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view src/stream/ngx_stream_upstream_random_module.c @ 7353:87d2ea860f38

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SSL: restore handlers after blocking. It is possible that after SSL_read() will return SSL_ERROR_WANT_WRITE, further calls will return SSL_ERROR_WANT_READ without reading any application data. We have to call ngx_handle_write_event() and switch back to normal write handling much like we do if there are some application data, or the write there will be reported again and again. Similarly, we have to switch back to normal read handling if there is saved read handler and SSL_write() returns SSL_ERROR_WANT_WRITE.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 10 Sep 2018 18:57:39 +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;
}