Add server name to Bolt

Reviewers: buda, teon.banek

Reviewed By: teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D2021

src/communication/bolt/v1/session.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <optional>
 #include <thread>
 
 #include "glog/logging.h"
@@ -64,6 +65,10 @@ class Session {
   virtual bool Authenticate(const std::string &username,
                             const std::string &password) = 0;
 
+  /** Return the name of the server that should be used for the Bolt INIT
+   * message. */
+  virtual std::optional<std::string> GetServerNameForInit() = 0;
+
   /**
    * Executes the session after data has been read into the buffer.
    * Goes through the bolt states in order to execute commands from the client.

src/communication/bolt/v1/states/init.hpp

@@ -93,9 +93,19 @@ State StateInitRun(Session &session) {
   }
 
   // Return success.
-  if (!session.encoder_.MessageSuccess()) {
+  {
-    DLOG(WARNING) << "Couldn't send success message to the client!";
+    bool success_sent = false;
-    return State::Close;
+    auto server_name = session.GetServerNameForInit();
+    if (server_name) {
+      success_sent =
+          session.encoder_.MessageSuccess({{"server", *server_name}});
+    } else {
+      success_sent = session.encoder_.MessageSuccess();
+    }
+    if (!success_sent) {
+      DLOG(WARNING) << "Couldn't send success message to the client!";
+      return State::Close;
+    }
   }
 
   return State::Idle;

src/memgraph_init.cpp

@@ -21,6 +21,9 @@ DEFINE_uint64(memory_warning_threshold, 1024,
               "Memory warning threshold, in MB. If Memgraph detects there is "
               "less available RAM it will log a warning. Set to 0 to "
               "disable.");
+DEFINE_string(bolt_server_name_for_init, "",
+              "Server name which the database should send to the client in the "
+              "Bolt INIT message.");
 
 BoltSession::BoltSession(SessionData *data,
                          const io::network::Endpoint &endpoint,
@@ -130,6 +133,11 @@ bool BoltSession::Authenticate(const std::string &username,
 #endif
 }
 
+std::optional<std::string> BoltSession::GetServerNameForInit() {
+  if (FLAGS_bolt_server_name_for_init.empty()) return std::nullopt;
+  return FLAGS_bolt_server_name_for_init;
+}
+
 #ifdef MG_SINGLE_NODE_V2
 BoltSession::TypedValueResultStream::TypedValueResultStream(
     TEncoder *encoder, const storage::Storage *db)

src/memgraph_init.hpp

@@ -66,6 +66,8 @@ class BoltSession final
   bool Authenticate(const std::string &username,
                     const std::string &password) override;
 
+  std::optional<std::string> GetServerNameForInit() override;
+
  private:
   /// Wrapper around TEncoder which converts TypedValue to Value
   /// before forwarding the calls to original TEncoder.

tests/manual/ha_proxy.cpp

@@ -107,6 +107,10 @@ class BoltSession final
     return true;
   }
 
+  std::optional<std::string> GetServerNameForInit() override {
+    return std::nullopt;
+  }
+
  private:
   SessionData *session_data_;
   io::network::Endpoint endpoint_;

tests/unit/bolt_session.cpp

@@ -55,6 +55,10 @@ class TestSession : public Session<TestInputStream, TestOutputStream> {
     return true;
   }
 
+  std::optional<std::string> GetServerNameForInit() override {
+    return std::nullopt;
+  }
+
  private:
   std::string query_;
 };