Mercurial > hg > nginx
comparison src/http/modules/ngx_http_degradation_module.c @ 3326:e6967a1dc8e9
ngx_http_degradation_module
author | Igor Sysoev <igor@sysoev.ru> |
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date | Mon, 16 Nov 2009 12:20:00 +0000 |
parents | |
children | de27a5d044ff |
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3325:42c16d8bddbe | 3326:e6967a1dc8e9 |
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1 | |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4 */ | |
5 | |
6 | |
7 #include <ngx_config.h> | |
8 #include <ngx_core.h> | |
9 #include <ngx_http.h> | |
10 | |
11 | |
12 typedef struct { | |
13 size_t sbrk_size; | |
14 } ngx_http_degradation_main_conf_t; | |
15 | |
16 | |
17 typedef struct { | |
18 ngx_uint_t degrade; | |
19 } ngx_http_degradation_loc_conf_t; | |
20 | |
21 | |
22 static ngx_conf_enum_t ngx_http_degrade[] = { | |
23 { ngx_string("204"), 204 }, | |
24 { ngx_string("444"), 444 }, | |
25 { ngx_null_string, 0 } | |
26 }; | |
27 | |
28 | |
29 static void *ngx_http_degradation_create_main_conf(ngx_conf_t *cf); | |
30 static void *ngx_http_degradation_create_loc_conf(ngx_conf_t *cf); | |
31 static char *ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, | |
32 void *child); | |
33 static char *ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, | |
34 void *conf); | |
35 static ngx_int_t ngx_http_degradation_init(ngx_conf_t *cf); | |
36 | |
37 | |
38 static ngx_command_t ngx_http_degradation_commands[] = { | |
39 | |
40 { ngx_string("degradation"), | |
41 NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1, | |
42 ngx_http_degradation, | |
43 NGX_HTTP_MAIN_CONF_OFFSET, | |
44 0, | |
45 NULL }, | |
46 | |
47 { ngx_string("degrade"), | |
48 NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, | |
49 ngx_conf_set_enum_slot, | |
50 NGX_HTTP_LOC_CONF_OFFSET, | |
51 offsetof(ngx_http_degradation_loc_conf_t, degrade), | |
52 &ngx_http_degrade }, | |
53 | |
54 ngx_null_command | |
55 }; | |
56 | |
57 | |
58 static ngx_http_module_t ngx_http_degradation_module_ctx = { | |
59 NULL, /* preconfiguration */ | |
60 ngx_http_degradation_init, /* postconfiguration */ | |
61 | |
62 ngx_http_degradation_create_main_conf, /* create main configuration */ | |
63 NULL, /* init main configuration */ | |
64 | |
65 NULL, /* create server configuration */ | |
66 NULL, /* merge server configuration */ | |
67 | |
68 ngx_http_degradation_create_loc_conf, /* create location configuration */ | |
69 ngx_http_degradation_merge_loc_conf /* merge location configuration */ | |
70 }; | |
71 | |
72 | |
73 ngx_module_t ngx_http_degradation_module = { | |
74 NGX_MODULE_V1, | |
75 &ngx_http_degradation_module_ctx, /* module context */ | |
76 ngx_http_degradation_commands, /* module directives */ | |
77 NGX_HTTP_MODULE, /* module type */ | |
78 NULL, /* init master */ | |
79 NULL, /* init module */ | |
80 NULL, /* init process */ | |
81 NULL, /* init thread */ | |
82 NULL, /* exit thread */ | |
83 NULL, /* exit process */ | |
84 NULL, /* exit master */ | |
85 NGX_MODULE_V1_PADDING | |
86 }; | |
87 | |
88 | |
89 static ngx_int_t | |
90 ngx_http_degradation_handler(ngx_http_request_t *r) | |
91 { | |
92 time_t now; | |
93 static size_t sbrk_size; | |
94 static time_t sbrk_time; | |
95 ngx_http_degradation_loc_conf_t *dlcf; | |
96 ngx_http_degradation_main_conf_t *dmcf; | |
97 | |
98 dlcf = ngx_http_get_module_loc_conf(r, ngx_http_degradation_module); | |
99 | |
100 if (dlcf->degrade == 0) { | |
101 return NGX_DECLINED; | |
102 } | |
103 | |
104 dmcf = ngx_http_get_module_main_conf(r, ngx_http_degradation_module); | |
105 | |
106 if (dmcf->sbrk_size) { | |
107 | |
108 now = ngx_time(); | |
109 | |
110 /* lock mutex */ | |
111 | |
112 if (now != sbrk_time) { | |
113 | |
114 /* | |
115 * ELF/i386 is loaded at 0x08000000, 128M | |
116 * ELF/amd64 is loaded at 0x00400000, 4M | |
117 * | |
118 * use a function address to substract the loading address | |
119 */ | |
120 | |
121 sbrk_size = (size_t) sbrk(0) - ((uintptr_t) ngx_palloc & ~0x3FFFFF); | |
122 sbrk_time = now; | |
123 } | |
124 | |
125 /* unlock mutex */ | |
126 | |
127 if (sbrk_size >= dmcf->sbrk_size) { | |
128 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, | |
129 "degradation sbrk: %uz", sbrk_size); | |
130 | |
131 return dlcf->degrade; | |
132 } | |
133 } | |
134 | |
135 return NGX_DECLINED; | |
136 } | |
137 | |
138 | |
139 static void * | |
140 ngx_http_degradation_create_main_conf(ngx_conf_t *cf) | |
141 { | |
142 ngx_http_degradation_main_conf_t *dmcf; | |
143 | |
144 dmcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_degradation_main_conf_t)); | |
145 if (dmcf == NULL) { | |
146 return NULL; | |
147 } | |
148 | |
149 return dmcf; | |
150 } | |
151 | |
152 | |
153 static void * | |
154 ngx_http_degradation_create_loc_conf(ngx_conf_t *cf) | |
155 { | |
156 ngx_http_degradation_loc_conf_t *conf; | |
157 | |
158 conf = ngx_palloc(cf->pool, sizeof(ngx_http_degradation_loc_conf_t)); | |
159 if (conf == NULL) { | |
160 return NULL; | |
161 } | |
162 | |
163 conf->degrade = NGX_CONF_UNSET_UINT; | |
164 | |
165 return conf; | |
166 } | |
167 | |
168 | |
169 static char * | |
170 ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) | |
171 { | |
172 ngx_http_degradation_loc_conf_t *prev = parent; | |
173 ngx_http_degradation_loc_conf_t *conf = child; | |
174 | |
175 ngx_conf_merge_uint_value(conf->degrade, prev->degrade, 0); | |
176 | |
177 return NGX_CONF_OK; | |
178 } | |
179 | |
180 | |
181 static char * | |
182 ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) | |
183 { | |
184 ngx_http_degradation_main_conf_t *dmcf = conf; | |
185 | |
186 ngx_str_t *value, s; | |
187 | |
188 value = cf->args->elts; | |
189 | |
190 if (ngx_strncmp(value[1].data, "sbrk=", 5) == 0) { | |
191 | |
192 s.len = value[1].len - 5; | |
193 s.data = value[1].data + 5; | |
194 | |
195 dmcf->sbrk_size = ngx_parse_size(&s); | |
196 if (dmcf->sbrk_size == (size_t) NGX_ERROR) { | |
197 ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, | |
198 "invalid sbrk size \"%V\"", &value[1]); | |
199 return NGX_CONF_ERROR; | |
200 } | |
201 } | |
202 | |
203 return NGX_CONF_OK; | |
204 } | |
205 | |
206 | |
207 static ngx_int_t | |
208 ngx_http_degradation_init(ngx_conf_t *cf) | |
209 { | |
210 ngx_http_handler_pt *h; | |
211 ngx_http_core_main_conf_t *cmcf; | |
212 | |
213 cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); | |
214 | |
215 h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers); | |
216 if (h == NULL) { | |
217 return NGX_ERROR; | |
218 } | |
219 | |
220 *h = ngx_http_degradation_handler; | |
221 | |
222 return NGX_OK; | |
223 } |