Synnefo

# vim: ts=4 sts=4 et ai sw=4 fileencoding=utf-8

from django.conf import settings

from django.db import models

from django.contrib.auth.models import User

import datetime

backend_prefix_id = settings.BACKEND_PREFIX_ID

class SynnefoUser(models.Model):

    name = models.CharField('Synnefo Username', max_length=255)

    credit = models.IntegerField('Credit Balance')

    created = models.DateTimeField('Time of creation', auto_now_add=True)

    updated = models.DateTimeField('Time of last update', auto_now=True)

    #

    # We do not rely on Django's user authentication mechanism.

    # Hence, no references to the User model.

    # [vkoukis], after discussion with [faidon].

    # user = models.ForeignKey(User)

    class Meta:

        verbose_name = u'Synnefo User'

    def __unicode__(self):

        return self.name 

    def get_limit(self, limit_name):

        """Returns the limit value for the specified limit"""

        limit_objs = Limit.objects.filter(name=limit_name, user=self)        

        if len(limit_objs) == 1:

            return limit_objs[0].value

        return 0

    def _get_credit_quota(self):

        """Internal getter function for credit quota"""

        return self.get_limit('QUOTA_CREDIT')

    credit_quota = property(_get_credit_quota)

    def _get_monthly_rate(self):

        """Internal getter function for monthly credit issue rate"""

        return self.get_limit('MONTHLY_RATE')

    monthly_rate = property(_get_monthly_rate)

    def _get_min_credits(self):

        """Internal getter function for maximum number of violations"""

        return self.get_limit('MIN_CREDITS')

    min_credits = property(_get_min_credits)

    def debit_account(self, amount, vm, description):

        """Charges the user with the specified amount of credits for a vm (resource)"""

        date_now = datetime.datetime.now()

        # FIXME: The following two actions (debiting the user

        # and creating the Debit instance must happen ATOMICALLY,

        # as specified in the documentation.

        self.credit = self.credit - amount

        self.save()

        # then write the debit entry

        debit = Debit()

        debit.user = self

        debit.vm = vm

        debit.when = date_now

        debit.description = description

        debit.save()

    def credit_account(self, amount, creditor, description):

        """No clue :)"""

        return

class Image(models.Model):

    # This is WIP, FIXME

    IMAGE_STATES = (

        ('ACTIVE', 'Active'),

        ('SAVING', 'Saving'),

        ('DELETED', 'Deleted')

    )

    name = models.CharField('Image name', max_length=255)

    state = models.CharField('Current Image State', choices=IMAGE_STATES, max_length=30)

    description = models.TextField('General description')

    size = models.PositiveIntegerField('Image size in MBs')

    owner = models.ForeignKey(SynnefoUser, blank=True, null=True)

    created = models.DateTimeField('Time of creation', auto_now_add=True)

    updated = models.DateTimeField('Time of last update', auto_now=True)

    sourcevm = models.ForeignKey("VirtualMachine", null=True)

    class Meta:

        verbose_name = u'Image'

    def __unicode__(self):

        return u'%s' % ( self.name, )

class ImageMetadata(models.Model):

    meta_key = models.CharField('Image metadata key name', max_length=50)

    meta_value = models.CharField('Image metadata value', max_length=500)

    image = models.ForeignKey(Image)

    class Meta:

        verbose_name = u'Key-value pair of Image metadata.'

    def __unicode__(self):

        return u'%s, %s for %s' % (self.meta_key, self.meta_value, self.image.name)

class Limit(models.Model):

    LIMITS = (

        ('QUOTA_CREDIT', 'Maximum amount of credits per user'),

        ('MIN_CREDITS', 'Minimum amount of credits per user'),

        ('MONTHLY_RATE', 'Monthly credit issue rate')

    )

    user = models.ForeignKey(SynnefoUser)

    name = models.CharField('Limit key name', choices=LIMITS, max_length=30, null=False)

    value = models.IntegerField('Limit current value')

    class Meta:

        verbose_name = u'Enforced limit for user'

    def __unicode__(self):

        return u'Limit %s for user %s: %d' % (self.value, self.user, self.value)

class Flavor(models.Model):

    cpu = models.IntegerField('Number of CPUs', default=0)

    ram = models.IntegerField('Size of RAM', default=0)

    disk = models.IntegerField('Size of Disk space', default=0)

    class Meta:

        verbose_name = u'Virtual machine flavor'

        unique_together = ("cpu","ram","disk")

    def _get_name(self):

        """Returns flavor name (generated)"""

        return u'C%dR%dD%d' % (self.cpu, self.ram, self.disk)

    def _current_cost(self, active):

        """Returns active/inactive cost value

        set active = True to get active cost and False for the inactive.

        """

        fch_list = FlavorCost.objects.filter(flavor=self).order_by('-effective_from')

        if len(fch_list) > 0:

            if active:

                return fch_list[0].cost_active

            else:

                return fch_list[0].cost_inactive

        return 0

    def _current_cost_active(self):

        """Returns current active cost (property method)"""

        return self._current_cost(True)

    def _current_cost_inactive(self):

        """Returns current inactive cost (property method)"""

        return self._current_cost(False)

    name = property(_get_name)

    current_cost_active = property(_current_cost_active)

    current_cost_inactive = property(_current_cost_inactive)

    def __unicode__(self):

        return self.name

    def _get_costs(self, start_datetime, end_datetime, active):

        """Return a list with FlavorCost objects for the specified duration"""

        def between(enh_fc, a_date):

            """Checks if a date is between a FlavorCost duration"""

            if enh_fc.effective_from <= a_date and enh_fc.effective_to is None:

                return True

            return enh_fc.effective_from <= a_date and enh_fc.effective_to >= a_date

        def calculate_cost(start_date, end_date, cost):

            """Calculate the total cost for the specified duration"""

            td = end_date - start_date

            sec = float(td.microseconds + (td.seconds + td.days * 24 * 3600) * 10**6) / float(10**6)

            total_hours = float(sec) / float(60.0*60.0)

            total_cost = float(cost)*total_hours

            return round(total_cost)

        # Get the related FlavorCost objects, sorted.

        price_list = FlavorCost.objects.filter(flavor=self).order_by('effective_from')

        # add the extra field FlavorCost.effective_to

        for idx in range(0, len(price_list)):

            if idx + 1 == len(price_list):

                price_list[idx].effective_to = None

            else:

                price_list[idx].effective_to = price_list[idx + 1].effective_from

        price_result = []

        found_start = False

        # Find the affected FlavorCost, according to the

        # dates, and put them in price_result

        for p in price_list:

            if between(p, start_datetime):

                found_start = True

                p.effective_from = start_datetime

            if between(p, end_datetime):

                p.effective_to = end_datetime

                price_result.append(p)

                break

            if found_start:

                price_result.append(p)

        results = []

        # Create the list and the result tuples

        for p in price_result:

            if active:

                cost = p.cost_active

            else:

                cost = p.cost_inactive

            results.append( ( str(p.effective_from), calculate_cost(p.effective_from, p.effective_to, cost)) )

        return results

    def get_cost_active(self, start_datetime, end_datetime):

        """Returns a list with the active costs for the specified duration"""

        return self._get_costs(start_datetime, end_datetime, True)

    def get_cost_inactive(self, start_datetime, end_datetime):

        """Returns a list with the inactive costs for the specified duration"""

        return self._get_costs(start_datetime, end_datetime, False)

class FlavorCost(models.Model):

    cost_active = models.PositiveIntegerField('Active Cost')

    cost_inactive = models.PositiveIntegerField('Inactive Cost')

    effective_from = models.DateTimeField()

    flavor = models.ForeignKey(Flavor)

    class Meta:

        verbose_name = u'Pricing history for flavors'

    def __unicode__(self):

        return u'Costs (up, down)=(%d, %d) for %s since %s' % (self.cost_active, self.cost_inactive, flavor.name, self.effective_from)

class VirtualMachine(models.Model):

    # The list of possible actions for a VM

    ACTIONS = (

       ('CREATE', 'Create VM'),

       ('START', 'Start VM'),

       ('STOP', 'Shutdown VM'),

       ('SUSPEND', 'Admin Suspend VM'),

       ('REBOOT', 'Reboot VM'),

       ('DESTROY', 'Destroy VM')

    )

    # The internal operating state of a VM

    OPER_STATES = (

        ('BUILD', 'Queued for creation'),

        ('ERROR', 'Creation failed'),

        ('STOPPED', 'Stopped'),

        ('STARTED', 'Started'),

        ('DESTROYED', 'Destroyed')

    )

    # The list of possible operations on the backend

    BACKEND_OPCODES = (

        ('OP_INSTANCE_CREATE', 'Create Instance'),

        ('OP_INSTANCE_REMOVE', 'Remove Instance'),

        ('OP_INSTANCE_STARTUP', 'Startup Instance'),

        ('OP_INSTANCE_SHUTDOWN', 'Shutdown Instance'),

        ('OP_INSTANCE_REBOOT', 'Reboot Instance')

    )

    # A backend job may be in one of the following possible states

    BACKEND_STATUSES = (

        ('queued', 'request queued'),

        ('waiting', 'request waiting for locks'),

        ('canceling', 'request being canceled'),

        ('running', 'request running'),

        ('canceled', 'request canceled'),

        ('success', 'request completed successfully'),

        ('error', 'request returned error')

    )

    # The operating state of a VM,

    # upon the successful completion of a backend operation.

    OPER_STATE_FROM_OPCODE = {

        'OP_INSTANCE_CREATE': 'STARTED',

        'OP_INSTANCE_REMOVE': 'DESTROYED',

        'OP_INSTANCE_STARTUP': 'STARTED',

        'OP_INSTANCE_SHUTDOWN': 'STOPPED',

        'OP_INSTANCE_REBOOT': 'STARTED'

    }

    # This dictionary contains the correspondence between

    # internal operating states and Server States as defined

    # by the Rackspace API.

    RSAPI_STATE_FROM_OPER_STATE = {

        "BUILD": "BUILD",

        "ERROR": "ERROR",

        "STOPPED": "STOPPED",

        "STARTED": "ACTIVE",

        "DESTROYED": "DELETED"

    }

    name = models.CharField('Virtual Machine Name', max_length=255)

    owner = models.ForeignKey(SynnefoUser)

    created = models.DateTimeField(auto_now_add=True)

    updated = models.DateTimeField(auto_now=True)

    charged = models.DateTimeField(default=datetime.datetime.now())

    sourceimage = models.ForeignKey("Image", null=False) 

    hostid = models.CharField(max_length=100)

    description = models.TextField()

    ipfour = models.IPAddressField()

    ipsix = models.CharField(max_length=100)

    flavor = models.ForeignKey(Flavor)

    deleted = models.BooleanField('Deleted', default=False)

    suspended = models.BooleanField('Administratively Suspended', default=False)

    # VM State 

    # The following fields are volatile data, in the sense

    # that they need not be persistent in the DB, but rather

    # get generated at runtime by quering Ganeti and applying

    # updates received from Ganeti.

    #

    # In the future they could be moved to a separate caching layer

    # and removed from the database.

    # [vkoukis] after discussion with [faidon].

    _action = models.CharField(choices=ACTIONS, max_length=30, null=True)

    _operstate = models.CharField(choices=OPER_STATES, max_length=30, null=True)

    _backendjobid = models.PositiveIntegerField(null=True)

    _backendopcode = models.CharField(choices=BACKEND_OPCODES, max_length=30, null=True)

    _backendjobstatus = models.CharField(choices=BACKEND_STATUSES, max_length=30, null=True)

    _backendlogmsg = models.TextField(null=True)

    # Error classes

    class InvalidBackendIdError(Exception):

         def __init__(self, value):

            self.value = value

         def __str__(self):

            return repr(self.value)

    class InvalidBackendMsgError(Exception):

         def __init__(self, opcode, status):

            self.opcode = opcode

            self.status = status

         def __str__(self):

            return repr("<opcode: %s, status: %s>" % (str(self.opcode), str(self.status)))

    class InvalidActionError(Exception):

         def __init__(self, action):

            self._action = action

         def __str__(self):

            return repr(str(self._action))

    @staticmethod

    def id_from_instance_name(name):

        """Returns VirtualMachine's Django id, given a ganeti machine name.

        Strips the ganeti prefix atm. Needs a better name!

        """

        if not str(name).startswith(backend_prefix_id):

            raise VirtualMachine.InvalidBackendIdError(str(name))

        ns = str(name).lstrip(backend_prefix_id)

        if not ns.isdigit():

            raise VirtualMachine.InvalidBackendIdError(str(name))

        return int(ns)

    def __init__(self, *args, **kw):

        """Initialize state for just created VM instances."""

        super(VirtualMachine, self).__init__(*args, **kw)

        # This gets called BEFORE an instance gets save()d for

        # the first time.

        if not self.pk: 

            self._action = None

            self._backendjobid = None

            self._backendjobstatus = None

            self._backendopcode = None

            self._backendlogmsg = None

            # Do not use _update_state() for this, 

            # as this may cause save() to get called in __init__(),

            # breaking VirtualMachine.object.create() among other things.

            self._operstate = 'BUILD'

    def process_backend_msg(self, jobid, opcode, status, logmsg):

        """Process a job progress notification from the backend.

        Process an incoming message from the backend (currently Ganeti).

        Job notifications with a terminating status (sucess, error, or canceled),

        also update the operating state of the VM.

        """

        if (opcode not in [x[0] for x in VirtualMachine.BACKEND_OPCODES] or

           status not in [x[0] for x in VirtualMachine.BACKEND_STATUSES]):

            raise VirtualMachine.InvalidBackendMsgError(opcode, status)

        self._backendjobid = jobid

        self._backendjobstatus = status

        self._backendopcode = opcode

        self._backendlogmsg = logmsg

        # Notifications of success change the operating state

        if status == 'success':

            self._update_state(VirtualMachine.OPER_STATE_FROM_OPCODE[opcode])

        # Special cases OP_INSTANCE_CREATE fails --> ERROR

        if status in ('canceled', 'error') and opcode == 'OP_INSTANCE_CREATE':

            self._update_state('ERROR')

        # Any other notification of failure leaves the operating state unchanged

        self.save()

    def start_action(self, action):

        """Update the state of a VM when a new action is initiated."""

        if not action in [x[0] for x in VirtualMachine.ACTIONS]:

            raise VirtualMachine.InvalidActionError(action)

        # No actions to deleted and no actions beside destroy to suspended vms

        if self.deleted:

            raise VirtualMachine.InvalidActionError(action)

        self._action = action

        self._backendjobid = None

        self._backendopcode = None

        self._backendlogmsg = None

        # Update the relevant flags if the VM is being suspended or destroyed

        if action == "DESTROY":

            self.deleted = True

        elif action == "SUSPEND":

            self.suspended = True

        elif action == "START":

            self.suspended = False

        self.save()

    # FIXME: Perhaps move somewhere else, outside the model?

    def _get_rsapi_state(self):

        try:

            return VirtualMachine.RSAPI_STATE_FROM_OPER_STATE[self._operstate]

        except KeyError:

            return "UNKNOWN"

    rsapi_state = property(_get_rsapi_state)

    def _get_backend_id(self):

        """Returns the backend id for this VM by prepending backend-prefix."""

        return '%s%s' % (backend_prefix_id, str(self.id))

    backend_id = property(_get_backend_id)

    class Meta:

        verbose_name = u'Virtual machine instance'

        get_latest_by = 'created'

    def __unicode__(self):

        return self.name

    def _update_state(self, new_operstate):

        """Wrapper around updates of the _operstate field

        Currently calls the charge() method when necessary.

        """

        # Call charge() unconditionally before any change of

        # internal state.

        self.charge()

        self._operstate = new_operstate

    def charge(self):

        """Charges the owner of this VM.

        Charges the owner of a VM for the period

        from vm.charged to datetime.now(), based on the

        current operating state.

        """

        charged_states = ('STARTED', 'STOPPED')

        start_datetime = self.charged

        self.charged = datetime.datetime.now()

        # Only charge for a specific set of states

        if self._operstate not in charged_states:

            self.save()

            return

        cost_list = []

        if self._operstate == 'STARTED':

            cost_list = self.flavor.get_cost_active(start_datetime, self.charged)

        elif self._operstate == 'STOPPED':

            cost_list = self.flavor.get_cost_inactive(start_datetime, self.charged)

        total_cost = sum([x[1] for x in cost_list])

        # FIXME: This must happen inside a transaction.

        # Debiting the owner of this VM and storing a persistent value

        # for self.charged must happen ATOMICALLY.

        description = "Server = %d, charge = %d for state: %s" % (self.id, total_cost, self._operstate)

        self.owner.debit_account(total_cost, self, description)

        self.save()

class VirtualMachineGroup(models.Model):

    """Groups of VMs for SynnefoUsers"""

    name = models.CharField(max_length=255)

    created = models.DateTimeField('Time of creation', auto_now_add=True)

    updated = models.DateTimeField('Time of last update', auto_now=True)

    owner = models.ForeignKey(SynnefoUser)

    machines = models.ManyToManyField(VirtualMachine)

    class Meta:

        verbose_name = u'Virtual Machine Group'

        verbose_name_plural = 'Virtual Machine Groups'

        ordering = ['name']

    def __unicode__(self):

        return self.name

class VirtualMachineMetadata(models.Model):

    meta_key = models.CharField(max_length=50)

    meta_value = models.CharField(max_length=500)

    vm = models.ForeignKey(VirtualMachine)

    class Meta:

        verbose_name = u'Key-value pair of metadata for a VM.'

    def __unicode__(self):

        return u'%s, %s for %s' % (self.meta_key, self.meta_value, self.vm.name)

class Debit(models.Model):

    when = models.DateTimeField()

    user = models.ForeignKey(SynnefoUser)

    vm = models.ForeignKey(VirtualMachine)

    description = models.TextField()

    class Meta:

        verbose_name = u'Accounting log'

    def __unicode__(self):

        return u'%s - %s - %s - %s' % ( self.user.id, self.vm.name, str(self.when), self.description)

class Disk(models.Model):

    name = models.CharField(max_length=255)

    created = models.DateTimeField('Time of creation', auto_now_add=True)

    updated = models.DateTimeField('Time of last update', auto_now=True)

    size = models.PositiveIntegerField('Disk size in GBs')

    vm = models.ForeignKey(VirtualMachine, blank=True, null=True)

    owner = models.ForeignKey(SynnefoUser, blank=True, null=True)  

    class Meta:

        verbose_name = u'Disk instance'

    def __unicode__(self):

        return self.name