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view src/http/modules/ngx_http_upstream_random_module.c @ 7612:1ce3f01a4355

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SSL: reworked posted next events. Introduced in 9d2ad2fb4423 available bytes handling in SSL relied on connection read handler being overwritten to set the ready flag and the amount of available bytes. This approach is, however, does not work properly when connection read handler is changed, for example, when switching to a next pipelined request, and can result in unexpected connection timeouts, see here: http://mailman.nginx.org/pipermail/nginx-devel/2019-December/012825.html Fix is to introduce ngx_event_process_posted_next() instead, which will set ready and available regardless of how event handler is set.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 24 Dec 2019 17:24:59 +0300
parents f2396ecf608b
children
line wrap: on
line source


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


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


typedef struct {
    ngx_http_upstream_rr_peer_t          *peer;
    ngx_uint_t                            range;
} ngx_http_upstream_random_range_t;


typedef struct {
    ngx_uint_t                            two;
    ngx_http_upstream_random_range_t     *ranges;
} ngx_http_upstream_random_srv_conf_t;


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

    ngx_http_upstream_random_srv_conf_t  *conf;
    u_char                                tries;
} ngx_http_upstream_random_peer_data_t;


static ngx_int_t ngx_http_upstream_init_random(ngx_conf_t *cf,
    ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_update_random(ngx_pool_t *pool,
    ngx_http_upstream_srv_conf_t *us);

static ngx_int_t ngx_http_upstream_init_random_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc,
    void *data);
static ngx_int_t ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc,
    void *data);
static ngx_uint_t ngx_http_upstream_peek_random_peer(
    ngx_http_upstream_rr_peers_t *peers,
    ngx_http_upstream_random_peer_data_t *rp);
static void *ngx_http_upstream_random_create_conf(ngx_conf_t *cf);
static char *ngx_http_upstream_random(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_http_upstream_random_commands[] = {

    { ngx_string("random"),
      NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE12,
      ngx_http_upstream_random,
      NGX_HTTP_SRV_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_upstream_random_module_ctx = {
    NULL,                                  /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

    ngx_http_upstream_random_create_conf,  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_upstream_random_module = {
    NGX_MODULE_V1,
    &ngx_http_upstream_random_module_ctx,  /* module context */
    ngx_http_upstream_random_commands,     /* module directives */
    NGX_HTTP_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_http_upstream_init_random(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
{
    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0, "init random");

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

    us->peer.init = ngx_http_upstream_init_random_peer;

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

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


static ngx_int_t
ngx_http_upstream_update_random(ngx_pool_t *pool,
    ngx_http_upstream_srv_conf_t *us)
{
    size_t                                size;
    ngx_uint_t                            i, total_weight;
    ngx_http_upstream_rr_peer_t          *peer;
    ngx_http_upstream_rr_peers_t         *peers;
    ngx_http_upstream_random_range_t     *ranges;
    ngx_http_upstream_random_srv_conf_t  *rcf;

    rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);

    peers = us->peer.data;

    size = peers->number * sizeof(ngx_http_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_http_upstream_init_random_peer(ngx_http_request_t *r,
    ngx_http_upstream_srv_conf_t *us)
{
    ngx_http_upstream_random_srv_conf_t   *rcf;
    ngx_http_upstream_random_peer_data_t  *rp;

    ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                   "init random peer");

    rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);

    rp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_random_peer_data_t));
    if (rp == NULL) {
        return NGX_ERROR;
    }

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

    if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
        return NGX_ERROR;
    }

    if (rcf->two) {
        r->upstream->peer.get = ngx_http_upstream_get_random2_peer;

    } else {
        r->upstream->peer.get = ngx_http_upstream_get_random_peer;
    }

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

    ngx_http_upstream_rr_peers_rlock(rp->rrp.peers);

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

    ngx_http_upstream_rr_peers_unlock(rp->rrp.peers);

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_get_random_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_http_upstream_random_peer_data_t  *rp = data;

    time_t                             now;
    uintptr_t                          m;
    ngx_uint_t                         i, n;
    ngx_http_upstream_rr_peer_t       *peer;
    ngx_http_upstream_rr_peers_t      *peers;
    ngx_http_upstream_rr_peer_data_t  *rrp;

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

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

    ngx_http_upstream_rr_peers_rlock(peers);

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

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

    now = ngx_time();

    for ( ;; ) {

        i = ngx_http_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_http_upstream_rr_peer_lock(peers, peer);

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

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

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

        break;

    next:

        if (++rp->tries > 20) {
            ngx_http_upstream_rr_peers_unlock(peers);
            return ngx_http_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_http_upstream_rr_peer_unlock(peers, peer);
    ngx_http_upstream_rr_peers_unlock(peers);

    rrp->tried[n] |= m;

    return NGX_OK;
}


static ngx_int_t
ngx_http_upstream_get_random2_peer(ngx_peer_connection_t *pc, void *data)
{
    ngx_http_upstream_random_peer_data_t  *rp = data;

    time_t                             now;
    uintptr_t                          m;
    ngx_uint_t                         i, n, p;
    ngx_http_upstream_rr_peer_t       *peer, *prev;
    ngx_http_upstream_rr_peers_t      *peers;
    ngx_http_upstream_rr_peer_data_t  *rrp;

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

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

    ngx_http_upstream_rr_peers_wlock(peers);

    if (rp->tries > 20 || peers->single) {
        ngx_http_upstream_rr_peers_unlock(peers);
        return ngx_http_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_http_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_http_upstream_rr_peers_unlock(peers);
            return ngx_http_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_http_upstream_rr_peers_unlock(peers);

    rrp->tried[n] |= m;

    return NGX_OK;
}


static ngx_uint_t
ngx_http_upstream_peek_random_peer(ngx_http_upstream_rr_peers_t *peers,
    ngx_http_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_http_upstream_random_create_conf(ngx_conf_t *cf)
{
    ngx_http_upstream_random_srv_conf_t  *conf;

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

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

    return conf;
}


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

    ngx_str_t                     *value;
    ngx_http_upstream_srv_conf_t  *uscf;

    uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_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_http_upstream_init_random;

    uscf->flags = NGX_HTTP_UPSTREAM_CREATE
                  |NGX_HTTP_UPSTREAM_WEIGHT
                  |NGX_HTTP_UPSTREAM_MAX_CONNS
                  |NGX_HTTP_UPSTREAM_MAX_FAILS
                  |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
                  |NGX_HTTP_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;
}