django_master_model.py

# coding: utf-8

import random

from django.conf import settings
from django.db import models

from library.cachemethod.decorator import cachemethod
from library.cachemethod.api import delete_method_cache


class MasterModelQuerySet(models.query.QuerySet):

  @property
  def db(self):
    if self._for_write:
      return self._db or router.db_for_write(self.model)
    if hasattr(settings, 'SLAVE_DATABASES') and isinstance(settings.SLAVE_DATABASES, list):
      return random.choice(settings.SLAVE_DATABASES)
    return self._db or router.db_for_read(self.model)


class MasterModelManager(models.Manager):

  def get_query_set(self):
    return MasterModelQuerySet(self.model)


class MasterModel(models.Model):

  objects = MasterModelManager()

  class Meta:
    abstract = True
    
  @classmethod
  @cachemethod
  def get(cls, pk):
      try:
          return cls.objects.get(pk=pk)
      except:
          return None

      
  @classmthod
  @cachemethod
  def get_all(cls):
      return list(cls.objects.all())

  def _delete_cache(self):
      delete_method_cache()
      
  def save(self, *args, **kwargs):
      super(self.__class__, self).save(*args, **kwargs)
      self.delete_cache()

  def delete(self, *args, **kwargs):
      super(self.__class__, self).delete(*args, **kwargs)
      self.delete_cache()