负载策略

通过 xorm.NewEngineGroup 创建 EngineGroup 时,第三个参数为 policies,我们可以通过该参数来指定 Slave 访问的负载策略。如创建EngineGroup 时未指定,则默认使用轮询的负载策略。

xorm 中内置五种负载策略,分别为随机访问负载策略,权重随机访问负载策略,轮询访问负载策略,权重轮询访问负载策略和最小连接数访问负载策略。开发者也可以通过实现 GroupPolicy 接口,来实现自定义负载策略。

  • 随机访问负载策略
  1. import (
  2. _ "github.com/lib/pq"
  3. "xorm.io/xorm"
  4. )
  5. var eg *xorm.EngineGroup
  6. func main() {
  7. conns := []string{
  8. "postgres://postgres:root@localhost:5432/test?sslmode=disable;",
  9. "postgres://postgres:root@localhost:5432/test1?sslmode=disable;",
  10. "postgres://postgres:root@localhost:5432/test2?sslmode=disable",
  11. }
  12. var err error
  13. eg, err = xorm.NewEngineGroup("postgres", conns, xorm.RandomPolicy())
  14. }
  • 权重随机访问负载策略
  1. import (
  2. _ "github.com/lib/pq"
  3. "xorm.io/xorm"
  4. )
  5. var eg *xorm.EngineGroup
  6. func main() {
  7. conns := []string{
  8. "postgres://postgres:root@localhost:5432/test?sslmode=disable;",
  9. "postgres://postgres:root@localhost:5432/test1?sslmode=disable;",
  10. "postgres://postgres:root@localhost:5432/test2?sslmode=disable",
  11. }
  12. var err error
  13. //此时设置的test1数据库和test2数据库的随机访问权重为2和3
  14. eg, err = xorm.NewEngineGroup("postgres", conns, xorm.WeightRandomPolicy([]int{2, 3}))
  15. }
  • 轮询访问负载策略
  1. import (
  2. _ "github.com/lib/pq"
  3. "xorm.io/xorm"
  4. )
  5. var eg *xorm.EngineGroup
  6. func main() {
  7. conns := []string{
  8. "postgres://postgres:root@localhost:5432/test?sslmode=disable;",
  9. "postgres://postgres:root@localhost:5432/test1?sslmode=disable;",
  10. "postgres://postgres:root@localhost:5432/test2?sslmode=disable",
  11. }
  12. var err error
  13. eg, err = xorm.NewEngineGroup("postgres", conns, xorm.RoundRobinPolicy())
  14. }
  • 权重轮询访问负载策略
  1. import (
  2. _ "github.com/lib/pq"
  3. "xorm.io/xorm"
  4. )
  5. var eg *xorm.EngineGroup
  6. func main() {
  7. conns := []string{
  8. "postgres://postgres:root@localhost:5432/test?sslmode=disable;",
  9. "postgres://postgres:root@localhost:5432/test1?sslmode=disable;",
  10. "postgres://postgres:root@localhost:5432/test2?sslmode=disable",
  11. }
  12. var err error
  13. //此时设置的test1数据库和test2数据库的轮询访问权重为2和3
  14. eg, err = xorm.NewEngineGroup("postgres", conns, xorm.WeightRoundRobinPolicy([]int{2, 3}))
  15. }
  • 最小连接数访问负载策略
  1. import (
  2. _ "github.com/lib/pq"
  3. "xorm.io/xorm"
  4. )
  5. var eg *xorm.EngineGroup
  6. func main() {
  7. conns := []string{
  8. "postgres://postgres:root@localhost:5432/test?sslmode=disable;",
  9. "postgres://postgres:root@localhost:5432/test1?sslmode=disable;",
  10. "postgres://postgres:root@localhost:5432/test2?sslmode=disable",
  11. }
  12. var err error
  13. eg, err = xorm.NewEngineGroup("postgres", conns, xorm.LeastConnPolicy())
  14. }
  • 自定义负载策略

你也可以通过实现 GroupPolicy 接口来实现自定义负载策略。

  1. type GroupPolicy interface {
  2. Slave(*EngineGroup) *Engine
  3. }