[FAB-1416] Make Policy message more generic

Today, the Policy message uses a oneof construct to enumerate the
allowable values.  This makes coding somewhat more convenient, but it
makes extending things with additional types more difficult.

This changeset switches the Policy message to use the more traditional
integer enumerate type with marshaled bytes construct.

Change-Id: Ic8e51ce4d1fa5e7fa99352e7dcb456a5b51f6e39
Signed-off-by: Jason Yellick <jyellick@us.ibm.com>

common/policies/policy.go

@@ -22,8 +22,8 @@ import (
 	"github.com/hyperledger/fabric/common/cauthdsl"
 	cb "github.com/hyperledger/fabric/protos/common"
 
-	"github.com/golang/protobuf/proto"
 	"errors"
+	"github.com/golang/protobuf/proto"
 )
 
 // Policy is used to determine if a signature is valid
@@ -46,18 +46,15 @@ type policy struct {
 }
 
 func newPolicy(policySource *cb.Policy, ch cauthdsl.CryptoHelper) (*policy, error) {
-	envelopeWrapper, ok := policySource.Type.(*cb.Policy_SignaturePolicy)
-
-	if !ok {
-		return nil, fmt.Errorf("Unknown policy type: %T", policySource.Type)
+	if policySource.Type != int32(cb.Policy_SIGNATURE) {
+		return nil, fmt.Errorf("Unknown policy type: %v", policySource.Type)
 	}
 
-	if envelopeWrapper.SignaturePolicy == nil {
-		return nil, errors.New("Nil signature policy received")
+	sigPolicy := &cb.SignaturePolicyEnvelope{}
+	if err := proto.Unmarshal(policySource.Policy, sigPolicy); err != nil {
+		return nil, fmt.Errorf("Error unmarshaling to SignaturePolicy: %s", err)
 	}
 
-	sigPolicy := envelopeWrapper.SignaturePolicy
-
 	evaluator, err := cauthdsl.NewSignaturePolicyEvaluator(sigPolicy, ch)
 	if err != nil {
 		return nil, err

common/policies/policy_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package policies
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/hyperledger/fabric/common/cauthdsl"
@@ -39,21 +40,26 @@ func init() {
 	rejectAllPolicy = makePolicySource(false)
 }
 
+// The proto utils has become a dumping ground of cyclic imports, it's easier to define this locally
+func marshalOrPanic(msg proto.Message) []byte {
+	data, err := proto.Marshal(msg)
+	if err != nil {
+		panic(fmt.Errorf("Error marshaling messages: %s, %s", msg, err))
+	}
+	return data
+}
+
 func makePolicySource(policyResult bool) []byte {
 	var policyData *cb.SignaturePolicyEnvelope
 	if policyResult {
 		policyData = cauthdsl.AcceptAllPolicy
 	} else {
 		policyData = cauthdsl.RejectAllPolicy
 	}
-	marshaledPolicy, err := proto.Marshal(&cb.Policy{
-		Type: &cb.Policy_SignaturePolicy{
-			SignaturePolicy: policyData,
-		},
+	marshaledPolicy := marshalOrPanic(&cb.Policy{
+		Type:   int32(cb.Policy_SIGNATURE),
+		Policy: marshalOrPanic(policyData),
 	})
-	if err != nil {
-		panic("Error marshaling policy")
-	}
 	return marshaledPolicy
 }
 

protos/common/configuration.proto

@@ -73,12 +73,18 @@ message ConfigurationSignature {
     bytes signature = 2; // Signature over the concatenation of configurationItem bytes and signatureHeader bytes
 }
 
+// 
+
 // Policy expresses a policy which the orderer can evaluate, because there has been some desire expressed to support
 // multiple policy engines, this is typed as a oneof for now
 message Policy {
-    oneof Type {
-        SignaturePolicyEnvelope SignaturePolicy = 1;
+    enum PolicyType {
+        UNKNOWN = 0; // Reserved to check for proper initialization
+        SIGNATURE = 1;
+        MSP = 2;
     }
+    int32 type = 1; // For outside implementors, consider the first 1000 types reserved, otherwise one of PolicyType
+    bytes policy = 2;
 }
 
 // SignaturePolicyEnvelope wraps a SignaturePolicy and includes a version for future enhancements

protos/utils/configurationutils.go

@@ -20,6 +20,8 @@ import (
 	"fmt"
 
 	cb "github.com/hyperledger/fabric/protos/common"
+
+	"github.com/golang/protobuf/proto"
 )
 
 // MakeConfigurationItem makes a ConfigurationItem.
@@ -40,29 +42,26 @@ func MakeConfigurationEnvelope(items ...*cb.SignedConfigurationItem) *cb.Configu
 }
 
 // MakePolicyOrPanic creates a Policy proto message out of a SignaturePolicyEnvelope, and panics if this operation fails.
-// NOTE Expand this as more policy types as supported.
 func MakePolicyOrPanic(policyEnvelope interface{}) *cb.Policy {
-	switch pe := policyEnvelope.(type) {
-	case *cb.SignaturePolicyEnvelope:
-		return &cb.Policy{
-			Type: &cb.Policy_SignaturePolicy{
-				SignaturePolicy: pe,
-			},
-		}
-	default:
-		panic("Unknown policy envelope type given")
+	policy, err := MakePolicy(policyEnvelope)
+	if err != nil {
+		panic(err)
 	}
+	return policy
 }
 
 // MakePolicy creates a Policy proto message out of a SignaturePolicyEnvelope.
 // NOTE Expand this as more policy types as supported.
 func MakePolicy(policyEnvelope interface{}) (*cb.Policy, error) {
 	switch pe := policyEnvelope.(type) {
 	case *cb.SignaturePolicyEnvelope:
+		m, err := proto.Marshal(pe)
+		if err != nil {
+			return nil, err
+		}
 		return &cb.Policy{
-			Type: &cb.Policy_SignaturePolicy{
-				SignaturePolicy: pe,
-			},
+			Type:   int32(cb.Policy_SIGNATURE),
+			Policy: m,
 		}, nil
 	default:
 		return nil, fmt.Errorf("Unknown policy envelope type given")