YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

// Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#ifndef YB_CONSENSUS_STATE_CHANGE_CONTEXT_H

#define YB_CONSENSUS_STATE_CHANGE_CONTEXT_H

namespace yb {

namespace consensus {

// Context provided for callback on master/tablet-server peer state change for post processing

// e.g., update in-memory contents.

struct StateChangeContext {

  explicit StateChangeContext(StateChangeReason in_reason)

      : reason(in_reason) {

  }

  StateChangeContext(StateChangeReason in_reason, bool is_locked)

      : reason(in_reason),

        is_config_locked_(is_locked) {

  }

  StateChangeContext(StateChangeReason in_reason, string uuid)

      : reason(in_reason),

        new_leader_uuid(uuid) {

  }

  StateChangeContext(StateChangeReason in_reason,

                     ChangeConfigRecordPB change_rec,

                     string remove = "")

      : reason(in_reason),

        change_record(change_rec),

        remove_uuid(remove) {

  }

  bool is_config_locked() const {

    return is_config_locked_;

  }

  ~StateChangeContext() {}

  std::string ToString() const {

    switch (reason) {

      case StateChangeReason::TABLET_PEER_STARTED:

        return "Started TabletPeer";

      case StateChangeReason::CONSENSUS_STARTED:

        return "RaftConsensus started";

      case StateChangeReason::NEW_LEADER_ELECTED:

        return strings::Substitute("New leader $0 elected", new_leader_uuid);

      case StateChangeReason::FOLLOWER_NO_OP_COMPLETE:

        return "Replicate of NO_OP complete on follower";

      case StateChangeReason::LEADER_CONFIG_CHANGE_COMPLETE:

        return strings::Substitute("Replicated change config $0 round complete on leader",

          change_record.ShortDebugString());

      case StateChangeReason::FOLLOWER_CONFIG_CHANGE_COMPLETE:

        return strings::Substitute("Config change $0 complete on follower",

          change_record.ShortDebugString());

      case StateChangeReason::INVALID_REASON: FALLTHROUGH_INTENDED;

      default:

        return "INVALID REASON";

    }

  }

  const StateChangeReason reason;

  // Auxiliary info for some of the reasons above.

  // Value is filled when the change reason is NEW_LEADER_ELECTED.

  const string new_leader_uuid;

  // Value is filled when the change reason is LEADER/FOLLOWER_CONFIG_CHANGE_COMPLETE.

  const ChangeConfigRecordPB change_record;

  // Value is filled when the change reason is LEADER_CONFIG_CHANGE_COMPLETE

  // and it is a REMOVE_SERVER, then that server's uuid is saved here by the master leader.

  const string remove_uuid;

  // If this is true, the call-stack above has taken the lock for the raft consensus state. Needed

  // in SysCatalogStateChanged for master to not re-get the lock. Not used for tserver callback.

  // Note that the state changes using the UpdateConsensus() mechanism always hold the lock, so

  // defaulting to true as they are majority. For ones that do not hold the lock, setting

  // it to false in their constructor suffices currently, so marking it const.

  const bool is_config_locked_ = true;

};

} // namespace consensus

} // namespace yb

#endif // YB_CONSENSUS_STATE_CHANGE_CONTEXT_H