shard_manager.hpp

#pragma once
#include <compare>
#include <list>
#include <optional>

#include <sisl/utility/enum.hpp>

#include "common.hpp"

namespace homeobject {

ENUM(ShardError, uint16_t, UNKNOWN = 1, TIMEOUT, INVALID_ARG, NOT_LEADER, UNSUPPORTED_OP, UNKNOWN_PG, UNKNOWN_SHARD,
     PG_NOT_READY, CRC_MISMATCH, NO_SPACE_LEFT);

struct ShardInfo {
    enum class State : uint8_t {
        OPEN = 0,
        SEALED = 1,
        DELETED = 2,
    };

    shard_id_t id;
    pg_id_t placement_group;
    State state;
    uint64_t lsn;
    uint64_t created_time;
    uint64_t last_modified_time;
    uint64_t available_capacity_bytes;
    uint64_t total_capacity_bytes;
    uint64_t deleted_capacity_bytes;
    std::optional< peer_id_t > current_leader{std::nullopt};

    auto operator<=>(ShardInfo const& rhs) const { return id <=> rhs.id; }
    auto operator==(ShardInfo const& rhs) const { return id == rhs.id; }
    bool is_open() { return state == State::OPEN; }
};

using InfoList = std::list< ShardInfo >;

class ShardManager : public Manager< ShardError > {
public:
    static uint64_t max_shard_size(); // Static function forces runtime evaluation.
    static uint64_t max_shard_num_in_pg();

    virtual AsyncResult< ShardInfo > get_shard(shard_id_t id) const = 0;
    virtual AsyncResult< InfoList > list_shards(pg_id_t id) const = 0;
    virtual AsyncResult< ShardInfo > create_shard(pg_id_t pg_owner, uint64_t size_bytes) = 0;
    virtual AsyncResult< ShardInfo > seal_shard(shard_id_t id) = 0;
};

} // namespace homeobject