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events.go
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events.go
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/*
Copyright IBM Corp. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package producer
import (
"fmt"
"sync"
"time"
pb "github.com/mcc-github/blockchain/protos/peer"
"github.com/pkg/errors"
)
type handlerList struct {
sync.Mutex
handlers Set
}
type Set map[*handler]struct{}
func (hl *handlerList) add(h *handler) (bool, error) {
if h == nil {
return false, fmt.Errorf("cannot add nil handler")
}
hl.Lock()
defer hl.Unlock()
handlers := hl.copyHandlers()
if _, ok := handlers[h]; ok {
logger.Warningf("handler already exists for event type")
return true, nil
}
handlers[h] = struct{}{}
hl.handlers = handlers
return true, nil
}
func (hl *handlerList) remove(h *handler) (bool, error) {
hl.Lock()
defer hl.Unlock()
handlers := hl.copyHandlers()
if _, ok := handlers[h]; !ok {
logger.Warningf("handler does not exist for event type")
return true, nil
}
delete(handlers, h)
hl.handlers = handlers
return true, nil
}
func (hl *handlerList) copyHandlers() Set {
handlerCopy := Set{}
for k, v := range hl.handlers {
handlerCopy[k] = v
}
return handlerCopy
}
func (hl *handlerList) getHandlers() Set {
hl.Lock()
defer hl.Unlock()
return hl.handlers
}
type eventProcessor struct {
sync.RWMutex
eventConsumers map[pb.EventType]*handlerList
eventChannel chan *pb.Event
*EventsServerConfig
}
var gEventProcessor *eventProcessor
func (ep *eventProcessor) start() {
defer ep.cleanup()
logger.Info("Event processor started")
for e := range ep.eventChannel {
hl, err := ep.getHandlerList(e)
if err != nil {
logger.Error(err.Error())
continue
}
failedHandlers := []*handler{}
for h := range hl.getHandlers() {
if h.hasSessionExpired() {
failedHandlers = append(failedHandlers, h)
continue
}
if e.Event != nil {
err := h.SendMessageWithTimeout(e, ep.SendTimeout)
if err != nil {
failedHandlers = append(failedHandlers, h)
}
}
}
for _, h := range failedHandlers {
ep.cleanupHandler(h)
}
}
}
func (ep *eventProcessor) getHandlerList(e *pb.Event) (*handlerList, error) {
eType := getMessageType(e)
ep.Lock()
defer ep.Unlock()
hl := ep.eventConsumers[eType]
if hl == nil {
return nil, errors.Errorf("event type %T not supported", e.Event)
}
return hl, nil
}
func (ep *eventProcessor) cleanupHandler(h *handler) {
ep.deregisterAll(h)
logger.Debug("handler cleanup complete for", h.RemoteAddr)
}
func getMessageType(e *pb.Event) pb.EventType {
switch e.Event.(type) {
case *pb.Event_Block:
return pb.EventType_BLOCK
case *pb.Event_FilteredBlock:
return pb.EventType_FILTEREDBLOCK
default:
return -1
}
}
func initializeEvents(config *EventsServerConfig) *eventProcessor {
if gEventProcessor != nil {
panic("should not be called twice")
}
gEventProcessor = &eventProcessor{
eventConsumers: map[pb.EventType]*handlerList{},
eventChannel: make(chan *pb.Event, config.BufferSize),
EventsServerConfig: config,
}
gEventProcessor.addSupportedEventTypes()
go gEventProcessor.start()
return gEventProcessor
}
func (ep *eventProcessor) cleanup() {
close(ep.eventChannel)
}
func (ep *eventProcessor) addSupportedEventTypes() {
ep.addEventType(pb.EventType_BLOCK)
ep.addEventType(pb.EventType_FILTEREDBLOCK)
}
func (ep *eventProcessor) addEventType(eventType pb.EventType) error {
ep.Lock()
defer ep.Unlock()
logger.Debugf("Registering %s", pb.EventType_name[int32(eventType)])
if _, ok := ep.eventConsumers[eventType]; ok {
return fmt.Errorf("event type %s already exists", pb.EventType_name[int32(eventType)])
}
switch eventType {
case pb.EventType_BLOCK, pb.EventType_FILTEREDBLOCK:
ep.eventConsumers[eventType] = &handlerList{handlers: Set{}}
default:
return fmt.Errorf("event type %T not supported", eventType)
}
return nil
}
func (ep *eventProcessor) registerHandler(ie *pb.Interest, h *handler) error {
logger.Debugf("Registering event type: %s", ie.EventType)
ep.Lock()
defer ep.Unlock()
if hl, ok := ep.eventConsumers[ie.EventType]; !ok {
return fmt.Errorf("event type %s does not exist", ie.EventType)
} else if _, err := hl.add(h); err != nil {
return fmt.Errorf("error registering handler for %s: %s", ie.EventType, err)
}
return nil
}
func (ep *eventProcessor) deregisterHandler(ie *pb.Interest, h *handler) error {
logger.Debugf("Deregistering event type %s", ie.EventType)
ep.Lock()
defer ep.Unlock()
if hl, ok := ep.eventConsumers[ie.EventType]; !ok {
return fmt.Errorf("event type %s does not exist", ie.EventType)
} else if _, err := hl.remove(h); err != nil {
return fmt.Errorf("error deregistering handler for %s: %s", ie.EventType, err)
}
return nil
}
func (ep *eventProcessor) deregisterAll(h *handler) {
for _, v := range h.interestedEvents {
if err := ep.deregisterHandler(v, h); err != nil {
logger.Errorf("failed deregistering event type %s for %s", v, h.RemoteAddr)
continue
}
}
}
func Send(e *pb.Event) error {
if e.Event == nil {
logger.Error("Event not set")
return fmt.Errorf("event not set")
}
if gEventProcessor == nil {
logger.Debugf("Event processor is nil")
return nil
}
switch {
case gEventProcessor.Timeout < 0:
select {
case gEventProcessor.eventChannel <- e:
default:
return fmt.Errorf("could not add block event to event processor queue")
}
case gEventProcessor.Timeout == 0:
gEventProcessor.eventChannel <- e
default:
select {
case gEventProcessor.eventChannel <- e:
case <-time.After(gEventProcessor.Timeout):
return fmt.Errorf("could not add block event to event processor queue")
}
}
logger.Debugf("Event added to event processor queue")
return nil
}