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

216 lines
8.3 KiB
Python

from django.contrib.contenttypes.fields import GenericForeignKey, GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.apps import apps
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.core import validators
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")),
)
_related = set() # keeps track of related models for resource cleanup
name = models.CharField(_("name"), max_length=32,
help_text=_('Required. 32 characters or fewer. Lowercase letters, '
'digits and hyphen only.'),
validators=[validators.validate_name])
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. e.g. <tt>10**9</tt>"))
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'])
# This only work on tests (multiprocessing used on real deployments)
apps.get_app_config('resources').reload_relations()
# TODO touch wsgi.py for code reloading?
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()
def get_scale(self):
return eval(self.scale)
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
# Clean previous state
for related in Resource._related:
try:
delattr(related, 'resource_set')
delattr(related, 'resources')
except AttributeError:
pass
else:
related._meta.virtual_fields = [
field for field in related._meta.virtual_fields if field.rel.to != ResourceData
]
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()
Resource._related.add(model)