edge/pkg/bus/memory/event_dispatcher.go
William Petit 17808d14c9
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fix: prevent bus congestion by flushing out messages
2023-04-26 15:53:23 +02:00

167 lines
2.6 KiB
Go

package memory
import (
"context"
"sync"
"time"
"forge.cadoles.com/arcad/edge/pkg/bus"
"github.com/pkg/errors"
"gitlab.com/wpetit/goweb/logger"
)
type eventDispatcherSet struct {
mutex sync.Mutex
items map[*eventDispatcher]struct{}
}
func (s *eventDispatcherSet) Add(d *eventDispatcher) {
s.mutex.Lock()
defer s.mutex.Unlock()
s.items[d] = struct{}{}
}
func (s *eventDispatcherSet) Remove(d *eventDispatcher) {
s.mutex.Lock()
defer s.mutex.Unlock()
d.close()
delete(s.items, d)
}
func (s *eventDispatcherSet) RemoveByOutChannel(out <-chan bus.Message) {
s.mutex.Lock()
defer s.mutex.Unlock()
for d := range s.items {
if d.IsOut(out) {
d.close()
delete(s.items, d)
}
}
}
func (s *eventDispatcherSet) List() []*eventDispatcher {
s.mutex.Lock()
defer s.mutex.Unlock()
dispatchers := make([]*eventDispatcher, 0, len(s.items))
for d := range s.items {
dispatchers = append(dispatchers, d)
}
return dispatchers
}
func newEventDispatcherSet() *eventDispatcherSet {
return &eventDispatcherSet{
items: make(map[*eventDispatcher]struct{}),
}
}
type eventDispatcher struct {
in chan bus.Message
out chan bus.Message
mutex sync.RWMutex
closed bool
}
func (d *eventDispatcher) Closed() bool {
d.mutex.RLock()
defer d.mutex.RUnlock()
return d.closed
}
func (d *eventDispatcher) Close() {
d.mutex.Lock()
defer d.mutex.Unlock()
d.close()
}
func (d *eventDispatcher) close() {
d.closed = true
close(d.in)
}
func (d *eventDispatcher) In(msg bus.Message) (err error) {
d.mutex.RLock()
defer d.mutex.RUnlock()
if d.closed {
return
}
d.in <- msg
return nil
}
func (d *eventDispatcher) Out() <-chan bus.Message {
return d.out
}
func (d *eventDispatcher) IsOut(out <-chan bus.Message) bool {
return d.out == out
}
func (d *eventDispatcher) Run(ctx context.Context) {
defer func() {
for {
logger.Debug(ctx, "closing dispatcher, flushing out incoming messages")
close(d.out)
// Flush all incoming messages
for {
_, ok := <-d.in
if !ok {
return
}
}
}
}()
for {
msg, ok := <-d.in
if !ok {
return
}
timeout := time.After(time.Second)
select {
case d.out <- msg:
case <-timeout:
logger.Error(
ctx,
"out message channel timeout",
logger.F("message", msg),
)
return
case <-ctx.Done():
logger.Error(
ctx,
"message subscription context canceled",
logger.F("message", msg),
logger.E(errors.WithStack(ctx.Err())),
)
return
}
}
}
func newEventDispatcher(bufferSize int64) *eventDispatcher {
return &eventDispatcher{
in: make(chan bus.Message, bufferSize),
out: make(chan bus.Message, bufferSize),
closed: false,
}
}