adjust buffering to improve stability; begin documentation; fix notifier

err handling

Author: i-norden

core/blockchain_test.go

@@ -2227,8 +2227,8 @@ func BenchmarkBlockChain_1x1000ValueTransferToExisting(b *testing.B) {
 
 func BenchmarkBlockChain_1x1000Executions(b *testing.B) {
 	var (
-		numTxs= 1000
-		numBlocks= 1
+		numTxs    = 1000
+		numBlocks = 1
 	)
 	b.StopTimer()
 	b.ResetTimer()

statediff/api.go

@@ -56,23 +56,30 @@ func (api *PublicStateDiffAPI) Stream(ctx context.Context) (*rpc.Subscription, e
 
 	go func() {
 		// subscribe to events from the state diff service
-		payloadChannel := make(chan Payload, 10)
-		quitChan := make(chan bool)
+		payloadChannel := make(chan Payload, chainEventChanSize)
+		quitChan := make(chan bool, 1)
 		api.sds.Subscribe(rpcSub.ID, payloadChannel, quitChan)
 		// loop and await state diff payloads and relay them to the subscriber with the notifier
 		for {
 			select {
 			case packet := <-payloadChannel:
-				if err := notifier.Notify(rpcSub.ID, packet); err != nil {
-					log.Error("Failed to send state diff packet", "err", err)
+				if notifyErr := notifier.Notify(rpcSub.ID, packet); notifyErr != nil {
+					log.Error("Failed to send state diff packet; error: " + notifyErr.Error())
+					unSubErr := api.sds.Unsubscribe(rpcSub.ID)
+					if unSubErr != nil {
+						log.Error("Failed to unsubscribe from the state diff service; error: " + unSubErr.Error())
+					}
+					return
 				}
 			case err := <-rpcSub.Err():
-				log.Error("State diff service rpcSub error", err)
-				err = api.sds.Unsubscribe(rpcSub.ID)
 				if err != nil {
-					log.Error("Failed to unsubscribe from the state diff service", err)
+					log.Error("State diff service rpcSub error: " + err.Error())
+					err = api.sds.Unsubscribe(rpcSub.ID)
+					if err != nil {
+						log.Error("Failed to unsubscribe from the state diff service; error: " + err.Error())
+					}
+					return
 				}
-				return
 			case <-quitChan:
 				// don't need to unsubscribe, statediff service does so before sending the quit signal
 				return

statediff/doc.go

@@ -0,0 +1,40 @@
+// Copyright 2019 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+/*
+This work is adapted from work by Charles Crain at https://github.com/jpmorganchase/quorum/blob/9b7fd9af8082795eeeb6863d9746f12b82dd5078/statediff/statediff.go
+
+Package statediff provides an auxiliary service that processes state diff objects from incoming chain events,
+relaying the objects to any rpc subscriptions.
+
+Rpc subscriptions to the service can be created using the rpc.Client.Subscribe() method,
+with the "statediff" namespace, a statediff.Payload channel, and the name of the statediff api's rpc method- "stream".
+
+e.g.
+
+stateDiffPayloadChan := make(chan statediff.Payload, 20000)
+rpcSub, err := Subscribe(context.Background(), "statediff", stateDiffPayloadChan, "stream"})
+for {
+	select {
+	case stateDiffPayload := <- stateDiffPayloadChan:
+		processPayload(stateDiffPayload)
+	case err := <= rpcSub.Err():
+		log.Error(err)
+	}
+}
+
+*/
+package statediff

statediff/service.go

@@ -34,6 +34,8 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 )
 
+const chainEventChanSize = 20000
+
 type blockChain interface {
 	SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription
 	GetBlockByHash(hash common.Hash) *types.Block
@@ -127,13 +129,11 @@ func (sds *Service) Loop(chainEventCh chan core.ChainEvent) {
 			}
 			sds.lastBlock = currentBlock
 			if parentBlock == nil {
-				log.Error("Parent block is nil, skipping this block",
-					"parent block hash", parentHash.String(),
-					"current block number", currentBlock.Number())
+				log.Error(fmt.Sprintf("Parent block is nil, skipping this block (%d)", currentBlock.Number()))
 				continue
 			}
 			if err := sds.processStateDiff(currentBlock, parentBlock); err != nil {
-				log.Error("Error building statediff", "block number", currentBlock.Number(), "error", err)
+				log.Error(fmt.Sprintf("Error building statediff for block %d; error: ", currentBlock.Number()) + err.Error())
 			}
 		case err := <-errCh:
 			log.Warn("Error from chain event subscription, breaking loop", "error", err)
@@ -210,7 +210,7 @@ func (sds *Service) Unsubscribe(id rpc.ID) error {
 func (sds *Service) Start(*p2p.Server) error {
 	log.Info("Starting statediff service")
 
-	chainEventCh := make(chan core.ChainEvent, 10)
+	chainEventCh := make(chan core.ChainEvent, chainEventChanSize)
 	go sds.Loop(chainEventCh)
 
 	return nil