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dns.go
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dns.go
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package dns
import (
"github.com/cuigh/auxo/data"
"github.com/cuigh/auxo/log"
"github.com/cuigh/auxo/net/rpc/resolver"
"github.com/cuigh/auxo/net/transport"
"github.com/cuigh/auxo/util/cast"
"github.com/cuigh/auxo/util/run"
"net"
"time"
)
const PkgName = "auxo.net.rpc.resolver.dns"
func init() {
resolver.Register(Builder{})
}
type Builder struct{}
func (Builder) Name() string {
return "dns"
}
func (Builder) Build(_ resolver.Client, opts data.Map) (resolver.Resolver, error) {
addr := cast.ToString(opts.Get("address"))
interval := cast.ToDuration(opts.Get("refresh_interval"))
if interval <= 0 {
interval = 10 * time.Second
}
return &Resolver{
addr: addr,
interval: interval,
logger: log.Get(PkgName),
}, nil
}
type Resolver struct {
addr string
interval time.Duration
logger log.Logger
canceler run.Canceler
}
func (r *Resolver) Resolve() ([]transport.Address, error) {
addrs, err := r.resolve(r.addr)
if err != nil {
return nil, err
}
return addrs, nil
}
func (r *Resolver) Watch(notify func([]transport.Address)) {
if r.canceler == nil {
r.canceler = run.Schedule(r.interval, func() {
addrs, err := r.Resolve()
if err != nil {
r.logger.Error("dns > Failed to refresh addresses: ", err)
}
notify(addrs)
}, nil)
}
}
func (r *Resolver) resolve(addr string) (addrs []transport.Address, err error) {
var (
host, port string
ips []string
)
host, port, err = net.SplitHostPort(addr)
if err != nil {
return nil, err
}
ips, err = net.LookupHost(host)
if err == nil {
addrs = make([]transport.Address, len(ips))
for i, ip := range ips {
addrs[i] = transport.Address{
URL: net.JoinHostPort(ip, port),
}
}
}
return
}
func (r *Resolver) Close() {
if r.canceler != nil {
r.canceler.Cancel()
r.logger.Debug("dns > Resolver stopped")
}
}