2019-06-12 01:59:25 +03:00
|
|
|
package router
|
|
|
|
|
|
|
|
import (
|
|
|
|
"errors"
|
|
|
|
)
|
|
|
|
|
|
|
|
var (
|
|
|
|
// ErrWatcherStopped is returned when routing table watcher has been stopped
|
|
|
|
ErrWatcherStopped = errors.New("routing table watcher stopped")
|
|
|
|
)
|
|
|
|
|
|
|
|
// Watcher is an interface that returns updates to the routing table
|
|
|
|
type Watcher interface {
|
|
|
|
// Next is a blocking call that returns watch result
|
|
|
|
Next() (*Result, error)
|
|
|
|
// Stop stops watcher
|
|
|
|
Stop()
|
|
|
|
}
|
|
|
|
|
|
|
|
// Result is returned by a call to Next on the watcher.
|
|
|
|
type Result struct {
|
|
|
|
// Action is routing table action which is either of add, remove or update
|
|
|
|
Action string
|
|
|
|
// Route is table rout
|
|
|
|
Route Route
|
|
|
|
}
|
|
|
|
|
|
|
|
// Watcher options
|
|
|
|
type WatchOptions struct {
|
|
|
|
// Specify destination address to watch
|
|
|
|
DestAddr string
|
|
|
|
// Specify network to watch
|
|
|
|
Network string
|
|
|
|
}
|
|
|
|
|
|
|
|
// WatchDestAddr sets what destination to watch
|
|
|
|
// Destination is usually microservice name
|
|
|
|
func WatchDestAddr(a string) WatchOption {
|
|
|
|
return func(o *WatchOptions) {
|
|
|
|
o.DestAddr = a
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// WatchNetwork sets what network to watch
|
|
|
|
func WatchNetwork(n string) WatchOption {
|
|
|
|
return func(o *WatchOptions) {
|
|
|
|
o.Network = n
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
type tableWatcher struct {
|
|
|
|
opts WatchOptions
|
|
|
|
resChan chan *Result
|
|
|
|
done chan struct{}
|
|
|
|
}
|
|
|
|
|
2019-06-13 00:30:42 +03:00
|
|
|
// TODO: this needs to be thought through properly
|
2019-06-12 01:59:25 +03:00
|
|
|
// Next returns the next noticed action taken on table
|
|
|
|
func (w *tableWatcher) Next() (*Result, error) {
|
|
|
|
for {
|
|
|
|
select {
|
|
|
|
case res := <-w.resChan:
|
|
|
|
switch w.opts.DestAddr {
|
2019-06-13 00:30:42 +03:00
|
|
|
case "*", "":
|
2019-06-12 01:59:25 +03:00
|
|
|
if w.opts.Network == "*" || w.opts.Network == res.Route.Options().Network {
|
|
|
|
return res, nil
|
|
|
|
}
|
|
|
|
case res.Route.Options().DestAddr:
|
|
|
|
if w.opts.Network == "*" || w.opts.Network == res.Route.Options().Network {
|
|
|
|
return res, nil
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// ignore if no match is found
|
|
|
|
continue
|
|
|
|
case <-w.done:
|
|
|
|
return nil, ErrWatcherStopped
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Stop stops routing table watcher
|
|
|
|
func (w *tableWatcher) Stop() {
|
|
|
|
select {
|
|
|
|
case <-w.done:
|
|
|
|
return
|
|
|
|
default:
|
|
|
|
close(w.done)
|
|
|
|
}
|
|
|
|
}
|