73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
// Copyright 2022 Memgraph Ltd.
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//
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// Use of this software is governed by the Business Source License
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// included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source
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// License, and you may not use this file except in compliance with the Business Source License.
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//
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// As of the Change Date specified in that file, in accordance with
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// the Business Source License, use of this software will be governed
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// by the Apache License, Version 2.0, included in the file
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// licenses/APL.txt.
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#pragma once
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#include <mutex>
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#include <stack>
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#include "rpc/client.hpp"
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namespace memgraph::rpc {
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/**
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* A simple client pool that creates new RPC clients on demand. Useful when you
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* want to send RPCs to the same server from multiple threads without them
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* blocking each other.
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*/
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class ClientPool {
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public:
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ClientPool(const io::network::Endpoint &endpoint, communication::ClientContext *context)
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: endpoint_(endpoint), context_(context) {}
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template <class TRequestResponse, class... Args>
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typename TRequestResponse::Response Call(Args &&...args) {
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return WithUnusedClient(
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[&](const auto &client) { return client->template Call<TRequestResponse>(std::forward<Args>(args)...); });
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}
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template <class TRequestResponse, class... Args>
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typename TRequestResponse::Response CallWithLoad(Args &&...args) {
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return WithUnusedClient([&](const auto &client) {
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return client->template CallWithLoad<TRequestResponse>(std::forward<Args>(args)...);
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});
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}
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private:
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template <class TFun>
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auto WithUnusedClient(const TFun &fun) {
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std::unique_ptr<Client> client;
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std::unique_lock<std::mutex> lock(mutex_);
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if (unused_clients_.empty()) {
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client = std::make_unique<Client>(endpoint_, context_);
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} else {
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client = std::move(unused_clients_.top());
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unused_clients_.pop();
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}
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lock.unlock();
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auto res = fun(client);
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lock.lock();
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unused_clients_.push(std::move(client));
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return res;
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}
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io::network::Endpoint endpoint_;
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communication::ClientContext *context_;
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std::mutex mutex_;
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std::stack<std::unique_ptr<Client>> unused_clients_;
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};
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} // namespace memgraph::rpc
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