hooks.h

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// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the Apache 2.0 License.
#pragma once
 
#include "ccf/service/node_info_network.h"
#include "ccf/service/reconfiguration_type.h"
#include "ds/internal_logger.h"
#include "service/tables/config.h"
#include "service/tables/signatures.h"
 
#include <stdexcept>
 
namespace ccf
{
  struct NodeAddr
  {
    std::string hostname;
    std::string port;
  };
 
  class ConfigurationChangeHook : public ccf::kv::ConsensusHook
  {
    ccf::kv::Version version;
    std::map<NodeId, std::optional<NodeAddr>> cfg_delta;
 
  public:
    ConfigurationChangeHook(ccf::kv::Version version_, const Nodes::Write& w) :
      version(version_)
    {
      for (const auto& [node_id, opt_ni] : w)
      {
        if (!opt_ni.has_value())
        {
          // Deleted node will have already been retired
          continue;
        }
 
        const auto& ni = opt_ni.value();
        const auto [host, port] =
          split_net_address(ni.node_to_node_interface.published_address);
        switch (ni.status)
        {
          case NodeStatus::PENDING:
          {
            // Pending nodes are not added to consensus until they are
            // trusted
            break;
          }
          case NodeStatus::TRUSTED:
          {
            cfg_delta.try_emplace(node_id, NodeAddr{host, port});
            break;
          }
          case NodeStatus::RETIRED:
          {
            cfg_delta.try_emplace(node_id, std::nullopt);
            break;
          }
          default:
          {
            throw std::logic_error(fmt::format(
              "Unknown node status {} for node {} in configuration change hook",
              static_cast<uint8_t>(ni.status),
              node_id));
          }
        }
      }
    }
 
    void call(ccf::kv::ConfigurableConsensus* consensus) override
    {
      auto configuration = consensus->get_latest_configuration_unsafe();
      for (const auto& [node_id, opt_ni] : cfg_delta)
      {
        if (opt_ni.has_value())
        {
          configuration.try_emplace(node_id, opt_ni->hostname, opt_ni->port);
        }
        else
        {
          configuration.erase(node_id);
        }
      }
      if (!cfg_delta.empty())
      {
        consensus->add_configuration(version, configuration);
      }
    }
  };
}