/
group.go
77 lines (64 loc) · 1.69 KB
/
group.go
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package sql
import (
"log"
"sync/atomic"
"gorm.io/driver/mysql"
"gorm.io/gorm"
)
// Client继承了*gorm.DB的所有方法, 详细的使用方法请参考:
// http://gorm.io/docs/connecting_to_the_database.html
type Client struct {
*gorm.DB
}
type Group struct {
name string
master *Client
replica []*Client
next uint64
total uint64
}
func openDB(name, address string, isMaster int, statLevel, format, logLevel string) (*Client, error) {
db, err := gorm.Open(mysql.Open(address), &gorm.Config{})
db = db.Debug()
return &Client{DB: db}, err
}
// NewGroup初始化一个Group, 一个Group包含一个master实例和零个或多个slave实例
func NewGroup(d SQLGroupConfig) (*Group, error) {
log.Printf("init sql group name [%s], master [%s], slave [%v]\n", d.Name, d.Master, d.Slaves)
g := Group{name: d.Name}
var err error
g.master, err = openDB(d.Name, d.Master, 1, d.StatLevel, d.LogFormat, d.LogLevel)
if err != nil {
return nil, err
}
g.replica = make([]*Client, 0, len(d.Slaves))
g.total = 0
for _, slave := range d.Slaves {
c, err := openDB(d.Name, slave, 0, d.StatLevel, d.LogFormat, d.LogLevel)
if err != nil {
return nil, err
}
g.replica = append(g.replica, c)
g.total++
}
return &g, nil
}
// Master返回master实例
func (g *Group) Master() *Client {
return g.master
}
// Slave返回一个slave实例,使用轮转算法
func (g *Group) Slave() *Client {
if g.total == 0 {
return g.master
}
next := atomic.AddUint64(&g.next, 1)
return g.replica[next%g.total]
}
// Instance函数如果isMaster是true, 返回master实例,否则返回slave实例
func (g *Group) Instance(isMaster bool) *Client {
if isMaster {
return g.Master()
}
return g.Slave()
}