mirror of https://github.com/minio/minio.git
72 lines
2.2 KiB
Go
72 lines
2.2 KiB
Go
// Copyright (c) 2015-2021 MinIO, Inc.
|
|
//
|
|
// This file is part of MinIO Object Storage stack
|
|
//
|
|
// This program is free software: you can redistribute it and/or modify
|
|
// it under the terms of the GNU Affero General Public License as published by
|
|
// the Free Software Foundation, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// This program is distributed in the hope that it will be useful
|
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
// GNU Affero General Public License for more details.
|
|
//
|
|
// You should have received a copy of the GNU Affero General Public License
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
package http
|
|
|
|
import (
|
|
"context"
|
|
"net"
|
|
"time"
|
|
|
|
"github.com/rs/dnscache"
|
|
)
|
|
|
|
// DialContextWithDNSCache is a helper function which returns `net.DialContext` function.
|
|
// It randomly fetches an IP from the DNS cache and dials it by the given dial
|
|
// function. It dials one by one and returns first connected `net.Conn`.
|
|
// If it fails to dial all IPs from cache it returns first error. If no baseDialFunc
|
|
// is given, it sets default dial function.
|
|
//
|
|
// You can use returned dial function for `http.Transport.DialContext`.
|
|
//
|
|
// In this function, it uses functions from `rand` package. To make it really random,
|
|
// you MUST call `rand.Seed` and change the value from the default in your application
|
|
func DialContextWithDNSCache(resolver *dnscache.Resolver, baseDialCtx DialContext) DialContext {
|
|
if baseDialCtx == nil {
|
|
// This is same as which `http.DefaultTransport` uses.
|
|
baseDialCtx = (&net.Dialer{
|
|
Timeout: 30 * time.Second,
|
|
KeepAlive: 30 * time.Second,
|
|
}).DialContext
|
|
}
|
|
return func(ctx context.Context, network, addr string) (conn net.Conn, err error) {
|
|
host, port, err := net.SplitHostPort(addr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if net.ParseIP(host) != nil {
|
|
// For IP only setups there is no need for DNS lookups.
|
|
return baseDialCtx(ctx, "tcp", addr)
|
|
}
|
|
|
|
ips, err := resolver.LookupHost(ctx, host)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
for _, ip := range ips {
|
|
conn, err = baseDialCtx(ctx, "tcp", net.JoinHostPort(ip, port))
|
|
if err == nil {
|
|
break
|
|
}
|
|
}
|
|
|
|
return
|
|
}
|
|
}
|