ngx_http_upstream_round_robin.c

来自「Nginx是一个高性能的HTTP和反向代理服务器」· C语言 代码 · 共 747 行 · 第 1/2 页

        c->write->lock = c->write->own_lock;
#endif

        pc->connection = c;
        pc->cached = 1;

        return NGX_OK;
    }

    pc->cached = 0;
    pc->connection = NULL;

    if (rrp->peers->single) {
        peer = &rrp->peers->peer[0];

    } else {

        /* there are several peers */

        if (pc->tries == rrp->peers->number) {

            /* it's a first try - get a current peer */

            i = pc->tries;

            for ( ;; ) {
                rrp->current = ngx_http_upstream_get_peer(rrp->peers);

                ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                               "get rr peer, current: %ui %i",
                               rrp->current,
                               rrp->peers->peer[rrp->current].current_weight);

                n = rrp->current / (8 * sizeof(uintptr_t));
                m = (uintptr_t) 1 << rrp->current % (8 * sizeof(uintptr_t));

                if (!(rrp->tried[n] & m)) {
                    peer = &rrp->peers->peer[rrp->current];

                    if (!peer->down) {

                        if (peer->max_fails == 0
                            || peer->fails < peer->max_fails)
                        {
                            break;
                        }

                        if (now - peer->accessed > peer->fail_timeout) {
                            peer->fails = 0;
                            break;
                        }

                        peer->current_weight = 0;

                    } else {
                        rrp->tried[n] |= m;
                    }

                    pc->tries--;
                }

                if (pc->tries == 0) {
                    goto failed;
                }

                if (--i == 0) {
                    ngx_log_error(NGX_LOG_ALERT, pc->log, 0,
                                  "round robin upstream stuck on %ui tries",
                                  pc->tries);
                    goto failed;
                }
            }

            peer->current_weight--;

        } else {

            i = pc->tries;

            for ( ;; ) {
                n = rrp->current / (8 * sizeof(uintptr_t));
                m = (uintptr_t) 1 << rrp->current % (8 * sizeof(uintptr_t));

                if (!(rrp->tried[n] & m)) {

                    peer = &rrp->peers->peer[rrp->current];

                    if (!peer->down) {

                        if (peer->max_fails == 0
                            || peer->fails < peer->max_fails)
                        {
                            break;
                        }

                        if (now - peer->accessed > peer->fail_timeout) {
                            peer->fails = 0;
                            break;
                        }

                        peer->current_weight = 0;

                    } else {
                        rrp->tried[n] |= m;
                    }

                    pc->tries--;
                }

                rrp->current++;

                if (rrp->current >= rrp->peers->number) {
                    rrp->current = 0;
                }

                if (pc->tries == 0) {
                    goto failed;
                }

                if (--i == 0) {
                    ngx_log_error(NGX_LOG_ALERT, pc->log, 0,
                                  "round robin upstream stuck on %ui tries",
                                  pc->tries);
                    goto failed;
                }
            }

            peer->current_weight--;
        }

        rrp->tried[n] |= m;
    }

    pc->sockaddr = peer->sockaddr;
    pc->socklen = peer->socklen;
    pc->name = &peer->name;

    /* ngx_unlock_mutex(rrp->peers->mutex); */

    if (pc->tries == 1 && rrp->peers->next) {
        pc->tries += rrp->peers->next->number;

        n = rrp->peers->next->number / (8 * sizeof(uintptr_t)) + 1;
        for (i = 0; i < n; i++) {
             rrp->tried[i] = 0;
        }
    }

    return NGX_OK;

failed:

    peers = rrp->peers;

    if (peers->next) {

        /* ngx_unlock_mutex(peers->mutex); */

        ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0, "backup servers");

        rrp->peers = peers->next;
        pc->tries = rrp->peers->number;

        n = rrp->peers->number / (8 * sizeof(uintptr_t)) + 1;
        for (i = 0; i < n; i++) {
             rrp->tried[i] = 0;
        }

        rc = ngx_http_upstream_get_round_robin_peer(pc, rrp);

        if (rc != NGX_BUSY) {
            return rc;
        }

        /* ngx_lock_mutex(peers->mutex); */
    }

    /* all peers failed, mark them as live for quick recovery */

    for (i = 0; i < peers->number; i++) {
        peers->peer[i].fails = 0;
    }

    /* ngx_unlock_mutex(peers->mutex); */

    pc->name = peers->name;

    return NGX_BUSY;
}


static ngx_uint_t
ngx_http_upstream_get_peer(ngx_http_upstream_rr_peers_t *peers)
{
    ngx_uint_t                    i, n;
    ngx_http_upstream_rr_peer_t  *peer;

    peer = &peers->peer[0];

    for ( ;; ) {

        for (i = 0; i < peers->number; i++) {

            if (peer[i].current_weight <= 0) {
                continue;
            }

            n = i;

            while (i < peers->number - 1) {

                i++;

                if (peer[i].current_weight <= 0) {
                    continue;
                }

                if (peer[n].current_weight * 1000 / peer[i].current_weight
                    > peer[n].weight * 1000 / peer[i].weight)
                {
                    return n;
                }

                n = i;
            }

            if (peer[i].current_weight > 0) {
                n = i;
            }

            return n;
        }

        for (i = 0; i < peers->number; i++) {
            peer[i].current_weight = peer[i].weight;
        }
    }
}


void
ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
    ngx_uint_t state)
{
    ngx_http_upstream_rr_peer_data_t  *rrp = data;

    time_t                       now;
    ngx_http_upstream_rr_peer_t  *peer;

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                   "free rr peer %ui %ui", pc->tries, state);

    if (state == 0 && pc->tries == 0) {
        return;
    }

    /* TODO: NGX_PEER_KEEPALIVE */

    if (rrp->peers->single) {
        pc->tries = 0;
        return;
    }

    if (state & NGX_PEER_FAILED) {
        now = ngx_time();

        peer = &rrp->peers->peer[rrp->current];

        /* ngx_lock_mutex(rrp->peers->mutex); */

        peer->fails++;
        peer->accessed = now;

        peer->current_weight -= peer->weight / peer->max_fails;

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                       "free rr peer failed: %ui %i",
                       rrp->current, peer->current_weight);

        if (peer->current_weight < 0) {
            peer->current_weight = 0;
        }

        /* ngx_unlock_mutex(rrp->peers->mutex); */
    }

    rrp->current++;

    if (rrp->current >= rrp->peers->number) {
        rrp->current = 0;
    }

    if (pc->tries) {
        pc->tries--;
    }

    /* ngx_unlock_mutex(rrp->peers->mutex); */
}


#if (NGX_HTTP_SSL)

ngx_int_t
ngx_http_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data)
{
    ngx_http_upstream_rr_peer_data_t  *rrp = data;

    ngx_int_t                     rc;
    ngx_ssl_session_t            *ssl_session;
    ngx_http_upstream_rr_peer_t  *peer;

    peer = &rrp->peers->peer[rrp->current];

    /* TODO: threads only mutex */
    /* ngx_lock_mutex(rrp->peers->mutex); */

    ssl_session = peer->ssl_session;

    rc = ngx_ssl_set_session(pc->connection, ssl_session);

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                   "set session: %p:%d",
                   ssl_session, ssl_session ? ssl_session->references : 0);

    /* ngx_unlock_mutex(rrp->peers->mutex); */

    return rc;
}


void
ngx_http_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data)
{
    ngx_http_upstream_rr_peer_data_t  *rrp = data;

    ngx_ssl_session_t            *old_ssl_session, *ssl_session;
    ngx_http_upstream_rr_peer_t  *peer;

    ssl_session = ngx_ssl_get_session(pc->connection);

    if (ssl_session == NULL) {
        return;
    }

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                   "save session: %p:%d", ssl_session, ssl_session->references);

    peer = &rrp->peers->peer[rrp->current];

    /* TODO: threads only mutex */
    /* ngx_lock_mutex(rrp->peers->mutex); */

    old_ssl_session = peer->ssl_session;
    peer->ssl_session = ssl_session;

    /* ngx_unlock_mutex(rrp->peers->mutex); */

    if (old_ssl_session) {

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
                       "old session: %p:%d",
                       old_ssl_session, old_ssl_session->references);

        /* TODO: may block */

        ngx_ssl_free_session(old_ssl_session);
    }
}

#endif