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[PATCH 1 of 6] Upstream: re-resolvable servers

Aleksei Bavshin
January 31, 2023 08:40PM
# HG changeset patch
# User Ruslan Ermilov <ru@nginx.com>
# Date 1392462754 -14400
# Sat Feb 15 15:12:34 2014 +0400
# Node ID b6e13aa0330c8434add55c88598480016b80fc0e
# Parent 106328a70f4ecb32f828d33e5cd66c861e455f92
Upstream: re-resolvable servers.

Specifying the upstream server by a hostname together with the
"resolve" parameter will make the hostname to be periodically
resolved, and upstream servers added/removed as necessary.

This requires a "resolver" at the "http" configuration block.

The "resolver_timeout" parameter also affects when the failed
DNS requests will be attempted again. Responses with NXDOMAIN
will be attempted again in 10 seconds.

Upstream has a configuration generation number that is incremented each
time servers are added/removed to the primary/backup list. This number
is remembered by the peer.init method, and if peer.get detects a change
in configuration, it returns NGX_BUSY.

Each server has a reference counter. It is incremented by peer.get and
decremented by peer.free. When a server is removed, it is removed from
the list of servers and is marked as "zombie". The memory allocated by
a zombie peer is freed only when its reference count becomes zero.

Re-resolvable servers utilize timers that also hold a reference. A
reference is also held while upstream keepalive caches an idle
connection.

Co-authored-by: Roman Arutyunyan <arut@nginx.com>
Co-authored-by: Sergey Kandaurov <pluknet@nginx.com>
Co-authored-by: Vladimir Homutov <vl@nginx.com>

diff --git a/src/http/modules/ngx_http_upstream_hash_module.c b/src/http/modules/ngx_http_upstream_hash_module.c
--- a/src/http/modules/ngx_http_upstream_hash_module.c
+++ b/src/http/modules/ngx_http_upstream_hash_module.c
@@ -24,6 +24,9 @@ typedef struct {

typedef struct {
ngx_http_complex_value_t key;
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ ngx_uint_t config;
+#endif
ngx_http_upstream_chash_points_t *points;
} ngx_http_upstream_hash_srv_conf_t;

@@ -49,6 +52,8 @@ static ngx_int_t ngx_http_upstream_get_h

static ngx_int_t ngx_http_upstream_init_chash(ngx_conf_t *cf,
ngx_http_upstream_srv_conf_t *us);
+static ngx_int_t ngx_http_upstream_update_chash(ngx_pool_t *pool,
+ ngx_http_upstream_srv_conf_t *us);
static int ngx_libc_cdecl
ngx_http_upstream_chash_cmp_points(const void *one, const void *two);
static ngx_uint_t ngx_http_upstream_find_chash_point(
@@ -178,11 +183,18 @@ ngx_http_upstream_get_hash_peer(ngx_peer

ngx_http_upstream_rr_peers_rlock(hp->rrp.peers);

- if (hp->tries > 20 || hp->rrp.peers->single || hp->key.len == 0) {
+ if (hp->tries > 20 || hp->rrp.peers->number < 2 || hp->key.len == 0) {
ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
return hp->get_rr_peer(pc, &hp->rrp);
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (hp->rrp.peers->config && hp->rrp.config != *hp->rrp.peers->config) {
+ ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+ return hp->get_rr_peer(pc, &hp->rrp);
+ }
+#endif
+
now = ngx_time();

pc->cached = 0;
@@ -262,6 +274,7 @@ ngx_http_upstream_get_hash_peer(ngx_peer
}

hp->rrp.current = peer;
+ ngx_http_upstream_rr_peer_ref(hp->rrp.peers, peer);

pc->sockaddr = peer->sockaddr;
pc->socklen = peer->socklen;
@@ -285,6 +298,26 @@ ngx_http_upstream_get_hash_peer(ngx_peer
static ngx_int_t
ngx_http_upstream_init_chash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
{
+ if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
+ return NGX_ERROR;
+ }
+
+ us->peer.init = ngx_http_upstream_init_chash_peer;
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (us->shm_zone) {
+ return NGX_OK;
+ }
+#endif
+
+ return ngx_http_upstream_update_chash(cf->pool, us);
+}
+
+
+static ngx_int_t
+ngx_http_upstream_update_chash(ngx_pool_t *pool,
+ ngx_http_upstream_srv_conf_t *us)
+{
u_char *host, *port, c;
size_t host_len, port_len, size;
uint32_t hash, base_hash;
@@ -299,25 +332,32 @@ ngx_http_upstream_init_chash(ngx_conf_t
u_char byte[4];
} prev_hash;

- if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
- return NGX_ERROR;
+ hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module);
+
+ if (hcf->points) {
+ ngx_free(hcf->points);
+ hcf->points = NULL;
}

- us->peer.init = ngx_http_upstream_init_chash_peer;
-
peers = us->peer.data;
npoints = peers->total_weight * 160;

size = sizeof(ngx_http_upstream_chash_points_t)
- + sizeof(ngx_http_upstream_chash_point_t) * (npoints - 1);
+ - sizeof(ngx_http_upstream_chash_point_t)
+ + sizeof(ngx_http_upstream_chash_point_t) * npoints;

- points = ngx_palloc(cf->pool, size);
+ points = pool ? ngx_palloc(pool, size) : ngx_alloc(size, ngx_cycle->log);
if (points == NULL) {
return NGX_ERROR;
}

points->number = 0;

+ if (npoints == 0) {
+ hcf->points = points;
+ return NGX_OK;
+ }
+
for (peer = peers->peer; peer; peer = peer->next) {
server = &peer->server;

@@ -401,7 +441,6 @@ ngx_http_upstream_init_chash(ngx_conf_t

points->number = i + 1;

- hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module);
hcf->points = points;

return NGX_OK;
@@ -481,7 +520,22 @@ ngx_http_upstream_init_chash_peer(ngx_ht

ngx_http_upstream_rr_peers_rlock(hp->rrp.peers);

- hp->hash = ngx_http_upstream_find_chash_point(hcf->points, hash);
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (hp->rrp.peers->config
+ && (hcf->points == NULL || hcf->config != *hp->rrp.peers->config))
+ {
+ if (ngx_http_upstream_update_chash(NULL, us) != NGX_OK) {
+ ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+ return NGX_ERROR;
+ }
+
+ hcf->config = *hp->rrp.peers->config;
+ }
+#endif
+
+ if (hcf->points->number) {
+ hp->hash = ngx_http_upstream_find_chash_point(hcf->points, hash);
+ }

ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);

@@ -517,6 +571,20 @@ ngx_http_upstream_get_chash_peer(ngx_pee
pc->cached = 0;
pc->connection = NULL;

+ if (hp->rrp.peers->number == 0) {
+ pc->name = hp->rrp.peers->name;
+ ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+ return NGX_BUSY;
+ }
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (hp->rrp.peers->config && hp->rrp.config != *hp->rrp.peers->config) {
+ pc->name = hp->rrp.peers->name;
+ ngx_http_upstream_rr_peers_unlock(hp->rrp.peers);
+ return NGX_BUSY;
+ }
+#endif
+
now = ngx_time();
hcf = hp->conf;

@@ -597,6 +665,7 @@ ngx_http_upstream_get_chash_peer(ngx_pee
found:

hp->rrp.current = best;
+ ngx_http_upstream_rr_peer_ref(hp->rrp.peers, best);

pc->sockaddr = best->sockaddr;
pc->socklen = best->socklen;
@@ -664,6 +733,7 @@ ngx_http_upstream_hash(ngx_conf_t *cf, n
}

uscf->flags = NGX_HTTP_UPSTREAM_CREATE
+ |NGX_HTTP_UPSTREAM_MODIFY
|NGX_HTTP_UPSTREAM_WEIGHT
|NGX_HTTP_UPSTREAM_MAX_CONNS
|NGX_HTTP_UPSTREAM_MAX_FAILS
diff --git a/src/http/modules/ngx_http_upstream_ip_hash_module.c b/src/http/modules/ngx_http_upstream_ip_hash_module.c
--- a/src/http/modules/ngx_http_upstream_ip_hash_module.c
+++ b/src/http/modules/ngx_http_upstream_ip_hash_module.c
@@ -163,11 +163,19 @@ ngx_http_upstream_get_ip_hash_peer(ngx_p

ngx_http_upstream_rr_peers_rlock(iphp->rrp.peers);

- if (iphp->tries > 20 || iphp->rrp.peers->single) {
+ if (iphp->tries > 20 || iphp->rrp.peers->number < 2) {
ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
return iphp->get_rr_peer(pc, &iphp->rrp);
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (iphp->rrp.peers->config && iphp->rrp.config != *iphp->rrp.peers->config)
+ {
+ ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
+ return iphp->get_rr_peer(pc, &iphp->rrp);
+ }
+#endif
+
now = ngx_time();

pc->cached = 0;
@@ -232,6 +240,7 @@ ngx_http_upstream_get_ip_hash_peer(ngx_p
}

iphp->rrp.current = peer;
+ ngx_http_upstream_rr_peer_ref(iphp->rrp.peers, peer);

pc->sockaddr = peer->sockaddr;
pc->socklen = peer->socklen;
@@ -268,6 +277,7 @@ ngx_http_upstream_ip_hash(ngx_conf_t *cf
uscf->peer.init_upstream = ngx_http_upstream_init_ip_hash;

uscf->flags = NGX_HTTP_UPSTREAM_CREATE
+ |NGX_HTTP_UPSTREAM_MODIFY
|NGX_HTTP_UPSTREAM_WEIGHT
|NGX_HTTP_UPSTREAM_MAX_CONNS
|NGX_HTTP_UPSTREAM_MAX_FAILS
diff --git a/src/http/modules/ngx_http_upstream_least_conn_module.c b/src/http/modules/ngx_http_upstream_least_conn_module.c
--- a/src/http/modules/ngx_http_upstream_least_conn_module.c
+++ b/src/http/modules/ngx_http_upstream_least_conn_module.c
@@ -124,6 +124,12 @@ ngx_http_upstream_get_least_conn_peer(ng

ngx_http_upstream_rr_peers_wlock(peers);

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (peers->config && rrp->config != *peers->config) {
+ goto busy;
+ }
+#endif
+
best = NULL;
total = 0;

@@ -244,6 +250,7 @@ ngx_http_upstream_get_least_conn_peer(ng
best->conns++;

rrp->current = best;
+ ngx_http_upstream_rr_peer_ref(peers, best);

n = p / (8 * sizeof(uintptr_t));
m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
@@ -278,8 +285,18 @@ failed:
}

ngx_http_upstream_rr_peers_wlock(peers);
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (peers->config && rrp->config != *peers->config) {
+ goto busy;
+ }
+#endif
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+busy:
+#endif
+
ngx_http_upstream_rr_peers_unlock(peers);

pc->name = peers->name;
@@ -303,6 +320,7 @@ ngx_http_upstream_least_conn(ngx_conf_t
uscf->peer.init_upstream = ngx_http_upstream_init_least_conn;

uscf->flags = NGX_HTTP_UPSTREAM_CREATE
+ |NGX_HTTP_UPSTREAM_MODIFY
|NGX_HTTP_UPSTREAM_WEIGHT
|NGX_HTTP_UPSTREAM_MAX_CONNS
|NGX_HTTP_UPSTREAM_MAX_FAILS
diff --git a/src/http/modules/ngx_http_upstream_random_module.c b/src/http/modules/ngx_http_upstream_random_module.c
--- a/src/http/modules/ngx_http_upstream_random_module.c
+++ b/src/http/modules/ngx_http_upstream_random_module.c
@@ -17,6 +17,9 @@ typedef struct {

typedef struct {
ngx_uint_t two;
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ ngx_uint_t config;
+#endif
ngx_http_upstream_random_range_t *ranges;
} ngx_http_upstream_random_srv_conf_t;

@@ -127,6 +130,11 @@ ngx_http_upstream_update_random(ngx_pool

rcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_random_module);

+ if (rcf->ranges) {
+ ngx_free(rcf->ranges);
+ rcf->ranges = NULL;
+ }
+
peers = us->peer.data;

size = peers->number * sizeof(ngx_http_upstream_random_range_t);
@@ -186,11 +194,15 @@ ngx_http_upstream_init_random_peer(ngx_h
ngx_http_upstream_rr_peers_rlock(rp->rrp.peers);

#if (NGX_HTTP_UPSTREAM_ZONE)
- if (rp->rrp.peers->shpool && rcf->ranges == NULL) {
+ if (rp->rrp.peers->config
+ && (rcf->ranges == NULL || rcf->config != *rp->rrp.peers->config))
+ {
if (ngx_http_upstream_update_random(NULL, us) != NGX_OK) {
ngx_http_upstream_rr_peers_unlock(rp->rrp.peers);
return NGX_ERROR;
}
+
+ rcf->config = *rp->rrp.peers->config;
}
#endif

@@ -220,11 +232,18 @@ ngx_http_upstream_get_random_peer(ngx_pe

ngx_http_upstream_rr_peers_rlock(peers);

- if (rp->tries > 20 || peers->single) {
+ if (rp->tries > 20 || peers->number < 2) {
ngx_http_upstream_rr_peers_unlock(peers);
return ngx_http_upstream_get_round_robin_peer(pc, rrp);
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (peers->config && rrp->config != *peers->config) {
+ ngx_http_upstream_rr_peers_unlock(peers);
+ return ngx_http_upstream_get_round_robin_peer(pc, rrp);
+ }
+#endif
+
pc->cached = 0;
pc->connection = NULL;

@@ -274,6 +293,7 @@ ngx_http_upstream_get_random_peer(ngx_pe
}

rrp->current = peer;
+ ngx_http_upstream_rr_peer_ref(peers, peer);

if (now - peer->checked > peer->fail_timeout) {
peer->checked = now;
@@ -314,11 +334,18 @@ ngx_http_upstream_get_random2_peer(ngx_p

ngx_http_upstream_rr_peers_wlock(peers);

- if (rp->tries > 20 || peers->single) {
+ if (rp->tries > 20 || peers->number < 2) {
ngx_http_upstream_rr_peers_unlock(peers);
return ngx_http_upstream_get_round_robin_peer(pc, rrp);
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (peers->config && rrp->config != *peers->config) {
+ ngx_http_upstream_rr_peers_unlock(peers);
+ return ngx_http_upstream_get_round_robin_peer(pc, rrp);
+ }
+#endif
+
pc->cached = 0;
pc->connection = NULL;

@@ -384,6 +411,7 @@ ngx_http_upstream_get_random2_peer(ngx_p
}

rrp->current = peer;
+ ngx_http_upstream_rr_peer_ref(peers, peer);

if (now - peer->checked > peer->fail_timeout) {
peer->checked = now;
@@ -467,6 +495,7 @@ ngx_http_upstream_random(ngx_conf_t *cf,
uscf->peer.init_upstream = ngx_http_upstream_init_random;

uscf->flags = NGX_HTTP_UPSTREAM_CREATE
+ |NGX_HTTP_UPSTREAM_MODIFY
|NGX_HTTP_UPSTREAM_WEIGHT
|NGX_HTTP_UPSTREAM_MAX_CONNS
|NGX_HTTP_UPSTREAM_MAX_FAILS
diff --git a/src/http/modules/ngx_http_upstream_zone_module.c b/src/http/modules/ngx_http_upstream_zone_module.c
--- a/src/http/modules/ngx_http_upstream_zone_module.c
+++ b/src/http/modules/ngx_http_upstream_zone_module.c
@@ -18,6 +18,10 @@ static ngx_http_upstream_rr_peers_t *ngx
ngx_slab_pool_t *shpool, ngx_http_upstream_srv_conf_t *uscf);
static ngx_http_upstream_rr_peer_t *ngx_http_upstream_zone_copy_peer(
ngx_http_upstream_rr_peers_t *peers, ngx_http_upstream_rr_peer_t *src);
+static void ngx_http_upstream_zone_set_single(
+ ngx_http_upstream_srv_conf_t *uscf);
+static void ngx_http_upstream_zone_remove_peer_locked(
+ ngx_http_upstream_rr_peers_t *peers, ngx_http_upstream_rr_peer_t *peer);


static ngx_command_t ngx_http_upstream_zone_commands[] = {
@@ -33,6 +37,11 @@ static ngx_command_t ngx_http_upstream_
};


+static ngx_int_t ngx_http_upstream_zone_init_worker(ngx_cycle_t *cycle);
+static void ngx_http_upstream_zone_resolve_timer(ngx_event_t *event);
+static void ngx_http_upstream_zone_resolve_handler(ngx_resolver_ctx_t *ctx);
+
+
static ngx_http_module_t ngx_http_upstream_zone_module_ctx = {
NULL, /* preconfiguration */
NULL, /* postconfiguration */
@@ -55,7 +64,7 @@ ngx_module_t ngx_http_upstream_zone_mod
NGX_HTTP_MODULE, /* module type */
NULL, /* init master */
NULL, /* init module */
- NULL, /* init process */
+ ngx_http_upstream_zone_init_worker, /* init process */
NULL, /* init thread */
NULL, /* exit thread */
NULL, /* exit process */
@@ -188,9 +197,15 @@ ngx_http_upstream_zone_copy_peers(ngx_sl
ngx_http_upstream_srv_conf_t *uscf)
{
ngx_str_t *name;
+ ngx_uint_t *config;
ngx_http_upstream_rr_peer_t *peer, **peerp;
ngx_http_upstream_rr_peers_t *peers, *backup;

+ config = ngx_slab_calloc(shpool, sizeof(ngx_uint_t));
+ if (config == NULL) {
+ return NULL;
+ }
+
peers = ngx_slab_alloc(shpool, sizeof(ngx_http_upstream_rr_peers_t));
if (peers == NULL) {
return NULL;
@@ -214,6 +229,7 @@ ngx_http_upstream_zone_copy_peers(ngx_sl
peers->name = name;

peers->shpool = shpool;
+ peers->config = config;

for (peerp = &peers->peer; *peerp; peerp = &peer->next) {
/* pool is unlocked */
@@ -223,6 +239,17 @@ ngx_http_upstream_zone_copy_peers(ngx_sl
}

*peerp = peer;
+ peer->id = (*peers->config)++;
+ }
+
+ for (peerp = &peers->resolve; *peerp; peerp = &peer->next) {
+ peer = ngx_http_upstream_zone_copy_peer(peers, *peerp);
+ if (peer == NULL) {
+ return NULL;
+ }
+
+ *peerp = peer;
+ peer->id = (*peers->config)++;
}

if (peers->next == NULL) {
@@ -239,6 +266,7 @@ ngx_http_upstream_zone_copy_peers(ngx_sl
backup->name = name;

backup->shpool = shpool;
+ backup->config = config;

for (peerp = &backup->peer; *peerp; peerp = &peer->next) {
/* pool is unlocked */
@@ -248,6 +276,17 @@ ngx_http_upstream_zone_copy_peers(ngx_sl
}

*peerp = peer;
+ peer->id = (*backup->config)++;
+ }
+
+ for (peerp = &backup->resolve; *peerp; peerp = &peer->next) {
+ peer = ngx_http_upstream_zone_copy_peer(backup, *peerp);
+ if (peer == NULL) {
+ return NULL;
+ }
+
+ *peerp = peer;
+ peer->id = (*backup->config)++;
}

peers->next = backup;
@@ -279,6 +318,7 @@ ngx_http_upstream_zone_copy_peer(ngx_htt
dst->sockaddr = NULL;
dst->name.data = NULL;
dst->server.data = NULL;
+ dst->host = NULL;
}

dst->sockaddr = ngx_slab_calloc_locked(pool, sizeof(ngx_sockaddr_t));
@@ -301,12 +341,37 @@ ngx_http_upstream_zone_copy_peer(ngx_htt
}

ngx_memcpy(dst->server.data, src->server.data, src->server.len);
+
+ if (src->host) {
+ dst->host = ngx_slab_calloc_locked(pool,
+ sizeof(ngx_http_upstream_host_t));
+ if (dst->host == NULL) {
+ goto failed;
+ }
+
+ dst->host->name.data = ngx_slab_alloc_locked(pool,
+ src->host->name.len);
+ if (dst->host->name.data == NULL) {
+ goto failed;
+ }
+
+ dst->host->peers = peers;
+ dst->host->peer = dst;
+
+ dst->host->name.len = src->host->name.len;
+ ngx_memcpy(dst->host->name.data, src->host->name.data,
+ src->host->name.len);
+ }
}

return dst;

failed:

+ if (dst->host) {
+ ngx_slab_free_locked(pool, dst->host);
+ }
+
if (dst->server.data) {
ngx_slab_free_locked(pool, dst->server.data);
}
@@ -323,3 +388,338 @@ failed:

return NULL;
}
+
+
+static void
+ngx_http_upstream_zone_set_single(ngx_http_upstream_srv_conf_t *uscf)
+{
+ ngx_http_upstream_rr_peers_t *peers;
+
+ peers = uscf->peer.data;
+
+ if (peers->number == 1
+ && (peers->next == NULL || peers->next->number == 0))
+ {
+ peers->single = 1;
+
+ } else {
+ peers->single = 0;
+ }
+}
+
+
+static void
+ngx_http_upstream_zone_remove_peer_locked(ngx_http_upstream_rr_peers_t *peers,
+ ngx_http_upstream_rr_peer_t *peer)
+{
+ peers->total_weight -= peer->weight;
+ peers->number--;
+ peers->tries -= (peer->down == 0);
+ (*peers->config)++;
+ peers->weighted = (peers->total_weight != peers->number);
+
+ ngx_http_upstream_rr_peer_free(peers, peer);
+}
+
+
+static ngx_int_t
+ngx_http_upstream_zone_init_worker(ngx_cycle_t *cycle)
+{
+ ngx_uint_t i;
+ ngx_event_t *event;
+ ngx_http_upstream_rr_peer_t *peer;
+ ngx_http_upstream_rr_peers_t *peers;
+ ngx_http_upstream_srv_conf_t *uscf, **uscfp;
+ ngx_http_upstream_main_conf_t *umcf;
+
+ if (ngx_process != NGX_PROCESS_WORKER
+ && ngx_process != NGX_PROCESS_SINGLE)
+ {
+ return NGX_OK;
+ }
+
+ umcf = ngx_http_cycle_get_module_main_conf(cycle, ngx_http_upstream_module);
+
+ if (umcf == NULL) {
+ return NGX_OK;
+ }
+
+ uscfp = umcf->upstreams.elts;
+
+ for (i = 0; i < umcf->upstreams.nelts; i++) {
+
+ uscf = uscfp[i];
+
+ if (uscf->shm_zone == NULL) {
+ continue;
+ }
+
+ peers = uscf->peer.data;
+
+ do {
+ ngx_http_upstream_rr_peers_wlock(peers);
+
+ for (peer = peers->resolve; peer; peer = peer->next) {
+
+ if (peer->host->worker != ngx_worker) {
+ continue;
+ }
+
+ event = &peer->host->event;
+ ngx_memzero(event, sizeof(ngx_event_t));
+
+ event->data = uscf;
+ event->handler = ngx_http_upstream_zone_resolve_timer;
+ event->log = cycle->log;
+ event->cancelable = 1;
+
+ ngx_http_upstream_rr_peer_ref(peers, peer);
+ ngx_add_timer(event, 1);
+ }
+
+ ngx_http_upstream_rr_peers_unlock(peers);
+
+ peers = peers->next;
+
+ } while (peers);
+ }
+
+ return NGX_OK;
+}
+
+
+static void
+ngx_http_upstream_zone_resolve_timer(ngx_event_t *event)
+{
+ ngx_resolver_ctx_t *ctx;
+ ngx_http_upstream_host_t *host;
+ ngx_http_upstream_rr_peer_t *template;
+ ngx_http_upstream_rr_peers_t *peers;
+ ngx_http_upstream_srv_conf_t *uscf;
+
+ host = (ngx_http_upstream_host_t *) event;
+ uscf = event->data;
+ peers = host->peers;
+ template = host->peer;
+
+ if (template->zombie) {
+ (void) ngx_http_upstream_rr_peer_unref(peers, template);
+
+ ngx_shmtx_lock(&peers->shpool->mutex);
+
+ if (host->service.len) {
+ ngx_slab_free_locked(peers->shpool, host->service.data);
+ }
+
+ ngx_slab_free_locked(peers->shpool, host->name.data);
+ ngx_slab_free_locked(peers->shpool, host);
+ ngx_shmtx_unlock(&peers->shpool->mutex);
+
+ return;
+ }
+
+ ctx = ngx_resolve_start(uscf->resolver, NULL);
+ if (ctx == NULL) {
+ goto retry;
+ }
+
+ if (ctx == NGX_NO_RESOLVER) {
+ ngx_log_error(NGX_LOG_ERR, event->log, 0,
+ "no resolver defined to resolve %V", &host->name);
+ return;
+ }
+
+ ctx->name = host->name;
+ ctx->handler = ngx_http_upstream_zone_resolve_handler;
+ ctx->data = host;
+ ctx->timeout = uscf->resolver_timeout;
+ ctx->cancelable = 1;
+
+ if (ngx_resolve_name(ctx) == NGX_OK) {
+ return;
+ }
+
+retry:
+
+ ngx_add_timer(event, ngx_max(uscf->resolver_timeout, 1000));
+}
+
+
+static void
+ngx_http_upstream_zone_resolve_handler(ngx_resolver_ctx_t *ctx)
+{
+ time_t now;
+ in_port_t port;
+ ngx_msec_t timer;
+ ngx_uint_t i, j;
+ ngx_event_t *event;
+ ngx_resolver_addr_t *addr;
+ ngx_http_upstream_host_t *host;
+ ngx_http_upstream_rr_peer_t *peer, *template, **peerp;
+ ngx_http_upstream_rr_peers_t *peers;
+ ngx_http_upstream_srv_conf_t *uscf;
+
+ host = ctx->data;
+ event = &host->event;
+ uscf = event->data;
+ peers = host->peers;
+ template = host->peer;
+
+ ngx_http_upstream_rr_peers_wlock(peers);
+
+ if (template->zombie) {
+ (void) ngx_http_upstream_rr_peer_unref(peers, template);
+
+ ngx_http_upstream_rr_peers_unlock(peers);
+
+ ngx_shmtx_lock(&peers->shpool->mutex);
+ ngx_slab_free_locked(peers->shpool, host->name.data);
+ ngx_slab_free_locked(peers->shpool, host);
+ ngx_shmtx_unlock(&peers->shpool->mutex);
+
+ ngx_resolve_name_done(ctx);
+
+ return;
+ }
+
+ now = ngx_time();
+
+ if (ctx->state) {
+ ngx_log_error(NGX_LOG_ERR, event->log, 0,
+ "%V could not be resolved (%i: %s)",
+ &ctx->name, ctx->state,
+ ngx_resolver_strerror(ctx->state));
+
+ if (ctx->state != NGX_RESOLVE_NXDOMAIN) {
+ ngx_http_upstream_rr_peers_unlock(peers);
+
+ ngx_resolve_name_done(ctx);
+
+ ngx_add_timer(event, ngx_max(uscf->resolver_timeout, 1000));
+ return;
+ }
+
+ /* NGX_RESOLVE_NXDOMAIN */
+
+ ctx->naddrs = 0;
+ }
+
+#if (NGX_DEBUG)
+ {
+ u_char text[NGX_SOCKADDR_STRLEN];
+ size_t len;
+
+ for (i = 0; i < ctx->naddrs; i++) {
+ len = ngx_sock_ntop(ctx->addrs[i].sockaddr, ctx->addrs[i].socklen,
+ text, NGX_SOCKADDR_STRLEN, 0);
+
+ ngx_log_debug3(NGX_LOG_DEBUG_HTTP, event->log, 0,
+ "name %V was resolved to %*s", &host->name, len, text);
+ }
+ }
+#endif
+
+ for (peerp = &peers->peer; *peerp; /* void */ ) {
+ peer = *peerp;
+
+ if (peer->host != host) {
+ goto next;
+ }
+
+ for (j = 0; j < ctx->naddrs; j++) {
+
+ addr = &ctx->addrs[j];
+
+ if (addr->name.len == 0
+ && ngx_cmp_sockaddr(peer->sockaddr, peer->socklen,
+ addr->sockaddr, addr->socklen, 0)
+ == NGX_OK)
+ {
+ addr->name.len = 1;
+ goto next;
+ }
+ }
+
+ *peerp = peer->next;
+ ngx_http_upstream_zone_remove_peer_locked(peers, peer);
+
+ ngx_http_upstream_zone_set_single(uscf);
+
+ continue;
+
+ next:
+
+ peerp = &peer->next;
+ }
+
+ for (i = 0; i < ctx->naddrs; i++) {
+
+ addr = &ctx->addrs[i];
+
+ if (addr->name.len == 1) {
+ addr->name.len = 0;
+ continue;
+ }
+
+ ngx_shmtx_lock(&peers->shpool->mutex);
+ peer = ngx_http_upstream_zone_copy_peer(peers, NULL);
+ ngx_shmtx_unlock(&peers->shpool->mutex);
+
+ if (peer == NULL) {
+ ngx_log_error(NGX_LOG_ERR, event->log, 0,
+ "cannot add new server to upstream \"%V\", "
+ "memory exhausted", peers->name);
+ break;
+ }
+
+ ngx_memcpy(peer->sockaddr, addr->sockaddr, addr->socklen);
+
+ port = ((struct sockaddr_in *) template->sockaddr)->sin_port;
+
+ switch (peer->sockaddr->sa_family) {
+#if (NGX_HAVE_INET6)
+ case AF_INET6:
+ ((struct sockaddr_in6 *) peer->sockaddr)->sin6_port = port;
+ break;
+#endif
+ default: /* AF_INET */
+ ((struct sockaddr_in *) peer->sockaddr)->sin_port = port;
+ }
+
+ peer->socklen = addr->socklen;
+
+ peer->name.len = ngx_sock_ntop(peer->sockaddr, peer->socklen,
+ peer->name.data, NGX_SOCKADDR_STRLEN, 1);
+
+ peer->host = template->host;
+ peer->server = template->server;
+
+ peer->weight = template->weight;
+ peer->effective_weight = peer->weight;
+ peer->max_conns = template->max_conns;
+ peer->max_fails = template->max_fails;
+ peer->fail_timeout = template->fail_timeout;
+ peer->slow_start = template->slow_start;
+ peer->down = template->down;
+
+ *peerp = peer;
+ peerp = &peer->next;
+
+ peers->number++;
+ peers->tries += (peer->down == 0);
+ peers->total_weight += peer->weight;
+ peers->weighted = (peers->total_weight != peers->number);
+ peer->id = (*peers->config)++;
+
+ ngx_http_upstream_zone_set_single(uscf);
+ }
+
+ ngx_http_upstream_rr_peers_unlock(peers);
+
+ timer = (ngx_msec_t) 1000 * (ctx->valid > now ? ctx->valid - now + 1 : 1);
+ timer = ngx_min(timer, uscf->resolver_timeout);
+
+ ngx_resolve_name_done(ctx);
+
+ ngx_add_timer(event, timer);
+}
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -1545,6 +1545,26 @@ ngx_http_upstream_connect(ngx_http_reque

u->state->peer = u->peer.name;

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (u->upstream && u->upstream->shm_zone
+ && (u->upstream->flags & NGX_HTTP_UPSTREAM_MODIFY)
+ ) {
+ u->state->peer = ngx_palloc(r->pool,
+ sizeof(ngx_str_t) + u->peer.name->len);
+ if (u->state->peer == NULL) {
+ ngx_http_upstream_finalize_request(r, u,
+ NGX_HTTP_INTERNAL_SERVER_ERROR);
+ return;
+ }
+
+ u->state->peer->len = u->peer.name->len;
+ u->state->peer->data = (u_char *) (u->state->peer + 1);
+ ngx_memcpy(u->state->peer->data, u->peer.name->data, u->peer.name->len);
+
+ u->peer.name = u->state->peer;
+ }
+#endif
+
if (rc == NGX_BUSY) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "no live upstreams");
ngx_http_upstream_next(r, u, NGX_HTTP_UPSTREAM_FT_NOLIVE);
@@ -6029,6 +6049,7 @@ ngx_http_upstream(ngx_conf_t *cf, ngx_co
u.no_port = 1;

uscf = ngx_http_upstream_add(cf, &u, NGX_HTTP_UPSTREAM_CREATE
+ |NGX_HTTP_UPSTREAM_MODIFY
|NGX_HTTP_UPSTREAM_WEIGHT
|NGX_HTTP_UPSTREAM_MAX_CONNS
|NGX_HTTP_UPSTREAM_MAX_FAILS
@@ -6114,7 +6135,11 @@ ngx_http_upstream(ngx_conf_t *cf, ngx_co
return rv;
}

- if (uscf->servers->nelts == 0) {
+ if (uscf->servers->nelts == 0
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ && uscf->shm_zone == NULL
+#endif
+ ) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
"no servers are inside upstream");
return NGX_CONF_ERROR;
@@ -6134,6 +6159,9 @@ ngx_http_upstream_server(ngx_conf_t *cf,
ngx_url_t u;
ngx_int_t weight, max_conns, max_fails;
ngx_uint_t i;
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ ngx_uint_t resolve;
+#endif
ngx_http_upstream_server_t *us;

us = ngx_array_push(uscf->servers);
@@ -6149,6 +6177,9 @@ ngx_http_upstream_server(ngx_conf_t *cf,
max_conns = 0;
max_fails = 1;
fail_timeout = 10;
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ resolve = 0;
+#endif

for (i = 2; i < cf->args->nelts; i++) {

@@ -6237,6 +6268,13 @@ ngx_http_upstream_server(ngx_conf_t *cf,
continue;
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (ngx_strcmp(value[i].data, "resolve") == 0) {
+ resolve = 1;
+ continue;
+ }
+#endif
+
goto invalid;
}

@@ -6245,6 +6283,13 @@ ngx_http_upstream_server(ngx_conf_t *cf,
u.url = value[1];
u.default_port = 80;

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (resolve) {
+ /* resolve at run time */
+ u.no_resolve = 1;
+ }
+#endif
+
if (ngx_parse_url(cf->pool, &u) != NGX_OK) {
if (u.err) {
ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
@@ -6255,8 +6300,45 @@ ngx_http_upstream_server(ngx_conf_t *cf,
}

us->name = u.url;
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+
+ if (resolve && u.naddrs == 0) {
+ ngx_addr_t *addr;
+
+ /* save port */
+
+ addr = ngx_pcalloc(cf->pool, sizeof(ngx_addr_t));
+ if (addr == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ addr->sockaddr = ngx_palloc(cf->pool, u.socklen);
+ if (addr->sockaddr == NULL) {
+ return NGX_CONF_ERROR;
+ }
+
+ ngx_memcpy(addr->sockaddr, &u.sockaddr, u.socklen);
+
+ addr->socklen = u.socklen;
+
+ us->addrs = addr;
+ us->naddrs = 1;
+
+ us->host = u.host;
+
+ } else {
+ us->addrs = u.addrs;
+ us->naddrs = u.naddrs;
+ }
+
+#else
+
us->addrs = u.addrs;
us->naddrs = u.naddrs;
+
+#endif
+
us->weight = weight;
us->max_conns = max_conns;
us->max_fails = max_fails;
diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -104,7 +104,11 @@ typedef struct {

unsigned backup:1;

- NGX_COMPAT_BEGIN(6)
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ ngx_str_t host;
+#endif
+
+ NGX_COMPAT_BEGIN(4)
NGX_COMPAT_END
} ngx_http_upstream_server_t;

@@ -115,6 +119,7 @@ typedef struct {
#define NGX_HTTP_UPSTREAM_FAIL_TIMEOUT 0x0008
#define NGX_HTTP_UPSTREAM_DOWN 0x0010
#define NGX_HTTP_UPSTREAM_BACKUP 0x0020
+#define NGX_HTTP_UPSTREAM_MODIFY 0x0040
#define NGX_HTTP_UPSTREAM_MAX_CONNS 0x0100


@@ -133,6 +138,8 @@ struct ngx_http_upstream_srv_conf_s {

#if (NGX_HTTP_UPSTREAM_ZONE)
ngx_shm_zone_t *shm_zone;
+ ngx_resolver_t *resolver;
+ ngx_msec_t resolver_timeout;
#endif
};

diff --git a/src/http/ngx_http_upstream_round_robin.c b/src/http/ngx_http_upstream_round_robin.c
--- a/src/http/ngx_http_upstream_round_robin.c
+++ b/src/http/ngx_http_upstream_round_robin.c
@@ -32,10 +32,15 @@ ngx_http_upstream_init_round_robin(ngx_c
ngx_http_upstream_srv_conf_t *us)
{
ngx_url_t u;
- ngx_uint_t i, j, n, w, t;
+ ngx_uint_t i, j, n, r, w, t;
ngx_http_upstream_server_t *server;
ngx_http_upstream_rr_peer_t *peer, **peerp;
ngx_http_upstream_rr_peers_t *peers, *backup;
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ ngx_uint_t resolve;
+ ngx_http_core_loc_conf_t *clcf;
+ ngx_http_upstream_rr_peer_t **rpeerp;
+#endif

us->peer.init = ngx_http_upstream_init_round_robin_peer;

@@ -43,23 +48,99 @@ ngx_http_upstream_init_round_robin(ngx_c
server = us->servers->elts;

n = 0;
+ r = 0;
w = 0;
t = 0;

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ resolve = 0;
+#endif
+
for (i = 0; i < us->servers->nelts; i++) {
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (server[i].host.len) {
+ resolve = 1;
+ }
+#endif
+
if (server[i].backup) {
continue;
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (server[i].host.len) {
+ r++;
+
+ } else {
+ n += server[i].naddrs;
+ w += server[i].naddrs * server[i].weight;
+
+ if (!server[i].down) {
+ t += server[i].naddrs;
+ }
+ }
+#else
n += server[i].naddrs;
w += server[i].naddrs * server[i].weight;

if (!server[i].down) {
t += server[i].naddrs;
}
+#endif
}

- if (n == 0) {
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (us->shm_zone) {
+
+ if (resolve && !(us->flags & NGX_HTTP_UPSTREAM_MODIFY)) {
+ ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+ "load balancing method does not support"
+ " resolving names at run time in"
+ " upstream \"%V\" in %s:%ui",
+ &us->host, us->file_name, us->line);
+ return NGX_ERROR;
+ }
+
+ clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
+
+ us->resolver = clcf->resolver;
+ us->resolver_timeout = clcf->resolver_timeout;
+
+ /*
+ * Without "resolver_timeout" in http{}, the value is unset.
+ * Even if we set it in ngx_http_core_merge_loc_conf(), it's
+ * still dependent on the module order and unreliable.
+ */
+ ngx_conf_init_msec_value(us->resolver_timeout, 30000);
+
+ if (resolve
+ && (us->resolver == NULL
+ || us->resolver->connections.nelts == 0))
+ {
+ ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+ "no resolver defined to resolve names"
+ " at run time in upstream \"%V\" in %s:%ui",
+ &us->host, us->file_name, us->line);
+ return NGX_ERROR;
+ }
+
+ } else if (resolve) {
+
+ ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
+ "resolving names at run time requires"
+ " upstream \"%V\" in %s:%ui"
+ " to be in shared memory",
+ &us->host, us->file_name, us->line);
+ return NGX_ERROR;
+ }
+#endif
+
+ if (n == 0
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ && us->shm_zone == NULL
+#endif
+ ) {
ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
"no servers in upstream \"%V\" in %s:%ui",
&us->host, us->file_name, us->line);
@@ -71,7 +152,8 @@ ngx_http_upstream_init_round_robin(ngx_c
return NGX_ERROR;
}

- peer = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_rr_peer_t) * n);
+ peer = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_rr_peer_t)
+ * (n + r));
if (peer == NULL) {
return NGX_ERROR;
}
@@ -86,11 +168,47 @@ ngx_http_upstream_init_round_robin(ngx_c
n = 0;
peerp = &peers->peer;

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ rpeerp = &peers->resolve;
+#endif
+
for (i = 0; i < us->servers->nelts; i++) {
if (server[i].backup) {
continue;
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (server[i].host.len) {
+
+ peer[n].host = ngx_pcalloc(cf->pool,
+ sizeof(ngx_http_upstream_host_t));
+ if (peer[n].host == NULL) {
+ return NGX_ERROR;
+ }
+
+ peer[n].host->name = server[i].host;
+
+ peer[n].sockaddr = server[i].addrs[0].sockaddr;
+ peer[n].socklen = server[i].addrs[0].socklen;
+ peer[n].name = server[i].addrs[0].name;
+ peer[n].weight = server[i].weight;
+ peer[n].effective_weight = server[i].weight;
+ peer[n].current_weight = 0;
+ peer[n].max_conns = server[i].max_conns;
+ peer[n].max_fails = server[i].max_fails;
+ peer[n].fail_timeout = server[i].fail_timeout;
+ peer[n].slow_start = server[i].slow_start;
+ peer[n].down = server[i].down;
+ peer[n].server = server[i].name;
+
+ *rpeerp = &peer[n];
+ rpeerp = &peer[n].next;
+ n++;
+
+ continue;
+ }
+#endif
+
for (j = 0; j < server[i].naddrs; j++) {
peer[n].sockaddr = server[i].addrs[j].sockaddr;
peer[n].socklen = server[i].addrs[j].socklen;
@@ -115,6 +233,7 @@ ngx_http_upstream_init_round_robin(ngx_c
/* backup servers */

n = 0;
+ r = 0;
w = 0;
t = 0;

@@ -123,15 +242,37 @@ ngx_http_upstream_init_round_robin(ngx_c
continue;
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (server[i].host.len) {
+ r++;
+
+ } else {
+ n += server[i].naddrs;
+ w += server[i].naddrs * server[i].weight;
+
+ if (!server[i].down) {
+ t += server[i].naddrs;
+ }
+ }
+#else
n += server[i].naddrs;
w += server[i].naddrs * server[i].weight;

if (!server[i].down) {
t += server[i].naddrs;
}
+#endif
}

- if (n == 0) {
+ if (n == 0
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ && us->shm_zone == NULL
+#endif
+ ) {
+ return NGX_OK;
+ }
+
+ if (n + r == 0 && !(us->flags & NGX_HTTP_UPSTREAM_BACKUP)) {
return NGX_OK;
}

@@ -140,12 +281,16 @@ ngx_http_upstream_init_round_robin(ngx_c
return NGX_ERROR;
}

- peer = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_rr_peer_t) * n);
+ peer = ngx_pcalloc(cf->pool, sizeof(ngx_http_upstream_rr_peer_t)
+ * (n + r));
if (peer == NULL) {
return NGX_ERROR;
}

- peers->single = 0;
+ if (n > 0) {
+ peers->single = 0;
+ }
+
backup->single = 0;
backup->number = n;
backup->weighted = (w != n);
@@ -156,11 +301,47 @@ ngx_http_upstream_init_round_robin(ngx_c
n = 0;
peerp = &backup->peer;

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ rpeerp = &backup->resolve;
+#endif
+
for (i = 0; i < us->servers->nelts; i++) {
if (!server[i].backup) {
continue;
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (server[i].host.len) {
+
+ peer[n].host = ngx_pcalloc(cf->pool,
+ sizeof(ngx_http_upstream_host_t));
+ if (peer[n].host == NULL) {
+ return NGX_ERROR;
+ }
+
+ peer[n].host->name = server[i].host;
+
+ peer[n].sockaddr = server[i].addrs[0].sockaddr;
+ peer[n].socklen = server[i].addrs[0].socklen;
+ peer[n].name = server[i].addrs[0].name;
+ peer[n].weight = server[i].weight;
+ peer[n].effective_weight = server[i].weight;
+ peer[n].current_weight = 0;
+ peer[n].max_conns = server[i].max_conns;
+ peer[n].max_fails = server[i].max_fails;
+ peer[n].fail_timeout = server[i].fail_timeout;
+ peer[n].slow_start = server[i].slow_start;
+ peer[n].down = server[i].down;
+ peer[n].server = server[i].name;
+
+ *rpeerp = &peer[n];
+ rpeerp = &peer[n].next;
+ n++;
+
+ continue;
+ }
+#endif
+
for (j = 0; j < server[i].naddrs; j++) {
peer[n].sockaddr = server[i].addrs[j].sockaddr;
peer[n].socklen = server[i].addrs[j].socklen;
@@ -273,7 +454,12 @@ ngx_http_upstream_init_round_robin_peer(

rrp->peers = us->peer.data;
rrp->current = NULL;
- rrp->config = 0;
+
+ ngx_http_upstream_rr_peers_rlock(rrp->peers);
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ rrp->config = rrp->peers->config ? *rrp->peers->config : 0;
+#endif

n = rrp->peers->number;

@@ -281,6 +467,10 @@ ngx_http_upstream_init_round_robin_peer(
n = rrp->peers->next->number;
}

+ r->upstream->peer.tries = ngx_http_upstream_tries(rrp->peers);
+
+ ngx_http_upstream_rr_peers_unlock(rrp->peers);
+
if (n <= 8 * sizeof(uintptr_t)) {
rrp->tried = &rrp->data;
rrp->data = 0;
@@ -296,7 +486,6 @@ ngx_http_upstream_init_round_robin_peer(

r->upstream->peer.get = ngx_http_upstream_get_round_robin_peer;
r->upstream->peer.free = ngx_http_upstream_free_round_robin_peer;
- r->upstream->peer.tries = ngx_http_upstream_tries(rrp->peers);
#if (NGX_HTTP_SSL)
r->upstream->peer.set_session =
ngx_http_upstream_set_round_robin_peer_session;
@@ -446,6 +635,12 @@ ngx_http_upstream_get_round_robin_peer(n
peers = rrp->peers;
ngx_http_upstream_rr_peers_wlock(peers);

+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (peers->config && rrp->config != *peers->config) {
+ goto busy;
+ }
+#endif
+
if (peers->single) {
peer = peers->peer;

@@ -458,6 +653,7 @@ ngx_http_upstream_get_round_robin_peer(n
}

rrp->current = peer;
+ ngx_http_upstream_rr_peer_ref(peers, peer);

} else {

@@ -508,8 +704,18 @@ failed:
}

ngx_http_upstream_rr_peers_wlock(peers);
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ if (peers->config && rrp->config != *peers->config) {
+ goto busy;
+ }
+#endif
}

+#if (NGX_HTTP_UPSTREAM_ZONE)
+busy:
+#endif
+
ngx_http_upstream_rr_peers_unlock(peers);

pc->name = peers->name;
@@ -580,6 +786,7 @@ ngx_http_upstream_get_peer(ngx_http_upst
}

rrp->current = best;
+ ngx_http_upstream_rr_peer_ref(rrp->peers, best);

n = p / (8 * sizeof(uintptr_t));
m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
@@ -617,9 +824,16 @@ ngx_http_upstream_free_round_robin_peer(

if (rrp->peers->single) {

+ if (peer->fails) {
+ peer->fails = 0;
+ }
+
peer->conns--;

- ngx_http_upstream_rr_peer_unlock(rrp->peers, peer);
+ if (ngx_http_upstream_rr_peer_unref(rrp->peers, peer) == NGX_OK) {
+ ngx_http_upstream_rr_peer_unlock(rrp->peers, peer);
+ }
+
ngx_http_upstream_rr_peers_unlock(rrp->peers);

pc->tries = 0;
@@ -661,7 +875,10 @@ ngx_http_upstream_free_round_robin_peer(

peer->conns--;

- ngx_http_upstream_rr_peer_unlock(rrp->peers, peer);
+ if (ngx_http_upstream_rr_peer_unref(rrp->peers, peer) == NGX_OK) {
+ ngx_http_upstream_rr_peer_unlock(rrp->peers, peer);
+ }
+
ngx_http_upstream_rr_peers_unlock(rrp->peers);

if (pc->tries) {
diff --git a/src/http/ngx_http_upstream_round_robin.h b/src/http/ngx_http_upstream_round_robin.h
--- a/src/http/ngx_http_upstream_round_robin.h
+++ b/src/http/ngx_http_upstream_round_robin.h
@@ -14,8 +14,23 @@
#include <ngx_http.h>


+typedef struct ngx_http_upstream_rr_peers_s ngx_http_upstream_rr_peers_t;
typedef struct ngx_http_upstream_rr_peer_s ngx_http_upstream_rr_peer_t;

+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+
+typedef struct {
+ ngx_event_t event; /* must be first */
+ ngx_uint_t worker;
+ ngx_str_t name;
+ ngx_http_upstream_rr_peers_t *peers;
+ ngx_http_upstream_rr_peer_t *peer;
+} ngx_http_upstream_host_t;
+
+#endif
+
+
struct ngx_http_upstream_rr_peer_s {
struct sockaddr *sockaddr;
socklen_t socklen;
@@ -46,7 +61,12 @@ struct ngx_http_upstream_rr_peer_s {
#endif

#if (NGX_HTTP_UPSTREAM_ZONE)
+ unsigned zombie:1;
+
ngx_atomic_t lock;
+ ngx_uint_t id;
+ ngx_uint_t refs;
+ ngx_http_upstream_host_t *host;
#endif

ngx_http_upstream_rr_peer_t *next;
@@ -56,8 +76,6 @@ struct ngx_http_upstream_rr_peer_s {
};


-typedef struct ngx_http_upstream_rr_peers_s ngx_http_upstream_rr_peers_t;
-
struct ngx_http_upstream_rr_peers_s {
ngx_uint_t number;

@@ -78,6 +96,12 @@ struct ngx_http_upstream_rr_peers_s {
ngx_http_upstream_rr_peers_t *next;

ngx_http_upstream_rr_peer_t *peer;
+
+#if (NGX_HTTP_UPSTREAM_ZONE)
+ ngx_uint_t *config;
+ ngx_http_upstream_rr_peer_t *resolve;
+ ngx_uint_t zombies;
+#endif
};


@@ -114,6 +138,67 @@ struct ngx_http_upstream_rr_peers_s {
ngx_rwlock_unlock(&peer->lock); \
}

+
+#define ngx_http_upstream_rr_peer_ref(peers, peer) \
+ (peer)->refs++;
+
+
+static ngx_inline void
+ngx_http_upstream_rr_peer_free_locked(ngx_http_upstream_rr_peers_t *peers,
+ ngx_http_upstream_rr_peer_t *peer)
+{
+ if (peer->refs) {
+ peer->zombie = 1;
+ peers->zombies++;
+ return;
+ }
+
+ ngx_slab_free_locked(peers->shpool, peer->sockaddr);
+ ngx_slab_free_locked(peers->shpool, peer->name.data);
+
+ if (peer->server.data && (peer->host == NULL || peer->host->peer == peer)) {
+ ngx_slab_free_locked(peers->shpool, peer->server.data);
+ }
+
+#if (NGX_HTTP_SSL)
+ if (peer->ssl_session) {
+ ngx_slab_free_locked(peers->shpool, peer->ssl_session);
+ }
+#endif
+
+ ngx_slab_free_locked(peers->shpool, peer);
+}
+
+
+static ngx_inline void
+ngx_http_upstream_rr_peer_free(ngx_http_upstream_rr_peers_t *peers,
+ ngx_http_upstream_rr_peer_t *peer)
+{
+ ngx_shmtx_lock(&peers->shpool->mutex);
+ ngx_http_upstream_rr_peer_free_locked(peers, peer);
+ ngx_shmtx_unlock(&peers->shpool->mutex);
+}
+
+
+static ngx_inline ngx_int_t
+ngx_http_upstream_rr_peer_unref(ngx_http_upstream_rr_peers_t *peers,
+ ngx_http_upstream_rr_peer_t *peer)
+{
+ peer->refs--;
+
+ if (peers->shpool == NULL) {
+ return NGX_OK;
+ }
+
+ if (peer->refs == 0 && peer->zombie) {
+ ngx_http_upstream_rr_peer_free(peers, peer);
+ peers->zombies--;
+ return NGX_DONE;
+ }
+
+ return NGX_OK;
+}
+
#else

#define ngx_http_upstream_rr_peers_rlock(peers)
@@ -121,6 +206,8 @@ struct ngx_http_upstream_rr_peers_s {
#define ngx_http_upstream_rr_peers_unlock(peers)
#define ngx_http_upstream_rr_peer_lock(peers, peer)
#define ngx_http_upstream_rr_peer_unlock(peers, peer)
+#define ngx_http_upstream_rr_peer_ref(peers, peer)
+#define ngx_http_upstream_rr_peer_unref(peers, peer) NGX_OK

#endif

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Subject Author Views Posted

[PATCH 0 of 6] Upstream: re-resolvable servers.

Aleksei Bavshin 584 January 31, 2023 08:40PM

[PATCH 1 of 6] Upstream: re-resolvable servers

Aleksei Bavshin 203 January 31, 2023 08:40PM

[PATCH 2 of 6] Stream: re-resolvable servers

Aleksei Bavshin 166 January 31, 2023 08:40PM

[PATCH 3 of 6] Upstream: construct upstream peers from DNS SRV records

Aleksei Bavshin 182 January 31, 2023 08:40PM

[PATCH 4 of 6] Upstream: per-upstream resolver

Aleksei Bavshin 167 January 31, 2023 08:42PM

[PATCH 5 of 6] Upstream: allow any worker to resolve upstream servers

Aleksei Bavshin 155 January 31, 2023 08:42PM

Re: [PATCH 5 of 6] Upstream: allow any worker to resolve upstream servers

J Carter 199 February 05, 2023 10:02PM

Re: [PATCH 5 of 6] Upstream: allow any worker to resolve upstream servers

Aleksei Bavshin 144 February 09, 2023 11:46AM

Re: [PATCH 5 of 6] Upstream: allow any worker to resolve upstream servers

J Carter 167 February 09, 2023 07:06PM

[PATCH 6 of 6] Upstream: reschedule in-progress resolve tasks at worker exit

Aleksei Bavshin 150 January 31, 2023 08:42PM



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