// 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())
}
for _, entry := range added {
c.addEngine(entry.String())
}
case err := <-errCh:
log.Errorf("Discovery error: %v", err)
}
}
}
