diff options
Diffstat (limited to 'app/nginx/src/http/modules/ngx_http_degradation_module.c')
| -rw-r--r-- | app/nginx/src/http/modules/ngx_http_degradation_module.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/app/nginx/src/http/modules/ngx_http_degradation_module.c b/app/nginx/src/http/modules/ngx_http_degradation_module.c new file mode 100644 index 0000000..b9c65cd --- /dev/null +++ b/app/nginx/src/http/modules/ngx_http_degradation_module.c @@ -0,0 +1,243 @@ + +/* + * Copyright (C) Igor Sysoev + * Copyright (C) Nginx, Inc. + */ + + +#include <ngx_config.h> +#include <ngx_core.h> +#include <ngx_http.h> + + +typedef struct { + size_t sbrk_size; +} ngx_http_degradation_main_conf_t; + + +typedef struct { + ngx_uint_t degrade; +} ngx_http_degradation_loc_conf_t; + + +static ngx_conf_enum_t ngx_http_degrade[] = { + { ngx_string("204"), 204 }, + { ngx_string("444"), 444 }, + { ngx_null_string, 0 } +}; + + +static void *ngx_http_degradation_create_main_conf(ngx_conf_t *cf); +static void *ngx_http_degradation_create_loc_conf(ngx_conf_t *cf); +static char *ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, + void *child); +static char *ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, + void *conf); +static ngx_int_t ngx_http_degradation_init(ngx_conf_t *cf); + + +static ngx_command_t ngx_http_degradation_commands[] = { + + { ngx_string("degradation"), + NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1, + ngx_http_degradation, + NGX_HTTP_MAIN_CONF_OFFSET, + 0, + NULL }, + + { ngx_string("degrade"), + NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, + ngx_conf_set_enum_slot, + NGX_HTTP_LOC_CONF_OFFSET, + offsetof(ngx_http_degradation_loc_conf_t, degrade), + &ngx_http_degrade }, + + ngx_null_command +}; + + +static ngx_http_module_t ngx_http_degradation_module_ctx = { + NULL, /* preconfiguration */ + ngx_http_degradation_init, /* postconfiguration */ + + ngx_http_degradation_create_main_conf, /* create main configuration */ + NULL, /* init main configuration */ + + NULL, /* create server configuration */ + NULL, /* merge server configuration */ + + ngx_http_degradation_create_loc_conf, /* create location configuration */ + ngx_http_degradation_merge_loc_conf /* merge location configuration */ +}; + + +ngx_module_t ngx_http_degradation_module = { + NGX_MODULE_V1, + &ngx_http_degradation_module_ctx, /* module context */ + ngx_http_degradation_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_degradation_handler(ngx_http_request_t *r) +{ + ngx_http_degradation_loc_conf_t *dlcf; + + dlcf = ngx_http_get_module_loc_conf(r, ngx_http_degradation_module); + + if (dlcf->degrade && ngx_http_degraded(r)) { + return dlcf->degrade; + } + + return NGX_DECLINED; +} + + +ngx_uint_t +ngx_http_degraded(ngx_http_request_t *r) +{ + time_t now; + ngx_uint_t log; + static size_t sbrk_size; + static time_t sbrk_time; + ngx_http_degradation_main_conf_t *dmcf; + + dmcf = ngx_http_get_module_main_conf(r, ngx_http_degradation_module); + + if (dmcf->sbrk_size) { + + log = 0; + now = ngx_time(); + + /* lock mutex */ + + if (now != sbrk_time) { + + /* + * ELF/i386 is loaded at 0x08000000, 128M + * ELF/amd64 is loaded at 0x00400000, 4M + * + * use a function address to subtract the loading address + */ + + sbrk_size = (size_t) sbrk(0) - ((uintptr_t) ngx_palloc & ~0x3FFFFF); + sbrk_time = now; + log = 1; + } + + /* unlock mutex */ + + if (sbrk_size >= dmcf->sbrk_size) { + if (log) { + ngx_log_error(NGX_LOG_NOTICE, r->connection->log, 0, + "degradation sbrk:%uzM", + sbrk_size / (1024 * 1024)); + } + + return 1; + } + } + + return 0; +} + + +static void * +ngx_http_degradation_create_main_conf(ngx_conf_t *cf) +{ + ngx_http_degradation_main_conf_t *dmcf; + + dmcf = ngx_pcalloc(cf->pool, sizeof(ngx_http_degradation_main_conf_t)); + if (dmcf == NULL) { + return NULL; + } + + return dmcf; +} + + +static void * +ngx_http_degradation_create_loc_conf(ngx_conf_t *cf) +{ + ngx_http_degradation_loc_conf_t *conf; + + conf = ngx_palloc(cf->pool, sizeof(ngx_http_degradation_loc_conf_t)); + if (conf == NULL) { + return NULL; + } + + conf->degrade = NGX_CONF_UNSET_UINT; + + return conf; +} + + +static char * +ngx_http_degradation_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) +{ + ngx_http_degradation_loc_conf_t *prev = parent; + ngx_http_degradation_loc_conf_t *conf = child; + + ngx_conf_merge_uint_value(conf->degrade, prev->degrade, 0); + + return NGX_CONF_OK; +} + + +static char * +ngx_http_degradation(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) +{ + ngx_http_degradation_main_conf_t *dmcf = conf; + + ngx_str_t *value, s; + + value = cf->args->elts; + + if (ngx_strncmp(value[1].data, "sbrk=", 5) == 0) { + + s.len = value[1].len - 5; + s.data = value[1].data + 5; + + dmcf->sbrk_size = ngx_parse_size(&s); + if (dmcf->sbrk_size == (size_t) NGX_ERROR) { + ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, + "invalid sbrk size \"%V\"", &value[1]); + return NGX_CONF_ERROR; + } + + return NGX_CONF_OK; + } + + ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, + "invalid parameter \"%V\"", &value[1]); + + return NGX_CONF_ERROR; +} + + +static ngx_int_t +ngx_http_degradation_init(ngx_conf_t *cf) +{ + ngx_http_handler_pt *h; + ngx_http_core_main_conf_t *cmcf; + + cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); + + h = ngx_array_push(&cmcf->phases[NGX_HTTP_PREACCESS_PHASE].handlers); + if (h == NULL) { + return NGX_ERROR; + } + + *h = ngx_http_degradation_handler; + + return NGX_OK; +} |