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/*
Copyright 2018-2021, Barcelona Supercomputing Center (BSC), Spain
Copyright 2015-2021, Johannes Gutenberg Universitaet Mainz, Germany
This software was partially supported by the
EC H2020 funded project NEXTGenIO (Project ID: 671951, www.nextgenio.eu).
This software was partially supported by the
ADA-FS project under the SPPEXA project funded by the DFG.
This file is part of GekkoFS.
GekkoFS is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
GekkoFS is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GekkoFS. If not, see <https://www.gnu.org/licenses/>.
SPDX-License-Identifier: GPL-3.0-or-later
*/
/**
* @brief Class declaration for MetadataDB class which uses RocksDB and provides
* a single instance within the daemon.
*/
#ifndef GEKKOFS_METADATA_DB_HPP
#define GEKKOFS_METADATA_DB_HPP
#include <rocksdb/db.h>
#include <daemon/backend/exceptions.hpp>
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#include <tuple>
/**
* @brief MetadataDB class providing an abstraction layer to the KV store
* RocksDB.
*/
std::unique_ptr<rdb::DB> db; ///< RocksDB instance
rdb::Options options; ///< RocksDB configuration
rdb::WriteOptions write_opts; ///< RocksDB write configuration
std::string path; ///< Path to where RocksDB persists its data
std::shared_ptr<spdlog::logger> log_; ///< MetadataDB internal logger
/**
* @brief Sets up specific settings to optimize RocksDB instance to
* environment on launch.
* @param options RocksDB configurations
*/
static void
optimize_rocksdb_options(rdb::Options& options);
public:
/**
* @brief Exception wrapper on Status object.
* @param s RocksDB status
* @throws Throws NotFoundException if s.IsNotFound(), general DBException
* otherwise
*/
static inline void
throw_rdb_status_excpt(const rdb::Status& s);
/**
* @brief Constructor, called when daemon is started and connects to KV
* store.
* @param path Path to where RocksDB persists its data
*/
explicit MetadataDB(const std::string& path);
/**
* @brief Gets the KV store value for a key.
* @param key KV store key
* @return KV store value
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
[[nodiscard]] std::string
get(const std::string& key) const;
/**
* @brief Puts an entry into the KV store.
* @param key KV store key
* @param val KV store value
* @throws DBException
*/
void
put(const std::string& key, const std::string& val);
/**
* @brief Puts an entry into the KV store if it doesn't exist.
* @param key KV store key
* @param val KV store value
* @throws DBException on failure, ExistException if entry already exists
*/
void
put_no_exist(const std::string& key, const std::string& val);
/**
* @brief Removes an entry from the KV store.
* @param key KV store key
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
remove(const std::string& key);
/**
* @brief Checks for existence of an entry.
* @param key KV store key
* @return true if exists
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
bool
exists(const std::string& key);
/**
* Updates a metadata entry atomically and also allows to change keys.
* @param old_key KV store key to be replaced
* @param new_key new KV store key
* @param val KV store value
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
update(const std::string& old_key, const std::string& new_key,
const std::string& val);
/**
* @brief Increases only the size part of the metadata entry via a RocksDB
* Operand.
* @param key KV store key
* @param size new size for entry
* @param append
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
increase_size(const std::string& key, size_t size, bool append);
/**
* @brief Decreases only the size part of the metadata entry via a RocksDB
* Operand/
* @param key KV store key
* @param size new size for entry
* @throws DBException on failure, NotFoundException if entry doesn't exist
*/
void
decrease_size(const std::string& key, size_t size);
/**
* @brief Return all file names and modes for the first-level entries of the
* given directory.
* @param dir directory prefix string
* @return vector of pair <std::string name, bool is_dir>,
* where name is the name of the entries and is_dir
* is true in the case the entry is a directory.
*/
[[nodiscard]] std::vector<std::pair<std::string, bool>>
get_dirents(const std::string& dir) const;
/**
* @brief Return all file names and modes for the first-level entries of the
* given directory including their sizes and creation time.
* @param dir directory prefix string
* @return vector of pair <std::string name, bool is_dir - size - ctime>,
* where name is the name of the entries and is_dir
* is true in the case the entry is a directory.
*/
[[nodiscard]] std::vector<std::tuple<std::string, bool, size_t, time_t>>
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get_dirents_extended(const std::string& dir) const;
/**
* @brief Iterate over complete database, note ONLY used for debugging and
* is therefore unused.
*/
#endif // GEKKOFS_METADATA_DB_HPP