mysql - 如何在Django中自动切换多个数据库服务器？

Question

我已经设置了一个主远程 MySQL 数据库服务器，并将其副本配置为我的 Django 应用程序的从数据库。两者都在亚马逊 ubuntu ec2 实例上运行。如何配置 Django 在主数据库宕机时自动访问从数据库？

Answer 1

Djangor使用db router来解决这个问题，我给你举个例子:

class DBRouter(object):
"""
A router to control all database operations on models in the
auth application.
"""
def db_for_read(self, model, **hints):
    """
    Attempts to read auth models go to auth_db.
    """
    if model._meta.app_label == 'xxx':
        return 'salvedb' # this name you defined in settings of django project
    return None

def db_for_write(self, model, **hints):
    """
    Attempts to write auth models go to auth_db.
    """
    if model._meta.app_label == 'xxx':
        return 'salvedb'
    return None

def allow_relation(self, obj1, obj2, **hints):
    """
    Allow relations if a model in the auth app is involved.
    """
    #if obj1._meta.app_label == 'auth' or \
    #   obj2._meta.app_label == 'auth':
    #   return True
    return None

def allow_migrate(self, db, app_label, model_name=None, **hints):
    """
    Make sure the auth app only appears in the 'auth_db'
    database.
    """
    #if app_label == 'auth':
    #    return db == 'auth_db'
    return None

并将此路由器添加到您的设置中:

DATABASE_ROUTERS = ['path.routers.DBRouter']

或者你可以阅读django官网的文档:https://docs.djangoproject.com/en/1.11/topics/db/multi-db/#automatic-database-routing