refactor: rename MessageID to message_seq_no in ordering.proto

This avoids the protobuf vs Go impedance mismatch for initialisms like
message_id (in protobuf) which is compiled to MessageId in Go, which is
not a recommended identifier in Go. To avoid this problem altogether, we
simply change the field to message_seq_no, which becomes a valid Go
identifier MessageSeqNo.

Author: meling

.vscode/gorums.txt

@@ -54,6 +54,7 @@ multicast
 naddr
 netrwhist
 obj's
+objc
 oneway
 Paxos
 Pedersen

encoding.go

@@ -98,7 +98,7 @@ func (m *Message) GetMessageID() uint64 {
 	if m == nil {
 		return 0
 	}
-	return m.metadata.GetMessageID()
+	return m.metadata.GetMessageSeqNo()
 }
 
 func (m *Message) GetStatus() *status.Status {

ordering/gorums_metadata.go

@@ -13,7 +13,7 @@ import (
 // This is used to pass client-specific metadata to the server via Gorums.
 // This method should be used by generated code only.
 func NewGorumsMetadata(ctx context.Context, msgID uint64, method string) *Metadata {
-	gorumsMetadata := Metadata_builder{MessageID: msgID, Method: method}
+	gorumsMetadata := Metadata_builder{MessageSeqNo: msgID, Method: method}
 	md, _ := metadata.FromOutgoingContext(ctx)
 	for k, vv := range md {
 		for _, v := range vv {

ordering/ordering.pb.go

@@ -2,29 +2,29 @@ edition = "2023";
 
 package ordering;
 option go_package = "github.com/relab/gorums/ordering";
-
 option features.field_presence = IMPLICIT;
 
 import "google/rpc/status.proto";
 
+// Gorums is the main service for Gorums' per-node stream communication.
 service Gorums {
     // NodeStream is a stream that connects a client to a Node.
     // The messages that are sent on the stream contain both Metadata
     // and an application-specific message.
-    rpc NodeStream(stream Metadata) returns (stream Metadata);
+  rpc NodeStream(stream Metadata) returns (stream Metadata);
 }
 
 // Metadata is sent together with application-specific message types,
 // and contains information necessary for Gorums to handle the messages.
 message Metadata {
-    uint64 MessageID         = 1;
-    string Method            = 2;
-    google.rpc.Status Status = 3;
-    // per message client-generated metadata
-    repeated MetadataEntry Entry = 4;
+  uint64                 message_seq_no = 1; // sequence number for this message
+  string                 method         = 2; // method name to invoke on the server
+  google.rpc.Status      status         = 3; // status of an invocation (for responses)
+  repeated MetadataEntry entry          = 4; // per message client-generated metadata
 }
 
+// MetadataEntry is a key-value pair for Metadata entries.
 message MetadataEntry {
-    string Key   = 1;
-    string Value = 2;
+  string key   = 1;
+  string value = 2;
 }