Add Raft RPC messages

Summary:
Basic RPC messages for Raft protocol. They will most likely be updated as we
move along with the implementation.

Reviewers: msantl, teon.banek, mferencevic

Reviewed By: msantl, teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1726

.gitignore

@@ -85,6 +85,10 @@ src/durability/single_node_ha/state_delta.hpp
 src/query/plan/distributed_ops.capnp
 src/query/plan/distributed_ops.hpp
 src/query/plan/operator.hpp
+src/raft/log_entry.capnp
+src/raft/log_entry.hpp
+src/raft/raft_rpc_messages.capnp
+src/raft/raft_rpc_messages.hpp
 src/stats/stats_rpc_messages.capnp
 src/stats/stats_rpc_messages.hpp
 src/storage/distributed/rpc/concurrent_id_mapper_rpc_messages.capnp

src/CMakeLists.txt

@@ -291,6 +291,10 @@ add_lcp_single_node_ha(database/single_node_ha/serialization.lcp CAPNP_SCHEMA @0
 add_capnp_single_node_ha(database/single_node_ha/serialization.capnp)
 add_lcp_single_node_ha(query/frontend/ast/ast.lcp)
 add_lcp_single_node_ha(query/plan/operator.lcp)
+add_lcp_single_node_ha(raft/raft_rpc_messages.lcp CAPNP_SCHEMA @0xa6c29b4287233b66)
+add_capnp_single_node_ha(raft/raft_rpc_messages.capnp)
+add_lcp_single_node_ha(raft/log_entry.lcp CAPNP_SCHEMA @0x96c07fe13850c22a)
+add_capnp_single_node_ha(raft/log_entry.capnp)
 
 add_custom_target(generate_lcp_single_node_ha DEPENDS ${generated_lcp_single_node_ha_files})
 

src/raft/log_entry.lcp

@@ -0,0 +1,19 @@
+#>cpp
+#pragma once
+
+#include "database/single_node_ha/serialization.hpp"
+#include "durability/single_node_ha/state_delta.hpp"
+#include "raft/log_entry.capnp.h"
+cpp<#
+
+(lcp:namespace raft)
+
+(lcp:capnp-namespace "raft")
+
+(lcp:capnp-import 'database "/database/single_node_ha/serialization.capnp")
+
+(lcp:define-struct log-entry ()
+  ((deltas "std::vector<database::StateDelta>" :capnp-type "List(Database.StateDelta)"))
+  (:serialize :capnp))
+
+(lcp:pop-namespace) ;; raft

src/raft/raft_rpc_messages.lcp

@@ -0,0 +1,39 @@
+#>cpp
+#pragma once
+
+#include <vector>
+
+#include "communication/rpc/messages.hpp"
+#include "raft/log_entry.hpp"
+#include "raft/raft_rpc_messages.capnp.h"
+cpp<#
+
+(lcp:namespace raft)
+
+(lcp:capnp-namespace "raft")
+
+(lcp:capnp-import 'raft "/raft/log_entry.capnp")
+
+(lcp:define-rpc request-vote
+  (:request
+    ((candidate-id :uint16_t)
+     (term :uint64_t)
+     (last-log-index :uint64_t)
+     (last-log-term :uint64_t)))
+  (:response
+    ((vote-granted :bool)
+     (term :uint64_t))))
+
+(lcp:define-rpc append-entries
+  (:request
+    ((leader-id :uint16_t)
+     (leader-commit :uint16_t)
+     (term :uint64_t)
+     (prev-log-index :uint64_t)
+     (prev-log-term :uint64_t)
+     (entries "std::vector<raft::LogEntry>" :capnp-type "List(Raft.LogEntry)")))
+  (:response
+    ((success :bool)
+     (term :uint64_t))))
+
+(lcp:pop-namespace) ;; raft