchedulerBreakout:
+ pass
+ else:
+ asyncore.loop(count=1, use_poll=True)
+
+ # Check whether a signal was raised
+ for sig in signal_handlers:
+ handler = signal_handlers[sig]
+ if handler.called:
+ self._CallSignalWaiters(sig)
+ running = sig not in (signal.SIGTERM, signal.SIGINT)
+ handler.Clear()
+
+ def _CallSignalWaiters(self, signum):
+ """Calls all signal waiters for a certain signal.
+
+ @type signum: int
+ @param signum: Signal number
+
+ """
+ for owner in self._signal_wait:
+ owner.OnSignal(signum)
def RegisterSignal(self, owner):
"""Registers a receiver for signal notifications
self._signal_wait.append(owner)
-def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn):
+def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn,
+ multithreaded=False, console_logging=False,
+ default_ssl_cert=None, default_ssl_key=None,
+ user=_DEFAULT_RUN_USER, group=_DEFAULT_RUN_GROUP):
"""Shared main function for daemons.
@type daemon_name: string
@param daemon_name: daemon name
- @type optionparser: L{optparse.OptionParser}
+ @type optionparser: optparse.OptionParser
@param optionparser: initialized optionparser with daemon-specific options
(common -f -d options will be handled by this module)
- @type options: object @param options: OptionParser result, should contain at
- least the fork and the debug options
- @type dirs: list of strings
- @param dirs: list of directories that must exist for this daemon to work
+ @type dirs: list of (string, integer)
+ @param dirs: list of directories that must be created if they don't exist,
+ and the permissions to be used to create them
@type check_fn: function which accepts (options, args)
@param check_fn: function that checks start conditions and exits if they're
not met
@type exec_fn: function which accepts (options, args)
@param exec_fn: function that's executed with the daemon's pid file held, and
runs the daemon itself.
+ @type multithreaded: bool
+ @param multithreaded: Whether the daemon uses threads
+ @type console_logging: boolean
+ @param console_logging: if True, the daemon will fall back to the system
+ console if logging fails
+ @type default_ssl_cert: string
+ @param default_ssl_cert: Default SSL certificate path
+ @type default_ssl_key: string
+ @param default_ssl_key: Default SSL key path
+ @param user: Default user to run as
+ @type user: string
+ @param group: Default group to run as
+ @type group: string
"""
optionparser.add_option("-f", "--foreground", dest="fork",
optionparser.add_option("-d", "--debug", dest="debug",
help="Enable some debug messages",
default=False, action="store_true")
+ optionparser.add_option("--syslog", dest="syslog",
+ help="Enable logging to syslog (except debug"
+ " messages); one of 'no', 'yes' or 'only' [%s]" %
+ constants.SYSLOG_USAGE,
+ default=constants.SYSLOG_USAGE,
+ choices=["no", "yes", "only"])
+
if daemon_name in constants.DAEMONS_PORTS:
- # for networked daemons we also allow choosing the bind port and address.
- # by default we use the port provided by utils.GetDaemonPort, and bind to
- # 0.0.0.0 (which is represented by and empty bind address.
- port = utils.GetDaemonPort(daemon_name)
+ default_bind_address = constants.IP4_ADDRESS_ANY
+ default_port = netutils.GetDaemonPort(daemon_name)
+
+ # For networked daemons we allow choosing the port and bind address
optionparser.add_option("-p", "--port", dest="port",
- help="Network port (%s default)." % port,
- default=port, type="int")
+ help="Network port (default: %s)" % default_port,
+ default=default_port, type="int")
optionparser.add_option("-b", "--bind", dest="bind_address",
- help="Bind address",
- default="", metavar="ADDRESS")
+ help=("Bind address (default: %s)" %
+ default_bind_address),
+ default=default_bind_address, metavar="ADDRESS")
- if daemon_name in constants.DAEMONS_SSL:
- default_cert, default_key = constants.DAEMONS_SSL[daemon_name]
+ if default_ssl_key is not None and default_ssl_cert is not None:
optionparser.add_option("--no-ssl", dest="ssl",
help="Do not secure HTTP protocol with SSL",
default=True, action="store_false")
optionparser.add_option("-K", "--ssl-key", dest="ssl_key",
- help="SSL key",
- default=default_key, type="string")
+ help=("SSL key path (default: %s)" %
+ default_ssl_key),
+ default=default_ssl_key, type="string",
+ metavar="SSL_KEY_PATH")
optionparser.add_option("-C", "--ssl-cert", dest="ssl_cert",
- help="SSL certificate",
- default=default_cert, type="string")
+ help=("SSL certificate path (default: %s)" %
+ default_ssl_cert),
+ default=default_ssl_cert, type="string",
+ metavar="SSL_CERT_PATH")
- multithread = utils.no_fork = daemon_name in constants.MULTITHREADED_DAEMONS
+ # Disable the use of fork(2) if the daemon uses threads
+ utils.no_fork = multithreaded
options, args = optionparser.parse_args()
- if hasattr(options, 'ssl') and options.ssl:
- if not (options.ssl_cert and options.ssl_key):
- print >> sys.stderr, "Need key and certificate to use ssl"
- sys.exit(constants.EXIT_FAILURE)
- for fname in (options.ssl_cert, options.ssl_key):
- if not os.path.isfile(fname):
- print >> sys.stderr, "Need ssl file %s to run" % fname
+ if getattr(options, "ssl", False):
+ ssl_paths = {
+ "certificate": options.ssl_cert,
+ "key": options.ssl_key,
+ }
+
+ for name, path in ssl_paths.iteritems():
+ if not os.path.isfile(path):
+ print >> sys.stderr, "SSL %s file '%s' was not found" % (name, path)
sys.exit(constants.EXIT_FAILURE)
+ # TODO: By initiating http.HttpSslParams here we would only read the files
+ # once and have a proper validation (isfile returns False on directories)
+ # at the same time.
+
if check_fn is not None:
check_fn(options, args)
utils.EnsureDirs(dirs)
if options.fork:
+ try:
+ uid = pwd.getpwnam(user).pw_uid
+ gid = grp.getgrnam(group).gr_gid
+ except KeyError:
+ raise errors.ConfigurationError("User or group not existing on system:"
+ " %s:%s" % (user, group))
utils.CloseFDs()
- utils.Daemonize(logfile=constants.DAEMONS_LOGFILES[daemon_name])
+ utils.Daemonize(constants.DAEMONS_LOGFILES[daemon_name], uid, gid)
utils.WritePidFile(daemon_name)
try:
utils.SetupLogging(logfile=constants.DAEMONS_LOGFILES[daemon_name],
debug=options.debug,
stderr_logging=not options.fork,
- multithreaded=multithread)
- logging.info("%s daemon startup" % daemon_name)
+ multithreaded=multithreaded,
+ program=daemon_name,
+ syslog=options.syslog,
+ console_logging=console_logging)
+ logging.info("%s daemon startup", daemon_name)
exec_fn(options, args)
finally:
utils.RemovePidFile(daemon_name)
-
projects / ganeti-local / blobdiff