from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation from django.contrib.contenttypes.models import ContentType from django.core import validators from django.db import models from django.utils import timezone from django.utils.translation import ugettext_lazy as _ from djcelery.models import PeriodicTask, CrontabSchedule from orchestra.models import queryset, fields from . import helpers from .backends import ServiceMonitor class ResourceQuerySet(models.QuerySet): group_by = queryset.group_by class Resource(models.Model): """ Defines a resource, a resource is basically an interpretation of data gathered by a Monitor """ LAST = 'LAST' MONTHLY_SUM = 'MONTHLY_SUM' MONTHLY_AVG = 'MONTHLY_AVG' PERIODS = ( (LAST, _("Last")), (MONTHLY_SUM, _("Monthly Sum")), (MONTHLY_AVG, _("Monthly Average")), ) name = models.CharField(_("name"), max_length=32, help_text=_('Required. 32 characters or fewer. Lowercase letters, ' 'digits and hyphen only.'), validators=[validators.RegexValidator(r'^[a-z0-9_\-]+$', _('Enter a valid name.'), 'invalid')]) verbose_name = models.CharField(_("verbose name"), max_length=256) content_type = models.ForeignKey(ContentType, help_text=_("Model where this resource will be hooked.")) period = models.CharField(_("period"), max_length=16, choices=PERIODS, default=LAST, help_text=_("Operation used for aggregating this resource monitored" "data.")) # TODO rename to on_deman ondemand = models.BooleanField(_("on demand"), default=False, help_text=_("If enabled the resource will not be pre-allocated, " "but allocated under the application demand")) default_allocation = models.PositiveIntegerField(_("default allocation"), null=True, blank=True, help_text=_("Default allocation value used when this is not an " "on demand resource")) unit = models.CharField(_("unit"), max_length=16, help_text=_("The unit in which this resource is measured. " "For example GB, KB or subscribers")) scale = models.PositiveIntegerField(_("scale"), help_text=_("Scale in which this resource monitoring resoults should " "be prorcessed to match with unit.")) disable_trigger = models.BooleanField(_("disable trigger"), default=False, help_text=_("Disables monitors exeeded and recovery triggers")) crontab = models.ForeignKey(CrontabSchedule, verbose_name=_("crontab"), null=True, blank=True, help_text=_("Crontab for periodic execution. " "Leave it empty to disable periodic monitoring")) monitors = fields.MultiSelectField(_("monitors"), max_length=256, blank=True, choices=ServiceMonitor.get_plugin_choices(), help_text=_("Monitor backends used for monitoring this resource.")) is_active = models.BooleanField(_("is active"), default=True) objects = ResourceQuerySet.as_manager() class Meta: unique_together = ( ('name', 'content_type'), ('verbose_name', 'content_type') ) def __unicode__(self): return "{}-{}".format(str(self.content_type), self.name) def save(self, *args, **kwargs): # created = not self.pk super(Resource, self).save(*args, **kwargs) # Create Celery periodic task name = 'monitor.%s' % str(self) try: task = PeriodicTask.objects.get(name=name) except PeriodicTask.DoesNotExist: if self.is_active: PeriodicTask.objects.create( name=name, task='resources.Monitor', args=[self.pk], crontab=self.crontab ) else: if not self.is_active: task.delete() elif task.crontab != self.crontab: task.crontab = self.crontab task.save() # if created: # create_resource_relation() def delete(self, *args, **kwargs): super(Resource, self).delete(*args, **kwargs) name = 'monitor.%s' % str(self) PeriodicTask.objects.filter( name=name, task='resources.Monitor', args=[self.pk] ).delete() class ResourceData(models.Model): """ Stores computed resource usage and allocation """ resource = models.ForeignKey(Resource, related_name='dataset') content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() used = models.PositiveIntegerField(null=True) last_update = models.DateTimeField(null=True) allocated = models.PositiveIntegerField(null=True, blank=True) content_object = GenericForeignKey() class Meta: unique_together = ('resource', 'content_type', 'object_id') verbose_name_plural = _("resource data") @classmethod def get_or_create(cls, obj, resource): ct = ContentType.objects.get_for_model(type(obj)) try: return cls.objects.get(content_type=ct, object_id=obj.pk, resource=resource) except cls.DoesNotExist: return cls.objects.create(content_object=obj, resource=resource, allocated=resource.default_allocation) def get_used(self): return helpers.compute_resource_usage(self) def update(self, current=None): if current is None: current = self.get_used() self.used = current or 0 self.last_update = timezone.now() self.save() class MonitorData(models.Model): """ Stores monitored data """ monitor = models.CharField(_("monitor"), max_length=256, choices=ServiceMonitor.get_plugin_choices()) content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() date = models.DateTimeField(_("date"), auto_now_add=True) value = models.DecimalField(_("value"), max_digits=16, decimal_places=2) content_object = GenericForeignKey() class Meta: get_latest_by = 'date' verbose_name_plural = _("monitor data") def __unicode__(self): return str(self.monitor) def create_resource_relation(): class ResourceHandler(object): """ account.resources.web """ def __getattr__(self, attr): """ get or build ResourceData """ try: data = self.obj.resource_set.get(resource__name=attr) except ResourceData.DoesNotExist: model = self.obj._meta.model_name resource = Resource.objects.get(content_type__model=model, name=attr, is_active=True) data = ResourceData(content_object=self.obj, resource=resource) return data def __get__(self, obj, cls): """ proxy handled object """ self.obj = obj return self relation = GenericRelation('resources.ResourceData') for ct, resources in Resource.objects.group_by('content_type').iteritems(): model = ct.model_class() model.add_to_class('resource_set', relation) model.resources = ResourceHandler()