/* This function takes the oldest request on the queue
* (maxconn_cf->waiting_requests) and dispatches it to the backends. This
* calls ngx_http_upstream_connect() which will in turn call the peer get
* callback, peer_get(). peer_get() will do
* the actual selection of backend. Here we're just giving the request the
* go-ahead to proceed.
*/
static void
dispatch (max_connections_srv_conf_t *maxconn_cf)
{
if (ngx_queue_empty(&maxconn_cf->waiting_requests)) return;
if (maxconn_cf->connections >= maxconn_cf->max_connections) return;
max_connections_peer_data_t *peer_data = queue_shift(maxconn_cf);
ngx_http_request_t *r = peer_data->r;
ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
"max_connections dispatch (queue_length: %ui, conn: %ui)",
maxconn_cf->queue_length, maxconn_cf->connections);
peer_data->processing = 1;
maxconn_cf->connections++; /* keep track of how many slots are occupied */
ngx_http_upstream_connect(r, r->upstream);
}
static void
ngx_http_upstream_dynamic_handler(ngx_resolver_ctx_t *ctx)
{
ngx_http_request_t *r;
ngx_http_upstream_t *u;
ngx_peer_connection_t *pc;
struct sockaddr_in *sin, *csin;
in_port_t port;
ngx_str_t *addr;
u_char *p;
size_t len;
ngx_http_upstream_srv_conf_t *us;
ngx_http_upstream_dynamic_srv_conf_t *dscf;
r = ctx->data;
u = r->upstream;
us = u->conf->upstream;
pc = &u->peer;
dscf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_dynamic_module);
if (ctx->state) {
ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"%V could not be resolved (%i: %s)",
&ctx->name, ctx->state,
ngx_resolver_strerror(ctx->state));
dscf->fail_check = ngx_time();
pc->resolved = NGX_HTTP_UPSTREAM_DR_FAILED;
} else {
/* dns query ok */
dscf->fail_check = 0;
sin = ngx_pcalloc(r->pool, sizeof(struct sockaddr_in));
if (sin == NULL) {
ngx_http_upstream_finalize_request(r, u,
NGX_HTTP_INTERNAL_SERVER_ERROR);
return;
}
ngx_memcpy(sin, pc->sockaddr, pc->socklen);
/* only the first IP addr is used in version 1 */
csin = (struct sockaddr_in *) ctx->addrs[0].sockaddr;
if (sin->sin_addr.s_addr == csin->sin_addr.s_addr) {
pc->resolved = NGX_HTTP_UPSTREAM_DR_OK;
goto out;
}
sin->sin_addr.s_addr = csin->sin_addr.s_addr;
len = NGX_INET_ADDRSTRLEN + sizeof(":65535") - 1;
p = ngx_pnalloc(r->pool, len);
if (p == NULL) {
ngx_http_upstream_finalize_request(r, u,
NGX_HTTP_INTERNAL_SERVER_ERROR);
return;
}
port = ntohs(sin->sin_port);
len = ngx_inet_ntop(AF_INET, &sin->sin_addr.s_addr,
p, NGX_INET_ADDRSTRLEN);
len = ngx_sprintf(&p[len], ":%d", port) - p;
addr = ngx_palloc(r->pool, sizeof(ngx_str_t));
if (addr == NULL) {
ngx_http_upstream_finalize_request(r, u,
NGX_HTTP_INTERNAL_SERVER_ERROR);
return;
}
addr->data = p;
addr->len = len;
pc->sockaddr = (struct sockaddr *) sin;
pc->socklen = sizeof(struct sockaddr_in);
pc->name = addr;
ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
"name was resolved to %V", pc->name);
pc->resolved = NGX_HTTP_UPSTREAM_DR_OK;
}
out:
ngx_resolve_name_done(ctx);
u->dyn_resolve_ctx = NULL;
ngx_http_upstream_connect(r, u);
}
