Load balance policy

Load balance policy

We can indicate a special load balance policy when we create engine group. There are 5 load balances on xorm. They are RandomPolicy, WeightRandomPolicy, RoundRobinPolicy, WeightRoundRobinPolicy and LeastConnPolicy. You can also implement yourself policy according GroupPolicy interface.

• RandomPolicy

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)
var eg *xorm.EngineGroup
func main() {
    conns := []string{
        "postgres://postgres:[email protected]:5432/test?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test1?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test2?sslmode=disable",
    }
    var err error
    eg, err = xorm.NewEngineGroup("postgres", conns, xorm.RandomPolicy())
}

• WeightRandomPolicy

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)
var eg *xorm.EngineGroup
func main() {
    conns := []string{
        "postgres://postgres:[email protected]:5432/test?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test1?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test2?sslmode=disable",
    }
    var err error
    // set the weights
    eg, err = xorm.NewEngineGroup("postgres", conns, xorm.WeightRandomPolicy([]int{2, 3}))
}

• RoundRobinPolicy

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)
var eg *xorm.EngineGroup
func main() {
    conns := []string{
        "postgres://postgres:[email protected]:5432/test?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test1?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test2?sslmode=disable",
    }
    var err error
    eg, err = xorm.NewEngineGroup("postgres", conns, xorm.RoundRobinPolicy())
}

• WeightRoundRobinPolicy

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)
var eg *xorm.EngineGroup
func main() {
    conns := []string{
        "postgres://postgres:[email protected]:5432/test?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test1?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test2?sslmode=disable",
    }
    var err error
    // set the weights
    eg, err = xorm.NewEngineGroup("postgres", conns, xorm.WeightRoundRobinPolicy([]int{2, 3}))
}

• LeastConnPolicy

import (
    _ "github.com/lib/pq"
    "xorm.io/xorm"
)
var eg *xorm.EngineGroup
func main() {
    conns := []string{
        "postgres://postgres:[email protected]:5432/test?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test1?sslmode=disable;",
        "postgres://postgres:[email protected]:5432/test2?sslmode=disable",
    }
    var err error
    eg, err = xorm.NewEngineGroup("postgres", conns, xorm.LeastConnPolicy())
}

• Customerize Policy

You can also implement yourself policy according GroupPolicy interface.

type GroupPolicy interface {
    Slave(*EngineGroup) *Engine
}