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- package discovery
- import (
- "fmt"
- "net"
- "strings"
- "time"
- "github.com/Sirupsen/logrus"
- )
- var (
- // Backends is a global map of discovery backends indexed by their
- // associated scheme.
- backends = make(map[string]Backend)
- )
- // Register makes a discovery backend available by the provided scheme.
- // If Register is called twice with the same scheme an error is returned.
- func Register(scheme string, d Backend) error {
- if _, exists := backends[scheme]; exists {
- return fmt.Errorf("scheme already registered %s", scheme)
- }
- logrus.WithField("name", scheme).Debugf("Registering discovery service")
- backends[scheme] = d
- return nil
- }
- func parse(rawurl string) (string, string) {
- parts := strings.SplitN(rawurl, "://", 2)
- // nodes:port,node2:port => nodes://node1:port,node2:port
- if len(parts) == 1 {
- return "nodes", parts[0]
- }
- return parts[0], parts[1]
- }
- // ParseAdvertise parses the --cluster-advertise daemon config which accepts
- // <ip-address>:<port> or <interface-name>:<port>
- func ParseAdvertise(advertise string) (string, error) {
- var (
- iface *net.Interface
- addrs []net.Addr
- err error
- )
- addr, port, err := net.SplitHostPort(advertise)
- if err != nil {
- return "", fmt.Errorf("invalid --cluster-advertise configuration: %s: %v", advertise, err)
- }
- ip := net.ParseIP(addr)
- // If it is a valid ip-address, use it as is
- if ip != nil {
- return advertise, nil
- }
- // If advertise is a valid interface name, get the valid IPv4 address and use it to advertise
- ifaceName := addr
- iface, err = net.InterfaceByName(ifaceName)
- if err != nil {
- return "", fmt.Errorf("invalid cluster advertise IP address or interface name (%s) : %v", advertise, err)
- }
- addrs, err = iface.Addrs()
- if err != nil {
- return "", fmt.Errorf("unable to get advertise IP address from interface (%s) : %v", advertise, err)
- }
- if len(addrs) == 0 {
- return "", fmt.Errorf("no available advertise IP address in interface (%s)", advertise)
- }
- addr = ""
- for _, a := range addrs {
- ip, _, err := net.ParseCIDR(a.String())
- if err != nil {
- return "", fmt.Errorf("error deriving advertise ip-address in interface (%s) : %v", advertise, err)
- }
- if ip.To4() == nil || ip.IsLoopback() {
- continue
- }
- addr = ip.String()
- break
- }
- if addr == "" {
- return "", fmt.Errorf("could not find a valid ip-address in interface %s", advertise)
- }
- addr = net.JoinHostPort(addr, port)
- return addr, nil
- }
- // New returns a new Discovery given a URL, heartbeat and ttl settings.
- // Returns an error if the URL scheme is not supported.
- func New(rawurl string, heartbeat time.Duration, ttl time.Duration, clusterOpts map[string]string) (Backend, error) {
- scheme, uri := parse(rawurl)
- if backend, exists := backends[scheme]; exists {
- logrus.WithFields(logrus.Fields{"name": scheme, "uri": uri}).Debugf("Initializing discovery service")
- err := backend.Initialize(uri, heartbeat, ttl, clusterOpts)
- return backend, err
- }
- return nil, ErrNotSupported
- }
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