micro/selector/selector.go

43 lines
1.2 KiB
Go
Raw Normal View History

2016-12-14 18:41:48 +03:00
// Package selector is a way to load balance service nodes
2015-12-09 22:23:16 +03:00
package selector
import (
"errors"
"github.com/micro/go-micro/registry"
)
// Selector builds on the registry as a mechanism to pick nodes
// and mark their status. This allows host pools and other things
// to be built using various algorithms.
type Selector interface {
2016-01-05 02:07:56 +03:00
Init(opts ...Option) error
Options() Options
2015-12-09 22:23:16 +03:00
// Select returns a function which should return the next node
Select(service string, opts ...SelectOption) (Next, error)
// Mark sets the success/error against a node
Mark(service string, node *registry.Node, err error)
// Reset returns state back to zero for a service
Reset(service string)
// Close renders the selector unusable
Close() error
2015-12-20 00:56:14 +03:00
// Name of the selector
String() string
2015-12-09 22:23:16 +03:00
}
// Next is a function that returns the next node
2016-05-04 00:06:19 +03:00
// based on the selector's strategy
2015-12-09 22:23:16 +03:00
type Next func() (*registry.Node, error)
2016-04-23 22:15:01 +03:00
// Filter is used to filter a service during the selection process
type Filter func([]*registry.Service) []*registry.Service
2015-12-09 22:23:16 +03:00
2016-05-04 00:06:19 +03:00
// Strategy is a selection strategy e.g random, round robin
type Strategy func([]*registry.Service) Next
2015-12-09 22:23:16 +03:00
var (
DefaultSelector = NewSelector()
2015-12-09 22:23:16 +03:00
ErrNotFound = errors.New("not found")
ErrNoneAvailable = errors.New("none available")
)