/*
* 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;
}
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