Mercurial > hg > nginx

view src/stream/ngx_stream_upstream_random_module.c @ 9300:5be23505292b default tip

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
SSI: fixed incorrect or duplicate stub output. Following 3518:eb3aaf8bd2a9 (0.8.37), r->request_output is only set if there are data in the first buffer sent in the subrequest. As a result, following the change mentioned this flag cannot be used to prevent duplicate ngx_http_ssi_stub_output() calls, since it is not set if there was already some output, but the first buffer was empty. Still, when there are multiple subrequests, even an empty subrequest response might be delayed by the postpone filter, leading to a second call of ngx_http_ssi_stub_output() during finalization from ngx_http_writer() the subreqest buffers are released by the postpone filter. Since r->request_output is not set after the first call, this resulted in duplicate stub output. Additionally, checking only the first buffer might be wrong in some unusual cases. For example, the first buffer might be empty if $r->flush() is called before printing any data in the embedded Perl module. Depending on the postpone_output value and corresponding sizes, this issue can result in either duplicate or unexpected stub output, or "zero size buf in writer" alerts. Following 8124:f5515e727656 (1.23.4), it became slightly easier to reproduce the issue, as empty static files and empty cache items now result in a response with an empty buffer. Before the change, an empty proxied response can be used to reproduce the issue. Fix is check all buffers and set r->request_output if any non-empty buffers are sent. This ensures that all unusual cases of non-empty responses are covered, and also that r->request_output will be set after the first stub output, preventing duplicate output. Reported by Jan Gassen.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 04 Jul 2024 17:41:28 +0300
parents f2396ecf608b
children
line wrap: on
line source


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


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


typedef struct {
    ngx_stream_upstream_rr_peer_t          *peer;
    ngx_uint_t                              range;
} ngx_stream_upstream_random_range_t;


typedef struct {
    ngx_uint_t                              two;
    ngx_stream_upstream_random_range_t     *ranges;
} ngx_stream_upstream_random_srv_conf_t;


typedef struct {
    /* the round robin data must be first */
    ngx_stream_upstream_rr_peer_data_t      rrp;

    ngx_stream_upstream_random_srv_conf_t  *conf;
    u_char                                  tries;
} ngx_stream_upstream_random_peer_data_t;


static ngx_int_t ngx_stream_upstream_init_random(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us);
static ngx_int_t ngx_stream_upstream_update_random(ngx_pool_t *pool,
    ngx_stream_upstream_srv_conf_t *us);

static ngx_int_t ngx_stream_upstream_init_random_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us);
static ngx_int_t ngx_stream_upstream_get_random_peer(ngx_peer_connection_t *pc,
    void *data);
static ngx_int_t ngx_stream_upstream_get_random2_peer(ngx_peer_connection_t *pc,
    void *data);
static ngx_uint_t ngx_stream_upstream_peek_random_peer(
    ngx_stream_upstream_rr_peers_t *peers,
    ngx_stream_upstream_random_peer_data_t *rp);
static void *ngx_stream_upstream_random_create_conf(ngx_conf_t *cf);
static char *ngx_stream_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_stream_upstream_random_commands[] = {

    { ngx_string("random"),
      NGX_STREAM_UPS_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE12,
      ngx_stream_upstream_random,
      NGX_STREAM_SRV_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_stream_module_t  ngx_stream_upstream_random_module_ctx = {
    NULL,                                    /* preconfiguration */
    NULL,                                    /* postconfiguration */

    NULL,                                    /* create main configuration */
    NULL,                                    /* init main configuration */

    ngx_stream_upstream_random_create_conf,  /* create server configuration */
    NULL                                     /* merge server configuration */
};


ngx_module_t  ngx_stream_upstream_random_module = {
    NGX_MODULE_V1,
    &ngx_stream_upstream_random_module_ctx,  /* module context */
    ngx_stream_upstream_random_commands,     /* module directives */
    NGX_STREAM_MODULE,                       /* module type */
    NULL,                                    /* init master */
    NULL,                                    /* init module */
    NULL,                                    /* init process */
    NULL,                                    /* init thread */
    NULL,                                    /* exit thread */
    NULL,                                    /* exit process */
    NULL,                                    /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_int_t
ngx_stream_upstream_init_random(ngx_conf_t *cf,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_log_debug0(NGX_LOG_DEBUG_STREAM, cf->log, 0, "init random");

    if (ngx_stream_upstream_init_round_robin(cf, us) != NGX_OK) {
        return NGX_ERROR;
    }

    us->peer.init = ngx_stream_upstream_init_random_peer;

#if (NGX_STREAM_UPSTREAM_ZONE)
    if (us->shm_zone) {
        return NGX_OK;
    }
#endif

    return ngx_stream_upstream_update_random(cf->pool, us);
}


static ngx_int_t
ngx_stream_upstream_update_random(ngx_pool_t *pool,
    ngx_stream_upstream_srv_conf_t *us)
{
    size_t                                  size;
    ngx_uint_t                              i, total_weight;
    ngx_stream_upstream_rr_peer_t          *peer;
    ngx_stream_upstream_rr_peers_t         *peers;
    ngx_stream_upstream_random_range_t     *ranges;
    ngx_stream_upstream_random_srv_conf_t  *rcf;

    rcf = ngx_stream_conf_upstream_srv_conf(us,
                                            ngx_stream_upstream_random_module);
    peers = us->peer.data;

    size = peers->number * sizeof(ngx_stream_upstream_random_range_t);

    ranges = pool ? ngx_palloc(pool, size) : ngx_alloc(size, ngx_cycle->log);
    if (ranges == NULL) {
        return NGX_ERROR;
    }

    total_weight = 0;

    for (peer = peers->peer, i = 0; peer; peer = peer->next, i++) {
        ranges[i].peer = peer;
        ranges[i].range = total_weight;
        total_weight += peer->weight;
    }

    rcf->ranges = ranges;

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_init_random_peer(ngx_stream_session_t *s,
    ngx_stream_upstream_srv_conf_t *us)
{
    ngx_stream_upstream_random_srv_conf_t   *rcf;
    ngx_stream_upstream_random_peer_data_t  *rp;

    ngx_log_debug0(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
                   "init random peer");

    rcf = ngx_stream_conf_upstream_srv_conf(us,
                                            ngx_stream_upstream_random_module);

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

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

    if (ngx_stream_upstream_init_round_robin_peer(s, us) != NGX_OK) {
        return NGX_ERROR;
    }

    if (rcf->two) {
        s->upstream->peer.get = ngx_stream_upstream_get_random2_peer;

    } else {
        s->upstream->peer.get = ngx_stream_upstream_get_random_peer;
    }

    rp->conf = rcf;
    rp->tries = 0;

    ngx_stream_upstream_rr_peers_rlock(rp->rrp.peers);

#if (NGX_STREAM_UPSTREAM_ZONE)
    if (rp->rrp.peers->shpool && rcf->ranges == NULL) {
        if (ngx_stream_upstream_update_random(NULL, us) != NGX_OK) {
            ngx_stream_upstream_rr_peers_unlock(rp->rrp.peers);
            return NGX_ERROR;
        }
    }
#endif

    ngx_stream_upstream_rr_peers_unlock(rp->rrp.peers);

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_get_random_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_stream_upstream_random_peer_data_t  *rp = data;

    time_t                               now;
    uintptr_t                            m;
    ngx_uint_t                           i, n;
    ngx_stream_upstream_rr_peer_t       *peer;
    ngx_stream_upstream_rr_peers_t      *peers;
    ngx_stream_upstream_rr_peer_data_t  *rrp;

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

    rrp = &rp->rrp;
    peers = rrp->peers;

    ngx_stream_upstream_rr_peers_rlock(peers);

    if (rp->tries > 20 || peers->single) {
        ngx_stream_upstream_rr_peers_unlock(peers);
        return ngx_stream_upstream_get_round_robin_peer(pc, rrp);
    }

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

    now = ngx_time();

    for ( ;; ) {

        i = ngx_stream_upstream_peek_random_peer(peers, rp);

        peer = rp->conf->ranges[i].peer;

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

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

        ngx_stream_upstream_rr_peer_lock(peers, peer);

        if (peer->down) {
            ngx_stream_upstream_rr_peer_unlock(peers, peer);
            goto next;
        }

        if (peer->max_fails
            && peer->fails >= peer->max_fails
            && now - peer->checked <= peer->fail_timeout)
        {
            ngx_stream_upstream_rr_peer_unlock(peers, peer);
            goto next;
        }

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            ngx_stream_upstream_rr_peer_unlock(peers, peer);
            goto next;
        }

        break;

    next:

        if (++rp->tries > 20) {
            ngx_stream_upstream_rr_peers_unlock(peers);
            return ngx_stream_upstream_get_round_robin_peer(pc, rrp);
        }
    }

    rrp->current = peer;

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

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

    peer->conns++;

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

    rrp->tried[n] |= m;

    return NGX_OK;
}


static ngx_int_t
ngx_stream_upstream_get_random2_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_stream_upstream_random_peer_data_t  *rp = data;

    time_t                               now;
    uintptr_t                            m;
    ngx_uint_t                           i, n, p;
    ngx_stream_upstream_rr_peer_t       *peer, *prev;
    ngx_stream_upstream_rr_peers_t      *peers;
    ngx_stream_upstream_rr_peer_data_t  *rrp;

    ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
                   "get random2 peer, try: %ui", pc->tries);

    rrp = &rp->rrp;
    peers = rrp->peers;

    ngx_stream_upstream_rr_peers_wlock(peers);

    if (rp->tries > 20 || peers->single) {
        ngx_stream_upstream_rr_peers_unlock(peers);
        return ngx_stream_upstream_get_round_robin_peer(pc, rrp);
    }

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

    now = ngx_time();

    prev = NULL;

#if (NGX_SUPPRESS_WARN)
    p = 0;
#endif

    for ( ;; ) {

        i = ngx_stream_upstream_peek_random_peer(peers, rp);

        peer = rp->conf->ranges[i].peer;

        if (peer == prev) {
            goto next;
        }

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

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

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

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

        if (peer->max_conns && peer->conns >= peer->max_conns) {
            goto next;
        }

        if (prev) {
            if (peer->conns * prev->weight > prev->conns * peer->weight) {
                peer = prev;
                n = p / (8 * sizeof(uintptr_t));
                m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
            }

            break;
        }

        prev = peer;
        p = i;

    next:

        if (++rp->tries > 20) {
            ngx_stream_upstream_rr_peers_unlock(peers);
            return ngx_stream_upstream_get_round_robin_peer(pc, rrp);
        }
    }

    rrp->current = peer;

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

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

    peer->conns++;

    ngx_stream_upstream_rr_peers_unlock(peers);

    rrp->tried[n] |= m;

    return NGX_OK;
}


static ngx_uint_t
ngx_stream_upstream_peek_random_peer(ngx_stream_upstream_rr_peers_t *peers,
    ngx_stream_upstream_random_peer_data_t *rp)
{
    ngx_uint_t  i, j, k, x;

    x = ngx_random() % peers->total_weight;

    i = 0;
    j = peers->number;

    while (j - i > 1) {
        k = (i + j) / 2;

        if (x < rp->conf->ranges[k].range) {
            j = k;

        } else {
            i = k;
        }
    }

    return i;
}


static void *
ngx_stream_upstream_random_create_conf(ngx_conf_t *cf)
{
    ngx_stream_upstream_random_srv_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_stream_upstream_random_srv_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc():
     *
     *     conf->two = 0;
     */

    return conf;
}


static char *
ngx_stream_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_stream_upstream_random_srv_conf_t  *rcf = conf;

    ngx_str_t                       *value;
    ngx_stream_upstream_srv_conf_t  *uscf;

    uscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_upstream_module);

    if (uscf->peer.init_upstream) {
        ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
                           "load balancing method redefined");
    }

    uscf->peer.init_upstream = ngx_stream_upstream_init_random;

    uscf->flags = NGX_STREAM_UPSTREAM_CREATE
                  |NGX_STREAM_UPSTREAM_WEIGHT
                  |NGX_STREAM_UPSTREAM_MAX_CONNS
                  |NGX_STREAM_UPSTREAM_MAX_FAILS
                  |NGX_STREAM_UPSTREAM_FAIL_TIMEOUT
                  |NGX_STREAM_UPSTREAM_DOWN;

    if (cf->args->nelts == 1) {
        return NGX_CONF_OK;
    }

    value = cf->args->elts;

    if (ngx_strcmp(value[1].data, "two") == 0) {
        rcf->two = 1;

    } else {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[1]);
        return NGX_CONF_ERROR;
    }

    if (cf->args->nelts == 2) {
        return NGX_CONF_OK;
    }

    if (ngx_strcmp(value[2].data, "least_conn") != 0) {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid parameter \"%V\"", &value[2]);
        return NGX_CONF_ERROR;
    }

    return NGX_CONF_OK;
}