a55b7688b6
To avoid an expensive stack unwind, instead of throwing an error, we can just return it thanks to the boost::result type that the affected methods use. The result with an exception needs to be constructed not implicitly, but with boost::outcome_v2::failure, because the exception, converted into coordinator_exception_container can be then converted into both into a successful response_id_type as well as into a failure.
46 lines
1.4 KiB
C++
46 lines
1.4 KiB
C++
/*
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* Copyright (C) 2022-present ScyllaDB
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*/
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/*
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* SPDX-License-Identifier: (AGPL-3.0-or-later and Apache-2.0)
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*/
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#pragma once
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#include "exceptions.hh"
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#include <boost/outcome/result.hpp>
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#include "utils/exception_container.hh"
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#include "utils/result.hh"
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namespace exceptions {
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// Allows to pass a coordinator exception as a value. With coordinator_result,
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// it is possible to handle exceptions and inspect their type/value without
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// resorting to costly rethrows. On the other hand, using them is more
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// cumbersome than just using exceptions and exception futures.
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//
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// Not all exceptions are passed in this way, therefore the container
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// does not allow all types of coordinator exceptions. On the other hand,
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// an exception being listed here does not mean it is _always_ passed
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// in an exception_container - it can be thrown in a regular fashion
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// as well.
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//
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// It is advised to use this mechanism mainly for exceptions which can
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// happen frequently, e.g. signalling timeouts, overloads or rate limits.
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using coordinator_exception_container = utils::exception_container<
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mutation_write_timeout_exception,
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read_timeout_exception,
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read_failure_exception,
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rate_limit_exception,
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overloaded_exception
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>;
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template<typename T = void>
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using coordinator_result = bo::result<T,
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coordinator_exception_container,
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utils::exception_container_throw_policy
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>;
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}
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