EventPublisher: docstrings and getTopicBuffer
also rename commitCh -> publishCh
This commit is contained in:
parent
2020e9c7c7
commit
f626c3d6c5
|
@ -28,7 +28,7 @@ type EventPublisher struct {
|
|||
// not that expensive, but having a cache for a few seconds can help
|
||||
// de-duplicate building the same snapshot over and over again when a
|
||||
// thundering herd of watchers all subscribe to the same topic within a few
|
||||
// seconds. TODO
|
||||
// seconds.
|
||||
snapCacheTTL time.Duration
|
||||
|
||||
// This lock protects the topicBuffers, snapCache and subsByToken maps.
|
||||
|
@ -38,8 +38,8 @@ type EventPublisher struct {
|
|||
// for a topic.
|
||||
topicBuffers map[stream.Topic]*stream.EventBuffer
|
||||
|
||||
// snapCache stores the head of any snapshot buffers still in cache if caching
|
||||
// is enabled.
|
||||
// snapCache if a cache of EventSnapshots indexed by topic and key.
|
||||
// TODO: new struct for snapCache and snapFns and snapCacheTTL
|
||||
snapCache map[stream.Topic]map[string]*stream.EventSnapshot
|
||||
|
||||
// snapFns is the set of snapshot functions that were registered bound to the
|
||||
|
@ -51,9 +51,10 @@ type EventPublisher struct {
|
|||
// ACL permissions change.
|
||||
subsByToken map[string]map[*stream.SubscribeRequest]*stream.Subscription
|
||||
|
||||
// commitCh decouples the Commit call in the FSM hot path from distributing
|
||||
// the resulting events.
|
||||
commitCh chan commitUpdate
|
||||
// publishCh is used to send messages from an active txn to a goroutine which
|
||||
// publishes events, so that publishing can happen asynchronously from
|
||||
// the Commit call in the FSM hot path.
|
||||
publishCh chan commitUpdate
|
||||
}
|
||||
|
||||
type commitUpdate struct {
|
||||
|
@ -70,7 +71,7 @@ func NewEventPublisher(store *Store, topicBufferSize int, snapCacheTTL time.Dura
|
|||
snapCache: make(map[stream.Topic]map[string]*stream.EventSnapshot),
|
||||
snapFns: make(map[stream.Topic]stream.SnapFn),
|
||||
subsByToken: make(map[string]map[*stream.SubscribeRequest]*stream.Subscription),
|
||||
commitCh: make(chan commitUpdate, 64),
|
||||
publishCh: make(chan commitUpdate, 64),
|
||||
}
|
||||
|
||||
// create a local handler table
|
||||
|
@ -98,7 +99,7 @@ func (e *EventPublisher) publishChanges(tx *txn, changes memdb.Changes) error {
|
|||
events = append(events, es...)
|
||||
}
|
||||
}
|
||||
e.commitCh <- commitUpdate{
|
||||
e.publishCh <- commitUpdate{
|
||||
// TODO: document why it must be created here, and not in the new thread
|
||||
//
|
||||
// Create a new transaction since it's going to be used from a different
|
||||
|
@ -113,7 +114,7 @@ func (e *EventPublisher) publishChanges(tx *txn, changes memdb.Changes) error {
|
|||
|
||||
func (e *EventPublisher) handleUpdates() {
|
||||
for {
|
||||
update := <-e.commitCh
|
||||
update := <-e.publishCh
|
||||
e.sendEvents(update)
|
||||
}
|
||||
}
|
||||
|
@ -158,17 +159,24 @@ func (e *EventPublisher) sendEvents(update commitUpdate) {
|
|||
eventsByTopic[event.Topic] = append(eventsByTopic[event.Topic], event)
|
||||
}
|
||||
|
||||
// Deliver events
|
||||
for topic, events := range eventsByTopic {
|
||||
buf, ok := e.topicBuffers[topic]
|
||||
if !ok {
|
||||
buf = stream.NewEventBuffer()
|
||||
e.topicBuffers[topic] = buf
|
||||
}
|
||||
buf.Append(events)
|
||||
e.getTopicBuffer(topic).Append(events)
|
||||
}
|
||||
}
|
||||
|
||||
// getTopicBuffer for the topic. Creates a new event buffer if one does not
|
||||
// already exist.
|
||||
//
|
||||
// EventPublisher.lock must be held to call this method.
|
||||
func (e *EventPublisher) getTopicBuffer(topic stream.Topic) *stream.EventBuffer {
|
||||
buf, ok := e.topicBuffers[topic]
|
||||
if !ok {
|
||||
buf = stream.NewEventBuffer()
|
||||
e.topicBuffers[topic] = buf
|
||||
}
|
||||
return buf
|
||||
}
|
||||
|
||||
// handleACLUpdate handles an ACL token/policy/role update. This method assumes
|
||||
// the lock is held.
|
||||
func (e *EventPublisher) handleACLUpdate(tx *txn, event stream.Event) error {
|
||||
|
@ -250,11 +258,7 @@ func (e *EventPublisher) Subscribe(
|
|||
|
||||
// Ensure there is a topic buffer for that topic so we start capturing any
|
||||
// future published events.
|
||||
buf, ok := e.topicBuffers[req.Topic]
|
||||
if !ok {
|
||||
buf = stream.NewEventBuffer()
|
||||
e.topicBuffers[req.Topic] = buf
|
||||
}
|
||||
buf := e.getTopicBuffer(req.Topic)
|
||||
|
||||
// See if we need a snapshot
|
||||
topicHead := buf.Head()
|
||||
|
|
Loading…
Reference in New Issue