[#324] morph/listener: Register handlers of new chain blocks

Extend Listener with RegisterBlockHandler method. All block handlers are
called on each block read from Subscriber.BlockNotifications channel.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
This commit is contained in:
Leonard Lyubich 2021-01-20 20:08:06 +03:00 committed by Alex Vanin
parent c65d1d9db9
commit 23c220ae28
3 changed files with 63 additions and 9 deletions

View file

@ -1,8 +1,15 @@
package event
import (
"github.com/nspcc-dev/neo-go/pkg/core/block"
)
// Handler is an Event processing function.
type Handler func(Event)
// BlockHandler is a chain block processing function.
type BlockHandler func(*block.Block)
// HandlerInfo is a structure that groups
// the parameters of the handler of particular
// contract event.

View file

@ -43,6 +43,13 @@ type Listener interface {
// Must stop the event listener.
Stop()
// Must register chain block handler.
//
// The specified handler must be called after each capture and parsing of the new block from chain.
//
// Must ignore nil handlers.
RegisterBlockHandler(BlockHandler)
}
// ListenerParams is a group of parameters
@ -67,6 +74,8 @@ type listener struct {
log *zap.Logger
subscriber subscriber.Subscriber
blockHandlers []BlockHandler
}
const newListenerFailMsg = "could not instantiate Listener"
@ -144,6 +153,13 @@ func (s listener) listen(ctx context.Context, intError chan<- error) error {
}
func (s listener) listenLoop(ctx context.Context, chEvent <-chan *state.NotificationEvent, intErr chan<- error) {
blockChan, err := s.subscriber.BlockNotifications()
if err != nil {
intErr <- errors.Wrap(err, "could not open block notifications channel")
return
}
loop:
for {
select {
@ -166,6 +182,23 @@ loop:
}
s.parseAndHandle(notifyEvent)
case b, ok := <-blockChan:
if !ok {
s.log.Warn("stop event listener by block channel")
if intErr != nil {
intErr <- errors.New("new block notification channel is closed")
}
break loop
} else if b == nil {
s.log.Warn("nil block was caught")
continue loop
}
// TODO: consider asynchronous execution
for i := range s.blockHandlers {
s.blockHandlers[i](b)
}
}
}
}
@ -313,6 +346,15 @@ func (s listener) Stop() {
s.subscriber.Close()
}
func (s *listener) RegisterBlockHandler(handler BlockHandler) {
if handler == nil {
s.log.Warn("ignore nil block handler")
return
}
s.blockHandlers = append(s.blockHandlers, handler)
}
// NewListener create the notification event listener instance and returns Listener interface.
func NewListener(p ListenerParams) (Listener, error) {
switch {

View file

@ -2,7 +2,6 @@ package subscriber
import (
"context"
"errors"
"sync"
"time"
@ -11,6 +10,7 @@ import (
"github.com/nspcc-dev/neo-go/pkg/rpc/client"
"github.com/nspcc-dev/neo-go/pkg/rpc/response"
"github.com/nspcc-dev/neo-go/pkg/util"
"github.com/pkg/errors"
"go.uber.org/zap"
)
@ -20,7 +20,7 @@ type (
SubscribeForNotification(...util.Uint160) (<-chan *state.NotificationEvent, error)
UnsubscribeForNotification()
Close()
BlockNotifications() <-chan *block.Block
BlockNotifications() (<-chan *block.Block, error)
}
subscriber struct {
@ -103,8 +103,18 @@ func (s *subscriber) Close() {
s.client.Close()
}
func (s *subscriber) BlockNotifications() <-chan *block.Block {
return s.blockChan
func (s *subscriber) BlockNotifications() (<-chan *block.Block, error) {
if err := s.client.Init(); err != nil {
return nil, errors.Wrap(err, "could not init ws client")
}
if _, err := s.client.SubscribeForNewBlocks(nil); err != nil {
return nil, errors.Wrap(err, "could not subscribe for new block events")
}
s.blockChan = make(chan *block.Block)
return s.blockChan, nil
}
func (s *subscriber) routeNotifications(ctx context.Context) {
@ -163,17 +173,12 @@ func New(ctx context.Context, p *Params) (Subscriber, error) {
return nil, err
}
if _, err := wsClient.SubscribeForNewBlocks(nil); err != nil {
return nil, err
}
sub := &subscriber{
RWMutex: new(sync.RWMutex),
log: p.Log,
client: wsClient,
notify: make(chan *state.NotificationEvent),
notifyIDs: make(map[util.Uint160]string),
blockChan: make(chan *block.Block),
}
// Worker listens all events from neo-go websocket and puts them