Create Engine Group

Create Engine Group

XORM supports to create EngineGroup to handle Master/Slave databases. You can invoke xorm.NewEngineGroup to do that. For example:

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)

var eg *xorm.EngineGroup

func main() {
	conns := []string{
		"postgres://postgres:root@localhost:5432/test?sslmode=disable;", // first one is master
		"postgres://postgres:root@localhost:5432/test1?sslmode=disable;", // slave
		"postgres://postgres:root@localhost:5432/test2?sslmode=disable", // slave
	}

    var err error
	eg, err = xorm.NewEngineGroup("postgres", conns)
}

Or

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)

var eg *xorm.EngineGroup

func main() {
    var err error
    master, err := xorm.NewEngine("postgres", "postgres://postgres:root@localhost:5432/test?sslmode=disable")
    if err != nil {
		return
	}

    slave1, err := xorm.NewEngine("postgres", "postgres://postgres:root@localhost:5432/test1?sslmode=disable")
    if err != nil {
		return
	}

    slave2, err := xorm.NewEngine("postgres", "postgres://postgres:root@localhost:5432/test2?sslmode=disable")
    if err != nil {
		return
	}

   	slaves := []*xorm.Engine{slave1, slave2}
	eg, err = xorm.NewEngineGroup(master, slaves)
}

You can create many engine groups for different databases. Generally, you just need to create only one engine group. EngineGroup is goroutine safe.

When you want to manually close the engine group, call enginegroup.Close.

  • NewEngineGroup
func NewEngineGroup(args1 interface{}, args2 interface{}, policies ...GroupPolicy) (*EngineGroup, error)
  • Master
func (eg *EngineGroup) Master() *Engine

It will return Master database Engine so that you can operate master only.

  • Slave
func (eg *EngineGroup) Slave() *Engine

It will return the current slave engine according the load balance policy.

  • Slaves
func (eg *EngineGroup) Slaves() []*Engine

It will return all the slaves.

  • GetSlave
func (eg *EngineGroup) GetSlave(i int) *Engine

It will return the slave engine according the index.

  • SetPolicy
func (eg *EngineGroup) SetPolicy(policy GroupPolicy) *EngineGroup

It will set a load balance policy.

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