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ngx_http_sysguard_module.c
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/*
* Copyright (C) 2010-2012 Alibaba Group Holding Limited
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#include <ngx_sysinfo.h>
typedef struct {
ngx_flag_t enable;
ngx_int_t load;
ngx_str_t load_action;
ngx_int_t swap;
ngx_str_t swap_action;
time_t interval;
ngx_uint_t log_level;
} ngx_http_sysguard_conf_t;
static void *ngx_http_sysguard_create_conf(ngx_conf_t *cf);
static char *ngx_http_sysguard_merge_conf(ngx_conf_t *cf, void *parent,
void *child);
static char *ngx_http_sysguard_load(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static char *ngx_http_sysguard_mem(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static ngx_int_t ngx_http_sysguard_init(ngx_conf_t *cf);
static ngx_conf_enum_t ngx_http_sysguard_log_levels[] = {
{ ngx_string("info"), NGX_LOG_INFO },
{ ngx_string("notice"), NGX_LOG_NOTICE },
{ ngx_string("warn"), NGX_LOG_WARN },
{ ngx_string("error"), NGX_LOG_ERR },
{ ngx_null_string, 0 }
};
static ngx_command_t ngx_http_sysguard_commands[] = {
{ ngx_string("sysguard"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_FLAG,
ngx_conf_set_flag_slot,
NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_sysguard_conf_t, enable),
NULL },
{ ngx_string("sysguard_load"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12,
ngx_http_sysguard_load,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL },
{ ngx_string("sysguard_mem"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE12,
ngx_http_sysguard_mem,
NGX_HTTP_LOC_CONF_OFFSET,
0,
NULL },
{ ngx_string("sysguard_interval"),
NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
ngx_conf_set_sec_slot,
NGX_HTTP_LOC_CONF_OFFSET,
offsetof(ngx_http_sysguard_conf_t, interval),
NULL },
{ ngx_string("sysguard_log_level"),
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_sysguard_conf_t, log_level),
&ngx_http_sysguard_log_levels },
ngx_null_command
};
static ngx_http_module_t ngx_http_sysguard_module_ctx = {
NULL, /* preconfiguration */
ngx_http_sysguard_init, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
NULL, /* create server configuration */
NULL, /* merge server configuration */
ngx_http_sysguard_create_conf, /* create location configuration */
ngx_http_sysguard_merge_conf /* merge location configuration */
};
ngx_module_t ngx_http_sysguard_module = {
NGX_MODULE_V1,
&ngx_http_sysguard_module_ctx, /* module context */
ngx_http_sysguard_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 time_t ngx_http_sysguard_cached_load_exptime;
static time_t ngx_http_sysguard_cached_swap_exptime;
static ngx_int_t ngx_http_sysguard_cached_load;
static ngx_int_t ngx_http_sysguard_cached_swapstat;
static ngx_int_t
ngx_http_sysguard_update_load(ngx_http_request_t *r, time_t exptime)
{
ngx_int_t load, rc;
ngx_http_sysguard_cached_load_exptime = ngx_time() + exptime;
rc = ngx_getloadavg(&load, 1, r->connection->log);
if (rc == NGX_ERROR) {
ngx_http_sysguard_cached_load = 0;
return NGX_ERROR;
}
ngx_http_sysguard_cached_load = load;
return NGX_OK;
}
static ngx_int_t
ngx_http_sysguard_update_swap(ngx_http_request_t *r, time_t exptime)
{
ngx_int_t rc;
ngx_meminfo_t m;
ngx_http_sysguard_cached_swap_exptime = ngx_time() + exptime;
rc = ngx_getmeminfo(&m, r->connection->log);
if (rc == NGX_ERROR) {
ngx_http_sysguard_cached_swapstat = 0;
return NGX_ERROR;
}
ngx_http_sysguard_cached_swapstat = m.totalswap == 0
? 0 : (m.totalswap - m.freeswap) * 100 / m.totalswap;
return NGX_OK;
}
static ngx_int_t
ngx_http_sysguard_do_redirect(ngx_http_request_t *r, ngx_str_t *path)
{
if (path->len == 0) {
return NGX_HTTP_SERVICE_UNAVAILABLE;
} else if (path->data[0] == '@') {
(void) ngx_http_named_location(r, path);
} else {
(void) ngx_http_internal_redirect(r, path, &r->args);
}
ngx_http_finalize_request(r, NGX_DONE);
return NGX_DONE;
}
static ngx_int_t
ngx_http_sysguard_handler(ngx_http_request_t *r)
{
ngx_http_sysguard_conf_t *glcf;
if (r->main->sysguard_set) {
return NGX_DECLINED;
}
glcf = ngx_http_get_module_loc_conf(r, ngx_http_sysguard_module);
if (!glcf->enable) {
return NGX_DECLINED;
}
r->main->sysguard_set = 1;
/* load */
if (glcf->load >= 0) {
if (ngx_http_sysguard_cached_load_exptime < ngx_time()) {
ngx_http_sysguard_update_load(r, glcf->interval);
}
ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http sysguard handler load: %i %i %V %V",
ngx_http_sysguard_cached_load,
glcf->load,
&r->uri,
&glcf->load_action);
if (ngx_http_sysguard_cached_load > glcf->load) {
ngx_log_error(glcf->log_level, r->connection->log, 0,
"sysguard load limited, current:%i conf:%i",
ngx_http_sysguard_cached_load,
glcf->load);
return ngx_http_sysguard_do_redirect(r, &glcf->load_action);
}
}
/* swap */
if (glcf->swap >= 0) {
if (ngx_http_sysguard_cached_swap_exptime < ngx_time()) {
ngx_http_sysguard_update_swap(r, glcf->interval);
}
ngx_log_debug4(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"http sysguard handler swap: %i %i %V %V",
ngx_http_sysguard_cached_swapstat,
glcf->swap,
&r->uri,
&glcf->swap_action);
if (ngx_http_sysguard_cached_swapstat > glcf->swap) {
ngx_log_error(glcf->log_level, r->connection->log, 0,
"sysguard swap limited, current:%i conf:%i",
ngx_http_sysguard_cached_swapstat,
glcf->swap);
return ngx_http_sysguard_do_redirect(r, &glcf->swap_action);
}
}
return NGX_DECLINED;
}
static void *
ngx_http_sysguard_create_conf(ngx_conf_t *cf)
{
ngx_http_sysguard_conf_t *conf;
conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_sysguard_conf_t));
if (conf == NULL) {
return NGX_CONF_ERROR;
}
/*
* set by ngx_pcalloc():
*
* conf->load_action = {0, NULL};
* conf->swap_action = {0, NULL};
*/
conf->enable = NGX_CONF_UNSET;
conf->load = NGX_CONF_UNSET;
conf->swap = NGX_CONF_UNSET;
conf->interval = NGX_CONF_UNSET;
conf->log_level = NGX_CONF_UNSET_UINT;
return conf;
}
static char *
ngx_http_sysguard_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
ngx_http_sysguard_conf_t *prev = parent;
ngx_http_sysguard_conf_t *conf = child;
ngx_conf_merge_value(conf->enable, prev->enable, 0);
ngx_conf_merge_str_value(conf->load_action, prev->load_action, "");
ngx_conf_merge_str_value(conf->swap_action, prev->swap_action, "");
ngx_conf_merge_value(conf->load, prev->load, -1);
ngx_conf_merge_value(conf->swap, prev->swap, -1);
ngx_conf_merge_value(conf->interval, prev->interval, 1);
ngx_conf_merge_uint_value(conf->log_level, prev->log_level, NGX_LOG_ERR);
return NGX_CONF_OK;
}
static char *
ngx_http_sysguard_load(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_sysguard_conf_t *glcf = conf;
ngx_str_t *value;
ngx_uint_t i;
value = cf->args->elts;
i = 1;
if (ngx_strncmp(value[i].data, "load=", 5) == 0) {
if (glcf->load != NGX_CONF_UNSET) {
return "is duplicate";
}
if (value[i].len == 5) {
goto invalid;
}
glcf->load = ngx_atofp(value[i].data + 5, value[i].len - 5, 3);
if (glcf->load == NGX_ERROR) {
goto invalid;
}
if (cf->args->nelts == 2) {
return NGX_CONF_OK;
}
i++;
if (ngx_strncmp(value[i].data, "action=", 7) != 0) {
goto invalid;
}
if (value[i].len == 7) {
goto invalid;
}
if (value[i].data[7] != '/' && value[i].data[7] != '@') {
goto invalid;
}
glcf->load_action.data = value[i].data + 7;
glcf->load_action.len = value[i].len - 7;
return NGX_CONF_OK;
}
invalid:
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
static char *
ngx_http_sysguard_mem(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_sysguard_conf_t *glcf = conf;
ngx_str_t *value;
ngx_uint_t i;
value = cf->args->elts;
i = 1;
if (ngx_strncmp(value[i].data, "swapratio=", 10) == 0) {
if (glcf->swap != NGX_CONF_UNSET) {
return "is duplicate";
}
if (value[i].data[value[i].len - 1] != '%') {
goto invalid;
}
glcf->swap = ngx_atofp(value[i].data + 10, value[i].len - 11, 2);
if (glcf->swap == NGX_ERROR) {
goto invalid;
}
if (cf->args->nelts == 2) {
return NGX_CONF_OK;
}
i++;
if (ngx_strncmp(value[i].data, "action=", 7) != 0) {
goto invalid;
}
if (value[i].len == 7) {
goto invalid;
}
if (value[i].data[7] != '/' && value[i].data[7] != '@') {
goto invalid;
}
glcf->swap_action.data = value[i].data + 7;
glcf->swap_action.len = value[i].len - 7;
return NGX_CONF_OK;
}
invalid:
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}
static ngx_int_t
ngx_http_sysguard_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_sysguard_handler;
return NGX_OK;
}