pkg/srv/srv.go
func GetCluster(serviceScheme, service, name, dns string, apurls types.URLs) ([]string, error) {
	tempName := int(0)
	tcp2ap := make(map[string]url.URL)

	// First, resolve the apurls
	for _, url := range apurls {
		tcpAddr, err := resolveTCPAddr("tcp", url.Host)
		if err != nil {
			return nil, err
		}
		tcp2ap[tcpAddr.String()] = url
	}

	stringParts := []string{}
	updateNodeMap := func(service, scheme string) error {
		_, addrs, err := lookupSRV(service, "tcp", dns)
		if err != nil {
			return err
		}
		for _, srv := range addrs {
			port := fmt.Sprintf("%d", srv.Port)
			host := net.JoinHostPort(srv.Target, port)
			tcpAddr, terr := resolveTCPAddr("tcp", host)
			if terr != nil {
				err = terr
				continue
			}
			n := ""
			url, ok := tcp2ap[tcpAddr.String()]
			if ok {
				n = name
			}
			if n == "" {
				n = fmt.Sprintf("%d", tempName)
				tempName++
			}
			// SRV records have a trailing dot but URL shouldn't.
			shortHost := strings.TrimSuffix(srv.Target, ".")
			urlHost := net.JoinHostPort(shortHost, port)
			if ok && url.Scheme != scheme {
				err = fmt.Errorf("bootstrap at %s from DNS for %s has scheme mismatch with expected peer %s", scheme+"://"+urlHost, service, url.String())
			} else {
				stringParts = append(stringParts, fmt.Sprintf("%s=%s://%s", n, scheme, urlHost))
			}
		}
		if len(stringParts) == 0 {
			return err
		}
		return nil
	}

	err := updateNodeMap(service, serviceScheme)
	if err != nil {
		return nil, fmt.Errorf("error querying DNS SRV records for _%s %s", service, err)
	}
	return stringParts, nil
}
func GetCluster(serviceScheme, service, name, dns string, apurls types.URLs) ([]string, error) {
	tempName := int(0)
	tcp2ap := make(map[string]url.URL)

	// First, resolve the apurls
	for _, url := range apurls {
		tcpAddr, err := resolveTCPAddr("tcp", url.Host)
		if err != nil {
			return nil, err
		}
		tcp2ap[tcpAddr.String()] = url
	}

	stringParts := []string{}
	updateNodeMap := func(service, scheme string) error {
		_, addrs, err := lookupSRV(service, "tcp", dns)
		if err != nil {
			return err
		}
		for _, srv := range addrs {
			port := fmt.Sprintf("%d", srv.Port)
			host := net.JoinHostPort(srv.Target, port)
			tcpAddr, terr := resolveTCPAddr("tcp", host)
			if terr != nil {
				err = terr
				continue
			}
			n := ""
			url, ok := tcp2ap[tcpAddr.String()]
			if ok {
				n = name
			}
			if n == "" {
				n = fmt.Sprintf("%d", tempName)
				tempName++
			}
			// SRV records have a trailing dot but URL shouldn't.
			shortHost := strings.TrimSuffix(srv.Target, ".")
			urlHost := net.JoinHostPort(shortHost, port)
			if ok && url.Scheme != scheme {
				err = fmt.Errorf("bootstrap at %s from DNS for %s has scheme mismatch with expected peer %s", scheme+"://"+urlHost, service, url.String())
			} else {
				stringParts = append(stringParts, fmt.Sprintf("%s=%s://%s", n, scheme, urlHost))
			}
		}
		if len(stringParts) == 0 {
			return err
		}
		return nil
	}

	err := updateNodeMap(service, serviceScheme)
	if err != nil {
		return nil, fmt.Errorf("error querying DNS SRV records for _%s %s", service, err)
	}
	return stringParts, nil
}
func GetCluster ( serviceScheme , service , name , dns string , apurls types . URLs ) ( [ ] string , error ) { tempName := int ( 0 ) tcp2ap := make ( map [ string ] url . URL ) // First, resolve the apurls for _ , url := range apurls { tcpAddr , err := resolveTCPAddr ( " " , url . Host ) if err != nil { return nil , err } tcp2ap [ tcpAddr . String ( ) ] = url } stringParts := [ ] string { } updateNodeMap := func ( service , scheme string ) error { _ , addrs , err := lookupSRV ( service , " " , dns ) if err != nil { return err } for _ , srv := range addrs { port := fmt . Sprintf ( " " , srv . Port ) host := net . JoinHostPort ( srv . Target , port ) tcpAddr , terr := resolveTCPAddr ( " " , host ) if terr != nil { err = terr continue } n := " " url , ok := tcp2ap [ tcpAddr . String ( ) ] if ok { n = name } if n == " " { n = fmt . Sprintf ( " " , tempName ) tempName ++ } // SRV records have a trailing dot but URL shouldn't. shortHost := strings . TrimSuffix ( srv . Target , " " ) urlHost := net . JoinHostPort ( shortHost , port ) if ok && url . Scheme != scheme { err = fmt . Errorf ( " " , scheme + " " + urlHost , service , url . String ( ) ) } else { stringParts = append ( stringParts , fmt . Sprintf ( " " , n , scheme , urlHost ) ) } } if len ( stringParts ) == 0 { return err } return nil } err := updateNodeMap ( service , serviceScheme ) if err != nil { return nil , fmt . Errorf ( " " , service , err ) } return stringParts , nil }
// GetCluster gets the cluster information via DNS discovery.
// Also sees each entry as a separate instance.
GetCluster gets the cluster information via DNS discovery . Also sees each entry as a separate instance .