docs/discovery/discovery.go

107 lines
2.2 KiB
Go

package discovery
import (
"errors"
"fmt"
"net"
"strings"
log "github.com/Sirupsen/logrus"
)
// Entry is exported
type Entry struct {
Host string
Port string
}
// NewEntry is exported
func NewEntry(url string) (*Entry, error) {
host, port, err := net.SplitHostPort(url)
if err != nil {
return nil, err
}
return &Entry{host, port}, nil
}
func (m Entry) String() string {
return fmt.Sprintf("%s:%s", m.Host, m.Port)
}
// WatchCallback is exported
type WatchCallback func(entries []*Entry)
// Discovery is exported
type Discovery interface {
Initialize(string, uint64) error
Fetch() ([]*Entry, error)
Watch(WatchCallback)
Register(string) error
}
var (
discoveries map[string]Discovery
// ErrNotSupported is exported
ErrNotSupported = errors.New("discovery service not supported")
// ErrNotImplemented is exported
ErrNotImplemented = errors.New("not implemented in this discovery service")
)
func init() {
discoveries = make(map[string]Discovery)
}
// Register is exported
func Register(scheme string, d Discovery) error {
if _, exists := discoveries[scheme]; exists {
return fmt.Errorf("scheme already registered %s", scheme)
}
log.WithField("name", scheme).Debug("Registering discovery service")
discoveries[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]
}
// New is exported
func New(rawurl string, heartbeat uint64) (Discovery, error) {
scheme, uri := parse(rawurl)
if discovery, exists := discoveries[scheme]; exists {
log.WithFields(log.Fields{"name": scheme, "uri": uri}).Debug("Initializing discovery service")
err := discovery.Initialize(uri, heartbeat)
return discovery, err
}
return nil, ErrNotSupported
}
// CreateEntries is exported
func CreateEntries(addrs []string) ([]*Entry, error) {
entries := []*Entry{}
if addrs == nil {
return entries, nil
}
for _, addr := range addrs {
if len(addr) == 0 {
continue
}
entry, err := NewEntry(addr)
if err != nil {
return nil, err
}
entries = append(entries, entry)
}
return entries, nil
}