IGNITE-27870 added proxy class. by Erixonich · Pull Request #7607 · apache/ignite-3

Erixonich · 2026-02-16T21:02:45Z

https://issues.apache.org/jira/browse/IGNITE-27870

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Apache Ignite Coding Guidelines

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Pull request overview

This PR adds proxy classes to facilitate testing of network connections in the C++ client test suite. The changes introduce two proxy implementations: kgb_proxy (using Linux epoll) and asio_proxy (using the ASIO library), along with a new test that exercises the ASIO-based proxy.

Changes:

Added kgb_proxy class using Linux epoll for TCP proxying (header and implementation)
Added asio_proxy class using ASIO library for TCP proxying (header and implementation)
Added ASIO library as a test dependency in the CMake build configuration
Added test case using_asio to verify proxy functionality

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 29 comments.

Show a summary per file

File	Description
modules/platforms/cpp/tests/fake_server/proxy/kgb_proxy.h	Header defining kgb_proxy class, message_chunk, and proxy_connection structures
modules/platforms/cpp/tests/fake_server/proxy/kgb_proxy.cpp	Implementation of kgb_proxy using Linux epoll for TCP proxying
modules/platforms/cpp/tests/fake_server/proxy/asio_proxy.h	Header defining asio_proxy and session classes using ASIO library
modules/platforms/cpp/tests/fake_server/proxy/asio_proxy.cpp	Minimal implementation file for asio_proxy (header-only)
modules/platforms/cpp/tests/fake_server/connection_test.cpp	Added test case for asio_proxy, includes commented-out kgb_proxy test
modules/platforms/cpp/tests/fake_server/CMakeLists.txt	Added asio library dependency and asio_proxy.cpp to build
modules/platforms/cpp/cmake/dependencies.cmake	Added ASIO library fetching and configuration

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Copilot · 2026-02-19T19:32:44Z

modules/platforms/cpp/tests/fake_server/proxy/kgb_proxy.cpp

+        while (!queue.empty()) {
+
+            const message_chunk& chunk = queue.front();
+            ssize_t sent = send(dst, chunk.m_msg, chunk.m_size, 0);
+
+            if (sent <= 0) {
+                if (errno == EAGAIN || errno == EWOULDBLOCK) {
+                    break;
+                }
+
+                perror("send");
+                break;
+            }
+
+            queue.pop();


Potential partial send issue: send() may send fewer bytes than requested. The code assumes all bytes are sent in one call (line 249), but send() can return a value less than chunk.m_size. This could lead to incomplete message transmission. The message_chunk should track how many bytes have been sent and retry sending the remaining bytes.

Copilot · 2026-02-19T19:32:45Z

modules/platforms/cpp/tests/fake_server/proxy/asio_proxy.h

+    void do_accept() {
+        m_acceptor.async_accept(m_in_sock, [this](asio::error_code ec) {
+            if (!ec) {
+                auto ses = m_sessons.emplace_back(


Typo in variable name: m_sessons should be m_sessions (missing 'i'). This is the same variable referenced in line 193.

Copilot · 2026-02-19T19:32:45Z

modules/platforms/cpp/cmake/dependencies.cmake

+#    FetchContent_Declare(
+#            asio
+#            GIT_REPOSITORY https://github.com/chriskohlhoff/asio.git
+#            GIT_TAG asio-1-36-0
+#    )


Commented-out code should be removed rather than left in the codebase. If this alternative implementation using GIT_REPOSITORY is needed for reference, consider documenting it in a comment or external documentation instead.

Suggested change

# FetchContent_Declare(

# asio

# GIT_REPOSITORY https://github.com/chriskohlhoff/asio.git

# GIT_TAG asio-1-36-0

# )

Copilot · 2026-02-19T19:32:46Z

modules/platforms/cpp/tests/fake_server/proxy/asio_proxy.h

+        src.async_read_some(asio::buffer(buf, BUFF_SIZE),
+    [this, &queue, direction, &writable](asio::error_code ec, size_t len) {
+            if (ec) {
+                throw std::runtime_error("Error while reading from socket " + ec.message());
+            }
+
+            // we have one-threaded executor no synchronization is needed
+            queue.emplace(buf, len);
+
+            if (writable) { // there are pending write operation on this socket
+                do_write(direction);
+            }
+
+            do_read(direction);
+        });


The lambda captures references to queue and writable (&queue, &writable), which are local references in the do_read function that point to members of 'this'. If 'this' (the session) is destroyed before the async operation completes, these references will be dangling. The session should be kept alive by capturing shared_from_this() in the lambda to ensure the object outlives the async operation.

Copilot · 2026-02-19T19:32:46Z

modules/platforms/cpp/tests/fake_server/proxy/asio_proxy.h

+            asio::async_write(
+                dst, asio::buffer(msg.m_arr, msg.m_size), [this, &queue, direction, &writable](asio::error_code ec, size_t) {
+                    if (ec) {
+                        throw std::runtime_error("Error while writing to socket " + ec.message());
+                    }
+
+                    queue.pop();
+
+                    if (!queue.empty()) {
+                        // makes writes on the same socket strictly ordered
+                        do_write(direction);
+                    } else {
+                        writable = true; // now read operation can initiate writes
+                    }
+                });


Similar to the issue in do_read, the lambda captures references (&queue, &writable) which point to members of 'this'. If the session is destroyed before the async operation completes, these references will be dangling. The session should be kept alive by capturing shared_from_this() in the lambda.

Copilot · 2026-02-19T19:32:51Z

modules/platforms/cpp/tests/fake_server/proxy/kgb_proxy.h

+#include <queue>
+#include <sys/epoll.h>


The kgb_proxy class uses Linux-specific headers (sys/epoll.h, sys/eventfd.h) and system calls (epoll_create1, eventfd, epoll_ctl, epoll_wait) without any platform abstraction or guards. This code will not compile on non-Linux platforms (Windows, macOS). Consider adding platform guards or using a cross-platform abstraction layer, similar to how the codebase has separate linux/ and macos/ directories for network code.

Suggested change

#include <queue>

#include <sys/epoll.h>

#include <queue>

#if defined(__linux__)

#include <sys/epoll.h>

#else

struct epoll_event;

#endif

Copilot · 2026-02-19T19:32:51Z

modules/platforms/cpp/tests/fake_server/connection_test.cpp

+// TEST_F(connection_test, using_proxy) {
+//     fake_server fs{50900, get_logger()};
+//     proxy::kgb_proxy proxy{50800, 50900};
+//
+//     fs.start();
+//     proxy.start();
+//
+//     ignite_client_configuration cfg;
+//     cfg.set_logger(get_logger());
+//     cfg.set_endpoints(get_endpoints());
+//
+//     auto cl = ignite_client::start(cfg, 5s);
+//
+//     auto cluster_nodes = cl.get_cluster_nodes();
+//
+//     ASSERT_EQ(1, cluster_nodes.size());
+// }
+


The kgb_proxy class implementation is added but there is no active test for it. The test_F(connection_test, using_proxy) is commented out. While asio_proxy has a working test, leaving kgb_proxy untested could allow bugs to remain undetected. Either uncomment and fix the test, or remove the kgb_proxy implementation if it's not intended to be used.

Suggested change

// TEST_F(connection_test, using_proxy) {

// fake_server fs{50900, get_logger()};

// proxy::kgb_proxy proxy{50800, 50900};

//

// fs.start();

// proxy.start();

//

// ignite_client_configuration cfg;

// cfg.set_logger(get_logger());

// cfg.set_endpoints(get_endpoints());

//

// auto cl = ignite_client::start(cfg, 5s);

//

// auto cluster_nodes = cl.get_cluster_nodes();

//

// ASSERT_EQ(1, cluster_nodes.size());

// }

TEST_F(connection_test, using_proxy) {

fake_server fs{50900, get_logger()};

proxy::kgb_proxy proxy{50800, 50900};

fs.start();

proxy.start();

ignite_client_configuration cfg;

cfg.set_logger(get_logger());

cfg.set_endpoints(get_endpoints());

auto cl = ignite_client::start(cfg, 5s);

auto cluster_nodes = cl.get_cluster_nodes();

ASSERT_EQ(1, cluster_nodes.size());

}

Copilot · 2026-02-19T19:32:51Z

modules/platforms/cpp/tests/fake_server/proxy/asio_proxy.h

+    tcp::resolver m_resolver;
+    tcp::socket m_in_sock;
+
+    std::vector<std::shared_ptr<session>> m_sessons;


Typo in variable name: m_sessons should be m_sessions (missing 'i').

Copilot · 2026-02-19T19:32:52Z

modules/platforms/cpp/tests/fake_server/proxy/kgb_proxy.cpp

+    ep_ev.data.fd = fd;
+    ep_ev.events = EPOLLIN | EPOLLOUT | EPOLLET;
+
+    epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &ep_ev);


The return value of epoll_ctl should be checked for errors. In the existing codebase (e.g., linux_async_worker_thread.cpp:77-83), epoll_ctl failures are checked and proper error handling is performed. Ignoring errors could lead to silent failures where events are not properly registered or modified.

Copilot · 2026-02-19T19:32:52Z

modules/platforms/cpp/tests/fake_server/proxy/kgb_proxy.cpp

+    ev.events = EPOLLIN | EPOLLET;
+    ev.data.fd = fd;
+
+    epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fd, &ev);


The return value of epoll_ctl should be checked for errors. In the existing codebase (e.g., linux_async_worker_thread.cpp:77-83), epoll_ctl failures are checked and proper error handling is performed.

IGNITE-27870 added proxy class which can connect to one server

75c1612

Erixonich requested a review from isapego as a code owner February 16, 2026 21:02

Erixonich marked this pull request as draft February 16, 2026 21:02

Erixonich added 2 commits February 17, 2026 00:04

IGNITE-27870 removed empty lines

61d4f2a

IGNITE-27870 wip

753a35d

isapego requested a review from Copilot February 19, 2026 19:23

Copilot started reviewing on behalf of isapego February 19, 2026 19:23 View session

Copilot AI reviewed Feb 19, 2026

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IGNITE-27870 wip

42ec10f

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IGNITE-27870 added proxy class.#7607

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Erixonich commented Feb 16, 2026

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