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package autoconf
import (
"fmt"
"net"
"strconv"
"strings"
"github.com/hashicorp/consul/lib"
"github.com/hashicorp/go-discover"
"github.com/hashicorp/go-hclog"
)
func (ac *AutoConfig) discoverServers(servers []string) ([]string, error) {
providers := make(map[string]discover.Provider)
for k, v := range discover.Providers {
providers[k] = v
}
disco, err := discover.New(
discover.WithUserAgent(lib.UserAgent()),
discover.WithProviders(providers),
)
if err != nil {
return nil, fmt.Errorf("Failed to create go-discover resolver: %w", err)
}
var addrs []string
for _, addr := range servers {
switch {
case strings.Contains(addr, "provider="):
resolved, err := disco.Addrs(addr, ac.logger.StandardLogger(&hclog.StandardLoggerOptions{InferLevels: true}))
if err != nil {
ac.logger.Error("failed to resolve go-discover auto-config servers", "configuration", addr, "err", err)
continue
}
addrs = append(addrs, resolved...)
ac.logger.Debug("discovered auto-config servers", "servers", resolved)
default:
addrs = append(addrs, addr)
}
}
return addrs, nil
}
// autoConfigHosts is responsible for taking the list of server addresses
// and resolving any go-discover provider invocations. It will then return
// a list of hosts. These might be hostnames and is expected that DNS resolution
// may be performed after this function runs. Additionally these may contain
// ports so SplitHostPort could also be necessary.
func (ac *AutoConfig) autoConfigHosts() ([]string, error) {
// use servers known to gossip if there are any
if ac.acConfig.ServerProvider != nil {
if srv := ac.acConfig.ServerProvider.FindLANServer(); srv != nil {
return []string{srv.Addr.String()}, nil
}
}
addrs, err := ac.discoverServers(ac.config.AutoConfig.ServerAddresses)
if err != nil {
return nil, err
}
if len(addrs) == 0 {
return nil, fmt.Errorf("no auto-config server addresses available for use")
}
return addrs, nil
}
// resolveHost will take a single host string and convert it to a list of TCPAddrs
// This will process any port in the input as well as looking up the hostname using
// normal DNS resolution.
func (ac *AutoConfig) resolveHost(hostPort string) []net.TCPAddr {
port := ac.config.ServerPort
host, portStr, err := net.SplitHostPort(hostPort)
if err != nil {
if strings.Contains(err.Error(), "missing port in address") {
host = hostPort
} else {
ac.logger.Warn("error splitting host address into IP and port", "address", hostPort, "error", err)
return nil
}
} else {
port, err = strconv.Atoi(portStr)
if err != nil {
ac.logger.Warn("Parsed port is not an integer", "port", portStr, "error", err)
return nil
}
}
// resolve the host to a list of IPs
ips, err := net.LookupIP(host)
if err != nil {
ac.logger.Warn("IP resolution failed", "host", host, "error", err)
return nil
}
var addrs []net.TCPAddr
for _, ip := range ips {
addrs = append(addrs, net.TCPAddr{IP: ip, Port: port})
}
return addrs
}
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