micro/client/node_selector.go

38 lines
954 B
Go

package client
import (
"math/rand"
"time"
"github.com/micro/go-micro/errors"
"github.com/micro/go-micro/registry"
)
// NodeSelector is used to retrieve a node to which a request
// should be routed. It takes a list of services and selects
// a single node. If a node cannot be selected it should return
// an error. A list of services is provided as a service may
// have 1 or more versions.
type NodeSelector func(service []*registry.Service) (*registry.Node, error)
func init() {
rand.Seed(time.Now().UnixNano())
}
// Built in random hashed node selector
func nodeSelector(service []*registry.Service) (*registry.Node, error) {
if len(service) == 0 {
return nil, errors.NotFound("go.micro.client", "Service not found")
}
i := rand.Int()
j := i % len(service)
if len(service[j].Nodes) == 0 {
return nil, errors.NotFound("go.micro.client", "Service not found")
}
n := i % len(service[j].Nodes)
return service[j].Nodes[n], nil
}