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927c1c6e3a
Summary: related to T13767 T13767 Reviewers: ivica Reviewed By: ivica Subscribers: miljen, iljazovic Differential Revision: https://repo.mireo.local/D29686
98 lines
2.9 KiB
C++
98 lines
2.9 KiB
C++
//
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// Copyright (c) 2023-2024 Ivica Siladic, Bruno Iljazovic, Korina Simicevic
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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//[hello_world_in_multithreaded_env
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#include <iostream>
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#include <vector>
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#include <thread>
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#include <boost/asio/detached.hpp>
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#include <boost/asio/io_context.hpp>
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#include <boost/asio/post.hpp>
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#include <boost/asio/strand.hpp>
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#include <boost/asio/ip/tcp.hpp>
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#include <async_mqtt5.hpp>
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int main() {
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// Create a multithreaded environment where 4 threads
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// will be calling ioc.run().
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// Number of threads that will call io_context::run().
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int thread_num = 4;
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boost::asio::io_context ioc(4);
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// Create the remaining threads (aside of this one).
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std::vector<std::thread> threads;
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threads.reserve(thread_num - 1);
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// Create an explicit strand from io_context's executor.
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// The strand guarantees a serialised handler execution regardless of the
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// number of threads running in the io_context.
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boost::asio::strand strand = boost::asio::make_strand(ioc.get_executor());
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// Create the Client with the explicit strand as the default associated executor.
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async_mqtt5::mqtt_client<boost::asio::ip::tcp::socket> client(strand);
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// Configure the client.
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client.brokers("<your-mqtt-broker>", 1883);
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// Start the Client.
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// The async_run function call must be posted/dispatched to the strand.
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boost::asio::post(
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strand,
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[&client, &strand] {
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// Considering that the default associated executor of all completion handlers is the strand,
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// it is not necessary to explicitly bind it to async_run or other async_xxx's handlers.
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client.async_run(boost::asio::detached);
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}
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);
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// The async_publish function call must be posted/dispatched to the strand.
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// The associated executor of async_publish's completion handler must be the same strand.
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boost::asio::post(
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strand,
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[&client, &strand] {
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assert(strand.running_in_this_thread());
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client.async_publish<async_mqtt5::qos_e::at_least_once>(
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"<your-mqtt-topic>", "Hello world!", async_mqtt5::retain_e::no,
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async_mqtt5::publish_props {},
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// You may bind the strand to this handler, but it is not necessary
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// as the strand is already the default associated handler.
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// However, you must not bind it to any other executor!
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[&client, &strand](
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async_mqtt5::error_code ec, async_mqtt5::reason_code rc,
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async_mqtt5::puback_props props
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) {
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assert(strand.running_in_this_thread());
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std::cout << ec.message() << std::endl;
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std::cout << rc.message() << std::endl;
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// Stop the Client. This will cause ioc.run() to return.
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client.cancel();
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}
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);
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}
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);
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// Call ioc.run() on the other threads.
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for (int i = 0; i < thread_num - 1; ++i)
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threads.emplace_back([&ioc] { ioc.run(); });
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// Call ioc.run() on this thread.
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ioc.run();
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for (auto& t : threads)
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if (t.joinable()) t.join();
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return 0;
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}
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//]
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