django-orchestra/orchestra/apps/resources/models.py

200 lines
7.8 KiB
Python

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.apps import apps
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."))
on_demand = 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(_("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(update_fields=['crontab'])
if created:
# This only work on tests because of multiprocessing used on real deployments
apps.get_app_config('resources').reload_relations()
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', verbose_name=_("resource"))
content_type = models.ForeignKey(ContentType, verbose_name=_("content type"))
object_id = models.PositiveIntegerField(_("object id"))
used = models.PositiveIntegerField(_("used"), null=True)
updated_at = models.DateTimeField(_("updated"), null=True)
allocated = models.PositiveIntegerField(_("allocated"), 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)
@property
def unit(self):
return self.resource.unit
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.updated_at = timezone.now()
self.save(update_fields=['used', 'updated_at'])
class MonitorData(models.Model):
""" Stores monitored data """
monitor = models.CharField(_("monitor"), max_length=256,
choices=ServiceMonitor.get_plugin_choices())
content_type = models.ForeignKey(ContentType, verbose_name=_("content type"))
object_id = models.PositiveIntegerField(_("object id"))
created_at = models.DateTimeField(_("created"), auto_now_add=True)
value = models.DecimalField(_("value"), max_digits=16, decimal_places=2)
content_object = GenericForeignKey()
class Meta:
get_latest_by = 'id'
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,
allocated=resource.default_allocation)
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()