libzmq/tests/test_router_handover.cpp

/* SPDX-License-Identifier: MPL-2.0 */

#include "testutil.hpp"
#include "testutil_unity.hpp"

SETUP_TEARDOWN_TESTCONTEXT

void test_with_handover ()
{
    char my_endpoint[MAX_SOCKET_STRING];
    void *router = test_context_socket (ZMQ_ROUTER);
    bind_loopback_ipv4 (router, my_endpoint, sizeof my_endpoint);

    // Enable the handover flag
    int handover = 1;
    TEST_ASSERT_SUCCESS_ERRNO (zmq_setsockopt (router, ZMQ_ROUTER_HANDOVER,
                                               &handover, sizeof (handover)));

    //  Create dealer called "X" and connect it to our router
    void *dealer_one = test_context_socket (ZMQ_DEALER);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer_one, ZMQ_ROUTING_ID, "X", 1));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer_one, my_endpoint));

    //  Get message from dealer to know when connection is ready
    char buffer[255];
    send_string_expect_success (dealer_one, "Hello", 0);

    recv_string_expect_success (router, "X", 0);
    recv_string_expect_success (router, "Hello", 0);

    // Now create a second dealer that uses the same routing id
    void *dealer_two = test_context_socket (ZMQ_DEALER);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer_two, ZMQ_ROUTING_ID, "X", 1));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer_two, my_endpoint));

    //  Get message from dealer to know when connection is ready
    send_string_expect_success (dealer_two, "Hello", 0);

    recv_string_expect_success (router, "X", 0);
    recv_string_expect_success (router, "Hello", 0);

    //  Send a message to 'X' routing id. This should be delivered
    //  to the second dealer, instead of the first because of the handover.
    send_string_expect_success (router, "X", ZMQ_SNDMORE);
    send_string_expect_success (router, "Hello", 0);

    //  Ensure that the first dealer doesn't receive the message
    //  but the second one does
    const int timeout = SETTLE_TIME;
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer_one, ZMQ_RCVTIMEO, &timeout, sizeof timeout));
    TEST_ASSERT_FAILURE_ERRNO (EAGAIN, zmq_recv (dealer_one, buffer, 255, 0));

    recv_string_expect_success (dealer_two, "Hello", 0);

    test_context_socket_close (router);
    test_context_socket_close (dealer_one);
    test_context_socket_close (dealer_two);
}

void test_without_handover ()
{
    size_t len = MAX_SOCKET_STRING;
    char my_endpoint[MAX_SOCKET_STRING];
    void *router = test_context_socket (ZMQ_ROUTER);

    TEST_ASSERT_SUCCESS_ERRNO (zmq_bind (router, "tcp://127.0.0.1:*"));

    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_getsockopt (router, ZMQ_LAST_ENDPOINT, my_endpoint, &len));

    //  Create dealer called "X" and connect it to our router
    void *dealer_one = test_context_socket (ZMQ_DEALER);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer_one, ZMQ_ROUTING_ID, "X", 1));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer_one, my_endpoint));

    //  Get message from dealer to know when connection is ready
    char buffer[255];
    send_string_expect_success (dealer_one, "Hello", 0);

    recv_string_expect_success (router, "X", 0);
    recv_string_expect_success (router, "Hello", 0);

    // Now create a second dealer that uses the same routing id
    void *dealer_two = test_context_socket (ZMQ_DEALER);
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer_two, ZMQ_ROUTING_ID, "X", 1));
    TEST_ASSERT_SUCCESS_ERRNO (zmq_connect (dealer_two, my_endpoint));

    //  Send message from second dealer
    send_string_expect_success (dealer_two, "Hello", 0);

    //  This should be ignored by the router
    const int timeout = SETTLE_TIME;
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (router, ZMQ_RCVTIMEO, &timeout, sizeof timeout));
    TEST_ASSERT_FAILURE_ERRNO (EAGAIN, zmq_recv (router, buffer, 255, 0));

    //  Send a message to 'X' routing id. This should be delivered
    //  to the second dealer, instead of the first because of the handover.
    send_string_expect_success (router, "X", ZMQ_SNDMORE);
    send_string_expect_success (router, "Hello", 0);

    //  Ensure that the second dealer doesn't receive the message
    //  but the first one does
    TEST_ASSERT_SUCCESS_ERRNO (
      zmq_setsockopt (dealer_two, ZMQ_RCVTIMEO, &timeout, sizeof timeout));
    TEST_ASSERT_FAILURE_ERRNO (EAGAIN, zmq_recv (dealer_two, buffer, 255, 0));

    recv_string_expect_success (dealer_one, "Hello", 0);

    test_context_socket_close (router);
    test_context_socket_close (dealer_one);
    test_context_socket_close (dealer_two);
}

int main ()
{
    setup_test_environment ();

    UNITY_BEGIN ();
    RUN_TEST (test_with_handover);
    RUN_TEST (test_without_handover);
    return UNITY_END ();
}