view src/http/modules/ngx_http_split_clients_module.c @ 6059:c81d79a7befd

SPDY: always push pending data. This helps to avoid suboptimal behavior when a client waits for a control frame or more data to increase window size, but the frames have been delayed in the socket buffer. The delays can be caused by bad interaction between Nagle's algorithm on nginx side and delayed ACK on the client side or by TCP_CORK/TCP_NOPUSH if SPDY was working without SSL and sendfile() was used. The pushing code is now very similar to ngx_http_set_keepalive().
author Valentin Bartenev <vbart@nginx.com>
date Mon, 23 Mar 2015 21:04:13 +0300
parents b78cf2414fda
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


typedef struct {
    uint32_t                    percent;
    ngx_http_variable_value_t   value;
} ngx_http_split_clients_part_t;


typedef struct {
    ngx_http_complex_value_t    value;
    ngx_array_t                 parts;
} ngx_http_split_clients_ctx_t;


static char *ngx_conf_split_clients_block(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);
static char *ngx_http_split_clients(ngx_conf_t *cf, ngx_command_t *dummy,
    void *conf);

static ngx_command_t  ngx_http_split_clients_commands[] = {

    { ngx_string("split_clients"),
      NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2,
      ngx_conf_split_clients_block,
      NGX_HTTP_MAIN_CONF_OFFSET,
      0,
      NULL },

      ngx_null_command
};


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

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

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

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


ngx_module_t  ngx_http_split_clients_module = {
    NGX_MODULE_V1,
    &ngx_http_split_clients_module_ctx,    /* module context */
    ngx_http_split_clients_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_split_clients_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    ngx_http_split_clients_ctx_t *ctx = (ngx_http_split_clients_ctx_t *) data;

    uint32_t                        hash;
    ngx_str_t                       val;
    ngx_uint_t                      i;
    ngx_http_split_clients_part_t  *part;

    *v = ngx_http_variable_null_value;

    if (ngx_http_complex_value(r, &ctx->value, &val) != NGX_OK) {
        return NGX_OK;
    }

    hash = ngx_murmur_hash2(val.data, val.len);

    part = ctx->parts.elts;

    for (i = 0; i < ctx->parts.nelts; i++) {

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http split: %uD %uD", hash, part[i].percent);

        if (hash < part[i].percent || part[i].percent == 0) {
            *v = part[i].value;
            return NGX_OK;
        }
    }

    return NGX_OK;
}


static char *
ngx_conf_split_clients_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    char                                *rv;
    uint32_t                             sum, last;
    ngx_str_t                           *value, name;
    ngx_uint_t                           i;
    ngx_conf_t                           save;
    ngx_http_variable_t                 *var;
    ngx_http_split_clients_ctx_t        *ctx;
    ngx_http_split_clients_part_t       *part;
    ngx_http_compile_complex_value_t     ccv;

    ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_split_clients_ctx_t));
    if (ctx == NULL) {
        return NGX_CONF_ERROR;
    }

    value = cf->args->elts;

    ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));

    ccv.cf = cf;
    ccv.value = &value[1];
    ccv.complex_value = &ctx->value;

    if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
        return NGX_CONF_ERROR;
    }

    name = value[2];

    if (name.data[0] != '$') {
        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                           "invalid variable name \"%V\"", &name);
        return NGX_CONF_ERROR;
    }

    name.len--;
    name.data++;

    var = ngx_http_add_variable(cf, &name, NGX_HTTP_VAR_CHANGEABLE);
    if (var == NULL) {
        return NGX_CONF_ERROR;
    }

    var->get_handler = ngx_http_split_clients_variable;
    var->data = (uintptr_t) ctx;

    if (ngx_array_init(&ctx->parts, cf->pool, 2,
                       sizeof(ngx_http_split_clients_part_t))
        != NGX_OK)
    {
        return NGX_CONF_ERROR;
    }

    save = *cf;
    cf->ctx = ctx;
    cf->handler = ngx_http_split_clients;
    cf->handler_conf = conf;

    rv = ngx_conf_parse(cf, NULL);

    *cf = save;

    if (rv != NGX_CONF_OK) {
        return rv;
    }

    sum = 0;
    last = 0;
    part = ctx->parts.elts;

    for (i = 0; i < ctx->parts.nelts; i++) {
        sum = part[i].percent ? sum + part[i].percent : 10000;
        if (sum > 10000) {
            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                               "percent total is greater than 100%%");
            return NGX_CONF_ERROR;
        }

        if (part[i].percent) {
            last += part[i].percent * (uint64_t) 0xffffffff / 10000;
            part[i].percent = last;
        }
    }

    return rv;
}


static char *
ngx_http_split_clients(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
{
    ngx_int_t                       n;
    ngx_str_t                      *value;
    ngx_http_split_clients_ctx_t   *ctx;
    ngx_http_split_clients_part_t  *part;

    ctx = cf->ctx;
    value = cf->args->elts;

    part = ngx_array_push(&ctx->parts);
    if (part == NULL) {
        return NGX_CONF_ERROR;
    }

    if (value[0].len == 1 && value[0].data[0] == '*') {
        part->percent = 0;

    } else {
        if (value[0].len == 0 || value[0].data[value[0].len - 1] != '%') {
            goto invalid;
        }

        n = ngx_atofp(value[0].data, value[0].len - 1, 2);
        if (n == NGX_ERROR || n == 0) {
            goto invalid;
        }

        part->percent = (uint32_t) n;
    }

    part->value.len = value[1].len;
    part->value.valid = 1;
    part->value.no_cacheable = 0;
    part->value.not_found = 0;
    part->value.data = value[1].data;

    return NGX_CONF_OK;

invalid:

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