docs/discovery/token/token.go

137 lines
2.8 KiB
Go

package token
import (
"encoding/json"
"errors"
"fmt"
"io/ioutil"
"net/http"
"strings"
"time"
"github.com/docker/swarm/discovery"
)
// DiscoveryUrl is exported
const DiscoveryURL = "https://discovery-stage.hub.docker.com/v1"
// Discovery is exported
type Discovery struct {
heartbeat time.Duration
url string
token string
}
func init() {
discovery.Register("token", &Discovery{})
}
// Initialize is exported
func (s *Discovery) Initialize(urltoken string, heartbeat time.Duration) error {
if i := strings.LastIndex(urltoken, "/"); i != -1 {
s.url = "https://" + urltoken[:i]
s.token = urltoken[i+1:]
} else {
s.url = DiscoveryURL
s.token = urltoken
}
if s.token == "" {
return errors.New("token is empty")
}
s.heartbeat = heartbeat
return nil
}
// Fetch returns the list of entries for the discovery service at the specified endpoint
func (s *Discovery) fetch() (discovery.Entries, error) {
resp, err := http.Get(fmt.Sprintf("%s/%s/%s", s.url, "clusters", s.token))
if err != nil {
return nil, err
}
defer resp.Body.Close()
var addrs []string
if resp.StatusCode == http.StatusOK {
if err := json.NewDecoder(resp.Body).Decode(&addrs); err != nil {
return nil, fmt.Errorf("Failed to decode response: %v", err)
}
} else {
return nil, fmt.Errorf("Failed to fetch entries, Discovery service returned %d HTTP status code", resp.StatusCode)
}
return discovery.CreateEntries(addrs)
}
// Watch is exported
func (s *Discovery) Watch(stopCh <-chan struct{}) (<-chan discovery.Entries, <-chan error) {
ch := make(chan discovery.Entries)
ticker := time.NewTicker(s.heartbeat)
errCh := make(chan error)
go func() {
defer close(ch)
defer close(errCh)
// Send the initial entries if available.
currentEntries, err := s.fetch()
if err != nil {
errCh <- err
} else {
ch <- currentEntries
}
// Periodically send updates.
for {
select {
case <-ticker.C:
newEntries, err := s.fetch()
if err != nil {
errCh <- err
continue
}
// Check if the file has really changed.
if !newEntries.Equals(currentEntries) {
ch <- newEntries
}
currentEntries = newEntries
case <-stopCh:
ticker.Stop()
return
}
}
}()
return ch, nil
}
// Register adds a new entry identified by the into the discovery service
func (s *Discovery) Register(addr string) error {
buf := strings.NewReader(addr)
resp, err := http.Post(fmt.Sprintf("%s/%s/%s", s.url,
"clusters", s.token), "application/json", buf)
if err != nil {
return err
}
resp.Body.Close()
return nil
}
// CreateCluster returns a unique cluster token
func (s *Discovery) CreateCluster() (string, error) {
resp, err := http.Post(fmt.Sprintf("%s/%s", s.url, "clusters"), "", nil)
if err != nil {
return "", err
}
defer resp.Body.Close()
token, err := ioutil.ReadAll(resp.Body)
return string(token), err
}