handler.go

/*
Copyright IBM Corp. 2016 All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

		 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package chaincode

import (
	"fmt"
	"io"
	"sync"
	"time"

	"github.com/golang/protobuf/proto"
	ccintf "github.com/hyperledger/fabric/core/container/ccintf"
	"github.com/hyperledger/fabric/core/crypto"
	"github.com/hyperledger/fabric/core/ledger"
	"github.com/hyperledger/fabric/core/util"
	pb "github.com/hyperledger/fabric/protos"
	"github.com/looplab/fsm"
	"github.com/op/go-logging"
	"golang.org/x/net/context"
)

const (
	createdstate     = "created"     //start state
	establishedstate = "established" //in: CREATED, rcv:  REGISTER, send: REGISTERED, INIT
	initstate        = "init"        //in:ESTABLISHED, rcv:-, send: INIT
	readystate       = "ready"       //in:ESTABLISHED,TRANSACTION, rcv:COMPLETED
	transactionstate = "transaction" //in:READY, rcv: xact from consensus, send: TRANSACTION
	busyinitstate    = "busyinit"    //in:INIT, rcv: PUT_STATE, DEL_STATE, INVOKE_CHAINCODE
	busyxactstate    = "busyxact"    //in:TRANSACION, rcv: PUT_STATE, DEL_STATE, INVOKE_CHAINCODE
	endstate         = "end"         //in:INIT,ESTABLISHED, rcv: error, terminate container

)

var chaincodeLogger = logging.MustGetLogger("chaincode")

// MessageHandler interface for handling chaincode messages (common between Peer chaincode support and chaincode)
type MessageHandler interface {
	HandleMessage(msg *pb.ChaincodeMessage) error
	SendMessage(msg *pb.ChaincodeMessage) error
}

type transactionContext struct {
	transactionSecContext *pb.Transaction
	responseNotifier      chan *pb.ChaincodeMessage

	// tracks open iterators used for range queries
	rangeQueryIteratorMap map[string]ledger.ResultsIterator

	txsimulator ledger.TxSimulator
}

type nextStateInfo struct {
	msg      *pb.ChaincodeMessage
	sendToCC bool
}

// Handler responsbile for management of Peer's side of chaincode stream
type Handler struct {
	sync.RWMutex
	//peer to shim grpc serializer. User only in serialSend
	serialLock  sync.Mutex
	ChatStream  ccintf.ChaincodeStream
	FSM         *fsm.FSM
	ChaincodeID *pb.ChaincodeID

	// A copy of decrypted deploy tx this handler manages, no code
	deployTXSecContext *pb.Transaction

	chaincodeSupport *ChaincodeSupport
	registered       bool
	readyNotify      chan bool
	// Map of tx txid to either invoke or query tx (decrypted). Each tx will be
	// added prior to execute and remove when done execute
	txCtxs map[string]*transactionContext

	txidMap map[string]bool

	// Track which TXIDs are queries; Although the shim maintains this, it cannot be trusted.
	isTransaction map[string]bool

	// used to do Send after making sure the state transition is complete
	nextState chan *nextStateInfo
}

func shorttxid(txid string) string {
	if len(txid) < 8 {
		return txid
	}
	return txid[0:8]
}

func (handler *Handler) serialSend(msg *pb.ChaincodeMessage) error {
	handler.serialLock.Lock()
	defer handler.serialLock.Unlock()
	if err := handler.ChatStream.Send(msg); err != nil {
		chaincodeLogger.Errorf("Error sending %s: %s", msg.Type.String(), err)
		return fmt.Errorf("Error sending %s: %s", msg.Type.String(), err)
	}
	return nil
}

func (handler *Handler) createTxContext(ctxt context.Context, txid string, tx *pb.Transaction) (*transactionContext, error) {
	if handler.txCtxs == nil {
		return nil, fmt.Errorf("cannot create notifier for txid:%s", txid)
	}
	handler.Lock()
	defer handler.Unlock()
	if handler.txCtxs[txid] != nil {
		return nil, fmt.Errorf("txid:%s exists", txid)
	}
	txctx := &transactionContext{transactionSecContext: tx, responseNotifier: make(chan *pb.ChaincodeMessage, 1),
		rangeQueryIteratorMap: make(map[string]ledger.ResultsIterator)}
	handler.txCtxs[txid] = txctx
	txctx.txsimulator = getTxSimulator(ctxt)

	return txctx, nil
}

func (handler *Handler) getTxContext(txid string) *transactionContext {
	handler.Lock()
	defer handler.Unlock()
	return handler.txCtxs[txid]
}

func (handler *Handler) deleteTxContext(txid string) {
	handler.Lock()
	defer handler.Unlock()
	if handler.txCtxs != nil {
		delete(handler.txCtxs, txid)
	}
}

func (handler *Handler) putRangeQueryIterator(txContext *transactionContext, txid string,
	rangeScanIterator ledger.ResultsIterator) {
	handler.Lock()
	defer handler.Unlock()
	txContext.rangeQueryIteratorMap[txid] = rangeScanIterator
}

func (handler *Handler) getRangeQueryIterator(txContext *transactionContext, txid string) ledger.ResultsIterator {
	handler.Lock()
	defer handler.Unlock()
	return txContext.rangeQueryIteratorMap[txid]
}

func (handler *Handler) deleteRangeQueryIterator(txContext *transactionContext, txid string) {
	handler.Lock()
	defer handler.Unlock()
	delete(txContext.rangeQueryIteratorMap, txid)
}

//THIS CAN BE REMOVED ONCE WE FULL SUPPORT (Invoke and Query) CONFIDENTIALITY WITH CC-CALLING-CC
//Only invocation are allowed, not queries
func (handler *Handler) canCallChaincode(txid string, isQuery bool) *pb.ChaincodeMessage {
	secHelper := handler.chaincodeSupport.getSecHelper()
	if secHelper == nil {
		return nil
	}

	var errMsg string
	txctx := handler.getTxContext(txid)
	if txctx == nil {
		errMsg = fmt.Sprintf("[%s]Error no context while checking for confidentiality. Sending %s", shorttxid(txid), pb.ChaincodeMessage_ERROR)
	} else if txctx.transactionSecContext == nil {
		errMsg = fmt.Sprintf("[%s]Error transaction context is nil while checking for confidentiality. Sending %s", shorttxid(txid), pb.ChaincodeMessage_ERROR)
	} else if txctx.transactionSecContext.ConfidentialityLevel != pb.ConfidentialityLevel_PUBLIC {
		if isQuery {
			errMsg = fmt.Sprintf("[%s]Error chaincode-chaincode interactions not supported for with privacy enabled. Sending %s", shorttxid(txid), pb.ChaincodeMessage_ERROR)
		}
	}

	if errMsg != "" {
		return &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: []byte(errMsg), Txid: txid}
	}

	//not CONFIDENTIAL transaction, OK to call CC
	return nil
}

func (handler *Handler) encryptOrDecrypt(encrypt bool, txid string, payload []byte) ([]byte, error) {
	secHelper := handler.chaincodeSupport.getSecHelper()
	if secHelper == nil {
		return payload, nil
	}

	txctx := handler.getTxContext(txid)
	if txctx == nil {
		return nil, fmt.Errorf("[%s]No context for txid %s", shorttxid(txid), txid)
	}
	if txctx.transactionSecContext == nil {
		return nil, fmt.Errorf("[%s]transaction context is nil for txid %s", shorttxid(txid), txid)
	}
	// TODO: this must be removed
	if txctx.transactionSecContext.ConfidentialityLevel == pb.ConfidentialityLevel_PUBLIC {
		return payload, nil
	}

	var enc crypto.StateEncryptor
	var err error
	if txctx.transactionSecContext.Type == pb.Transaction_CHAINCODE_DEPLOY {
		if enc, err = secHelper.GetStateEncryptor(handler.deployTXSecContext, handler.deployTXSecContext); err != nil {
			chaincodeLogger.Errorf("error getting crypto encryptor for deploy tx :%s", err)
			return nil, fmt.Errorf("error getting crypto encryptor for deploy tx :%s", err)
		}
	} else if txctx.transactionSecContext.Type == pb.Transaction_CHAINCODE_INVOKE || txctx.transactionSecContext.Type == pb.Transaction_CHAINCODE_QUERY {
		if enc, err = secHelper.GetStateEncryptor(handler.deployTXSecContext, txctx.transactionSecContext); err != nil {
			chaincodeLogger.Errorf("error getting crypto encryptor %s", err)
			return nil, fmt.Errorf("error getting crypto encryptor %s", err)
		}
	} else {
		return nil, fmt.Errorf("invalid transaction type %s", txctx.transactionSecContext.Type.String())
	}
	if enc == nil {
		return nil, fmt.Errorf("secure context returns nil encryptor for tx %s", txid)
	}
	if chaincodeLogger.IsEnabledFor(logging.DEBUG) {
		chaincodeLogger.Debugf("[%s]Payload before encrypt/decrypt: %v", shorttxid(txid), payload)
	}
	if encrypt {
		payload, err = enc.Encrypt(payload)
	} else {
		payload, err = enc.Decrypt(payload)
	}
	if chaincodeLogger.IsEnabledFor(logging.DEBUG) {
		chaincodeLogger.Debugf("[%s]Payload after encrypt/decrypt: %v", shorttxid(txid), payload)
	}

	return payload, err
}

func (handler *Handler) decrypt(txid string, payload []byte) ([]byte, error) {
	return handler.encryptOrDecrypt(false, txid, payload)
}

func (handler *Handler) encrypt(txid string, payload []byte) ([]byte, error) {
	return handler.encryptOrDecrypt(true, txid, payload)
}

func (handler *Handler) getSecurityBinding(tx *pb.Transaction) ([]byte, error) {
	secHelper := handler.chaincodeSupport.getSecHelper()
	if secHelper == nil {
		return nil, nil
	}

	return secHelper.GetTransactionBinding(tx)
}

func (handler *Handler) deregister() error {
	if handler.registered {
		handler.chaincodeSupport.deregisterHandler(handler)
	}
	return nil
}

func (handler *Handler) triggerNextState(msg *pb.ChaincodeMessage, send bool) {
	handler.nextState <- &nextStateInfo{msg, send}
}

func (handler *Handler) waitForKeepaliveTimer() <-chan time.Time {
	if handler.chaincodeSupport.keepalive > 0 {
		c := time.After(handler.chaincodeSupport.keepalive)
		return c
	}
	//no one will signal this channel, listner blocks forever
	c := make(chan time.Time, 1)
	return c
}

func (handler *Handler) processStream() error {
	defer handler.deregister()
	msgAvail := make(chan *pb.ChaincodeMessage)
	var nsInfo *nextStateInfo
	var in *pb.ChaincodeMessage
	var err error

	//recv is used to spin Recv routine after previous received msg
	//has been processed
	recv := true
	for {
		in = nil
		err = nil
		nsInfo = nil
		if recv {
			recv = false
			go func() {
				var in2 *pb.ChaincodeMessage
				in2, err = handler.ChatStream.Recv()
				msgAvail <- in2
			}()
		}
		select {
		case in = <-msgAvail:
			// Defer the deregistering of the this handler.
			if err == io.EOF {
				chaincodeLogger.Debugf("Received EOF, ending chaincode support stream, %s", err)
				return err
			} else if err != nil {
				chaincodeLogger.Errorf("Error handling chaincode support stream: %s", err)
				return err
			} else if in == nil {
				err = fmt.Errorf("Received nil message, ending chaincode support stream")
				chaincodeLogger.Debug("Received nil message, ending chaincode support stream")
				return err
			}
			chaincodeLogger.Debugf("[%s]Received message %s from shim", shorttxid(in.Txid), in.Type.String())
			if in.Type.String() == pb.ChaincodeMessage_ERROR.String() {
				chaincodeLogger.Errorf("Got error: %s", string(in.Payload))
			}

			// we can spin off another Recv again
			recv = true

			if in.Type == pb.ChaincodeMessage_KEEPALIVE {
				chaincodeLogger.Debug("Received KEEPALIVE Response")
				// Received a keep alive message, we don't do anything with it for now
				// and it does not touch the state machine
				continue
			}
		case nsInfo = <-handler.nextState:
			in = nsInfo.msg
			if in == nil {
				err = fmt.Errorf("Next state nil message, ending chaincode support stream")
				chaincodeLogger.Debug("Next state nil message, ending chaincode support stream")
				return err
			}
			chaincodeLogger.Debugf("[%s]Move state message %s", shorttxid(in.Txid), in.Type.String())
		case <-handler.waitForKeepaliveTimer():
			if handler.chaincodeSupport.keepalive <= 0 {
				chaincodeLogger.Errorf("Invalid select: keepalive not on (keepalive=%d)", handler.chaincodeSupport.keepalive)
				continue
			}

			//TODO we could use this to hook into container lifecycle (kill the chaincode if not in use, etc)
			kaerr := handler.serialSend(&pb.ChaincodeMessage{Type: pb.ChaincodeMessage_KEEPALIVE})
			if kaerr != nil {
				chaincodeLogger.Errorf("Error sending keepalive, err=%s", kaerr)
			} else {
				chaincodeLogger.Debug("Sent KEEPALIVE request")
			}
			//keepalive message kicked in. just continue
			continue
		}

		err = handler.HandleMessage(in)
		if err != nil {
			chaincodeLogger.Errorf("[%s]Error handling message, ending stream: %s", shorttxid(in.Txid), err)
			return fmt.Errorf("Error handling message, ending stream: %s", err)
		}

		if nsInfo != nil && nsInfo.sendToCC {
			chaincodeLogger.Debugf("[%s]sending state message %s", shorttxid(in.Txid), in.Type.String())
			if err = handler.serialSend(in); err != nil {
				chaincodeLogger.Debugf("[%s]serial sending received error %s", shorttxid(in.Txid), err)
				return fmt.Errorf("[%s]serial sending received error %s", shorttxid(in.Txid), err)
			}
		}
	}
}

// HandleChaincodeStream Main loop for handling the associated Chaincode stream
func HandleChaincodeStream(chaincodeSupport *ChaincodeSupport, ctxt context.Context, stream ccintf.ChaincodeStream) error {
	deadline, ok := ctxt.Deadline()
	chaincodeLogger.Debugf("Current context deadline = %s, ok = %v", deadline, ok)
	handler := newChaincodeSupportHandler(chaincodeSupport, stream)
	return handler.processStream()
}

func newChaincodeSupportHandler(chaincodeSupport *ChaincodeSupport, peerChatStream ccintf.ChaincodeStream) *Handler {
	v := &Handler{
		ChatStream: peerChatStream,
	}
	v.chaincodeSupport = chaincodeSupport
	//we want this to block
	v.nextState = make(chan *nextStateInfo)

	v.FSM = fsm.NewFSM(
		createdstate,
		fsm.Events{
			//Send REGISTERED, then, if deploy { trigger INIT(via INIT) } else { trigger READY(via COMPLETED) }
			{Name: pb.ChaincodeMessage_REGISTER.String(), Src: []string{createdstate}, Dst: establishedstate},
			{Name: pb.ChaincodeMessage_INIT.String(), Src: []string{establishedstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_READY.String(), Src: []string{establishedstate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_TRANSACTION.String(), Src: []string{readystate}, Dst: transactionstate},
			{Name: pb.ChaincodeMessage_PUT_STATE.String(), Src: []string{transactionstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_DEL_STATE.String(), Src: []string{transactionstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_INVOKE_CHAINCODE.String(), Src: []string{transactionstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_PUT_STATE.String(), Src: []string{initstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_DEL_STATE.String(), Src: []string{initstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_INVOKE_CHAINCODE.String(), Src: []string{initstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_COMPLETED.String(), Src: []string{initstate, readystate, transactionstate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_GET_STATE.String(), Src: []string{readystate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_GET_STATE.String(), Src: []string{initstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_GET_STATE.String(), Src: []string{busyinitstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_GET_STATE.String(), Src: []string{transactionstate}, Dst: transactionstate},
			{Name: pb.ChaincodeMessage_GET_STATE.String(), Src: []string{busyxactstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE.String(), Src: []string{readystate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE.String(), Src: []string{initstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE.String(), Src: []string{busyinitstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE.String(), Src: []string{transactionstate}, Dst: transactionstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE.String(), Src: []string{busyxactstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_NEXT.String(), Src: []string{readystate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_NEXT.String(), Src: []string{initstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_NEXT.String(), Src: []string{busyinitstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_NEXT.String(), Src: []string{transactionstate}, Dst: transactionstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_NEXT.String(), Src: []string{busyxactstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_CLOSE.String(), Src: []string{readystate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_CLOSE.String(), Src: []string{initstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_CLOSE.String(), Src: []string{busyinitstate}, Dst: busyinitstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_CLOSE.String(), Src: []string{transactionstate}, Dst: transactionstate},
			{Name: pb.ChaincodeMessage_RANGE_QUERY_STATE_CLOSE.String(), Src: []string{busyxactstate}, Dst: busyxactstate},
			{Name: pb.ChaincodeMessage_ERROR.String(), Src: []string{initstate}, Dst: endstate},
			{Name: pb.ChaincodeMessage_ERROR.String(), Src: []string{transactionstate}, Dst: readystate},
			{Name: pb.ChaincodeMessage_ERROR.String(), Src: []string{busyinitstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_ERROR.String(), Src: []string{busyxactstate}, Dst: transactionstate},
			{Name: pb.ChaincodeMessage_RESPONSE.String(), Src: []string{busyinitstate}, Dst: initstate},
			{Name: pb.ChaincodeMessage_RESPONSE.String(), Src: []string{busyxactstate}, Dst: transactionstate},
		},
		fsm.Callbacks{
			"before_" + pb.ChaincodeMessage_REGISTER.String():               func(e *fsm.Event) { v.beforeRegisterEvent(e, v.FSM.Current()) },
			"before_" + pb.ChaincodeMessage_COMPLETED.String():              func(e *fsm.Event) { v.beforeCompletedEvent(e, v.FSM.Current()) },
			"before_" + pb.ChaincodeMessage_INIT.String():                   func(e *fsm.Event) { v.beforeInitState(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_GET_STATE.String():               func(e *fsm.Event) { v.afterGetState(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_RANGE_QUERY_STATE.String():       func(e *fsm.Event) { v.afterRangeQueryState(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_RANGE_QUERY_STATE_NEXT.String():  func(e *fsm.Event) { v.afterRangeQueryStateNext(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_RANGE_QUERY_STATE_CLOSE.String(): func(e *fsm.Event) { v.afterRangeQueryStateClose(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_PUT_STATE.String():               func(e *fsm.Event) { v.afterPutState(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_DEL_STATE.String():               func(e *fsm.Event) { v.afterDelState(e, v.FSM.Current()) },
			"after_" + pb.ChaincodeMessage_INVOKE_CHAINCODE.String():        func(e *fsm.Event) { v.afterInvokeChaincode(e, v.FSM.Current()) },
			"enter_" + establishedstate:                                     func(e *fsm.Event) { v.enterEstablishedState(e, v.FSM.Current()) },
			"enter_" + initstate:                                            func(e *fsm.Event) { v.enterInitState(e, v.FSM.Current()) },
			"enter_" + readystate:                                           func(e *fsm.Event) { v.enterReadyState(e, v.FSM.Current()) },
			"enter_" + busyinitstate:                                        func(e *fsm.Event) { v.enterBusyState(e, v.FSM.Current()) },
			"enter_" + busyxactstate:                                        func(e *fsm.Event) { v.enterBusyState(e, v.FSM.Current()) },
			"enter_" + endstate:                                             func(e *fsm.Event) { v.enterEndState(e, v.FSM.Current()) },
		},
	)

	return v
}

func (handler *Handler) createTXIDEntry(txid string) bool {
	if handler.txidMap == nil {
		return false
	}
	handler.Lock()
	defer handler.Unlock()
	if handler.txidMap[txid] {
		return false
	}
	handler.txidMap[txid] = true
	return handler.txidMap[txid]
}

func (handler *Handler) deleteTXIDEntry(txid string) {
	handler.Lock()
	defer handler.Unlock()
	if handler.txidMap != nil {
		delete(handler.txidMap, txid)
	} else {
		chaincodeLogger.Warningf("TXID %s not found!", txid)
	}
}

// markIsTransaction marks a TXID as a transaction or a query; true = transaction, false = query
func (handler *Handler) markIsTransaction(txid string, isTrans bool) bool {
	handler.Lock()
	defer handler.Unlock()
	if handler.isTransaction == nil {
		return false
	}
	handler.isTransaction[txid] = isTrans
	return true
}

func (handler *Handler) getIsTransaction(txid string) bool {
	handler.Lock()
	defer handler.Unlock()
	if handler.isTransaction == nil {
		return false
	}
	return handler.isTransaction[txid]
}

func (handler *Handler) deleteIsTransaction(txid string) {
	handler.Lock()
	defer handler.Unlock()
	if handler.isTransaction != nil {
		delete(handler.isTransaction, txid)
	}
}

func (handler *Handler) notifyDuringStartup(val bool) {
	//if USER_RUNS_CC readyNotify will be nil
	if handler.readyNotify != nil {
		chaincodeLogger.Debug("Notifying during startup")
		handler.readyNotify <- val
	} else {
		chaincodeLogger.Debug("nothing to notify (dev mode ?)")
	}
}

// beforeRegisterEvent is invoked when chaincode tries to register.
func (handler *Handler) beforeRegisterEvent(e *fsm.Event, state string) {
	chaincodeLogger.Debugf("Received %s in state %s", e.Event, state)
	msg, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeID := &pb.ChaincodeID{}
	err := proto.Unmarshal(msg.Payload, chaincodeID)
	if err != nil {
		e.Cancel(fmt.Errorf("Error in received %s, could NOT unmarshal registration info: %s", pb.ChaincodeMessage_REGISTER, err))
		return
	}

	// Now register with the chaincodeSupport
	handler.ChaincodeID = chaincodeID
	err = handler.chaincodeSupport.registerHandler(handler)
	if err != nil {
		e.Cancel(err)
		handler.notifyDuringStartup(false)
		return
	}

	chaincodeLogger.Debugf("Got %s for chaincodeID = %s, sending back %s", e.Event, chaincodeID, pb.ChaincodeMessage_REGISTERED)
	if err := handler.serialSend(&pb.ChaincodeMessage{Type: pb.ChaincodeMessage_REGISTERED}); err != nil {
		e.Cancel(fmt.Errorf("Error sending %s: %s", pb.ChaincodeMessage_REGISTERED, err))
		handler.notifyDuringStartup(false)
		return
	}
}

func (handler *Handler) notify(msg *pb.ChaincodeMessage) {
	handler.Lock()
	defer handler.Unlock()
	tctx := handler.txCtxs[msg.Txid]
	if tctx == nil {
		chaincodeLogger.Debugf("notifier Txid:%s does not exist", msg.Txid)
	} else {
		chaincodeLogger.Debugf("notifying Txid:%s", msg.Txid)
		tctx.responseNotifier <- msg

		// clean up rangeQueryIteratorMap
		for _, v := range tctx.rangeQueryIteratorMap {
			v.Close()
		}
	}
}

// beforeCompletedEvent is invoked when chaincode has completed execution of init, invoke or query.
func (handler *Handler) beforeCompletedEvent(e *fsm.Event, state string) {
	msg, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	// Notify on channel once into READY state
	chaincodeLogger.Debugf("[%s]beforeCompleted - not in ready state will notify when in readystate", shorttxid(msg.Txid))
	return
}

// beforeInitState is invoked before an init message is sent to the chaincode.
func (handler *Handler) beforeInitState(e *fsm.Event, state string) {
	chaincodeLogger.Debugf("Before state %s.. notifying waiter that we are up", state)
	handler.notifyDuringStartup(true)
}

// afterGetState handles a GET_STATE request from the chaincode.
func (handler *Handler) afterGetState(e *fsm.Event, state string) {
	msg, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("[%s]Received %s, invoking get state from ledger", shorttxid(msg.Txid), pb.ChaincodeMessage_GET_STATE)

	// Query ledger for state
	handler.handleGetState(msg)
}

// Handles query to ledger to get state
func (handler *Handler) handleGetState(msg *pb.ChaincodeMessage) {
	// The defer followed by triggering a go routine dance is needed to ensure that the previous state transition
	// is completed before the next one is triggered. The previous state transition is deemed complete only when
	// the afterGetState function is exited. Interesting bug fix!!
	go func() {
		// Check if this is the unique state request from this chaincode txid
		uniqueReq := handler.createTXIDEntry(msg.Txid)
		if !uniqueReq {
			// Drop this request
			chaincodeLogger.Error("Another state request pending for this Txid. Cannot process.")
			return
		}

		var serialSendMsg *pb.ChaincodeMessage

		defer func() {
			handler.deleteTXIDEntry(msg.Txid)
			chaincodeLogger.Debugf("[%s]handleGetState serial send %s", shorttxid(serialSendMsg.Txid), serialSendMsg.Type)
			handler.serialSend(serialSendMsg)
		}()

		key := string(msg.Payload)

		// Invoke ledger to get state
		chaincodeID := handler.ChaincodeID.Name

		var res []byte
		var err error

		txContext := handler.getTxContext(msg.Txid)
		res, err = txContext.txsimulator.GetState(chaincodeID, key)

		if err != nil {
			// Send error msg back to chaincode. GetState will not trigger event
			payload := []byte(err.Error())
			chaincodeLogger.Errorf("[%s]Failed to get chaincode state(%s). Sending %s", shorttxid(msg.Txid), err, pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
		} else if res == nil {
			//The state object being requested does not exist, so don't attempt to decrypt it
			chaincodeLogger.Debugf("[%s]No state associated with key: %s. Sending %s with an empty payload", shorttxid(msg.Txid), key, pb.ChaincodeMessage_RESPONSE)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_RESPONSE, Payload: res, Txid: msg.Txid}
		} else {
			// Decrypt the data if the confidential is enabled
			if res, err = handler.decrypt(msg.Txid, res); err == nil {
				// Send response msg back to chaincode. GetState will not trigger event
				chaincodeLogger.Debugf("[%s]Got state. Sending %s", shorttxid(msg.Txid), pb.ChaincodeMessage_RESPONSE)
				serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_RESPONSE, Payload: res, Txid: msg.Txid}
			} else {
				// Send err msg back to chaincode.
				chaincodeLogger.Errorf("[%s]Got error (%s) while decrypting. Sending %s", shorttxid(msg.Txid), err, pb.ChaincodeMessage_ERROR)
				errBytes := []byte(err.Error())
				serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: errBytes, Txid: msg.Txid}
			}

		}

	}()
}

const maxRangeQueryStateLimit = 100

// afterRangeQueryState handles a RANGE_QUERY_STATE request from the chaincode.
func (handler *Handler) afterRangeQueryState(e *fsm.Event, state string) {
	msg, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("Received %s, invoking get state from ledger", pb.ChaincodeMessage_RANGE_QUERY_STATE)

	// Query ledger for state
	handler.handleRangeQueryState(msg)
	chaincodeLogger.Debug("Exiting GET_STATE")
}

// Handles query to ledger to rage query state
func (handler *Handler) handleRangeQueryState(msg *pb.ChaincodeMessage) {
	// The defer followed by triggering a go routine dance is needed to ensure that the previous state transition
	// is completed before the next one is triggered. The previous state transition is deemed complete only when
	// the afterRangeQueryState function is exited. Interesting bug fix!!
	go func() {
		// Check if this is the unique state request from this chaincode txid
		uniqueReq := handler.createTXIDEntry(msg.Txid)
		if !uniqueReq {
			// Drop this request
			chaincodeLogger.Error("Another state request pending for this Txid. Cannot process.")
			return
		}

		var serialSendMsg *pb.ChaincodeMessage

		defer func() {
			handler.deleteTXIDEntry(msg.Txid)
			chaincodeLogger.Debugf("[%s]handleRangeQueryState serial send %s", shorttxid(serialSendMsg.Txid), serialSendMsg.Type)
			handler.serialSend(serialSendMsg)
		}()

		rangeQueryState := &pb.RangeQueryState{}
		unmarshalErr := proto.Unmarshal(msg.Payload, rangeQueryState)
		if unmarshalErr != nil {
			payload := []byte(unmarshalErr.Error())
			chaincodeLogger.Errorf("Failed to unmarshall range query request. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		iterID := util.GenerateUUID()
		txContext := handler.getTxContext(msg.Txid)

		chaincodeID := handler.ChaincodeID.Name

		rangeIter, err := txContext.txsimulator.GetStateRangeScanIterator(chaincodeID, rangeQueryState.StartKey, rangeQueryState.EndKey)
		if err != nil {
			// Send error msg back to chaincode. GetState will not trigger event
			payload := []byte(err.Error())
			chaincodeLogger.Errorf("Failed to get ledger scan iterator. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		handler.putRangeQueryIterator(txContext, iterID, rangeIter)

		var keysAndValues []*pb.RangeQueryStateKeyValue
		var i = uint32(0)
		var qresult ledger.QueryResult
		for ; i < maxRangeQueryStateLimit; i++ {
			qresult, err := rangeIter.Next()
			if err != nil {
				chaincodeLogger.Errorf("Failed to get query result from iterator. Sending %s", pb.ChaincodeMessage_ERROR)
				return
			}
			if qresult == nil {
				break
			}
			//PDMP - let it panic if not KV
			kv := qresult.(ledger.KV)
			// Decrypt the data if the confidential is enabled
			decryptedValue, decryptErr := handler.decrypt(msg.Txid, kv.Value)
			if decryptErr != nil {
				payload := []byte(decryptErr.Error())
				chaincodeLogger.Errorf("Failed decrypt value. Sending %s", pb.ChaincodeMessage_ERROR)
				serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}

				rangeIter.Close()
				handler.deleteRangeQueryIterator(txContext, iterID)

				return
			}
			keyAndValue := pb.RangeQueryStateKeyValue{Key: kv.Key, Value: decryptedValue}
			keysAndValues = append(keysAndValues, &keyAndValue)
		}

		if qresult != nil {
			rangeIter.Close()
			handler.deleteRangeQueryIterator(txContext, iterID)
		}

		payload := &pb.RangeQueryStateResponse{KeysAndValues: keysAndValues, HasMore: qresult != nil, ID: iterID}
		payloadBytes, err := proto.Marshal(payload)
		if err != nil {
			rangeIter.Close()
			handler.deleteRangeQueryIterator(txContext, iterID)

			// Send error msg back to chaincode. GetState will not trigger event
			payload := []byte(err.Error())
			chaincodeLogger.Errorf("Failed marshall resopnse. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		chaincodeLogger.Debugf("Got keys and values. Sending %s", pb.ChaincodeMessage_RESPONSE)
		serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_RESPONSE, Payload: payloadBytes, Txid: msg.Txid}

	}()
}

// afterRangeQueryState handles a RANGE_QUERY_STATE_NEXT request from the chaincode.
func (handler *Handler) afterRangeQueryStateNext(e *fsm.Event, state string) {
	msg, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("Received %s, invoking get state from ledger", pb.ChaincodeMessage_RANGE_QUERY_STATE)

	// Query ledger for state
	handler.handleRangeQueryStateNext(msg)
	chaincodeLogger.Debug("Exiting RANGE_QUERY_STATE_NEXT")
}

// Handles query to ledger to rage query state next
func (handler *Handler) handleRangeQueryStateNext(msg *pb.ChaincodeMessage) {
	// The defer followed by triggering a go routine dance is needed to ensure that the previous state transition
	// is completed before the next one is triggered. The previous state transition is deemed complete only when
	// the afterRangeQueryState function is exited. Interesting bug fix!!
	go func() {
		// Check if this is the unique state request from this chaincode txid
		uniqueReq := handler.createTXIDEntry(msg.Txid)
		if !uniqueReq {
			// Drop this request
			chaincodeLogger.Debug("Another state request pending for this Txid. Cannot process.")
			return
		}

		var serialSendMsg *pb.ChaincodeMessage

		defer func() {
			handler.deleteTXIDEntry(msg.Txid)
			chaincodeLogger.Debugf("[%s]handleRangeQueryState serial send %s", shorttxid(serialSendMsg.Txid), serialSendMsg.Type)
			handler.serialSend(serialSendMsg)
		}()

		rangeQueryStateNext := &pb.RangeQueryStateNext{}
		unmarshalErr := proto.Unmarshal(msg.Payload, rangeQueryStateNext)
		if unmarshalErr != nil {
			payload := []byte(unmarshalErr.Error())
			chaincodeLogger.Errorf("Failed to unmarshall state range next query request. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		txContext := handler.getTxContext(msg.Txid)
		rangeIter := handler.getRangeQueryIterator(txContext, rangeQueryStateNext.ID)

		if rangeIter == nil {
			payload := []byte("Range query iterator not found")
			chaincodeLogger.Errorf("Range query iterator not found. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		var keysAndValues []*pb.RangeQueryStateKeyValue
		var i = uint32(0)

		var qresult ledger.QueryResult
		var err error
		for ; i < maxRangeQueryStateLimit; i++ {
			qresult, err = rangeIter.Next()
			if err != nil {
				chaincodeLogger.Errorf("Failed to get query result from iterator. Sending %s", pb.ChaincodeMessage_ERROR)
				return
			}
			if qresult != nil {
				break
			}
			//PDMP - let it panic if not KV
			kv := qresult.(ledger.KV)
			// Decrypt the data if the confidential is enabled
			decryptedValue, decryptErr := handler.decrypt(msg.Txid, kv.Value)
			if decryptErr != nil {
				payload := []byte(decryptErr.Error())
				chaincodeLogger.Errorf("Failed decrypt value. Sending %s", pb.ChaincodeMessage_ERROR)
				serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}

				rangeIter.Close()
				handler.deleteRangeQueryIterator(txContext, rangeQueryStateNext.ID)

				return
			}
			keyAndValue := pb.RangeQueryStateKeyValue{Key: kv.Key, Value: decryptedValue}
			keysAndValues = append(keysAndValues, &keyAndValue)
		}

		if qresult != nil {
			rangeIter.Close()
			handler.deleteRangeQueryIterator(txContext, rangeQueryStateNext.ID)
		}

		payload := &pb.RangeQueryStateResponse{KeysAndValues: keysAndValues, HasMore: qresult != nil, ID: rangeQueryStateNext.ID}
		payloadBytes, err := proto.Marshal(payload)
		if err != nil {
			rangeIter.Close()
			handler.deleteRangeQueryIterator(txContext, rangeQueryStateNext.ID)

			// Send error msg back to chaincode. GetState will not trigger event
			payload := []byte(err.Error())
			chaincodeLogger.Errorf("Failed marshall resopnse. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		chaincodeLogger.Debugf("Got keys and values. Sending %s", pb.ChaincodeMessage_RESPONSE)
		serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_RESPONSE, Payload: payloadBytes, Txid: msg.Txid}

	}()
}

// afterRangeQueryState handles a RANGE_QUERY_STATE_CLOSE request from the chaincode.
func (handler *Handler) afterRangeQueryStateClose(e *fsm.Event, state string) {
	msg, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("Received %s, invoking get state from ledger", pb.ChaincodeMessage_RANGE_QUERY_STATE)

	// Query ledger for state
	handler.handleRangeQueryStateClose(msg)
	chaincodeLogger.Debug("Exiting RANGE_QUERY_STATE_CLOSE")
}

// Handles the closing of a state iterator
func (handler *Handler) handleRangeQueryStateClose(msg *pb.ChaincodeMessage) {
	// The defer followed by triggering a go routine dance is needed to ensure that the previous state transition
	// is completed before the next one is triggered. The previous state transition is deemed complete only when
	// the afterRangeQueryState function is exited. Interesting bug fix!!
	go func() {
		// Check if this is the unique state request from this chaincode txid
		uniqueReq := handler.createTXIDEntry(msg.Txid)
		if !uniqueReq {
			// Drop this request
			chaincodeLogger.Error("Another state request pending for this Txid. Cannot process.")
			return
		}

		var serialSendMsg *pb.ChaincodeMessage

		defer func() {
			handler.deleteTXIDEntry(msg.Txid)
			chaincodeLogger.Debugf("[%s]handleRangeQueryState serial send %s", shorttxid(serialSendMsg.Txid), serialSendMsg.Type)
			handler.serialSend(serialSendMsg)
		}()

		rangeQueryStateClose := &pb.RangeQueryStateClose{}
		unmarshalErr := proto.Unmarshal(msg.Payload, rangeQueryStateClose)
		if unmarshalErr != nil {
			payload := []byte(unmarshalErr.Error())
			chaincodeLogger.Errorf("Failed to unmarshall state range query close request. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		txContext := handler.getTxContext(msg.Txid)
		iter := handler.getRangeQueryIterator(txContext, rangeQueryStateClose.ID)
		if iter != nil {
			iter.Close()
			handler.deleteRangeQueryIterator(txContext, rangeQueryStateClose.ID)
		}

		payload := &pb.RangeQueryStateResponse{HasMore: false, ID: rangeQueryStateClose.ID}
		payloadBytes, err := proto.Marshal(payload)
		if err != nil {

			// Send error msg back to chaincode. GetState will not trigger event
			payload := []byte(err.Error())
			chaincodeLogger.Errorf("Failed marshall resopnse. Sending %s", pb.ChaincodeMessage_ERROR)
			serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			return
		}

		chaincodeLogger.Debugf("Closed. Sending %s", pb.ChaincodeMessage_RESPONSE)
		serialSendMsg = &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_RESPONSE, Payload: payloadBytes, Txid: msg.Txid}

	}()
}

// afterPutState handles a PUT_STATE request from the chaincode.
func (handler *Handler) afterPutState(e *fsm.Event, state string) {
	_, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("Received %s in state %s, invoking put state to ledger", pb.ChaincodeMessage_PUT_STATE, state)

	// Put state into ledger handled within enterBusyState
}

// afterDelState handles a DEL_STATE request from the chaincode.
func (handler *Handler) afterDelState(e *fsm.Event, state string) {
	_, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("Received %s, invoking delete state from ledger", pb.ChaincodeMessage_DEL_STATE)

	// Delete state from ledger handled within enterBusyState
}

// afterInvokeChaincode handles an INVOKE_CHAINCODE request from the chaincode.
func (handler *Handler) afterInvokeChaincode(e *fsm.Event, state string) {
	_, ok := e.Args[0].(*pb.ChaincodeMessage)
	if !ok {
		e.Cancel(fmt.Errorf("Received unexpected message type"))
		return
	}
	chaincodeLogger.Debugf("Received %s in state %s, invoking another chaincode", pb.ChaincodeMessage_INVOKE_CHAINCODE, state)

	// Invoke another chaincode handled within enterBusyState
}

// Handles request to ledger to put state
func (handler *Handler) enterBusyState(e *fsm.Event, state string) {
	go func() {
		msg, _ := e.Args[0].(*pb.ChaincodeMessage)
		// First check if this TXID is a transaction; error otherwise
		if !handler.getIsTransaction(msg.Txid) {
			payload := []byte(fmt.Sprintf("Cannot handle %s in query context", msg.Type.String()))
			chaincodeLogger.Debugf("[%s]Cannot handle %s in query context. Sending %s", shorttxid(msg.Txid), msg.Type.String(), pb.ChaincodeMessage_ERROR)
			errMsg := &pb.ChaincodeMessage{Type: pb.ChaincodeMessage_ERROR, Payload: payload, Txid: msg.Txid}
			handler.triggerNextState(errMsg, true)
			return
		}