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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include <functional>
#include <memory>
#include "mongo/base/status_with.h"
#include "mongo/db/key_generator.h"
#include "mongo/db/keys_collection_cache.h"
#include "mongo/db/keys_collection_document_gen.h"
#include "mongo/db/keys_collection_manager_gen.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/platform/mutex.h"
#include "mongo/stdx/thread.h"
#include "mongo/util/concurrency/notification.h"
#include "mongo/util/duration.h"
namespace mongo {
class OperationContext;
class LogicalTime;
class ServiceContext;
class KeysCollectionClient;
namespace keys_collection_manager_util {
/**
* Returns the amount of time to wait until the monitoring thread should attempt to refresh again.
*/
Milliseconds howMuchSleepNeedFor(const LogicalTime& currentTime,
const LogicalTime& latestExpiredAt,
const Milliseconds& interval);
} // namespace keys_collection_manager_util
/**
* The KeysCollectionManager queries the config servers for keys that can be used for
* HMAC computation. It maintains an internal background thread that is used to periodically
* refresh the local key cache against the keys collection stored on the config servers.
*/
class KeysCollectionManager {
public:
static const std::string kKeyManagerPurposeString;
KeysCollectionManager(std::string purpose,
std::unique_ptr<KeysCollectionClient> client,
Seconds keyValidForInterval);
/**
* Returns the validation keys that are valid for the given time and also match the keyId. Does
* a blocking refresh if there is no matching internal key. If there is a matching internal key,
* includes it as first key in the resulting vector.
*
* Throws ExceededTimeLimit if the refresh times out, and KeyNotFound if there are no such keys.
*/
StatusWith<std::vector<KeysCollectionDocument>> getKeysForValidation(
OperationContext* opCtx, long long keyId, const LogicalTime& forThisTime);
/**
* Returns the signing key that is valid for the given time. Note that unlike
* getKeysForValidation, this will never do a refresh.
*/
StatusWith<KeysCollectionDocument> getKeyForSigning(OperationContext* opCtx,
const LogicalTime& forThisTime);
/**
* Request this manager to perform a refresh.
*/
void refreshNow(OperationContext* opCtx);
/**
* Starts a background thread that will constantly update the internal cache of keys.
*
* Cannot call this after stopMonitoring was called at least once.
*/
void startMonitoring(ServiceContext* service);
/**
* Stops the background thread updating the cache.
*/
void stopMonitoring();
/**
* Enable writing new keys to the config server primary. Should only be called if current node
* is the config primary.
*/
void enableKeyGenerator(OperationContext* opCtx, bool doEnable);
/**
* Returns true if the refresher has ever successfully returned keys from the config server.
*/
bool hasSeenKeys();
/**
* Clears the in memory cache of the keys.
*/
void clearCache();
/**
* Loads the given external key into the keys collection cache.
*/
void cacheExternalKey(ExternalKeysCollectionDocument key);
private:
/**
* This is responsible for periodically performing refresh in the background.
*/
class PeriodicRunner {
public:
using RefreshFunc = std::function<StatusWith<KeysCollectionDocument>(OperationContext*)>;
/**
* Preemptively inform the monitoring thread it needs to perform a refresh. Returns an
* object
* that gets notified after the current round of refresh is over. Note that being notified
* can
* mean either of these things:
*
* 1. An error occurred and refresh was not performed.
* 2. No error occurred but no new key was found.
* 3. No error occurred and new keys were found.
*/
void refreshNow(OperationContext* opCtx);
/**
* Sets the refresh function to use.
* Should only be used to bootstrap this refresher with initial strategy.
*/
void setFunc(RefreshFunc newRefreshStrategy);
/**
* Switches the current strategy with a new one. This also waits to make sure that the old
* strategy is not being used and will no longer be used after this call.
*/
void switchFunc(OperationContext* opCtx, RefreshFunc newRefreshStrategy);
/**
* Starts the refresh thread.
*/
void start(ServiceContext* service,
const std::string& threadName,
Milliseconds refreshInterval);
/**
* Stops the refresh thread.
*/
void stop();
/**
* Returns true if keys have ever successfully been returned from the config server.
*/
bool hasSeenKeys() const noexcept;
/**
* Returns if the periodic runner has entered shutdown.
*/
bool isInShutdown() const;
private:
void _doPeriodicRefresh(ServiceContext* service,
std::string threadName,
Milliseconds refreshInterval);
AtomicWord<bool> _hasSeenKeys{false};
// protects all the member variables below.
mutable Mutex _mutex = MONGO_MAKE_LATCH("PeriodicRunner::_mutex");
std::shared_ptr<Notification<void>> _refreshRequest;
stdx::condition_variable _refreshNeededCV;
stdx::thread _backgroundThread;
std::shared_ptr<RefreshFunc> _doRefresh;
bool _inShutdown = false;
};
std::unique_ptr<KeysCollectionClient> _client;
const std::string _purpose;
const Seconds _keyValidForInterval;
// No mutex needed since the members below have their own mutexes.
KeysCollectionCache _keysCache;
PeriodicRunner _refresher;
};
} // namespace mongo
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