FABGW-25 Endorse using generated ChaincodeInterest

Change the Endorse() method logic as described in the design document attached to the Jira.
- Process proposal on local org peer.
- Using the ChaincodeInterest in the propsal response, invoke discovery to obtain a layout that contains the local org
- Obtain the remaining endorsements
- Build the transaction to send back to the client.

Extra unit tests added to test the new logic.

Signed-off-by: andrew-coleman <andrew_coleman@uk.ibm.com>

internal/pkg/gateway/api.go

@@ -32,11 +32,16 @@ func (gs *Server) Evaluate(ctx context.Context, request *gp.EvaluateRequest) (*g
 		return nil, status.Error(codes.InvalidArgument, "an evaluate request is required")
 	}
 	signedProposal := request.GetProposedTransaction()
-	channel, chaincodeID, err := getChannelAndChaincodeFromSignedProposal(signedProposal)
+	channel, chaincodeID, _, err := getChannelAndChaincodeFromSignedProposal(signedProposal)
 	if err != nil {
 		return nil, status.Errorf(codes.InvalidArgument, "failed to unpack transaction proposal: %s", err)
 	}
 
+	err = gs.registry.registerChannel(channel)
+	if err != nil {
+		return nil, status.Errorf(codes.Unavailable, "%s", err)
+	}
+
 	endorser, err := gs.registry.evaluator(channel, chaincodeID, request.GetTargetOrganizations())
 	if err != nil {
 		return nil, status.Errorf(codes.Unavailable, "%s", err)
@@ -68,7 +73,7 @@ func (gs *Server) Evaluate(ctx context.Context, request *gp.EvaluateRequest) (*g
 		Result: retVal,
 	}
 
-	logger.Debugw("Evaluate call to endorser returned success", "channel", request.ChannelId, "txid", request.TransactionId, "endorserAddress", endorser.endpointConfig.address, "endorserMspid", endorser.endpointConfig.mspid, "status", retVal.Status, "message", retVal.Message)
+	logger.Debugw("Evaluate call to endorser returned success", "channel", request.ChannelId, "txid", request.TransactionId, "endorserAddress", endorser.endpointConfig.address, "endorserMspid", endorser.endpointConfig.mspid, "status", retVal.GetStatus(), "message", retVal.GetMessage())
 	return evaluateResponse, nil
 }
 
@@ -86,31 +91,105 @@ func (gs *Server) Endorse(ctx context.Context, request *gp.EndorseRequest) (*gp.
 	if err != nil {
 		return nil, status.Errorf(codes.InvalidArgument, "failed to unpack transaction proposal: %s", err)
 	}
-	channel, chaincodeID, err := getChannelAndChaincodeFromSignedProposal(signedProposal)
+	channel, chaincodeID, hasTransientData, err := getChannelAndChaincodeFromSignedProposal(signedProposal)
 	if err != nil {
 		return nil, status.Errorf(codes.InvalidArgument, "failed to unpack transaction proposal: %s", err)
 	}
 
-	var endorsers []*endorser
-	if len(request.EndorsingOrganizations) > 0 {
-		endorsers, err = gs.registry.endorsersForOrgs(channel, chaincodeID, request.EndorsingOrganizations)
-	} else {
-		endorsers, err = gs.registry.endorsers(channel, chaincodeID)
-	}
+	err = gs.registry.registerChannel(channel)
 	if err != nil {
 		return nil, status.Errorf(codes.Unavailable, "%s", err)
 	}
 
 	ctx, cancel := context.WithTimeout(ctx, gs.options.EndorsementTimeout)
 	defer cancel()
 
+	defaultInterest := &peer.ChaincodeInterest{
+		Chaincodes: []*peer.ChaincodeCall{{
+			Name: chaincodeID,
+		}},
+	}
+
+	var endorsers []*endorser
+	var responses []*peer.ProposalResponse
+	if len(request.EndorsingOrganizations) > 0 {
+		// The client is specifying the endorsing orgs and taking responsibility for ensuring it meets the signature policy
+		endorsers, err = gs.registry.endorsersForOrgs(channel, chaincodeID, request.EndorsingOrganizations)
+		if err != nil {
+			return nil, status.Errorf(codes.Unavailable, "%s", err)
+		}
+	} else {
+		// The client is delegating choice of endorsers to the gateway.
+
+		// 1. Choose an endorser from the gateway's organization
+		var firstEndorser *endorser
+		es, ok := gs.registry.endorsersByOrg(channel, chaincodeID)[gs.registry.localEndorser.mspid]
+		if !ok {
+			// No local org endorsers for this channel/chaincode. If transient data is involved, return error
+			if hasTransientData {
+				return nil, status.Error(codes.FailedPrecondition, "no endorsers found in the gateway's organization; retry specifying endorsing organization(s) to protect transient data")
+			}
+			// Otherwise, just let discovery pick one.
+			endorsers, err = gs.registry.endorsers(channel, defaultInterest, "")
+			if err != nil {
+				return nil, status.Errorf(codes.Unavailable, "%s", err)
+			}
+			firstEndorser = endorsers[0]
+		} else {
+			firstEndorser = es[0].endorser
+		}
+
+		gs.logger.Debugw("Sending to first endorser:", "channel", channel, "chaincode", chaincodeID, "MSPID", firstEndorser.mspid, "endpoint", firstEndorser.address)
+
+		// 2. Process the proposal on this endorser
+		firstResponse, err := firstEndorser.client.ProcessProposal(ctx, signedProposal)
+		if err != nil {
+			return nil, rpcError(codes.Aborted, "failed to endorse transaction", endpointError(firstEndorser, err))
+		}
+		if firstResponse.Response.Status < 200 || firstResponse.Response.Status >= 400 {
+			return nil, rpcError(codes.Aborted, "failed to endorse transaction", endpointError(firstEndorser, fmt.Errorf("error %d, %s", firstResponse.Response.Status, firstResponse.Response.Message)))
+		}
+
+		// 3. Extract ChaincodeInterest and SBE policies
+		// The chaincode interest could be nil for legacy peers and for chaincode functions that don't produce a read-write set
+		interest := firstResponse.Interest
+		if len(interest.GetChaincodes()) == 0 {
+			interest = defaultInterest
+		}
+
+		// 4. If transient data is involved, then we need to ensure that discovery only returns orgs which own the collections involved.
+		// Do this by setting NoPrivateReads to false on each collection
+		if hasTransientData {
+			for _, call := range interest.GetChaincodes() {
+				call.NoPrivateReads = false
+			}
+		}
+
+		// 5. Get a set of endorsers from discovery via the registry
+		// The preferred discovery layout will contain the firstEndorser's Org.
+		endorsers, err = gs.registry.endorsers(channel, interest, firstEndorser.mspid)
+		if err != nil {
+			return nil, status.Errorf(codes.Unavailable, "%s", err)
+		}
+
+		// 6. Remove the gateway org's endorser, since we've already done that
+		for i, e := range endorsers {
+			if e.mspid == firstEndorser.mspid {
+				endorsers = append(endorsers[:i], endorsers[i+1:]...)
+				responses = append(responses, firstResponse)
+				break
+			}
+		}
+	}
+
 	var wg sync.WaitGroup
 	responseCh := make(chan *endorserResponse, len(endorsers))
 	// send to all the endorsers
 	for _, e := range endorsers {
 		wg.Add(1)
 		go func(e *endorser) {
 			defer wg.Done()
+			gs.logger.Debugw("Sending to endorser:", "channel", channel, "chaincode", chaincodeID, "MSPID", e.mspid, "endpoint", e.address)
 			response, err := e.client.ProcessProposal(ctx, signedProposal)
 			switch {
 			case err != nil:
@@ -129,7 +208,6 @@ func (gs *Server) Endorse(ctx context.Context, request *gp.EndorseRequest) (*gp.
 	wg.Wait()
 	close(responseCh)
 
-	var responses []*peer.ProposalResponse
 	var errorDetails []proto.Message
 	for response := range responseCh {
 		if response.err != nil {