Log proposal response differences (#3420)

In the gateway, if proposal responses from different endorsing peers don’t match, then it’s very difficult for the end user to diagnose why.  This commit adds extra logging to help identify the cause of the mismatch.

If the log level is set to ‘debug’ for the ‘gateway’, then the proposal response payloads are unmarshalled and analysed to log specific differences between individual key/values in the read/write sets, SBE policy write differences, event differences and chaincode response differences.  For private collections, only the hashes are logged if they are different.

Signed-off-by: andrew-coleman <andrew_coleman@uk.ibm.com>
(cherry picked from commit 863cdd7)

# Conflicts:
#	internal/pkg/gateway/api_test.go

internal/pkg/gateway/api_test.go

@@ -10,6 +10,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"strings"
 	"testing"
 	"time"
 
@@ -23,7 +24,13 @@ import (
 	ab "github.com/hyperledger/fabric-protos-go/orderer"
 	"github.com/hyperledger/fabric-protos-go/peer"
 	"github.com/hyperledger/fabric/common/crypto/tlsgen"
+<<<<<<< HEAD
 	commonledger "github.com/hyperledger/fabric/common/ledger"
+=======
+	"github.com/hyperledger/fabric/common/flogging"
+	"github.com/hyperledger/fabric/common/flogging/mock"
+	"github.com/hyperledger/fabric/common/ledger"
+>>>>>>> 863cdd788 (Log proposal response differences (#3420))
 	"github.com/hyperledger/fabric/gossip/api"
 	"github.com/hyperledger/fabric/gossip/common"
 	gdiscovery "github.com/hyperledger/fabric/gossip/discovery"
@@ -36,6 +43,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/spf13/viper"
 	"github.com/stretchr/testify/require"
+	"go.uber.org/zap/zapcore"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
@@ -167,6 +175,8 @@ type preparedTest struct {
 	ledgerProvider *mocks.LedgerProvider
 	ledger         *mocks.Ledger
 	blockIterator  *mocks.ResultsIterator
+	logLevel       string
+	logFields      []string
 }
 
 type contextKey string
@@ -770,6 +780,26 @@ func TestEndorse(t *testing.T) {
 					Message: "ProposalResponsePayloads do not match",
 				},
 			},
+			postSetup: func(t *testing.T, def *preparedTest) {
+				def.logLevel = flogging.LoggerLevel("gateway")
+				flogging.ActivateSpec("debug")
+				logObserver := &mock.Observer{}
+				logObserver.WriteEntryStub = func(entry zapcore.Entry, fields []zapcore.Field) {
+					if strings.HasPrefix(entry.Message, "Proposal response mismatch") {
+						for _, field := range fields {
+							def.logFields = append(def.logFields, field.String)
+						}
+					}
+				}
+				flogging.SetObserver(logObserver)
+			},
+			postTest: func(t *testing.T, def *preparedTest) {
+				require.Equal(t, "chaincode response mismatch", def.logFields[0])
+				require.Equal(t, "status: 200, message: , payload: different_response", def.logFields[1])
+				require.Equal(t, "status: 200, message: , payload: mock_response", def.logFields[2])
+				flogging.ActivateSpec(def.logLevel)
+				flogging.SetObserver(nil)
+			},
 		},
 		{
 			name: "discovery fails",
@@ -963,6 +993,9 @@ func TestEndorse(t *testing.T) {
 
 			if checkError(t, &tt, err) {
 				require.Nil(t, response, "response on error")
+				if tt.postTest != nil {
+					tt.postTest(t, test)
+				}
 				return
 			}
 
@@ -979,6 +1012,10 @@ func TestEndorse(t *testing.T) {
 
 			// check the correct endorsers (mocks) were called with the right parameters
 			checkEndorsers(t, tt.expectedEndorsers, test)
+
+			if tt.postTest != nil {
+				tt.postTest(t, test)
+			}
 		})
 	}
 }