[FAB-8824] CC sample for state-based endorsement

This example chaincode demonstrates state-based endorsement, leveraging
the chaincode convenience layer.

Change-Id: I1cb34e2617a1068d5631b9d1b7040d938eab70e4
Signed-off-by: Matthias Neugschwandtner <[email protected]>
Signed-off-by: Alessandro Sorniotti <[email protected]>

examples/chaincode/go/keylevelep/chaincode.go

@@ -0,0 +1,194 @@
+/*
+Copyright IBM Corp. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0
+*/
+
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/hyperledger/fabric/core/chaincode/shim"
+	"github.com/hyperledger/fabric/core/chaincode/shim/ext/statebased"
+	pb "github.com/hyperledger/fabric/protos/peer"
+)
+
+/*
+EndorsementCC is an example chaincode that uses state-based endorsement.
+In the init function, it creates a single KVS state "endorsed_state" that
+can then be modified through chaincode functions that use the state-based
+endorsement chaincode convenience layer. The following chaincode functions
+are provided:
+-) "addorgs": supply a list of json-encoded MSP IDs that will be added to the
+   state's endorsement policy
+-) "delorgs": supply a list of json-encoded MSP IDs that will be removed from
+   the state's endorsement policy
+-) "delep": delete the key-level endorsement policy for the state altogether
+-) "listorgs": list the orgs included in the state's endorsement policy
+*/
+type EndorsementCC struct {
+}
+
+// Init callback
+func (cc *EndorsementCC) Init(stub shim.ChaincodeStubInterface) pb.Response {
+	err := stub.PutState("endorsed_state", []byte("foo"))
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	return shim.Success(nil)
+}
+
+// Invoke dispatcher
+func (cc *EndorsementCC) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
+	funcName, _ := stub.GetFunctionAndParameters()
+	if function, ok := functions[funcName]; ok {
+		return function(stub)
+	}
+	return shim.Error(fmt.Sprintf("Unknown function %s", funcName))
+}
+
+// function dispatch map used by Invoke()
+var functions = map[string]func(stub shim.ChaincodeStubInterface) pb.Response{
+	"addorgs":  addOrgs,
+	"delorgs":  delOrgs,
+	"listorgs": listOrgs,
+	"delep":    delEP,
+	"setval":   setVal,
+	"getval":   getVal,
+}
+
+// addOrgs adds the list of json-encoded MSP IDs from the invocation parameters
+// to the state's endorsement policy
+func addOrgs(stub shim.ChaincodeStubInterface) pb.Response {
+	_, parameters := stub.GetFunctionAndParameters()
+	if len(parameters) == 0 {
+		return shim.Error("No orgs to add specified")
+	}
+
+	// get the endorsement policy for the key
+	epBytes, err := stub.GetStateValidationParameter("endorsed_state")
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	ep, err := statebased.NewStateEP(epBytes)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	// add organizations to endorsement policy
+	err = ep.AddOrgs(statebased.RoleTypePeer, parameters...)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	epBytes, err = ep.Policy()
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	// set the modified endorsement policy for the key
+	err = stub.SetStateValidationParameter("endorsed_state", epBytes)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	return shim.Success([]byte{})
+}
+
+// delOrgs adds the list of json-encoded MSP IDs from the invocation parameters
+// from the state's endorsement policy
+func delOrgs(stub shim.ChaincodeStubInterface) pb.Response {
+	_, parameters := stub.GetFunctionAndParameters()
+	if len(parameters) == 0 {
+		return shim.Error("No orgs to delete specified")
+	}
+
+	// get the endorsement policy for the key
+	epBytes, err := stub.GetStateValidationParameter("endorsed_state")
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	ep, err := statebased.NewStateEP(epBytes)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	// delete organizations from the endorsement policy of that key
+	ep.DelOrgs(parameters...)
+	epBytes, err = ep.Policy()
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	// set the modified endorsement policy for the key
+	err = stub.SetStateValidationParameter("endorsed_state", epBytes)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	return shim.Success([]byte{})
+}
+
+// listOrgs returns the list of organizations currently part of
+// the state's endorsement policy
+func listOrgs(stub shim.ChaincodeStubInterface) pb.Response {
+	// get the endorsement policy for the key
+	epBytes, err := stub.GetStateValidationParameter("endorsed_state")
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	ep, err := statebased.NewStateEP(epBytes)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	// get the list of organizations in the endorsement policy
+	orgs := ep.ListOrgs()
+	orgsList, err := json.Marshal(orgs)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	return shim.Success(orgsList)
+}
+
+// delEP deletes the state-based endorsement policy for the key altogether
+func delEP(stub shim.ChaincodeStubInterface) pb.Response {
+	// set the modified endorsement policy for the key to nil
+	err := stub.SetStateValidationParameter("endorsed_state", nil)
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+
+	return shim.Success([]byte{})
+}
+
+// setVal sets the value of the KVS key
+func setVal(stub shim.ChaincodeStubInterface) pb.Response {
+	args := stub.GetArgs()
+	if len(args) != 2 {
+		return shim.Error("setval expects one argument")
+	}
+	err := stub.PutState("endorsed_state", args[1])
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	return shim.Success([]byte{})
+}
+
+// getVal retrieves the value of the KVS key
+func getVal(stub shim.ChaincodeStubInterface) pb.Response {
+	val, err := stub.GetState("endorsed_state")
+	if err != nil {
+		return shim.Error(err.Error())
+	}
+	return shim.Success(val)
+}
+
+func main() {
+	err := shim.Start(new(EndorsementCC))
+	if err != nil {
+		fmt.Printf("Error starting chaincode: %s", err)
+	}
+}