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/**
* Copyright (C) 2021-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 <vector>
#include "mongo/db/cancelable_operation_context.h"
#include "mongo/util/cancellation.h"
#include "mongo/util/functional.h"
#include "mongo/util/future.h"
#include "mongo/util/future_util.h"
#include "mongo/util/out_of_line_executor.h"
namespace mongo {
namespace resharding {
/**
* Converts a vector of SharedSemiFutures into a vector of ExecutorFutures.
*/
std::vector<ExecutorFuture<void>> thenRunAllOn(const std::vector<SharedSemiFuture<void>>& futures,
ExecutorPtr executor);
/**
* Given a vector of input futures, returns a future that becomes ready when either
*
* (a) all of the input futures have become ready with success, or
* (b) one of the input futures has become ready with an error.
*
* This function returns an immediately ready future when the vector of input futures is empty.
*/
ExecutorFuture<void> whenAllSucceedOn(const std::vector<SharedSemiFuture<void>>& futures,
ExecutorPtr executor);
/**
* Given a vector of input futures, returns a future that becomes ready when all of the input
* futures have become ready with success or failure.
*
* If one of the input futures becomes ready with an error, then the cancellation source is canceled
* in an attempt to speed up the other input futures becoming ready. After all of the input futures
* have become ready, the returned future becomes ready with the first error that had occurred.
*
* This function returns an immediately ready future when the vector of input futures is empty.
*/
ExecutorFuture<void> cancelWhenAnyErrorThenQuiesce(
const std::vector<SharedSemiFuture<void>>& futures,
ExecutorPtr executor,
CancellationSource cancelSource);
/**
* A fluent-style API for executing asynchronous, future-returning try-until loops, specialized
* around the retry logic for components within resharding's primary-only services.
*
* Example usage:
*
* ExecutorFuture<void> future =
* resharding::WithAutomaticRetry(
* [this, chainCtx] { chainCtx->moreToCome = doOneBatch(); })
* .onTransientError([](const Status& status) {
* LOGV2(123,
* "Transient error while doing batch",
* "error"_attr = redact(status));
* })
* .onUnrecoverableError([](const Status& status) {
* LOGV2_ERROR(456,
* "Operation-fatal error for resharding while doing batch",
* "error"_attr = redact(status));
* })
* .until([chainCtx](const Status& status) {
* return status.isOK() && !chainCtx->moreToCome;
* })
* .on(std::move(executor), std::move(cancelToken));
*/
template <typename BodyCallable>
class [[nodiscard]] WithAutomaticRetry {
public:
explicit WithAutomaticRetry(BodyCallable && body) : _body{std::move(body)} {}
decltype(auto) onTransientError(unique_function<void(const Status&)> onTransientError)&& {
invariant(!_onTransientError, "Cannot call onTransientError() twice");
_onTransientError = std::move(onTransientError);
return std::move(*this);
}
decltype(auto) onUnrecoverableError(
unique_function<void(const Status&)> onUnrecoverableError)&& {
invariant(!_onUnrecoverableError, "Cannot call onUnrecoverableError() twice");
_onUnrecoverableError = std::move(onUnrecoverableError);
return std::move(*this);
}
template <typename StatusType>
auto until(unique_function<bool(const StatusType&)> condition)&& {
invariant(_onTransientError, "Must call onTransientError() first");
invariant(_onUnrecoverableError, "Must call onUnrecoverableError() first");
return AsyncTry<BodyCallable>(std::move(_body))
.until([onTransientError = std::move(_onTransientError),
onUnrecoverableError = std::move(_onUnrecoverableError),
condition = std::move(condition)](const StatusType& statusOrStatusWith) {
Status status = _getStatus(statusOrStatusWith);
if (status.isA<ErrorCategory::RetriableError>() ||
status == ErrorCodes::FailedToSatisfyReadPreference ||
status.isA<ErrorCategory::CursorInvalidatedError>() ||
status == ErrorCodes::Interrupted ||
status.isA<ErrorCategory::CancellationError>() ||
status.isA<ErrorCategory::NotPrimaryError>()) {
// Always attempt to retry on any type of retryable error. Also retry on errors
// from stray killCursors and killOp commands being run. Cancellation and
// NotPrimary errors may indicate the primary-only service Instance will be shut
// down or is shutting down now. However, it is also possible that the error
// originated from a remote response rather than being an error generated by
// this shard itself. Defer whether or not to retry to the state of the
// cancellation token. This means the body of the AsyncTry may continue to run
// and error more times until the cancellation token is actually canceled if
// this shard was in the midst of stepping down.
onTransientError(status);
} else if (!status.isOK()) {
// Any other kind of error is fatal for the resharding operation. Do not attempt
// to retry.
onUnrecoverableError(status);
return true;
}
return condition(statusOrStatusWith);
});
}
private:
static const Status& _getStatus(const Status& status) {
return status;
}
template <typename ValueType>
static const Status& _getStatus(const StatusWith<ValueType>& statusWith) {
return statusWith.getStatus();
}
BodyCallable _body;
unique_function<void(const Status&)> _onTransientError;
unique_function<void(const Status&)> _onUnrecoverableError;
};
/**
* Wrapper class around CancelableOperationContextFactory which uses resharding::WithAutomaticRetry
* to ensure all cancelable operations will be retried if able upon failure.
*/
class RetryingCancelableOperationContextFactory {
public:
RetryingCancelableOperationContextFactory(CancellationToken cancelToken, ExecutorPtr executor)
: _factory{std::move(cancelToken), std::move(executor)} {}
template <typename BodyCallable>
decltype(auto) withAutomaticRetry(BodyCallable&& body) const {
return resharding::WithAutomaticRetry([this, body]() { return body(_factory); });
}
private:
const CancelableOperationContextFactory _factory;
};
} // namespace resharding
} // namespace mongo
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