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scylladb/service/qos/service_level_controller.hh

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/*
* Copyright (C) 2020-present ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla 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 Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "seastarx.hh"
#include "log.hh"
#include "auth/role_manager.hh"
#include "auth/authenticated_user.hh"
#include <seastar/core/sstring.hh>
#include <seastar/core/distributed.hh>
#include <seastar/core/abort_source.hh>
#include "auth/service.hh"
#include <map>
#include <unordered_set>
#include "qos_common.hh"
namespace db {
class system_distributed_keyspace;
}
namespace qos {
/**
* a structure to hold a service level
* data and configuration.
*/
struct service_level {
service_level_options slo;
bool marked_for_deletion;
bool is_static;
};
/**
* The service_level_controller class is an implementation of the service level
* controller design.
* It is logically divided into 2 parts:
* 1. Global controller which is responsible for all of the data and plumbing
* manipulation.
* 2. Local controllers that act upon the data and facilitates execution in
* the service level context
*/
class service_level_controller : public peering_sharded_service<service_level_controller> {
public:
class service_level_distributed_data_accessor {
public:
virtual future<qos::service_levels_info> get_service_levels() const = 0;
virtual future<qos::service_levels_info> get_service_level(sstring service_level_name) const = 0;
virtual future<> set_service_level(sstring service_level_name, qos::service_level_options slo) const = 0;
virtual future<> drop_service_level(sstring service_level_name) const = 0;
};
using service_level_distributed_data_accessor_ptr = ::shared_ptr<service_level_distributed_data_accessor>;
private:
struct global_controller_data {
service_levels_info static_configurations{};
int schedg_group_cnt = 0;
int io_priority_cnt = 0;
service_level_options default_service_level_config;
// The below future is used to serialize work so no reordering can occur.
// This is needed so for example: delete(x), add(x) will not reverse yielding
// a completely different result than the one intended.
future<> work_future = make_ready_future();
semaphore notifications_serializer = semaphore(1);
future<> distributed_data_update = make_ready_future();
abort_source dist_data_update_aborter;
};
std::unique_ptr<global_controller_data> _global_controller_db;
static constexpr shard_id global_controller = 0;
std::map<sstring, service_level> _service_levels_db;
std::unordered_map<sstring, sstring> _role_to_service_level;
service_level _default_service_level;
service_level_distributed_data_accessor_ptr _sl_data_accessor;
sharded<auth::service>& _auth_service;
std::chrono::time_point<seastar::lowres_clock> _last_successful_config_update;
unsigned _logged_intervals;
public:
service_level_controller(sharded<auth::service>& auth_service, service_level_options default_service_level_config);
/**
* this function must be called *once* from any shard before any other functions are called.
* No other function should be called before the future returned by the function is resolved.
* @return a future that resolves when the initialization is over.
*/
future<> start();
void set_distributed_data_accessor(service_level_distributed_data_accessor_ptr sl_data_accessor);
/**
* Adds a service level configuration if it doesn't exists, and updates
* an the existing one if it does exist.
* Handles both, static and non static service level configurations.
* @param name - the service level name.
* @param slo - the service level configuration
* @param is_static - is this configuration static or not
*/
future<> add_service_level(sstring name, service_level_options slo, bool is_static = false);
/**
* Removes a service level configuration if it exists.
* Handles both, static and non static service level configurations.
* @param name - the service level name.
* @param remove_static - indicates if it is a removal of a static configuration
* or not.
*/
future<> remove_service_level(sstring name, bool remove_static);
/**
* stops the distributed updater
* @return a future that is resolved when the updates stopped
*/
future<> drain();
/**
* stops all ongoing operations if exists
* @return a future that is resolved when all operations has stopped
*/
future<> stop();
/**
* Chack the distributed data for changes in a constant interval and updates
* the service_levels configuration in accordance (adds, removes, or updates
* service levels as necessairy).
* @param interval - the interval is seconds to check the distributed data.
* @return a future that is resolved when the update loop stops.
*/
void update_from_distributed_data(std::chrono::duration<float> interval);
/**
* Updates the service level data from the distributed data store.
* @return a future that is resolved when the update is done
*/
future<> update_service_levels_from_distributed_data();
future<> add_distributed_service_level(sstring name, service_level_options slo, bool if_not_exsists);
future<> alter_distributed_service_level(sstring name, service_level_options slo);
future<> drop_distributed_service_level(sstring name, bool if_exists);
future<service_levels_info> get_distributed_service_levels();
future<service_levels_info> get_distributed_service_level(sstring service_level_name);
/**
* Returns the service level options **in effect** for a user having the given
* collection of roles.
* @param roles - the collection of roles to consider
* @return the effective service level options - they may in particular be a combination
* of options from multiple service levels
*/
future<std::optional<service_level_options>> find_service_level(auth::role_set roles);
/**
* Gets the service level data by name.
* @param service_level_name - the name of the requested service level
* @return the service level data if it exists (in the local controller) or
* get_service_level("default") otherwise.
*/
service_level& get_service_level(sstring service_level_name) {
auto sl_it = _service_levels_db.find(service_level_name);
if (sl_it == _service_levels_db.end() || sl_it->second.marked_for_deletion) {
sl_it = _service_levels_db.find(default_service_level_name);
}
return sl_it->second;
}
private:
/**
* Adds a service level configuration if it doesn't exists, and updates
* an the existing one if it does exist.
* Handles both, static and non static service level configurations.
* @param name - the service level name.
* @param slo - the service level configuration
* @param is_static - is this configuration static or not
*/
future<> do_add_service_level(sstring name, service_level_options slo, bool is_static = false);
/**
* Removes a service level configuration if it exists.
* Handles both, static and non static service level configurations.
* @param name - the service level name.
* @param remove_static - indicates if it is a removal of a static configuration
* or not.
*/
future<> do_remove_service_level(sstring name, bool remove_static);
/**
* The notify functions are used by the global service level controller
* to propagate configuration changes to the local controllers.
* the returned future is resolved when the local controller is done acting
* on the notification. updates are done in sequence so their meaning will not
* change due to execution reordering.
*/
future<> notify_service_level_added(sstring name, service_level sl_data);
future<> notify_service_level_updated(sstring name, service_level_options slo);
future<> notify_service_level_removed(sstring name);
enum class set_service_level_op_type {
add_if_not_exists,
add,
alter
};
future<> set_distributed_service_level(sstring name, service_level_options slo, set_service_level_op_type op_type);
public:
static sstring default_service_level_name;
};
}