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 }
247
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