m/n/c/consensus: handle empty etcd member Name

When an etcd member has not been started yet, the member.Name field is
the empty string. In this case, we need to extract the node id from
PeerURLs instead.

Change-Id: I41aa39423bd4c7888467d65eb2a3f96e7d02e617
Reviewed-on: https://review.monogon.dev/c/monogon/+/3385
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>

metropolis/node/core/consensus/BUILD.bazel

@@ -23,6 +23,7 @@ go_library(
         "//osbase/logtree/unraw",
         "//osbase/pki",
         "//osbase/supervisor",
+        "@io_etcd_go_etcd_api_v3//etcdserverpb",
         "@io_etcd_go_etcd_client_v3//:client",
         "@io_etcd_go_etcd_server_v3//embed",
     ],

metropolis/node/core/consensus/consensus.go

@@ -97,6 +97,7 @@ import (
 	"net/url"
 	"time"
 
+	"go.etcd.io/etcd/api/v3/etcdserverpb"
 	clientv3 "go.etcd.io/etcd/client/v3"
 	"go.etcd.io/etcd/server/v3/embed"
 
@@ -143,6 +144,26 @@ func pkiPeerCertificate(pubkey ed25519.PublicKey, extraNames []string) x509.Cert
 	}
 }
 
+// GetEtcdMemberNodeId returns the node ID of an etcd member. It works even for
+// members which have not started, where member.Name is empty.
+func GetEtcdMemberNodeId(member *etcdserverpb.Member) string {
+	if member.Name != "" {
+		return member.Name
+	}
+	if len(member.PeerURLs) == 0 {
+		return ""
+	}
+	u, err := url.Parse(member.PeerURLs[0])
+	if err != nil {
+		return ""
+	}
+	nodeId, _, err := net.SplitHostPort(u.Host)
+	if err != nil {
+		return ""
+	}
+	return nodeId
+}
+
 // Service is the etcd cluster member service. See package-level documentation
 // for more information.
 type Service struct {
@@ -497,6 +518,10 @@ func (s *Service) autopromoter(ctx context.Context) error {
 			if !member.IsLearner {
 				continue
 			}
+			if member.Name == "" {
+				// If the name is empty, the member has not started.
+				continue
+			}
 			// Always call PromoteMember since the metadata necessary to decide if we should
 			// is private. Luckily etcd already does consistency checks internally and will
 			// refuse to promote nodes that aren't connected or are still behind on

metropolis/node/core/consensus/status.go

@@ -146,7 +146,7 @@ func (s *Status) AddNode(ctx context.Context, pk ed25519.PublicKey, opts ...*Add
 	var existingNodes []ExistingNode
 	var newExists bool
 	for _, m := range members.Members {
-		if m.Name == nodeID {
+		if GetEtcdMemberNodeId(m) == nodeID {
 			newExists = true
 		}
 		if m.IsLearner {

metropolis/node/core/curator/impl_leader_curator.go

@@ -16,6 +16,7 @@ import (
 	tpb "google.golang.org/protobuf/types/known/timestamppb"
 
 	common "source.monogon.dev/metropolis/node"
+	"source.monogon.dev/metropolis/node/core/consensus"
 	ipb "source.monogon.dev/metropolis/node/core/curator/proto/api"
 	"source.monogon.dev/metropolis/node/core/identity"
 	"source.monogon.dev/metropolis/node/core/rpc"
@@ -616,7 +617,7 @@ func (l *leaderCurator) GetConsensusStatus(ctx context.Context, _ *ipb.GetConsen
 	}
 	for _, member := range members.Members {
 		st := ipb.GetConsensusStatusResponse_EtcdMember{
-			Id:     member.Name,
+			Id:     consensus.GetEtcdMemberNodeId(member),
 			Status: ipb.GetConsensusStatusResponse_EtcdMember_STATUS_FULL,
 		}
 		if member.IsLearner {