micro/selector/dns/dns.go
2019-01-07 07:41:26 +00:00

101 lines
1.7 KiB
Go

// Package dns provides a dns SRV selector
package dns
import (
"net"
"github.com/micro/go-micro/registry"
"github.com/micro/go-micro/selector"
)
type dnsSelector struct {
options selector.Options
domain string
}
var (
DefaultDomain = "local"
)
func (d *dnsSelector) Init(opts ...selector.Option) error {
for _, o := range opts {
o(&d.options)
}
return nil
}
func (d *dnsSelector) Options() selector.Options {
return d.options
}
func (d *dnsSelector) Select(service string, opts ...selector.SelectOption) (selector.Next, error) {
_, srv, err := net.LookupSRV(service, "tcp", d.domain)
if err != nil {
return nil, err
}
var nodes []*registry.Node
for _, node := range srv {
nodes = append(nodes, &registry.Node{
Id: node.Target,
Address: node.Target,
Port: int(node.Port),
})
}
services := []*registry.Service{
&registry.Service{
Name: service,
Nodes: nodes,
},
}
sopts := selector.SelectOptions{
Strategy: d.options.Strategy,
}
for _, opt := range opts {
opt(&sopts)
}
// apply the filters
for _, filter := range sopts.Filters {
services = filter(services)
}
// if there's nothing left, return
if len(services) == 0 {
return nil, selector.ErrNoneAvailable
}
return sopts.Strategy(services), nil
}
func (d *dnsSelector) Mark(service string, node *registry.Node, err error) {
return
}
func (d *dnsSelector) Reset(service string) {
return
}
func (d *dnsSelector) Close() error {
return nil
}
func (d *dnsSelector) String() string {
return "dns"
}
func NewSelector(opts ...selector.Option) selector.Selector {
options := selector.Options{
Strategy: selector.Random,
}
for _, o := range opts {
o(&options)
}
return &dnsSelector{options: options, domain: DefaultDomain}
}