app/nginx/src/http/modules/ngx_http_split_clients_module.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  * Copyright (C) Nginx, Inc.
   5  */
   6
   7
   8 #include <ngx_config.h>
   9 #include <ngx_core.h>
  10 #include <ngx_http.h>
  11
  12
  13 typedef struct {
  14     uint32_t                    percent;
  15     ngx_http_variable_value_t   value;
  16 } ngx_http_split_clients_part_t;
  17
  18
  19 typedef struct {
  20     ngx_http_complex_value_t    value;
  21     ngx_array_t                 parts;
  22 } ngx_http_split_clients_ctx_t;
  23
  24
  25 static char *ngx_conf_split_clients_block(ngx_conf_t *cf, ngx_command_t *cmd,
  26     void *conf);
  27 static char *ngx_http_split_clients(ngx_conf_t *cf, ngx_command_t *dummy,
  28     void *conf);
  29
  30 static ngx_command_t  ngx_http_split_clients_commands[] = {
  31
  32     { ngx_string("split_clients"),
  33       NGX_HTTP_MAIN_CONF|NGX_CONF_BLOCK|NGX_CONF_TAKE2,
  34       ngx_conf_split_clients_block,
  35       NGX_HTTP_MAIN_CONF_OFFSET,
  36       0,
  37       NULL },
  38
  39       ngx_null_command
  40 };
  41
  42
  43 static ngx_http_module_t  ngx_http_split_clients_module_ctx = {
  44     NULL,                                  /* preconfiguration */
  45     NULL,                                  /* postconfiguration */
  46
  47     NULL,                                  /* create main configuration */
  48     NULL,                                  /* init main configuration */
  49
  50     NULL,                                  /* create server configuration */
  51     NULL,                                  /* merge server configuration */
  52
  53     NULL,                                  /* create location configuration */
  54     NULL                                   /* merge location configuration */
  55 };
  56
  57
  58 ngx_module_t  ngx_http_split_clients_module = {
  59     NGX_MODULE_V1,
  60     &ngx_http_split_clients_module_ctx,    /* module context */
  61     ngx_http_split_clients_commands,       /* module directives */
  62     NGX_HTTP_MODULE,                       /* module type */
  63     NULL,                                  /* init master */
  64     NULL,                                  /* init module */
  65     NULL,                                  /* init process */
  66     NULL,                                  /* init thread */
  67     NULL,                                  /* exit thread */
  68     NULL,                                  /* exit process */
  69     NULL,                                  /* exit master */
  70     NGX_MODULE_V1_PADDING
  71 };
  72
  73
  74 static ngx_int_t
  75 ngx_http_split_clients_variable(ngx_http_request_t *r,
  76     ngx_http_variable_value_t *v, uintptr_t data)
  77 {
  78     ngx_http_split_clients_ctx_t *ctx = (ngx_http_split_clients_ctx_t *) data;
  79
  80     uint32_t                        hash;
  81     ngx_str_t                       val;
  82     ngx_uint_t                      i;
  83     ngx_http_split_clients_part_t  *part;
  84
  85     *v = ngx_http_variable_null_value;
  86
  87     if (ngx_http_complex_value(r, &ctx->value, &val) != NGX_OK) {
  88         return NGX_OK;
  89     }
  90
  91     hash = ngx_murmur_hash2(val.data, val.len);
  92
  93     part = ctx->parts.elts;
  94
  95     for (i = 0; i < ctx->parts.nelts; i++) {
  96
  97         ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
  98                        "http split: %uD %uD", hash, part[i].percent);
  99
 100         if (hash < part[i].percent || part[i].percent == 0) {
 101             *v = part[i].value;
 102             return NGX_OK;
 103         }
 104     }
 105
 106     return NGX_OK;
 107 }
 108
 109
 110 static char *
 111 ngx_conf_split_clients_block(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 112 {
 113     char                                *rv;
 114     uint32_t                             sum, last;
 115     ngx_str_t                           *value, name;
 116     ngx_uint_t                           i;
 117     ngx_conf_t                           save;
 118     ngx_http_variable_t                 *var;
 119     ngx_http_split_clients_ctx_t        *ctx;
 120     ngx_http_split_clients_part_t       *part;
 121     ngx_http_compile_complex_value_t     ccv;
 122
 123     ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_split_clients_ctx_t));
 124     if (ctx == NULL) {
 125         return NGX_CONF_ERROR;
 126     }
 127
 128     value = cf->args->elts;
 129
 130     ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
 131
 132     ccv.cf = cf;
 133     ccv.value = &value[1];
 134     ccv.complex_value = &ctx->value;
 135
 136     if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
 137         return NGX_CONF_ERROR;
 138     }
 139
 140     name = value[2];
 141
 142     if (name.data[0] != '$') {
 143         ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 144                            "invalid variable name \"%V\"", &name);
 145         return NGX_CONF_ERROR;
 146     }
 147
 148     name.len--;
 149     name.data++;
 150
 151     var = ngx_http_add_variable(cf, &name, NGX_HTTP_VAR_CHANGEABLE);
 152     if (var == NULL) {
 153         return NGX_CONF_ERROR;
 154     }
 155
 156     var->get_handler = ngx_http_split_clients_variable;
 157     var->data = (uintptr_t) ctx;
 158
 159     if (ngx_array_init(&ctx->parts, cf->pool, 2,
 160                        sizeof(ngx_http_split_clients_part_t))
 161         != NGX_OK)
 162     {
 163         return NGX_CONF_ERROR;
 164     }
 165
 166     save = *cf;
 167     cf->ctx = ctx;
 168     cf->handler = ngx_http_split_clients;
 169     cf->handler_conf = conf;
 170
 171     rv = ngx_conf_parse(cf, NULL);
 172
 173     *cf = save;
 174
 175     if (rv != NGX_CONF_OK) {
 176         return rv;
 177     }
 178
 179     sum = 0;
 180     last = 0;
 181     part = ctx->parts.elts;
 182
 183     for (i = 0; i < ctx->parts.nelts; i++) {
 184         sum = part[i].percent ? sum + part[i].percent : 10000;
 185         if (sum > 10000) {
 186             ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 187                                "percent total is greater than 100%%");
 188             return NGX_CONF_ERROR;
 189         }
 190
 191         if (part[i].percent) {
 192             last += part[i].percent * (uint64_t) 0xffffffff / 10000;
 193             part[i].percent = last;
 194         }
 195     }
 196
 197     return rv;
 198 }
 199
 200
 201 static char *
 202 ngx_http_split_clients(ngx_conf_t *cf, ngx_command_t *dummy, void *conf)
 203 {
 204     ngx_int_t                       n;
 205     ngx_str_t                      *value;
 206     ngx_http_split_clients_ctx_t   *ctx;
 207     ngx_http_split_clients_part_t  *part;
 208
 209     ctx = cf->ctx;
 210     value = cf->args->elts;
 211
 212     part = ngx_array_push(&ctx->parts);
 213     if (part == NULL) {
 214         return NGX_CONF_ERROR;
 215     }
 216
 217     if (value[0].len == 1 && value[0].data[0] == '*') {
 218         part->percent = 0;
 219
 220     } else {
 221         if (value[0].len == 0 || value[0].data[value[0].len - 1] != '%') {
 222             goto invalid;
 223         }
 224
 225         n = ngx_atofp(value[0].data, value[0].len - 1, 2);
 226         if (n == NGX_ERROR || n == 0) {
 227             goto invalid;
 228         }
 229
 230         part->percent = (uint32_t) n;
 231     }
 232
 233     part->value.len = value[1].len;
 234     part->value.valid = 1;
 235     part->value.no_cacheable = 0;
 236     part->value.not_found = 0;
 237     part->value.data = value[1].data;
 238
 239     return NGX_CONF_OK;
 240
 241 invalid:
 242
 243     ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
 244                        "invalid percent value \"%V\"", &value[0]);
 245     return NGX_CONF_ERROR;
 246 }