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/**
* Copyright (C) 2020-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 "mongo/base/error_codes.h"
#include "mongo/db/cancelable_operation_context.h"
#include "mongo/s/grid.h"
#include "mongo/s/stale_exception.h"
#include "mongo/util/future_util.h"
#include "mongo/util/out_of_line_executor.h"
namespace mongo {
namespace shard_version_retry {
void checkErrorStatusAndMaxRetries(const Status& status,
const NamespaceString& nss,
CatalogCache* catalogCache,
StringData taskDescription,
size_t numAttempts);
/**
* Performs necessary cache invalidations based on the error status.
* Throws if it encountered an unexpected status or numAttempts exceeded maximum amount.
*/
template <typename T>
void checkErrorStatusAndMaxRetries(const StatusWith<T>& status,
const NamespaceString& nss,
CatalogCache* catalogCache,
StringData taskDescription,
size_t numAttempts) {
return checkErrorStatusAndMaxRetries(
status.getStatus(), nss, catalogCache, taskDescription, numAttempts);
}
} // namespace shard_version_retry
/**
* A retry loop which handles errors in ErrorCategory::StaleShardVersionError. When such an error is
* encountered, the CatalogCache is marked for refresh and 'callback' is retried. When retried,
* 'callback' will trigger a refresh of the CatalogCache and block until it's done when it next
* consults the CatalogCache.
*/
template <typename F>
auto shardVersionRetry(OperationContext* opCtx,
CatalogCache* catalogCache,
NamespaceString nss,
StringData taskDescription,
F&& callbackFn) {
size_t numAttempts = 0;
while (true) {
catalogCache->setOperationShouldBlockBehindCatalogCacheRefresh(opCtx, numAttempts);
try {
return callbackFn();
} catch (const DBException& ex) {
shard_version_retry::checkErrorStatusAndMaxRetries(
ex.toStatus(), nss, catalogCache, taskDescription, ++numAttempts);
}
}
}
/**
* Async loop for retrying stale database/shard version a finite number of times. callbackFn should
* accept OperationContext* as an argument.
*
* Note: Currently only supports void return type for callbackFn.
*/
template <typename Callable>
auto shardVersionRetry(ServiceContext* service,
NamespaceString nss,
CatalogCache* catalogCache,
StringData taskDescription,
ExecutorPtr executor,
CancellationToken cancelToken,
Callable&& callbackFn) {
auto numAttempts = std::make_shared<size_t>(0);
auto body = [service,
catalogCache,
taskDescription,
numAttempts,
_callbackFn = std::move(callbackFn),
executor,
cancelToken] {
boost::optional<ThreadClient> threadClient;
if (!haveClient()) {
threadClient.emplace(taskDescription, service);
}
CancelableOperationContextFactory opCtxFactory(cancelToken, executor);
auto cancelableOpCtx = opCtxFactory.makeOperationContext(&cc());
auto opCtx = cancelableOpCtx.get();
catalogCache->setOperationShouldBlockBehindCatalogCacheRefresh(opCtx, *numAttempts);
return _callbackFn(opCtx);
};
using ResultType = std::invoke_result_t<Callable, OperationContext*>;
return AsyncTry<decltype(body)>(std::move(body))
.until([numAttempts, _nss = std::move(nss), catalogCache, taskDescription](
const StatusOrStatusWith<ResultType>& statusOrStatusWith) {
if (statusOrStatusWith.isOK()) {
return true;
}
shard_version_retry::checkErrorStatusAndMaxRetries(
statusOrStatusWith, _nss, catalogCache, taskDescription, ++(*numAttempts));
return false;
})
.on(std::move(executor), cancelToken);
}
} // namespace mongo
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