Add node service

spacemesh/v2alpha1/node.proto

@@ -0,0 +1,25 @@
+syntax = "proto3";
+
+import "google/protobuf/empty.proto";
+
+package spacemesh.v2alpha1;
+
+message NodeStatusResponse {
+  uint64 connected_peers = 1; // number of connected neighbors
+  enum SyncStatus {
+    SYNC_STATUS_UNSPECIFIED = 0;
+    SYNC_STATUS_OFFLINE = 1;
+    SYNC_STATUS_SYNCING = 2;
+    SYNC_STATUS_SYNCED = 3;
+  }
+  SyncStatus status = 2;
+  uint32 synced_layer = 3; // last layer node has synced
+  uint32 verified_layer = 4; // last layer node has verified
+  uint32 head_layer = 5; // current chain head; the last layer the node has gossiped or seen
+  uint32 current_layer = 6; // current layer, based on clock time
+  uint32 head_block_id = 7;
+}
+
+service NodeService {
+  rpc Status(google.protobuf.Empty) returns (NodeStatusResponse);
+}