Add LatestHead relayer method to gRPC client and server implementatio…

…ns (#767)

* Add LatestHead method to relayer interface

* Add LatestHead implementation to relayerset server and clients

* Fix error message

pkg/loop/internal/pb/relayerset/relayerset.proto

@@ -76,6 +76,16 @@ message NewChainWriterResponse {
   uint32 chainWriterId = 1;
 }
 
+message LatestHeadRequest {
+  RelayerId relayerId = 1;
+}
+
+message LatestHeadResponse {
+  string height = 1;
+  bytes hash = 2;
+  uint64 timestamp = 3;
+}
+
 message RelayerHealthReportResponse {
   map<string, string> report = 1;
 }
@@ -96,6 +106,7 @@ service RelayerSet {
   rpc RelayerReady(RelayerId) returns (google.protobuf.Empty) {}
   rpc RelayerHealthReport(RelayerId) returns (RelayerHealthReportResponse) {}
   rpc RelayerName(RelayerId) returns (RelayerNameResponse) {}
+  rpc RelayerLatestHead(LatestHeadRequest) returns (LatestHeadResponse) {}
 }
 
 

pkg/loop/internal/relayerset/client.go

@@ -100,6 +100,21 @@ func (k *Client) RelayerName(ctx context.Context, relayID types.RelayID) (string
 	return resp.Name, nil
 }
 
+func (k *Client) RelayerLatestHead(ctx context.Context, relayID types.RelayID) (types.Head, error) {
+	req := &relayerset.LatestHeadRequest{
+		RelayerId: &relayerset.RelayerId{ChainId: relayID.ChainID, Network: relayID.Network},
+	}
+	resp, err := k.relayerSetClient.RelayerLatestHead(ctx, req)
+	if err != nil {
+		return types.Head{}, fmt.Errorf("error getting latest head from relayerset client for relayer: %w", err)
+	}
+	return types.Head{
+		Height:    resp.Height,
+		Hash:      resp.Hash,
+		Timestamp: resp.Timestamp,
+	}, nil
+}
+
 func (k *Client) NewPluginProvider(ctx context.Context, relayID types.RelayID, relayArgs core.RelayArgs, pluginArgs core.PluginArgs) (uint32, error) {
 	// TODO at a later phase these credentials should be set as part of the relay config and not as a separate field
 	var mercuryCredentials *relayerset.MercuryCredentials

pkg/loop/internal/relayerset/relayer.go

@@ -92,3 +92,12 @@ func (r *relayerClient) Name() string {
 
 	return name
 }
+
+func (r *relayerClient) LatestHead(_ context.Context) (types.Head, error) {
+	latestHead, err := r.relayerSetClient.RelayerLatestHead(context.Background(), r.relayerID)
+	if err != nil {
+		r.log.Error("error getting latestHead", "error", err)
+		return types.Head{}, err
+	}
+	return latestHead, err
+}

pkg/loop/internal/relayerset/server.go

@@ -315,6 +315,23 @@ func (s *Server) RelayerName(ctx context.Context, relayID *relayerset.RelayerId)
 	return &relayerset.RelayerNameResponse{Name: relayer.Name()}, nil
 }
 
+func (s *Server) RelayerLatestHead(ctx context.Context, req *relayerset.LatestHeadRequest) (*relayerset.LatestHeadResponse, error) {
+	relayer, err := s.getRelayer(ctx, req.RelayerId)
+	if err != nil {
+		return nil, err
+	}
+
+	latestHead, err := relayer.LatestHead(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return &relayerset.LatestHeadResponse{
+		Height:    latestHead.Height,
+		Hash:      latestHead.Hash,
+		Timestamp: latestHead.Timestamp,
+	}, nil
+}
+
 func (s *Server) getRelayer(ctx context.Context, relayerID *relayerset.RelayerId) (core.Relayer, error) {
 	relayer, err := s.impl.Get(ctx, types.RelayID{ChainID: relayerID.ChainId, Network: relayerID.Network})
 	if err != nil {

pkg/types/core/relayerset.go

@@ -32,4 +32,5 @@ type Relayer interface {
 	NewPluginProvider(context.Context, RelayArgs, PluginArgs) (types.PluginProvider, error)
 	NewContractReader(_ context.Context, contractReaderConfig []byte) (types.ContractReader, error)
 	NewChainWriter(_ context.Context, chainWriterConfig []byte) (types.ChainWriter, error)
+	LatestHead(context.Context) (types.Head, error)
 }