// Entries are Docker Engines
func (c *Cluster) monitorDiscovery(ch <-chan discovery.Entries, errCh <-chan error) {
// Watch changes on the discovery channel.
currentEntries := discovery.Entries{}
for {
select {
case entries := <-ch:
added, removed := currentEntries.Diff(entries)
currentEntries = entries
// Remove engines first. `addEngine` will refuse to add an engine
// if there's already an engine with the same ID. If an engine
// changes address, we have to first remove it then add it back.
for _, entry := range removed {
c.removeEngine(entry.String())
}
// Since `addEngine` can be very slow (it has to connect to the
// engine), we are going to do the adds in parallel.
for _, entry := range added {
go c.addEngine(entry.String())
}
case err := <-errCh:
log.Errorf("Discovery error: %v", err)
}
}
}
func TestWatch(t *testing.T) {
d := &Discovery{}
d.Initialize("1.1.1.1:1111,2.2.2.2:2222", 0, 0)
expected := discovery.Entries{
&discovery.Entry{Host: "1.1.1.1", Port: "1111"},
&discovery.Entry{Host: "2.2.2.2", Port: "2222"},
}
ch, _ := d.Watch(nil)
assert.True(t, expected.Equals(<-ch))
}
// Create a new endpoint
func newDiscoveryEndpoint(url, localAddr string, discPort string, weaveCli *WeaveClient, heartbeat time.Duration, ttl time.Duration) (*discoveryEndpoint, error) {
d, err := discovery.New(url, heartbeat, ttl)
if err != nil {
return nil, err
}
stopChan := make(chan struct{})
ep := discoveryEndpoint{
Discovery: d,
url: url,
stopChan: stopChan,
}
register := func() {}
var localAddrHost, localAddrPort string
if len(localAddr) > 0 {
localAddrHost, localAddrPort, err = net.SplitHostPort(localAddr)
if err != nil {
Log.Warningf("[manager] Invalid local address '%s': %s", localAddr, err)
return nil, err
}
register = func() {
Log.Debugf("[manager] Registering on '%s' we are at '%s' (%s period)...", url, localAddr, heartbeat)
if err := d.Register(localAddr); err != nil {
Log.Warningf("[manager] Registration failed: %s", err)
} else {
ep.lastRegister = time.Now()
}
}
}
hostAndPort := func(e *discovery.Entry) (string, string, bool) {
host := e.Host
port := e.Port
if len(discPort) > 0 {
port = discPort
}
return host, port, (host == localAddrHost && port == localAddrPort)
}
entriesChan, errorsChan := d.Watch(stopChan)
ticker := time.NewTicker(heartbeat)
go func() {
register()
currentEntries := discovery.Entries{}
for {
select {
case reportedEntries := <-entriesChan:
added, removed := currentEntries.Diff(reportedEntries)
ep.added += uint64(len(added))
ep.removed += uint64(len(removed))
currentEntries = reportedEntries
Log.Printf("[manager] Updates from '%s': %d added, %d removed...", url, len(added), len(removed))
for _, e := range added {
if host, port, isLocal := hostAndPort(e); !isLocal {
weaveCli.Join(host, port)
}
}
for _, e := range removed {
if host, port, isLocal := hostAndPort(e); !isLocal {
weaveCli.Forget(host, port)
}
}
case reportedError := <-errorsChan:
Log.Warningf("[manager] Error from endpoint %s: %s...", url, reportedError)
case <-ticker.C:
register()
case <-stopChan:
ticker.Stop()
return
}
}
}()
return &ep, nil
}