Mercurial > hg > nginx
view src/stream/ngx_stream_upstream_round_robin.h @ 8045:aa28c802409f
Resolver: make TCP write timer event cancelable.
Similar to 70e65bf8dfd7, the change is made to ensure that the ability to
cancel resolver tasks is fully controlled by the caller. As mentioned in the
referenced commit, it is safe to make this timer cancelable because resolve
tasks can have their own timeouts that are not cancelable.
The scenario where this may become a problem is a periodic background resolve
task (not tied to a specific request or a client connection), which receives a
response with short TTL, large enough to warrant fallback to a TCP query.
With each event loop wakeup, we either have a previously set write timer
instance or schedule a new one. The non-cancelable write timer can delay or
block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable
flag is set by the API user, and there are no other tasks or connections.
We use the resolver API in this way to maintain the list of upstream server
addresses specified with the 'resolve' parameter, and there could be third-party
modules implementing similar logic.
author | Aleksei Bavshin <a.bavshin@f5.com> |
---|---|
date | Wed, 01 Jun 2022 20:17:23 -0700 |
parents | 90cc7194e993 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_STREAM_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ #define _NGX_STREAM_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_stream.h> typedef struct ngx_stream_upstream_rr_peer_s ngx_stream_upstream_rr_peer_t; struct ngx_stream_upstream_rr_peer_s { struct sockaddr *sockaddr; socklen_t socklen; ngx_str_t name; ngx_str_t server; ngx_int_t current_weight; ngx_int_t effective_weight; ngx_int_t weight; ngx_uint_t conns; ngx_uint_t max_conns; ngx_uint_t fails; time_t accessed; time_t checked; ngx_uint_t max_fails; time_t fail_timeout; ngx_msec_t slow_start; ngx_msec_t start_time; ngx_uint_t down; void *ssl_session; int ssl_session_len; #if (NGX_STREAM_UPSTREAM_ZONE) ngx_atomic_t lock; #endif ngx_stream_upstream_rr_peer_t *next; NGX_COMPAT_BEGIN(25) NGX_COMPAT_END }; typedef struct ngx_stream_upstream_rr_peers_s ngx_stream_upstream_rr_peers_t; struct ngx_stream_upstream_rr_peers_s { ngx_uint_t number; #if (NGX_STREAM_UPSTREAM_ZONE) ngx_slab_pool_t *shpool; ngx_atomic_t rwlock; ngx_stream_upstream_rr_peers_t *zone_next; #endif ngx_uint_t total_weight; ngx_uint_t tries; unsigned single:1; unsigned weighted:1; ngx_str_t *name; ngx_stream_upstream_rr_peers_t *next; ngx_stream_upstream_rr_peer_t *peer; }; #if (NGX_STREAM_UPSTREAM_ZONE) #define ngx_stream_upstream_rr_peers_rlock(peers) \ \ if (peers->shpool) { \ ngx_rwlock_rlock(&peers->rwlock); \ } #define ngx_stream_upstream_rr_peers_wlock(peers) \ \ if (peers->shpool) { \ ngx_rwlock_wlock(&peers->rwlock); \ } #define ngx_stream_upstream_rr_peers_unlock(peers) \ \ if (peers->shpool) { \ ngx_rwlock_unlock(&peers->rwlock); \ } #define ngx_stream_upstream_rr_peer_lock(peers, peer) \ \ if (peers->shpool) { \ ngx_rwlock_wlock(&peer->lock); \ } #define ngx_stream_upstream_rr_peer_unlock(peers, peer) \ \ if (peers->shpool) { \ ngx_rwlock_unlock(&peer->lock); \ } #else #define ngx_stream_upstream_rr_peers_rlock(peers) #define ngx_stream_upstream_rr_peers_wlock(peers) #define ngx_stream_upstream_rr_peers_unlock(peers) #define ngx_stream_upstream_rr_peer_lock(peers, peer) #define ngx_stream_upstream_rr_peer_unlock(peers, peer) #endif typedef struct { ngx_uint_t config; ngx_stream_upstream_rr_peers_t *peers; ngx_stream_upstream_rr_peer_t *current; uintptr_t *tried; uintptr_t data; } ngx_stream_upstream_rr_peer_data_t; ngx_int_t ngx_stream_upstream_init_round_robin(ngx_conf_t *cf, ngx_stream_upstream_srv_conf_t *us); ngx_int_t ngx_stream_upstream_init_round_robin_peer(ngx_stream_session_t *s, ngx_stream_upstream_srv_conf_t *us); ngx_int_t ngx_stream_upstream_create_round_robin_peer(ngx_stream_session_t *s, ngx_stream_upstream_resolved_t *ur); ngx_int_t ngx_stream_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data); void ngx_stream_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data, ngx_uint_t state); #endif /* _NGX_STREAM_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ */