FAB-1129 Add cc return value to proposal response

https://jira.hyperledger.org/browse/FAB-1129

The return value from the chaincode invocation was not set by the endorser in
the payload of the Response message. This has been corrected.

Change-Id: I580e18d1813bc3447ef9900737ca3095746c3414
Signed-off-by: Alessandro Sorniotti <ale.linux@sopit.net>

core/endorser/endorser.go

@@ -343,7 +343,7 @@ func (e *Endorser) ProcessProposal(ctx context.Context, prop *pb.Proposal) (*pb.
 	//1 -- simulate
 	//TODO what do we do with response ? We need it for Invoke responses for sure
 	//Which field in PayloadResponse will carry return value ?
-	_, simulationResult, ccevent, err := e.simulateProposal(ctx, prop, hdrExt.ChaincodeID, txsim)
+	result, simulationResult, ccevent, err := e.simulateProposal(ctx, prop, hdrExt.ChaincodeID, txsim)
 	if err != nil {
 		return &pb.ProposalResponse{Response: &pb.Response2{Status: 500, Message: err.Error()}}, err
 	}
@@ -361,6 +361,11 @@ func (e *Endorser) ProcessProposal(ctx context.Context, prop *pb.Proposal) (*pb.
 		return nil, err
 	}
 
+	// Set the proposal response payload - it
+	// contains the "return value" from the
+	// chaincode invocation
+	pResp.Response.Payload = result
+
 	return pResp, nil
 }
 

examples/chaincode/go/invokereturnsvalue/invokereturnsvalue.go

@@ -0,0 +1,144 @@
+/*
+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 main
+
+//WARNING - this chaincode's ID is hard-coded in chaincode_example04 to illustrate one way of
+//calling chaincode from a chaincode. If this example is modified, chaincode_example04.go has
+//to be modified as well with the new ID of chaincode_example02.
+//chaincode_example05 show's how chaincode ID can be passed in as a parameter instead of
+//hard-coding.
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+
+	"github.com/hyperledger/fabric/core/chaincode/shim"
+)
+
+// SimpleChaincode example simple Chaincode implementation
+type SimpleChaincode struct {
+}
+
+// Init method of chaincode
+func (t *SimpleChaincode) Init(stub shim.ChaincodeStubInterface) ([]byte, error) {
+	_, args := stub.GetFunctionAndParameters()
+	var A, B string    // Entities
+	var Aval, Bval int // Asset holdings
+	var err error
+
+	if len(args) != 4 {
+		return nil, errors.New("Incorrect number of arguments. Expecting 4")
+	}
+
+	// Initialize the chaincode
+	A = args[0]
+	Aval, err = strconv.Atoi(args[1])
+	if err != nil {
+		return nil, errors.New("Expecting integer value for asset holding")
+	}
+	B = args[2]
+	Bval, err = strconv.Atoi(args[3])
+	if err != nil {
+		return nil, errors.New("Expecting integer value for asset holding")
+	}
+	fmt.Printf("Aval = %d, Bval = %d\n", Aval, Bval)
+
+	// Write the state to the ledger
+	err = stub.PutState(A, []byte(strconv.Itoa(Aval)))
+	if err != nil {
+		return nil, err
+	}
+
+	err = stub.PutState(B, []byte(strconv.Itoa(Bval)))
+	if err != nil {
+		return nil, err
+	}
+
+	return []byte("OK"), nil
+}
+
+// Invoke transaction makes payment of X units from A to B
+func (t *SimpleChaincode) Invoke(stub shim.ChaincodeStubInterface) ([]byte, error) {
+	_, args := stub.GetFunctionAndParameters()
+
+	var A, B string    // Entities
+	var Aval, Bval int // Asset holdings
+	var X int          // Transaction value
+	var err error
+
+	if len(args) != 3 {
+		return nil, errors.New("Incorrect number of arguments. Expecting 3")
+	}
+
+	A = args[0]
+	B = args[1]
+
+	// Get the state from the ledger
+	// TODO: will be nice to have a GetAllState call to ledger
+	Avalbytes, err := stub.GetState(A)
+	if err != nil {
+		return nil, errors.New("Failed to get state")
+	}
+	if Avalbytes == nil {
+		return nil, errors.New("Entity not found")
+	}
+	Aval, _ = strconv.Atoi(string(Avalbytes))
+
+	Bvalbytes, err := stub.GetState(B)
+	if err != nil {
+		return nil, errors.New("Failed to get state")
+	}
+	if Bvalbytes == nil {
+		return nil, errors.New("Entity not found")
+	}
+	Bval, _ = strconv.Atoi(string(Bvalbytes))
+
+	// Perform the execution
+	X, err = strconv.Atoi(args[2])
+	if err != nil {
+		return nil, errors.New("Invalid transaction amount, expecting a integer value")
+	}
+	Aval = Aval - X
+	Bval = Bval + X
+	fmt.Printf("Aval = %d, Bval = %d\n", Aval, Bval)
+
+	// Write the state back to the ledger
+	err = stub.PutState(A, []byte(strconv.Itoa(Aval)))
+	if err != nil {
+		return nil, err
+	}
+
+	err = stub.PutState(B, []byte(strconv.Itoa(Bval)))
+	if err != nil {
+		return nil, err
+	}
+
+	return []byte(fmt.Sprintf("{%d,%d}", Aval, Bval)), nil
+}
+
+// Query callback representing the query of a chaincode. Not used in 1.0 (remove when interface is removed)
+func (t *SimpleChaincode) Query(stub shim.ChaincodeStubInterface) ([]byte, error) {
+	return nil, nil
+}
+
+func main() {
+	err := shim.Start(new(SimpleChaincode))
+	if err != nil {
+		fmt.Printf("Error starting Simple chaincode: %s", err)
+	}
+}

examples/chaincode/go/invokereturnsvalue/invokereturnsvalue_test.go

@@ -0,0 +1,97 @@
+/*
+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 main
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/hyperledger/fabric/core/chaincode/shim"
+)
+
+func checkInit(t *testing.T, stub *shim.MockStub, args [][]byte, retval []byte) {
+	result, err := stub.MockInit("1", args)
+	if err != nil {
+		fmt.Println("Init failed", err)
+		t.FailNow()
+	}
+	if retval != nil {
+		if result == nil {
+			fmt.Printf("Init returned nil, expected %s", string(retval))
+			t.FailNow()
+		}
+		if string(result) != string(retval) {
+			fmt.Printf("Init returned %s, expected %s", string(result), string(retval))
+			t.FailNow()
+		}
+	}
+}
+
+func checkState(t *testing.T, stub *shim.MockStub, name string, value string) {
+	bytes := stub.State[name]
+	if bytes == nil {
+		fmt.Println("State", name, "failed to get value")
+		t.FailNow()
+	}
+	if string(bytes) != value {
+		fmt.Println("State value", name, "was not", value, "as expected")
+		t.FailNow()
+	}
+}
+
+func checkInvoke(t *testing.T, stub *shim.MockStub, args [][]byte, retval []byte) {
+	result, err := stub.MockInvoke("1", args)
+	if err != nil {
+		fmt.Println("Invoke", args, "failed", err)
+		t.FailNow()
+	}
+
+	if retval != nil {
+		if result == nil {
+			fmt.Printf("Invoke returned nil, expected %s", string(retval))
+			t.FailNow()
+		}
+		if string(result) != string(retval) {
+			fmt.Printf("Invoke returned %s, expected %s", string(result), string(retval))
+			t.FailNow()
+		}
+	}
+}
+
+func Test_Init(t *testing.T) {
+	scc := new(SimpleChaincode)
+	stub := shim.NewMockStub("ex02", scc)
+
+	// Init A=123 B=234
+	checkInit(t, stub, [][]byte{[]byte("init"), []byte("A"), []byte("123"), []byte("B"), []byte("234")}, []byte("OK"))
+
+	checkState(t, stub, "A", "123")
+	checkState(t, stub, "B", "234")
+}
+
+func Test_Invoke(t *testing.T) {
+	scc := new(SimpleChaincode)
+	stub := shim.NewMockStub("ex02", scc)
+
+	// Init A=567 B=678
+	checkInit(t, stub, [][]byte{[]byte("init"), []byte("A"), []byte("567"), []byte("B"), []byte("678")}, []byte("OK"))
+
+	// Invoke A->B for 123
+	checkInvoke(t, stub, [][]byte{[]byte("invoke"), []byte("A"), []byte("B"), []byte("123")}, []byte("{444,801}"))
+
+	// Invoke B->A for 234
+	checkInvoke(t, stub, [][]byte{[]byte("invoke"), []byte("B"), []byte("A"), []byte("234")}, []byte("{567,678}"))
+}