nginx/src/http/modules/ngx_http_upstream_keepalive_module.c
Maxim Dounin 29844cd55c Upstream keepalive: "single" parameter deprecated.
The original idea was to optimize edge cases in case of interchangeable
backends, i.e. don't establish a new connection if we have any one
cached.  This causes more harm than good though, as it screws up
underlying balancer's idea about backends used and may result in
various unexpected problems.
2012-06-18 14:23:42 +00:00

546 lines
14 KiB
C

/*
* Copyright (C) Maxim Dounin
* Copyright (C) Nginx, Inc.
*/
#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
typedef struct {
ngx_uint_t max_cached;
ngx_queue_t cache;
ngx_queue_t free;
ngx_http_upstream_init_pt original_init_upstream;
ngx_http_upstream_init_peer_pt original_init_peer;
} ngx_http_upstream_keepalive_srv_conf_t;
typedef struct {
ngx_http_upstream_keepalive_srv_conf_t *conf;
ngx_http_upstream_t *upstream;
void *data;
ngx_event_get_peer_pt original_get_peer;
ngx_event_free_peer_pt original_free_peer;
#if (NGX_HTTP_SSL)
ngx_event_set_peer_session_pt original_set_session;
ngx_event_save_peer_session_pt original_save_session;
#endif
ngx_uint_t failed; /* unsigned:1 */
} ngx_http_upstream_keepalive_peer_data_t;
typedef struct {
ngx_http_upstream_keepalive_srv_conf_t *conf;
ngx_queue_t queue;
ngx_connection_t *connection;
socklen_t socklen;
u_char sockaddr[NGX_SOCKADDRLEN];
} ngx_http_upstream_keepalive_cache_t;
static ngx_int_t ngx_http_upstream_init_keepalive_peer(ngx_http_request_t *r,
ngx_http_upstream_srv_conf_t *us);
static ngx_int_t ngx_http_upstream_get_keepalive_peer(ngx_peer_connection_t *pc,
void *data);
static void ngx_http_upstream_free_keepalive_peer(ngx_peer_connection_t *pc,
void *data, ngx_uint_t state);
static void ngx_http_upstream_keepalive_dummy_handler(ngx_event_t *ev);
static void ngx_http_upstream_keepalive_close_handler(ngx_event_t *ev);
static void ngx_http_upstream_keepalive_close(ngx_connection_t *c);
#if (NGX_HTTP_SSL)
static ngx_int_t ngx_http_upstream_keepalive_set_session(
ngx_peer_connection_t *pc, void *data);
static void ngx_http_upstream_keepalive_save_session(ngx_peer_connection_t *pc,
void *data);
#endif
static void *ngx_http_upstream_keepalive_create_conf(ngx_conf_t *cf);
static char *ngx_http_upstream_keepalive(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
static ngx_command_t ngx_http_upstream_keepalive_commands[] = {
{ ngx_string("keepalive"),
NGX_HTTP_UPS_CONF|NGX_CONF_TAKE12,
ngx_http_upstream_keepalive,
0,
0,
NULL },
ngx_null_command
};
static ngx_http_module_t ngx_http_upstream_keepalive_module_ctx = {
NULL, /* preconfiguration */
NULL, /* postconfiguration */
NULL, /* create main configuration */
NULL, /* init main configuration */
ngx_http_upstream_keepalive_create_conf, /* create server configuration */
NULL, /* merge server configuration */
NULL, /* create location configuration */
NULL /* merge location configuration */
};
ngx_module_t ngx_http_upstream_keepalive_module = {
NGX_MODULE_V1,
&ngx_http_upstream_keepalive_module_ctx, /* module context */
ngx_http_upstream_keepalive_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_upstream_init_keepalive(ngx_conf_t *cf,
ngx_http_upstream_srv_conf_t *us)
{
ngx_uint_t i;
ngx_http_upstream_keepalive_srv_conf_t *kcf;
ngx_http_upstream_keepalive_cache_t *cached;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, cf->log, 0,
"init keepalive");
kcf = ngx_http_conf_upstream_srv_conf(us,
ngx_http_upstream_keepalive_module);
if (kcf->original_init_upstream(cf, us) != NGX_OK) {
return NGX_ERROR;
}
kcf->original_init_peer = us->peer.init;
us->peer.init = ngx_http_upstream_init_keepalive_peer;
/* allocate cache items and add to free queue */
cached = ngx_pcalloc(cf->pool,
sizeof(ngx_http_upstream_keepalive_cache_t) * kcf->max_cached);
if (cached == NULL) {
return NGX_ERROR;
}
ngx_queue_init(&kcf->cache);
ngx_queue_init(&kcf->free);
for (i = 0; i < kcf->max_cached; i++) {
ngx_queue_insert_head(&kcf->free, &cached[i].queue);
cached[i].conf = kcf;
}
return NGX_OK;
}
static ngx_int_t
ngx_http_upstream_init_keepalive_peer(ngx_http_request_t *r,
ngx_http_upstream_srv_conf_t *us)
{
ngx_http_upstream_keepalive_peer_data_t *kp;
ngx_http_upstream_keepalive_srv_conf_t *kcf;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"init keepalive peer");
kcf = ngx_http_conf_upstream_srv_conf(us,
ngx_http_upstream_keepalive_module);
kp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_keepalive_peer_data_t));
if (kp == NULL) {
return NGX_ERROR;
}
if (kcf->original_init_peer(r, us) != NGX_OK) {
return NGX_ERROR;
}
kp->conf = kcf;
kp->upstream = r->upstream;
kp->data = r->upstream->peer.data;
kp->original_get_peer = r->upstream->peer.get;
kp->original_free_peer = r->upstream->peer.free;
r->upstream->peer.data = kp;
r->upstream->peer.get = ngx_http_upstream_get_keepalive_peer;
r->upstream->peer.free = ngx_http_upstream_free_keepalive_peer;
#if (NGX_HTTP_SSL)
kp->original_set_session = r->upstream->peer.set_session;
kp->original_save_session = r->upstream->peer.save_session;
r->upstream->peer.set_session = ngx_http_upstream_keepalive_set_session;
r->upstream->peer.save_session = ngx_http_upstream_keepalive_save_session;
#endif
return NGX_OK;
}
static ngx_int_t
ngx_http_upstream_get_keepalive_peer(ngx_peer_connection_t *pc, void *data)
{
ngx_http_upstream_keepalive_peer_data_t *kp = data;
ngx_http_upstream_keepalive_cache_t *item;
ngx_int_t rc;
ngx_queue_t *q, *cache;
ngx_connection_t *c;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0,
"get keepalive peer");
kp->failed = 0;
/* ask balancer */
rc = kp->original_get_peer(pc, kp->data);
if (rc != NGX_OK) {
return rc;
}
/* search cache for suitable connection */
cache = &kp->conf->cache;
for (q = ngx_queue_head(cache);
q != ngx_queue_sentinel(cache);
q = ngx_queue_next(q))
{
item = ngx_queue_data(q, ngx_http_upstream_keepalive_cache_t, queue);
c = item->connection;
if (ngx_memn2cmp((u_char *) &item->sockaddr, (u_char *) pc->sockaddr,
item->socklen, pc->socklen)
== 0)
{
ngx_queue_remove(q);
ngx_queue_insert_head(&kp->conf->free, q);
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
"get keepalive peer: using connection %p", c);
c->idle = 0;
c->log = pc->log;
c->read->log = pc->log;
c->write->log = pc->log;
c->pool->log = pc->log;
pc->connection = c;
pc->cached = 1;
return NGX_DONE;
}
}
return NGX_OK;
}
static void
ngx_http_upstream_free_keepalive_peer(ngx_peer_connection_t *pc, void *data,
ngx_uint_t state)
{
ngx_http_upstream_keepalive_peer_data_t *kp = data;
ngx_http_upstream_keepalive_cache_t *item;
ngx_queue_t *q;
ngx_connection_t *c;
ngx_http_upstream_t *u;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, pc->log, 0,
"free keepalive peer");
/* remember failed state - peer.free() may be called more than once */
if (state & NGX_PEER_FAILED) {
kp->failed = 1;
}
/* cache valid connections */
u = kp->upstream;
c = pc->connection;
if (kp->failed
|| c == NULL
|| c->read->eof
|| c->read->error
|| c->read->timedout
|| c->write->error
|| c->write->timedout)
{
goto invalid;
}
if (!u->keepalive) {
goto invalid;
}
if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
goto invalid;
}
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
"free keepalive peer: saving connection %p", c);
if (ngx_queue_empty(&kp->conf->free)) {
q = ngx_queue_last(&kp->conf->cache);
ngx_queue_remove(q);
item = ngx_queue_data(q, ngx_http_upstream_keepalive_cache_t, queue);
ngx_http_upstream_keepalive_close(item->connection);
} else {
q = ngx_queue_head(&kp->conf->free);
ngx_queue_remove(q);
item = ngx_queue_data(q, ngx_http_upstream_keepalive_cache_t, queue);
}
item->connection = c;
ngx_queue_insert_head(&kp->conf->cache, q);
pc->connection = NULL;
if (c->read->timer_set) {
ngx_del_timer(c->read);
}
if (c->write->timer_set) {
ngx_del_timer(c->write);
}
c->write->handler = ngx_http_upstream_keepalive_dummy_handler;
c->read->handler = ngx_http_upstream_keepalive_close_handler;
c->data = item;
c->idle = 1;
c->log = ngx_cycle->log;
c->read->log = ngx_cycle->log;
c->write->log = ngx_cycle->log;
c->pool->log = ngx_cycle->log;
item->socklen = pc->socklen;
ngx_memcpy(&item->sockaddr, pc->sockaddr, pc->socklen);
if (c->read->ready) {
ngx_http_upstream_keepalive_close_handler(c->read);
}
invalid:
kp->original_free_peer(pc, kp->data, state);
}
static void
ngx_http_upstream_keepalive_dummy_handler(ngx_event_t *ev)
{
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ev->log, 0,
"keepalive dummy handler");
}
static void
ngx_http_upstream_keepalive_close_handler(ngx_event_t *ev)
{
ngx_http_upstream_keepalive_srv_conf_t *conf;
ngx_http_upstream_keepalive_cache_t *item;
int n;
char buf[1];
ngx_connection_t *c;
ngx_log_debug0(NGX_LOG_DEBUG_HTTP, ev->log, 0,
"keepalive close handler");
c = ev->data;
if (c->close) {
goto close;
}
n = recv(c->fd, buf, 1, MSG_PEEK);
if (n == -1 && ngx_socket_errno == NGX_EAGAIN) {
/* stale event */
if (ngx_handle_read_event(c->read, 0) != NGX_OK) {
goto close;
}
return;
}
close:
item = c->data;
conf = item->conf;
ngx_http_upstream_keepalive_close(c);
ngx_queue_remove(&item->queue);
ngx_queue_insert_head(&conf->free, &item->queue);
}
static void
ngx_http_upstream_keepalive_close(ngx_connection_t *c)
{
#if (NGX_HTTP_SSL)
if (c->ssl) {
c->ssl->no_wait_shutdown = 1;
c->ssl->no_send_shutdown = 1;
if (ngx_ssl_shutdown(c) == NGX_AGAIN) {
c->ssl->handler = ngx_http_upstream_keepalive_close;
return;
}
}
#endif
ngx_destroy_pool(c->pool);
ngx_close_connection(c);
}
#if (NGX_HTTP_SSL)
static ngx_int_t
ngx_http_upstream_keepalive_set_session(ngx_peer_connection_t *pc, void *data)
{
ngx_http_upstream_keepalive_peer_data_t *kp = data;
return kp->original_set_session(pc, kp->data);
}
static void
ngx_http_upstream_keepalive_save_session(ngx_peer_connection_t *pc, void *data)
{
ngx_http_upstream_keepalive_peer_data_t *kp = data;
kp->original_save_session(pc, kp->data);
return;
}
#endif
static void *
ngx_http_upstream_keepalive_create_conf(ngx_conf_t *cf)
{
ngx_http_upstream_keepalive_srv_conf_t *conf;
conf = ngx_pcalloc(cf->pool,
sizeof(ngx_http_upstream_keepalive_srv_conf_t));
if (conf == NULL) {
return NULL;
}
/*
* set by ngx_pcalloc():
*
* conf->original_init_upstream = NULL;
* conf->original_init_peer = NULL;
*/
conf->max_cached = 1;
return conf;
}
static char *
ngx_http_upstream_keepalive(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
ngx_http_upstream_srv_conf_t *uscf;
ngx_http_upstream_keepalive_srv_conf_t *kcf;
ngx_int_t n;
ngx_str_t *value;
ngx_uint_t i;
uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);
kcf = ngx_http_conf_upstream_srv_conf(uscf,
ngx_http_upstream_keepalive_module);
kcf->original_init_upstream = uscf->peer.init_upstream
? uscf->peer.init_upstream
: ngx_http_upstream_init_round_robin;
uscf->peer.init_upstream = ngx_http_upstream_init_keepalive;
/* read options */
value = cf->args->elts;
n = ngx_atoi(value[1].data, value[1].len);
if (n == NGX_ERROR || n == 0) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid value \"%V\" in \"%V\" directive",
&value[1], &cmd->name);
return NGX_CONF_ERROR;
}
kcf->max_cached = n;
for (i = 2; i < cf->args->nelts; i++) {
if (ngx_strcmp(value[i].data, "single") == 0) {
ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
"the \"single\" parameter is deprecated");
continue;
}
goto invalid;
}
return NGX_CONF_OK;
invalid:
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"invalid parameter \"%V\"", &value[i]);
return NGX_CONF_ERROR;
}