source: server/lib/gutenbach/server/job.py @ c1cebbc

from . import errors
from .player import Player
from gutenbach.ipp import JobStates as States
import logging
import os

# initialize logger
logger = logging.getLogger(__name__)

class GutenbachJob(object):

    def __init__(self, job_id=None, creator=None, name=None,
                 priority=None, document=None):
        """Create an empty Gutenbach job.

        Parameters
        ----------
        job_id : integer
            A unique id for this job.
        creator : string
            The user creating the job.
        name : string
            The human-readable name of the job.
        priority : integer
            The priority of the job, used for ordering.
        document : file object
            A file object containing the job data.

        """

        self.player = None
        self.document = None

        self.id = job_id
        self.creator = creator
        self.name = name
        self.priority = priority
        
        self._why_done = None

        if document is not None:
            self.spool(document)

    def __repr__(self):
        return str(self)

    def __str__(self):
        return "<Job %d '%s'>" % (self.id, self.name)

    def __cmp__(self, other):
        """Compares two GutenbachJobs based on their priorities.

        """
        return cmp(self.priority, other.priority)

    ######################################################################
    ###                          Properties                            ###
    ######################################################################

    @property
    def id(self):
        """Unique job identifier (integer).  Should be a positive
        integer, except when unassigned, when it defaults to -1.
        
        """
        return self._id
    @id.setter
    def id(self, val):
        try:
            self._id = max(int(val), -1)
        except:
            self._id = -1

    @property
    def priority(self):
        """Job priority (integer).  Should be a nonzero positive
        integer; defaults to 1 when unassigned.

        """
        return self._priority
    @priority.setter
    def priority(self, val):
        try:
            self._priority = max(int(val), 1)
        except:
            self._priority = 1

    @property
    def creator(self):
        """The user who created the job (string).  Defaults to an
        empty string.

        """
        return self._creator
    @creator.setter
    def creator(self, val):
        if val is None:
            self._creator = ""
        else:
            self._creator = str(val)

    @property
    def name(self):
        """The job's human-readable name (string).  Defaults to an
        empty string.

        """
        return self._name
    @name.setter
    def name(self, val):
        if val is None:
            self._name = ""
        else:
            self._name = str(val)

    @property
    def size(self):
        """The size of the job in octets/bytes (integer).  Defaults to
        0 if no document is specified or if there is an error reading
        the document.

        """
        try:
            size = os.path.getsize(self.document)
        except:
            size = 0
        return size

    ######################################################################
    ###                            State                               ###
    ######################################################################

    @property
    def is_valid(self):
        """Whether the job is ready to be manipulated (spooled,
        played, etc).  Note that playing the job still requires it to
        be spooled first.

        """

        return self.id > 0 and \
               self.priority > 0

    @property
    def is_ready(self):
        """Whether the job is ready to be played; i.e., it has all the
        necessary data to actually play the audio data.

        """

        return self.is_valid and \
               self.player is not None and \
               not self.player.is_playing and \
               not self._why_done == "cancelled" and \
               not self._why_done == "aborted"

    @property
    def is_playing(self):
        """Whether the job is currently playing (regardless of whether
        it's paused).

        """

        return self.is_valid and \
               self.player is not None and \
               self.player.is_playing

    @property
    def is_paused(self):
        """Whether the job is currently paused.

        """

        return self.is_valid and \
               self.player is not None and \
               self.player.is_paused        

    @property
    def is_done(self):
        """Whether the job is done playing, regardless of whether it
        completed successfully or not.

        """

        return (self.is_valid and \
                self.player is not None and \
                self.player.is_done) or \
                (self._why_done == "cancelled" or \
                 self._why_done == "aborted")

    @property
    def is_completed(self):
        """Whether the job completed successfully.

        """

        return self.is_done and self._why_done == "completed"

    @property
    def is_cancelled(self):
        """Whether the job was cancelled.

        """

        return self.is_done and self._why_done == "cancelled"

    @property
    def is_aborted(self):
        """Whether the job was aborted.

        """

        return self.is_done and self._why_done == "aborted"

    @property
    def state(self):
        """State status codes (these are equivalent to the IPP
        job-state status codes).  State transitions are as follows:
        
            HELD ---> PENDING ---> PROCESSING <--> STOPPED (aka paused)
                         ^              |---> CANCELLED
                         |              |---> ABORTED
                         |              |---> COMPLETE ---|
                         |--------------------------------|
                     
        """

        if self.is_ready:
            state = States.PENDING
        elif self.is_playing and not self.is_paused:
            state = States.PROCESSING
        elif self.is_playing and self.is_paused:
            state = States.STOPPED
        elif self.is_completed:
            state = States.COMPLETE
        elif self.is_cancelled:
            state = States.CANCELLED
        elif self.is_aborted:
            state = States.ABORTED
        else:
            state = States.HELD
        return state

    ######################################################################
    ###                            Methods                             ###
    ######################################################################

    @staticmethod
    def verify_document(document):
        """Verifies that a document has the 'name', 'read', and
        'close' attributes (i.e., it should be like a file object).

        """
        
        if not hasattr(document, "name"):
            raise errors.InvalidDocument, "no name attribute"
        if not hasattr(document, "read"):
            raise errors.InvalidDocument, "no read attribute"
        if not hasattr(document, "close"):
            raise errors.InvalidDocument, "no close attribute"

    def spool(self, document=None):
        """Non-blocking spool.  Job must be valid (see
        'GutenbachJob.is_valid'), and the document must be an open
        file handler.

        Raises
        ------
        InvalidDocument
            If the document is not valid.
        InvalidJobStateException
            If the job is not valid or it is already
            spooled/ready/finished.

        """

        if not self.is_valid or self.state != States.HELD:
            raise errors.InvalidJobStateException(self.state)
        self.verify_document(document)
        self.document = document.name
        self.player = Player(document)
        logger.debug("document for job %d is '%s'" % (self.id, self.document))

    def play(self):
        """Non-blocking play.  Job must be ready (see
        'GutenbachJob.is_ready').

        Raises
        ------
        InvalidJobStateException
            If the job is not ready to be played.

        """
        
        # make sure the job is waiting to be played and that it's
        # valid
        if not self.is_ready:
            raise errors.InvalidJobStateException(self.state)
        
        # and set the state to processing if we're good to go
        logger.info("playing job %s" % str(self))

        def _completed():
            logger.info("completed job %s" % str(self))
            self._why_done = "completed"
        self.player.callback = _completed
        self.player.start()

    def pause(self):
        """Non-blocking pause.  Job must be playing (see
        'GutenbachJob.is_playing').

        Raises
        ------
        InvalidJobStateException
            If the job is not playing.

        """
        
        if not self.is_playing:
            raise errors.InvalidJobStateException(self.state)
        self.player.mplayer_pause()

    def cancel(self):
        """Blocking cancel. The job must not have been previously
        aborted or completed (though this method will succeed if it
        was previously cancelled).  This should be used to stop the
        job following an external request.

        Raises
        ------
        InvalidJobStateException
            If the job has already finished.

        """
        
        if self.is_playing:
            self.player._callback = None
            self.player.mplayer_stop()

        elif self.is_done and not self._why_done == "cancelled":
            raise errors.InvalidJobStateException(self.state)

        logger.info("cancelled job %s" % str(self))
        self._why_done = "cancelled"

    def abort(self):
        """Blocking abort. The job must not have been previously
        cancelled or completed (though this method will succeed if it
        was previously aborted).  This should be used to stop the job
        following internal errors.

        Raises
        ------
        InvalidJobStateException
            If the job has already finished.

        """

        if self.is_playing:
            self.player._callback = None
            self.player.mplayer_stop()

        elif self.is_done and not self._why_done == "aborted":
            raise errors.InvalidJobStateException(self.state)

        logger.info("aborted job %s" % str(self))
        self._why_done = "aborted"

    def restart(self):
        """Non-blocking restart.  Job must be finished (see
        'GutenbachJob.is_done'), and will be ready to be played (see
        'GutenbachJob.is_ready') if this method is successful.

        Raises
        ------
        InvalidJobStateException
            If the job is not done.

        """

        if not self.is_done:
            raise errors.InvalidJobStateException(self.state)

        logger.debug("restarting job %d" % (self.id, self.document))

        self._why_done = None
        self.spool(self.document)