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view src/stream/ngx_stream_upstream_round_robin.c @ 6694:ea9dfe2f62e7

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Stream: preread phase. In this phase, head of a stream is read and analysed before proceeding to the content phase. Amount of data read is controlled by the module implementing the phase, but not more than defined by the "preread_buffer_size" directive. The time spent on processing preread is controlled by the "preread_timeout" directive. The typical preread phase module will parse the beginning of a stream and set variable that may be used by the content phase, for example to make routing decision.
author Vladimir Homutov <vl@nginx.com>
date Thu, 15 Sep 2016 14:56:02 +0300
parents 9757cffc1e2f
children 914d8a63dbad
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_stream.h>


#define ngx_stream_upstream_tries(p) ((p)->number                             \
                                      + ((p)->next ? (p)->next->number : 0))


static ngx_stream_upstream_rr_peer_t *ngx_stream_upstream_get_peer(
    ngx_stream_upstream_rr_peer_data_t *rrp);

#if (NGX_STREAM_SSL)

static ngx_int_t ngx_stream_upstream_set_round_robin_peer_session(
    ngx_peer_connection_t *pc, void *data);
static void ngx_stream_upstream_save_round_robin_peer_session(
    ngx_peer_connection_t *pc, void *data);
static ngx_int_t ngx_stream_upstream_empty_set_session(
    ngx_peer_connection_t *pc, void *data);
static void ngx_stream_upstream_empty_save_session(ngx_peer_connection_t *pc,
    void *data);

#endif


ngx_int_t
ngx_stream_upstream_init_round_robin(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_url_t                        u;
    ngx_uint_t                       i, j, n, w;
    ngx_stream_upstream_server_t    *server;
    ngx_stream_upstream_rr_peer_t   *peer, **peerp;
    ngx_stream_upstream_rr_peers_t  *peers, *backup;

    us->peer.init = ngx_stream_upstream_init_round_robin_peer;

    if (us->servers) {
        server = us->servers->elts;

        n = 0;
        w = 0;

        for (i = 0; i < us->servers->nelts; i++) {
            if (server[i].backup) {
                continue;
            }

            n += server[i].naddrs;
            w += server[i].naddrs * server[i].weight;
        }

        if (n == 0) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "no servers in upstream \"%V\" in %s:%ui",
                          &us->host, us->file_name, us->line);
            return NGX_ERROR;
        }

        peers = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peers_t));
        if (peers == NULL) {
            return NGX_ERROR;
        }

        peer = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peer_t) * n);
        if (peer == NULL) {
            return NGX_ERROR;
        }

        peers->single = (n == 1);
        peers->number = n;
        peers->weighted = (w != n);
        peers->total_weight = w;
        peers->name = &us->host;

        n = 0;
        peerp = &peers->peer;

        for (i = 0; i < us->servers->nelts; i++) {
            if (server[i].backup) {
                continue;
            }

            for (j = 0; j < server[i].naddrs; j++) {
                peer[n].sockaddr = server[i].addrs[j].sockaddr;
                peer[n].socklen = server[i].addrs[j].socklen;
                peer[n].name = server[i].addrs[j].name;
                peer[n].weight = server[i].weight;
                peer[n].effective_weight = server[i].weight;
                peer[n].current_weight = 0;
                peer[n].max_fails = server[i].max_fails;
                peer[n].fail_timeout = server[i].fail_timeout;
                peer[n].down = server[i].down;
                peer[n].server = server[i].name;

                *peerp = &peer[n];
                peerp = &peer[n].next;
                n++;
            }
        }

        us->peer.data = peers;

        /* backup servers */

        n = 0;
        w = 0;

        for (i = 0; i < us->servers->nelts; i++) {
            if (!server[i].backup) {
                continue;
            }

            n += server[i].naddrs;
            w += server[i].naddrs * server[i].weight;
        }

        if (n == 0) {
            return NGX_OK;
        }

        backup = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peers_t));
        if (backup == NULL) {
            return NGX_ERROR;
        }

        peer = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peer_t) * n);
        if (peer == NULL) {
            return NGX_ERROR;
        }

        peers->single = 0;
        backup->single = 0;
        backup->number = n;
        backup->weighted = (w != n);
        backup->total_weight = w;
        backup->name = &us->host;

        n = 0;
        peerp = &backup->peer;

        for (i = 0; i < us->servers->nelts; i++) {
            if (!server[i].backup) {
                continue;
            }

            for (j = 0; j < server[i].naddrs; j++) {
                peer[n].sockaddr = server[i].addrs[j].sockaddr;
                peer[n].socklen = server[i].addrs[j].socklen;
                peer[n].name = server[i].addrs[j].name;
                peer[n].weight = server[i].weight;
                peer[n].effective_weight = server[i].weight;
                peer[n].current_weight = 0;
                peer[n].max_fails = server[i].max_fails;
                peer[n].fail_timeout = server[i].fail_timeout;
                peer[n].down = server[i].down;
                peer[n].server = server[i].name;

                *peerp = &peer[n];
                peerp = &peer[n].next;
                n++;
            }
        }

        peers->next = backup;

        return NGX_OK;
    }


    /* an upstream implicitly defined by proxy_pass, etc. */

    if (us->port == 0) {
        ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                      "no port in upstream \"%V\" in %s:%ui",
                      &us->host, us->file_name, us->line);
        return NGX_ERROR;
    }

    ngx_memzero(&u, sizeof(ngx_url_t));

    u.host = us->host;
    u.port = us->port;

    if (ngx_inet_resolve_host(cf->pool, &u) != NGX_OK) {
        if (u.err) {
            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                          "%s in upstream \"%V\" in %s:%ui",
                          u.err, &us->host, us->file_name, us->line);
        }

        return NGX_ERROR;
    }

    n = u.naddrs;

    peers = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peers_t));
    if (peers == NULL) {
        return NGX_ERROR;
    }

    peer = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_rr_peer_t) * n);
    if (peer == NULL) {
        return NGX_ERROR;
    }

    peers->single = (n == 1);
    peers->number = n;
    peers->weighted = 0;
    peers->total_weight = n;
    peers->name = &us->host;

    peerp = &peers->peer;

    for (i = 0; i < u.naddrs; i++) {
        peer[i].sockaddr = u.addrs[i].sockaddr;
        peer[i].socklen = u.addrs[i].socklen;
        peer[i].name = u.addrs[i].name;
        peer[i].weight = 1;
        peer[i].effective_weight = 1;
        peer[i].current_weight = 0;
        peer[i].max_fails = 1;
        peer[i].fail_timeout = 10;
        *peerp = &peer[i];
        peerp = &peer[i].next;
    }

    us->peer.data = peers;

    /* implicitly defined upstream has no backup servers */

    return NGX_OK;
}


ngx_int_t
ngx_stream_upstream_init_round_robin_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_uint_t                           n;
    ngx_stream_upstream_rr_peer_data_t  *rrp;

    rrp = s->upstream->peer.data;

    if (rrp == NULL) {
        rrp = ngx_palloc(s->connection->pool,
                         sizeof(ngx_stream_upstream_rr_peer_data_t));
        if (rrp == NULL) {
            return NGX_ERROR;
        }

        s->upstream->peer.data = rrp;
    }

    rrp->peers = us->peer.data;
    rrp->current = NULL;

    n = rrp->peers->number;

    if (rrp->peers->next && rrp->peers->next->number > n) {
        n = rrp->peers->next->number;
    }

    if (n <= 8 * sizeof(uintptr_t)) {
        rrp->tried = &rrp->data;
        rrp->data = 0;

    } else {
        n = (n + (8 * sizeof(uintptr_t) - 1)) / (8 * sizeof(uintptr_t));

        rrp->tried = ngx_pcalloc(s->connection->pool, n * sizeof(uintptr_t));
        if (rrp->tried == NULL) {
            return NGX_ERROR;
        }
    }

    s->upstream->peer.get = ngx_stream_upstream_get_round_robin_peer;
    s->upstream->peer.free = ngx_stream_upstream_free_round_robin_peer;
    s->upstream->peer.tries = ngx_stream_upstream_tries(rrp->peers);
#if (NGX_STREAM_SSL)
    s->upstream->peer.set_session =
                             ngx_stream_upstream_set_round_robin_peer_session;
    s->upstream->peer.save_session =
                             ngx_stream_upstream_save_round_robin_peer_session;
#endif

    return NGX_OK;
}


ngx_int_t
ngx_stream_upstream_create_round_robin_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_resolved_t *ur)
{
    u_char                              *p;
    size_t                               len;
    socklen_t                            socklen;
    ngx_uint_t                           i, n;
    struct sockaddr                     *sockaddr;
    ngx_stream_upstream_rr_peer_t       *peer, **peerp;
    ngx_stream_upstream_rr_peers_t      *peers;
    ngx_stream_upstream_rr_peer_data_t  *rrp;

    rrp = s->upstream->peer.data;

    if (rrp == NULL) {
        rrp = ngx_palloc(s->connection->pool,
                         sizeof(ngx_stream_upstream_rr_peer_data_t));
        if (rrp == NULL) {
            return NGX_ERROR;
        }

        s->upstream->peer.data = rrp;
    }

    peers = ngx_pcalloc(s->connection->pool,
                        sizeof(ngx_stream_upstream_rr_peers_t));
    if (peers == NULL) {
        return NGX_ERROR;
    }

    peer = ngx_pcalloc(s->connection->pool,
                       sizeof(ngx_stream_upstream_rr_peer_t) * ur->naddrs);
    if (peer == NULL) {
        return NGX_ERROR;
    }

    peers->single = (ur->naddrs == 1);
    peers->number = ur->naddrs;
    peers->name = &ur->host;

    if (ur->sockaddr) {
        peer[0].sockaddr = ur->sockaddr;
        peer[0].socklen = ur->socklen;
        peer[0].name = ur->host;
        peer[0].weight = 1;
        peer[0].effective_weight = 1;
        peer[0].current_weight = 0;
        peer[0].max_fails = 1;
        peer[0].fail_timeout = 10;
        peers->peer = peer;

    } else {
        peerp = &peers->peer;

        for (i = 0; i < ur->naddrs; i++) {

            socklen = ur->addrs[i].socklen;

            sockaddr = ngx_palloc(s->connection->pool, socklen);
            if (sockaddr == NULL) {
                return NGX_ERROR;
            }

            ngx_memcpy(sockaddr, ur->addrs[i].sockaddr, socklen);
            ngx_inet_set_port(sockaddr, ur->port);

            p = ngx_pnalloc(s->connection->pool, NGX_SOCKADDR_STRLEN);
            if (p == NULL) {
                return NGX_ERROR;
            }

            len = ngx_sock_ntop(sockaddr, socklen, p, NGX_SOCKADDR_STRLEN, 1);

            peer[i].sockaddr = sockaddr;
            peer[i].socklen = socklen;
            peer[i].name.len = len;
            peer[i].name.data = p;
            peer[i].weight = 1;
            peer[i].effective_weight = 1;
            peer[i].current_weight = 0;
            peer[i].max_fails = 1;
            peer[i].fail_timeout = 10;
            *peerp = &peer[i];
            peerp = &peer[i].next;
        }
    }

    rrp->peers = peers;
    rrp->current = NULL;

    if (rrp->peers->number <= 8 * sizeof(uintptr_t)) {
        rrp->tried = &rrp->data;
        rrp->data = 0;

    } else {
        n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
                / (8 * sizeof(uintptr_t));

        rrp->tried = ngx_pcalloc(s->connection->pool, n * sizeof(uintptr_t));
        if (rrp->tried == NULL) {
            return NGX_ERROR;
        }
    }

    s->upstream->peer.get = ngx_stream_upstream_get_round_robin_peer;
    s->upstream->peer.free = ngx_stream_upstream_free_round_robin_peer;
    s->upstream->peer.tries = ngx_stream_upstream_tries(rrp->peers);
#if (NGX_STREAM_SSL)
    s->upstream->peer.set_session = ngx_stream_upstream_empty_set_session;
    s->upstream->peer.save_session = ngx_stream_upstream_empty_save_session;
#endif

    return NGX_OK;
}


ngx_int_t
ngx_stream_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_stream_upstream_rr_peer_data_t *rrp = data;

    ngx_int_t                        rc;
    ngx_uint_t                       i, n;
    ngx_stream_upstream_rr_peer_t   *peer;
    ngx_stream_upstream_rr_peers_t  *peers;

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "get rr peer, try: %ui", pc->tries);

    pc->connection = NULL;

    peers = rrp->peers;
    ngx_stream_upstream_rr_peers_wlock(peers);

    if (peers->single) {
        peer = peers->peer;

        if (peer->down) {
            goto failed;
        }

        rrp->current = peer;

    } else {

        /* there are several peers */

        peer = ngx_stream_upstream_get_peer(rrp);

        if (peer == NULL) {
            goto failed;
        }

        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "get rr peer, current: %p %i",
                       peer, peer->current_weight);
    }

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

    peer->conns++;

    ngx_stream_upstream_rr_peers_unlock(peers);

    return NGX_OK;

failed:

    if (peers->next) {

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

        rrp->peers = peers->next;

        n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
                / (8 * sizeof(uintptr_t));

        for (i = 0; i < n; i++) {
            rrp->tried[i] = 0;
        }

        ngx_stream_upstream_rr_peers_unlock(peers);

        rc = ngx_stream_upstream_get_round_robin_peer(pc, rrp);

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

        ngx_stream_upstream_rr_peers_wlock(peers);
    }

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

    for (peer = peers->peer; peer; peer = peer->next) {
        peer->fails = 0;
    }

    ngx_stream_upstream_rr_peers_unlock(peers);

    pc->name = peers->name;

    return NGX_BUSY;
}


static ngx_stream_upstream_rr_peer_t *
ngx_stream_upstream_get_peer(ngx_stream_upstream_rr_peer_data_t *rrp)
{
    time_t                          now;
    uintptr_t                       m;
    ngx_int_t                       total;
    ngx_uint_t                      i, n, p;
    ngx_stream_upstream_rr_peer_t  *peer, *best;

    now = ngx_time();

    best = NULL;
    total = 0;

#if (NGX_SUPPRESS_WARN)
    p = 0;
#endif

    for (peer = rrp->peers->peer, i = 0;
         peer;
         peer = peer->next, i++)
    {

        n = i / (8 * sizeof(uintptr_t));
        m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));

        if (rrp->tried[n] & m) {
            continue;
        }

        if (peer->down) {
            continue;
        }

        if (peer->max_fails
            && peer->fails >= peer->max_fails
            && now - peer->checked <= peer->fail_timeout)
        {
            continue;
        }

        peer->current_weight += peer->effective_weight;
        total += peer->effective_weight;

        if (peer->effective_weight < peer->weight) {
            peer->effective_weight++;
        }

        if (best == NULL || peer->current_weight > best->current_weight) {
            best = peer;
            p = i;
        }
    }

    if (best == NULL) {
        return NULL;
    }

    rrp->current = best;

    n = p / (8 * sizeof(uintptr_t));
    m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));

    rrp->tried[n] |= m;

    best->current_weight -= total;

    if (now - best->checked > best->fail_timeout) {
        best->checked = now;
    }

    return best;
}


void
ngx_stream_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data,
    ngx_uint_t state)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    time_t                          now;
    ngx_stream_upstream_rr_peer_t  *peer;

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

    peer = rrp->current;

    ngx_stream_upstream_rr_peers_rlock(rrp->peers);
    ngx_stream_upstream_rr_peer_lock(rrp->peers, peer);

    if (rrp->peers->single) {
        peer->conns--;

        ngx_stream_upstream_rr_peer_unlock(rrp->peers, peer);
        ngx_stream_upstream_rr_peers_unlock(rrp->peers);

        pc->tries = 0;
        return;
    }

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

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

        if (peer->max_fails) {
            peer->effective_weight -= peer->weight / peer->max_fails;

            if (peer->fails >= peer->max_fails) {
                ngx_log_error(NGX_LOG_WARN, pc->log, 0,
                              "upstream server temporarily disabled");
            }
        }

        ngx_log_debug2(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "free rr peer failed: %p %i",
                       peer, peer->effective_weight);

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

    } else {

        /* mark peer live if check passed */

        if (peer->accessed < peer->checked) {
            peer->fails = 0;
        }
    }

    peer->conns--;

    ngx_stream_upstream_rr_peer_unlock(rrp->peers, peer);
    ngx_stream_upstream_rr_peers_unlock(rrp->peers);

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


#if (NGX_STREAM_SSL)

static ngx_int_t
ngx_stream_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    ngx_int_t                        rc;
    ngx_ssl_session_t               *ssl_session;
    ngx_stream_upstream_rr_peer_t   *peer;
#if (NGX_STREAM_UPSTREAM_ZONE)
    int                              len;
#if OPENSSL_VERSION_NUMBER >= 0x0090707fL
    const
#endif
    u_char                          *p;
    ngx_stream_upstream_rr_peers_t  *peers;
    u_char                           buf[NGX_SSL_MAX_SESSION_SIZE];
#endif

    peer = rrp->current;

#if (NGX_STREAM_UPSTREAM_ZONE)
    peers = rrp->peers;

    if (peers->shpool) {
        ngx_stream_upstream_rr_peers_rlock(peers);
        ngx_stream_upstream_rr_peer_lock(peers, peer);

        if (peer->ssl_session == NULL) {
            ngx_stream_upstream_rr_peer_unlock(peers, peer);
            ngx_stream_upstream_rr_peers_unlock(peers);
            return NGX_OK;
        }

        len = peer->ssl_session_len;

        ngx_memcpy(buf, peer->ssl_session, len);

        ngx_stream_upstream_rr_peer_unlock(peers, peer);
        ngx_stream_upstream_rr_peers_unlock(peers);

        p = buf;
        ssl_session = d2i_SSL_SESSION(NULL, &p, len);

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

        ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "set session: %p", ssl_session);

        ngx_ssl_free_session(ssl_session);

        return rc;
    }
#endif

    ssl_session = peer->ssl_session;

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

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "set session: %p", ssl_session);

    return rc;
}


static void
ngx_stream_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc,
    void *data)
{
    ngx_stream_upstream_rr_peer_data_t  *rrp = data;

    ngx_ssl_session_t               *old_ssl_session, *ssl_session;
    ngx_stream_upstream_rr_peer_t   *peer;
#if (NGX_STREAM_UPSTREAM_ZONE)
    int                              len;
    u_char                          *p;
    ngx_stream_upstream_rr_peers_t  *peers;
    u_char                           buf[NGX_SSL_MAX_SESSION_SIZE];
#endif

#if (NGX_STREAM_UPSTREAM_ZONE)
    peers = rrp->peers;

    if (peers->shpool) {

        ssl_session = SSL_get0_session(pc->connection->ssl->connection);

        if (ssl_session == NULL) {
            return;
        }

        ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "save session: %p", ssl_session);

        len = i2d_SSL_SESSION(ssl_session, NULL);

        /* do not cache too big session */

        if (len > NGX_SSL_MAX_SESSION_SIZE) {
            return;
        }

        p = buf;
        (void) i2d_SSL_SESSION(ssl_session, &p);

        peer = rrp->current;

        ngx_stream_upstream_rr_peers_rlock(peers);
        ngx_stream_upstream_rr_peer_lock(peers, peer);

        if (len > peer->ssl_session_len) {
            ngx_shmtx_lock(&peers->shpool->mutex);

            if (peer->ssl_session) {
                ngx_slab_free_locked(peers->shpool, peer->ssl_session);
            }

            peer->ssl_session = ngx_slab_alloc_locked(peers->shpool, len);

            ngx_shmtx_unlock(&peers->shpool->mutex);

            if (peer->ssl_session == NULL) {
                peer->ssl_session_len = 0;

                ngx_stream_upstream_rr_peer_unlock(peers, peer);
                ngx_stream_upstream_rr_peers_unlock(peers);
                return;
            }

            peer->ssl_session_len = len;
        }

        ngx_memcpy(peer->ssl_session, buf, len);

        ngx_stream_upstream_rr_peer_unlock(peers, peer);
        ngx_stream_upstream_rr_peers_unlock(peers);

        return;
    }
#endif

    ssl_session = ngx_ssl_get_session(pc->connection);

    if (ssl_session == NULL) {
        return;
    }

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "save session: %p", ssl_session);

    peer = rrp->current;

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

    if (old_ssl_session) {

        ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                       "old session: %p", old_ssl_session);

        /* TODO: may block */

        ngx_ssl_free_session(old_ssl_session);
    }
}


static ngx_int_t
ngx_stream_upstream_empty_set_session(ngx_peer_connection_t *pc, void *data)
{
    return NGX_OK;
}


static void
ngx_stream_upstream_empty_save_session(ngx_peer_connection_t *pc, void *data)
{
    return;
}

#endif