Golang TxSimulator.GetTxSimulationResults方法代碼示例

//simulate the proposal by calling the chaincode
func (e *Endorser) simulateProposal(ctx context.Context, chainID string, txid string, prop *pb.Proposal, cid *pb.ChaincodeID, txsim ledger.TxSimulator) ([]byte, []byte, *pb.ChaincodeEvent, error) {
	//we do expect the payload to be a ChaincodeInvocationSpec
	//if we are supporting other payloads in future, this be glaringly point
	//as something that should change
	cis, err := putils.GetChaincodeInvocationSpec(prop)
	if err != nil {
		return nil, nil, nil, err
	}
	//---1. check ACL
	if err = e.checkACL(prop); err != nil {
		return nil, nil, nil, err
	}

	//---2. check ESCC and VSCC for the chaincode
	if err = e.checkEsccAndVscc(prop); err != nil {
		return nil, nil, nil, err
	}

	//---3. execute the proposal and get simulation results
	var simResult []byte
	var resp []byte
	var ccevent *pb.ChaincodeEvent
	resp, ccevent, err = e.callChaincode(ctx, chainID, txid, prop, cis, cid, txsim)
	if err != nil {
		return nil, nil, nil, err
	}

	if txsim != nil {
		if simResult, err = txsim.GetTxSimulationResults(); err != nil {
			return nil, nil, nil, err
		}
	}

	return resp, simResult, ccevent, nil
}

// TransferFunds simulates a transaction for transferring fund from fromAccount to toAccount
func (app *App) TransferFunds(fromAccount string, toAccount string, transferAmt int) (*common.Envelope, error) {
	// act as endorsing peer shim code to simulate a transaction on behalf of chaincode
	var txSimulator ledger.TxSimulator
	var err error
	if txSimulator, err = app.ledger.NewTxSimulator(); err != nil {
		return nil, err
	}
	defer txSimulator.Done()
	var balFromBytes []byte
	if balFromBytes, err = txSimulator.GetState(app.name, fromAccount); err != nil {
		return nil, err
	}
	balFrom := toInt(balFromBytes)
	if balFrom-transferAmt < 0 {
		return nil, fmt.Errorf("Not enough balance in account [%s]. Balance = [%d], transfer request = [%d]",
			fromAccount, balFrom, transferAmt)
	}

	var balToBytes []byte
	if balToBytes, err = txSimulator.GetState(app.name, toAccount); err != nil {
		return nil, err
	}
	balTo := toInt(balToBytes)
	txSimulator.SetState(app.name, fromAccount, toBytes(balFrom-transferAmt))
	txSimulator.SetState(app.name, toAccount, toBytes(balTo+transferAmt))
	var txSimulationResults []byte
	if txSimulationResults, err = txSimulator.GetTxSimulationResults(); err != nil {
		return nil, err
	}

	// act as endorsing peer to create an Action with the SimulationResults
	// then act as SDK to create a Transaction with the EndorsedAction
	tx := constructTransaction(txSimulationResults)
	return tx, nil
}

// CreateMarble simulates init transaction
func (marbleApp *MarbleApp) CreateMarble(args []string) (*common.Envelope, error) {
	//   0       1       2     3
	// "asdf", "blue", "35", "bob"
	logger.Debugf("===COUCHDB=== Entering ----------CreateMarble()----------")
	marbleName := args[0]
	marbleJsonBytes, err := init_marble(args)
	if err != nil {
		return nil, err
	}

	var txSimulator ledger.TxSimulator
	if txSimulator, err = marbleApp.ledger.NewTxSimulator(); err != nil {
		return nil, err
	}
	defer txSimulator.Done()

	txSimulator.SetState(marbleApp.name, marbleName, marbleJsonBytes)

	var txSimulationResults []byte
	if txSimulationResults, err = txSimulator.GetTxSimulationResults(); err != nil {
		return nil, err
	}
	logger.Debugf("===COUCHDB=== CreateMarble() simulation done, packaging into a transaction...")
	tx := constructTransaction(txSimulationResults)
	logger.Debugf("===COUCHDB=== Exiting CreateMarble()")
	return tx, nil
}

// TransferMarble simulates transfer transaction
func (marbleApp *MarbleApp) TransferMarble(args []string) (*common.Envelope, error) {
	//   0       1
	// "name", "bob"
	if len(args) < 2 {
		return nil, errors.New("Incorrect number of arguments. Expecting 2")
	}
	marbleName := args[0]
	marbleNewOwner := args[1]

	logger.Debugf("===COUCHDB=== Entering ----------TransferMarble----------")
	var txSimulator ledger.TxSimulator
	var err error
	if txSimulator, err = marbleApp.ledger.NewTxSimulator(); err != nil {
		return nil, err
	}
	defer txSimulator.Done()

	marbleBytes, err := txSimulator.GetState(marbleApp.name, marbleName)
	logger.Debugf("===COUCHDB=== marbleBytes is: %v", marbleBytes)
	if marbleBytes != nil {
		jsonString := string(marbleBytes[:])
		logger.Debugf("===COUCHDB=== TransferMarble() Retrieved jsonString: \n   %s", jsonString)
	}

	theMarble := Marble{}
	json.Unmarshal(marbleBytes, &theMarble) //Unmarshal JSON bytes into a Marble struct

	logger.Debugf("===COUCHDB===  theMarble after unmarshal: %v", theMarble)

	logger.Debugf("===COUCHDB===  Setting the owner to: %s", marbleNewOwner)
	theMarble.User = marbleNewOwner      //change the user
	theMarble.Txid = "tx000000000000002" // COUCHDB hardcode a txid for now for demo purpose

	updatedMarbleBytes, _ := json.Marshal(theMarble)
	if updatedMarbleBytes != nil {
		updatedJsonString := string(updatedMarbleBytes[:])
		logger.Debugf("===COUCHDB=== updatedJsonString:\n   %s", updatedJsonString)
	}
	err = txSimulator.SetState(marbleApp.name, marbleName, updatedMarbleBytes)
	if err != nil {
		return nil, err
	}

	var txSimulationResults []byte
	if txSimulationResults, err = txSimulator.GetTxSimulationResults(); err != nil {
		return nil, err
	}
	logger.Debugf("===COUCHDB=== TransferMarble() simulation done, packaging into a transaction...")
	tx := constructTransaction(txSimulationResults)
	return tx, nil
}

// Init simulates init transaction
func (app *App) Init(initialBalances map[string]int) (*common.Envelope, error) {
	var txSimulator ledger.TxSimulator
	var err error
	if txSimulator, err = app.ledger.NewTxSimulator(); err != nil {
		return nil, err
	}
	defer txSimulator.Done()
	for accountID, bal := range initialBalances {
		txSimulator.SetState(app.name, accountID, toBytes(bal))
	}
	var txSimulationResults []byte
	if txSimulationResults, err = txSimulator.GetTxSimulationResults(); err != nil {
		return nil, err
	}
	tx := constructTransaction(txSimulationResults)
	return tx, nil
}

func endTxSimulation(chainID string, txsim ledger.TxSimulator, payload []byte, commit bool, prop *pb.Proposal) error {
	txsim.Done()
	if lgr := peer.GetLedger(chainID); lgr != nil {
		if commit {
			var txSimulationResults []byte
			var err error

			//get simulation results
			if txSimulationResults, err = txsim.GetTxSimulationResults(); err != nil {
				return err
			}

			// assemble a (signed) proposal response message
			resp, err := putils.CreateProposalResponse(prop.Header, prop.Payload, txSimulationResults, nil, nil, signer)
			if err != nil {
				return err
			}

			// get the envelope
			env, err := putils.CreateSignedTx(prop, signer, resp)
			if err != nil {
				return err
			}

			envBytes, err := putils.GetBytesEnvelope(env)
			if err != nil {
				return err
			}

			//create the block with 1 transaction
			block := common.NewBlock(1, []byte{})
			block.Data.Data = [][]byte{envBytes}
			//commit the block
			if err := lgr.Commit(block); err != nil {
				return err
			}
		}
	}

	return nil
}