Function clusterSendMessage

app/redis-6.2.6/src/cluster.c:2397–2408

Put stuff into the send buffer. * * It is guaranteed that this function will never have as a side effect * the link to be invalidated, so it is safe to call this function * from event handlers that will do stuff with the same link later. */

 * the link to be invalidated, so it is safe to call this function
 * from event handlers that will do stuff with the same link later. */
void clusterSendMessage(clusterLink *link, unsigned char *msg, size_t msglen) {
    if (sdslen(link->sndbuf) == 0 && msglen != 0)
        connSetWriteHandlerWithBarrier(link->conn, clusterWriteHandler, 1);

    link->sndbuf = sdscatlen(link->sndbuf, msg, msglen);

    /* Populate sent messages stats. */
    clusterMsg *hdr = (clusterMsg*) msg;
    uint16_t type = ntohs(hdr->type);
    if (type < CLUSTERMSG_TYPE_COUNT)
        server.cluster->stats_bus_messages_sent[type]++;
}

/* Send a message to all the nodes that are part of the cluster having
 * a connected link.